Upload
steveislary
View
247
Download
3
Embed Size (px)
DESCRIPTION
from askiitian
Citation preview
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 1
BRINGiiT on – Study Pack By ASKIITIANS.COM – powered by IITians
SUBJECT – CHEMISTRY
TOPIC – ALCOHOL, PHENOL AND ETHER
COURSE CODE – AISM-09/C/APE
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 2
Contents :- ALCOHOL, PHENOL AND ETHER
Introduction, Aliphatic hydroxyl compound………………………………………………………3
Preparation of Alcohols………………………………………………………………………………….….5
Physical properties, chemical properties ………………………………………………………….15
Periodate oxidation…………………………………………………………………………………………..28
Pinacol, pinacol- rearrangement ………………………………………………………………………30
Ether …………………………………………………………………..……………………………………………34
Preparation of ethers………………………………………………………………………………………..35
Properties of ether…………………………………………………………………………………………….39
Chemical reaction ……………………………………………………………………………………………..40
Phenol……………………………………………………………………………………………………………….47
Physical properties …………………………………………………………………………………………...50
Chemical properties…………………………………………………………………………………………..52
Mercuration………………………………………………………………………………………………………59
Answers to exercises……………………………………………………………………………….…………82
Miscelleneous exercises…………………………………………………………………………………….90
Solved problems………………………………………………………………………………………………..98
IIT level questions……………………………………………………………………………….…………….102
Objective problems……………………………………………………………………………….………….109
Fill in the blanks…………………………………………………………………………………………………117
Assignment problems………………………………………………………………………………………..122
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 3
ALCOHOL, PHENOL, ETHER
INTRODUCTION
Hydroxy compound can be classified in the following three categories.
Aliphatic hydroxy compound
Monohydric i.e.
C CH
H
H H
H
OH Contain only one - OH group
Dihydric
C COH
H
H H
H
OH Contain tw o - OH group
Polyhydric
C CH
H
OH OH
H
C
H
OH
H
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 4
Contain three and more than three hydroxyl group.
Monohydric alcohols are of three types.
Monohydric Alcohols
Primary or 10
R CH2OH
Secondary
R C
OH
R
H
Tertiary
R C
OH
R
R
or 20 or 30Alcohol
Illustration 1:
Classify the following into primary, secondary and tertiary
alcohols:
(a)
OH
CH3
(b)
CH3
OH
(c)
OH
Solution:
(a) Tertiary, (b) Secondary, (c) Tertiary
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 5
PREPARATION OF ALCOHOLS
1. From Alkanes
Alkanes having tertiary carbon on oxidation with cold alkaline KMnO4 give
tertiary alcohol.
R C
H
R
R
KMnO 4/OHR C
OH
R
R
2. From Alkenes
Alkenes can be converted into alcohol by the following reactions:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 6
R CH CH2
HOH/H 2SO4
(i) Conc. H 2SO4
(ii) HOH
(i) Hg(OCOCH 3)2/HOH
(ii) NaBH 4
(i) BH 3/THF
(ii) H 2O2/OH
CO H2
Co(CO) 4
R CH2 CH2 CHO
H2/Pt
R CH2CH2CH2OH
R CH2 CH2OH
R CH CH3
OH
R CH CH3
OH
R CH CH3
OH
(anti markonikov's product)
[Oxo process]
3. From alkyl halides
Alkyl halides give alcohol with KOH/NaOH or with moist Ag2O.
R X
HOH/NaOH
moist Ag 2O
R OH
R OH
4. Reduction of aldehydes and ketones
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 7
(a) Reduction by reducing agents
(i) Aldehyde gives primary alcohol
R C H
O
[H]
Reducing agentR CH2OH
(ii) Ketone gives secondary alcohol
R C R
O
[H]
Reducing agentR CH
OH
R
Reducing agents
(i) LiAlH4
(ii) NaBH4
(iii) Na/C2H5OH
(iv) Metal (Zn, Fe or Sn)/Acid (HCl, dil H2SO4 or CH3COOH)
(v) (a) Aluminium isopropoxide/isopropylalcohol, (b) H2O
(vi) H2/Ni
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 8
NaBH4 and aluminium isopropoxide reduces only carbonyl
group and has no effect on any other group.
4NaBH
3 3 2CH CH CH CHO CH CH CH CH OH
Reduction with aluminium isopropoxide is known as
Meerwein–Ponndorf Verley (MPV) reduction.
LiAlH4 has no effect on double and triple bonds but if
compound is - aryl, , - unsaturated carbonyl compound
then double bond also undergoes reduction.
H2C CH C CH3
O
LiAlH 4CH3 CH2 CH CH3
OH
H5C6 CH CH CHOLiAlH4
H5C6 CH2 CH2 CH2OH
(b) Reduction by Grignard reagents
Addition followed by hydrolysis
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 9
R Mg X
H C H
O
R' C H
O
R' C R''
O
R C H
O MgX
H
R C H
OMgX
R'
R C R''
OMgX
R'
H2O/H
H2O/H
H2O/H
R C H
OH
H
Mg
OH
X
R C H
OH
R'
Mg
OH
X
R C R'
OH
R''
Mg
OH
X
30 alcohol
20 alcohol
10 alcohol
Methanol cannot be prepared by this method.
5. Reduction of carboxylic acid, Acid chlorides and esters:
(a) Reduction by LiAlH4
R C G
O
LiAlH 4R CH2OH H G
G = OH (acid)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 10
G = Cl (acid chloride)
G = OR (ester)
(b) Reduction by BH3
Carboxylic acids and esters are reduced in to primary alcohol by BH3.
R C
O
OH3
2
i BH / THF
ii H O/HRCH 2OH
R C
O
O R' 3
2
i BH /THF
ii H O/HR CH2OH R'OH
(c) Bouveault – Blanc reaction
R C
O
OR'Na/C2H5OH
RCH 2OH R'OH
Illustration 2:
(CH2)n
COOH
COOCH3LiAlH4
(i) BH3/THF
(ii) H2O/H
A
B
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 11
Solution:
(CH2)n
COOH
CH2OH
A =
If compound has COOH as well as ester group then reactivity of ester is
more than acid towards LiAlH4.
(CH2)n
COOCH 3
CH2OH
B =
Acid is more reactive than ester towards BH3.
Exercise 1:
Find A and B.
(i)
CH3
2
2
Hg OAC
THF / H OA 4NaBH
OHB
(ii) 2 4CuO CuCr O
3 2 3CH CH COOCH A B
6. From aliphatic primary amines
It react with nitrous acid to give alcohol.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 12
Nature of alcohol depends on the nature of carbon having NH2
group.
Reaction proceeds through carbocation hence rearranged alcohol
is obtained.
CH3 CH2 CH2 NH2
NaNO 2/HClCH3 CH2 CH2OH CH3 CH
OH
CH3
7. From Oxiranes
Oxiranes react with Grignard reagent to give mono hydric alcohol. Nature of
G.R is basic hence it attack on less hindered carbon of oxirane ring.
H2C CH2
O
R Mg X H2C CH2 R
OMgX
HOH/H
HO CH2 CH2 R
δ
δ δ δ
Illustration 3:
(a) Find A, B, C, D, E.
PhBrMg
dry etherA
O
B
O
HC
(b) 3
2
i CH MgBr
3 2 5 ii H O / HCH COOC H D E
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 13
Solution:
(a) A = PhMgBr B = Ph
OC =
Ph
OH
(b)
CH3 C
CH3
CH3
OH C2H5OH
8. Fermentation of carbohydrates
Sucrose
InvertaseC6H12O6 C6H12O6
glucose fructose
Zymase
C12H22O11 H2O
2C2H5OH 2CO2
Illustration 4:
(i)
C2H5MgBr
(i) C CH2
CH3
CH3
O
(ii) HOH/H
A
(ii)
CH C
CH3
CH3CH3
CH CH2 CH3Oxymercuration
DemercurationB
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 14
Solution:
(i)
CH3 C
CH3
OH
CH2 C2H5 ( 2 methyl 2 pentanol)
(ii)
CH3 CH
CH3
C
CH3
OH
CH2 CH2CH3
(30 alcohol)
Exercise 2:
(i) Identify A, B & C
RCO2Et + (CH2)5
MgBr
MgBr 3+H O
A 2
Δ
-H OB 2H /Ni C
(ii)
H C
O
CH2 CH2 OH RMgX RH H C
O
CH2 CH2 OMgX
( 1 eq)
H C
O
CH2 CH2 OH RMgX H C(OH)
R
CH2 CH2 OH
( 2 eq)
Account the reason for the above reactions.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 15
PHYSICAL PROPERTIES
Solubility
Alcohols are soluble in water due to formation of H – bonding between water
& them. As the molecular mass increases, the alkyl group become
larger which resists the formation of H – bonds with water molecules
and hence the solubility goes an decreasing.
Boiling Point
Intermolecular H – bonding is present between alcohol molecules. This
makes high boiling point.
H O
R
H O
R
H O
R
Amongst the isomeric alcohols, the order of boiling point is 1 > 2 > 3
alcohol.
CHEMICAL PROPERTIES
Chemical properties of alcohols can be discussed under following categories:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 16
(A) Reaction involving breaking of carbon – oxygen bond.
(B) Reaction involving breaking of oxygen – hydrogen bond.
(C) Oxidation of alcohols.
(D) Dehydrogenation of alcohols.
(E) Some miscellaneous reactions of monohydric alcohol.
(A) Reaction involving breaking of carbon – oxygen bond
Order of reactivity of alcohol. 3 > 2 > 1
(i) SN reaction
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 17
R OH
HCl/Anhy ZnCl2
Δ
NaX/H2SO4
PCl5 or PCl3
P/Br2 or PBr3
Δ
SOCl2/Py ridine
SOCl2/Ether
or
R Cl
R X NaHSO 4 H2O
R Cl
R Br
R Cl SO2 HCl
(ii) Dehydration of alcohol
Dehydration of alcohol to give alkene.
(a) Dehydrating agents are
Conc H2SO4/ , KHSO4/ , H3PO4/ , Anhyd Al2O3/ , Anhyd PCl5/ ,
Anhyd ZnCl2/ , BF3/ , P2O5/ .
(b) Reactivity of alcohols. (Ease of dehydration)
3 > 2 > 1
(c) Product formation always takes place by saytzeff rule.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 18
CH3 CH2 CH
OH
CH32 4Conc. H SO
ΔCH3 CH CH CH3
(Major)
CH3 CH2 CH CH2
(Minor product)
* Alcohols on acetylation gives acetyl derivative which on pyrolytic
elimination always gives Hofmann product.
CH3 CH2 CH
OH
CH33 2
CH CO O /Py CH3 CH2 CH CH3
OCOCH 3
(Major)
CH3 CH2 CH CH2
(Minor)
Δ
CH3 CH CH CH3
Mechanism in presence of acidic medium
E1 mechanism: follow saytzeff‘s rule.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 19
CH3 C
CH3
CH3
CH2 O H H 2 4Conc.H SOCH3 C
CH3
CH3
CH2 O H
H
CH3 C
CH3
CH3
CH2
1,2methyl shiftCH3 C
CH3
CH2 CH3
CH3 C
CH3
CH CH3
Exercise 3:
Write mechanism
CH3
CH CH3
OH
H
CH3
CH3
(B) Reactions due to breaking of oxygen hydrogen bond.
(Reactions due to acidic character of alcohols)
(a) Alcohols are acidic in nature because hydrogen is present on
electro negative oxygen atom.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 20
(b) Alcohol is weaker acid R O H H R O acidity
stability of acid anions.
Acidity of 1 > 2 > 3
Alcohols give following reactions due to breaking of oxygen – hydrogen
bond.
(i) Reaction with metal
R O H M R O M 1/2 H2
Metal alkoxide
M = 1st group metal.
M = Al, Mg, Zn
23
33R OH Al RO Al H
2
Aluminium alkoxide
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 21
(ii) Esterification (With carboxylic acid)
R' OH R C OH
O
H
R C O
O
R' H2O
It is reversible acid catalysed reaction. It follow SN1 mechanism.
CH3 C
O
O H
CH3 C
O
OH
H
CH3 C
OH
OH
R O H
CH3 C
OH
OH
O RCH3 C
OH
O
OR
H H
CH3 C
OH
ORH2O
CH3 C
O
OR
H
Increasing the size of alkyl group on alcohol part decreases the
nucleophilic character because steric hindrance increases.
1Reactivityα
Steric hindrence in RCOOH/ROH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 22
Order of reactivity of alcohols CH3OH > 1 alc > 2 alc > 3 alc
(iii) Ester formation with proton acid having –OH group: to give
inorganic ester.
(a) R O H OH N O
(nitrous acid)
R O N O
(Alkyl nitrite)
H2O
(b)
R O H OH S OH
O
O
RO S OH
O
OAlkyl hydrogen sulphate
(iv) Alkylation of Alcohol
3 42
3 2 3
CH SO /NaOH
3orCH I/K CO
R O H R O CH
Methylation is mainly used for determination of hydroxyl groups in an
unknown compound.
Molecular weight of methylated ether prodcued molecular weight of reac tantNo. of hydroxyl groups
14
Exercise 4:
Arrange the following in increasing order of acidic strength.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 23
(a)
CH3 CHOH
CH3
(i)
CH3 CH2OH
(ii)
CH3 OH
(iii)
CH3 C
CH3
CH3
OH
(iv)
(b) Arrange the following in increasing order of esterification:
MeCOOH EtCOOH (Et)2CHCOOH
(i) (ii) (iii)
(C) Oxidation of alcohol
Oxidation of alcohol is dehydrogenation reaction which is 1,
2–elimination reaction.
R C
O
H
H
R'1, 2 elimination
R C
O
R' H2
So oxidation of alcohol numbers of - hydrogen atom.
(a) With mild oxidising agents like:
(i) X2
(ii) Fenton reagent [FeSO4/H2O2]
(iii) Jones reagent / CH3COCH3 [CrO3/dil. BaSO4]
(iv) K2Cr2O7/H+ cold
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 24
R CH2OH[O]
RCHO
R CH R'
OH
[O]R C
O
R'
CH3 C OH
CH3
CH3
[O]no reaction
Note:
PCC (Pyridinium chloro chromate) is a selective reagent which converts
1 alc to aldehyde.
(b) With strong oxidising agent
Oxidising agents are
(i) 4KMnO /OH /
(ii) 4KMnO /H /
(iii) 2 2 7K Cr O /H /
(iv) 3Conc. HNO /O
2n carbonn carbon
RCH OH RCOOH
R C
H
OH
R[O]
R C
O
R
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 25
(D) Dehydrogenation with Cu/573K or Ag/573K
(a) 1 alcohol aldehyde
Cu/ 573K
2R CH OH RCHO
(b) 2 alcohol ketone
Cu/573KR CHOH R R CO R
(c) 3 alc undergo dehydration to form alkene.
CH3 C
CH3
CH3
OHCu/ 573 K
CH3 C
CH3
CH2
H2O
Reduction
R O HHI/Red P
R H
(E) Miscellaneous reactions of mono hydric alcohol
(i) Methylation with CH2N2 in presence of BF3.
2 2
3
CH N
3 2BFR O H R O CH N
(ii) Haloform reaction
Ethyl alcohol and 2 methyl alcohol gives haloform reaction.
C C
H
H
H
H
H OH 2
2
CaOCl
H O(HCOO) 2Ca CHCl 3
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 26
Exercise 5:
(i) Out of these compound which gives iodoform test:
(a) CH3 CH2 CHOHCH3
(b) PhCH2CHOHCH3
(c) PhCHOHCH3
(d) CH3CH2OH
(e) CH3COCH2 COOC2H5
(ii) O
O
ONaBH4
CH3OH
LiAlH4
(A)
(B)
Distinguishing 1 , 2 , 3 alcohol
Test 1 alc 2 alc 3 alc
(I) Lucas test
[ZnCl2 + HCl]
No reaction at
room
temperatur
e
White turbidity
after 5-
10 min.
HCl
ZnCl 2
R CH R
Cl
H2O
RCH(OH)R
White turbidity
instantan
eously
R3C OH HCl
ZnCl 2
R3C Cl
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 27
(II) Victor Meyer test
(P/I2,AgNO2,
HNO2, NaOH)
Red colour Blue colour Colourless
RCH 2OH
P/I 2
RCH 2I
AgNO2
RCH 2NO 2
HONO
R C
NOH
NO 2
Nitrollic acid
NaOH
R C
NO Na
NO 2
Sodium nitrolate (red )
CHOH
R
RP/I 2
CHI
R
RAgNO2
CHNO 2
R
RHNO 2
C
R
R
NO 2
N O
NaOH
(Pseudo nitrole)
Blue
R3C OH
P/I 2
AgNO 2
R3C NO 2
HNO 2
R3C I
No reaction
(colourless)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 28
PERIODATE OXIDATION
Compounds that have hydroxyl group on adjacent atoms undergo oxidation
cleavage when they are treated with aq. Periodic acid (HIO4). The
reaction breaks carbon carbon bonds and produced carbonyl
compounds (aldehyde, ketones or acids)
H C
H
OH
CCH3 OH
H
HIO 4 HC O
H
HIO 3 H2OCH3CHO
It takes place through a cyclic intermediate.
C OH
C
CH3
H
CH3
OHCH3
IO 4
C O
C
CH3
H
CH3
OCH3
I O
O
O
CH3 C
CH3
O H C
CH3
O IO 3
Other examples
R C
O
C
O
R' HIO 4RCOOH R'COOH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 29
OH
R' OH R
OH
2HIO 4 RCHO HCOOH R'CHO
This oxidation is useful in determination of structure.
Illustration 5:
Write the products of the reaction of t-butyl alcohol with PBr3, conc. H2SO4,
CH3COCl, Na, CH3MgBr, Na2Cr2O7/H2SO4.
Solution:
3 3 2 3 3 3 43 3 3 3CH CBr, CH C CH ; CH COCOCH , CH CO Na ,CH , no reaction .
Illustration 6:
Write products
(a)
H C
H
C
OH
O
CH OH
H
IO4
(b)
H C
H
CH2
CH3
CH OH
H
IO4
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 30
Solution:
(a) 2HCHO + CO2
(b) No reaction (as it is not a vicinal diol)
Exercise 6:
(a) Arrange the following alcohols in order of ease of
dehydration.
6 5 2 6 5 3 6 5 33 2C H CCH OH, C H CHOHCH , C H COHCH
(b) Find product
(a) CH2OCH3
CHOH
CH2R
IO4
(b) OH OH
OH
OHOH
OH IO4
(c) R CHOH
CHR' NH2
PINACOL – PINACOLONE REARRANGEMENT
Action of H2SO4 on 1, 2 diols.
Ditertiory – 1, 2 diols convert in to ketones on treatment with H2SO4.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 31
R C
OH
R
C
OH
R
RH
R C
R
R
C
O
R
Mechanism
CH3 C
OH
CH3
C
O
CH3
CH3
H
HCH3 C
OH
CH3
C CH3
CH3CH3 C
OH
C CH3
CH3
CH3
δ δ
δ
Transition state
CH3 C
OH
C CH3
CH3
CH3
Methyl shift
CH3 C
O
CH3
C CH3
CH3
HCH3
-HCH3 C
O
C CH3
CH3
CH3
Migratory preference of the group
Migration depends on the stability of Transition state.
In general migration of C6H5 > alkyl
Illustration 7:
List three methods with chemical equations for the preparation of alcohols
from alkenes.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 32
Solution:
Hydration, hydroboration and oxymercuration – demercuration of alkenes.
Hydration:
CH3 C
CH3
CH3
CH CH22H O
HCH3 C
CH3
CH3
CHCH 3
OH
Hydroboration
CH3 C
CH3
CH3
CH CH23
2 2
i BH
ii H O , OHCH3 C
CH3
CH3
CH2CH2OH
Oxymercuration – demercuration
CH3 C
CH3
CH3
CH CH222
4
i Hg OAC , THF, H O
ii NaBHCH3 C
CH3
CH3
CHCH 3
OH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 33
Illustration 8:
Which of the following alcohols would react fastest with Lucas
reagent?
CH3CH2CH2CH2OH , CH3CH2CH
OH
CH3 , CH3CH
OH
CH2OH , CH3 C
CH3
CH3
OH
Solution:
3 3CH COH , it being a tertiary alcohol.
Exercise 7:
Find out
(i)
CH3 CH3
Ph
OH
Ph
OH
HA
(ii)
CH3 Ph
CH3
OH
Ph
OH
B
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 34
Exercise 8:
Give a possible structure for the substance C5H10O2 behaving in the following
manner.
C5H10O26 5 2C H NHNH
O
2I ,NaOH
Fehling
Solution
ETHER
* R O R Alkoxy alkane (Di alkyl ether)
* R = R Symmetrical ether.
R R Unsymmetrical or mixed ether.
‗O‘ is to be counted with least number of C atom.
Example:
CH3 O C2H5 Methoxy ethane
CH3 O C6H5 Methoxy benzene
There are various types of cyclic ethers also.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 35
O
Oxirane
(Epoxide)
Oxetane
(Oxacyclo butane)
O
O
Tetra hydro furan
(Oxacyclo pentane)
PREPARATION OF ETHERS
(i) From 1 alcohol
(a) With H2SO4
2 4
02 3
H SO
140 C or Al O /525KR O H R O H R O R symmetrical ether
Order of dehydration 1 > 2 > 3 alcohol
(b) With diazomethane
2 2
2 5 3
CH N
3 2C H O AlR O H R O CH N
(c) Alcohol having at least one hydrogen at fourth carbon gives five
membered cyclic ether with Pb(OAC)4. The reaction is free
radical reaction which is initiated by heat or light.
CH3 CH2 CH2 CH2 OH6 64
0
Pb OAC hν /C H
80 C
OTetrahydro furan
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 36
H2C (CH2)3
H
CH2OH6 64
0
Pb OAC hν /C H
80 C
O CH3
2 methyl tetra hydro furan
Williamson’s synthesis
NS 2 reaction of a sodium alkoxide with alkyl halide, alkyl sulphonate or alkyl
sulphate is known as Williamson synthesis of ethers.
2SNR ONa R'L R O R' NaL
2 2L X, SO R'' , O SO OR'
In this reaction alkoxide may be alkoxide of primary, secondary
as well as tertiary alcohol.
Alkyl halide must be primary.
In case of tertiary alkyl halide, elimination occurs giving alkenes
With a secondary alkyl halide, both elimination and substitution
products are obtained.
R X Na . O R R O R' Na X
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 37
CH3Br Na O C
CH3
CH3
CH3 C
CH3
CH3
CH3OCH3
Sodium ter. butoxide ter. butyl methyl ether
Illustration 9:
Write the product
(i)
C
CH3
CH3
O NaCH3CH3Cl
(A)
(ii)
C
CH3
CH3
BrCH3C2H5ONa
B C
Solution:
(i)
C
CH3
CH3
OCH3 CH3
(ii)
C
CH3
CH2
CH3 C2H5Br
Exercise 9:
Find product
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 38
(i)
Br
CH2OH NaOH
p XyleneX
(ii)
20
NaOH / H O
25 CY
OH
Cl
(3) From Alkane
(a)
R CH CH22
4
i Hg OAC /R'OH
ii NaBH /OHR CH CH3
OR'
C
CH3
CH3
CH232
4
i Hg OAC / CH OH
ii NaBH / OHCH3 C
OCH 3
CH3
CH3
(b)
CH3 C
CH3
CH2 H OCH 32 4H SO
CH3 C
CH3
O CH3
CH3
(4) From Grignard reagent
Higher ethers can be prepared by treating - halo ethers with suitable
reagents.
CH3 O CH2Cl CH3MgI Dry ether CH3 O CH2CH3 MgCl
I
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 39
(5) From Alkyl halide
2dry
2RI Ag O R O R 2AgI
PROPERTIES OF ETHERS
Dipole nature of ether
Ethers have a tetrahedral geometry i.e. oxygen is sp3 hybridized. The C–O–C
bond angle in ether is 110 . Because of the greater electronegativity of
oxygen than carbon, the C O bonds are slightly polar and are
inclined to each other at an angle of 110 C, resulting in a net dipole
moment.
O
R
R
O
R
R
net μ1100C
The bond angle is slightly greater than the tetrahedral angle due to repulsive
interaction between the two bulky groups.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 40
Chemical Reaction
Dialkyl ethers reacts with very few reagents other than acids. The only
active site for other reagents are the C H bonds of the alkyls. Ethers
has ability to solvate cations (electrophile) by donating an electron pair
from their oxygen atom. These properties make ether as solvents for
many reactions.
On standing in contact with air, most aliphatic ethers are converted slowly
into unstable peroxides.
Ether gives following reactions:
1. Nucleophilic substitution reactions
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 41
R O R
δ δ
Conc. H2SO4
1 mole warm
Conc. H2SO4
2 mole warm
H O H / Δ / h igh pressure
H
HI ( 1 mole)
Cold
2HI
Cold
3 mole HI/Red P
Δ
R C Cl
O
δ
δ/Anhy ZnCl 2
R' C O
O
C R'
O
5PCl /ΔR Cl R Cl POCl 3
R O C
O
R' R O C
O
R'
R Cl R O C
O
R
R H R H
R I R I
R I
2R O H
R OH
R O SO3H R O SO3H
R OH R O SO3H
Note:
Type of ethers also make a difference in the mechanism followed during the
cleavage of C—O by HI/HBr.
Combinations Mechanism follows
1°R + 2°R Less sterically hindered SN2
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 42
2°R + 3°R More sterically hindered SN1
1°R + 3°R
Nature of mechanism decoded by
nature of solvent.
Aprotic orNon polar
Proticpolar
SN2 SN1
Methylcation is stabler than phenylcations
(B) Dehydration with H2SO4/ and Anhy Al2O3/
(i) When both alkyl groups has -hydrogen.
CH3 CH2 O CH CH2 CH3
CH3
α β
2 4Conc. H SO /Δ
CH2 CH2 H3C CH CH CH3 H2O
(ii) When only alkyl group has - hydrogen.
CH3 C
CH3
CH3
O CH32 4Conc. H SO
ΔCH2 C
CH3
CH3
CH3OHβ α
α
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 43
Hot conc. H2SO4 react with secondary and tertiary ethers to
give a mixture of alcohols and alkenes.
(CH3)3CO—CH3 42Conc.H SO
hot (CH3)2—C=CH2 + CH3OH
(CH3)3CO—
hot
SOH.conc 42 (CH3)2—C=CH2 + HO
Cyclohexyl tert butyl ether isobutene
cyclohexanol
(C) Miscellaneous reactions
(1) Halogenation:
Monohalogenation takes place at carbon (with small amount)
(a)
CH2 O CH2 CH3CH3
Excess
2Cl /hν
CH3 CH O CH2
Cl
CH3
(b) CH2 O CH2 CH3CH3
Small
2Cl excess /hνCl 5C2 O C2Cl 5
(2) Reaction with CO: give ester
0
3
125 180 C
200 atm, BFR O R CO RCOOR
Illustration 10:
Explain why sometimes explosion occurs while distilling ethers.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 44
Solution:
It is due to formation of peroxide
CH3CH2—O—CH2CH3 + O2 h
CH3—CH—O—CH2CH3
OOH
Illustration 11:
The basicity of the ethers towards BF3 has the following order, explain.
O
> (CH3)2O >(C2H5)2O >[(CH3)2CH]2O
Solution:
There are steric effects in the Lewis acid-Lewis base complex formation
between BF3 and the respective ethers.
Illustration 12:
What are crown ethers? How can the following reaction be made to proceed?
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 45
CH2BrKF
CH2F
KBr
Solution:
Crown ethers are large ring polyethers and are basically cyclic oligomers of
oxirane which may have annulated rings. They are designated
according to ring size and the number of complexing oxygen atoms,
thus 18-crown – 6 denotes an 18-membered ring with 6-oxygens. The
molecule is shaped like a ―doughnut‖, and has a hole in the middle.
OO
O
O O
O
These are phase transfer catalysts. This is a unique example of ―host-guest
relationship‖. The crown ether is the host, the cation is the guest. The
cavity is well suited to fit a K+ or Rb+ which is held as a complex.
Interaction between host and guest in all these complexes are mainly
through electrostatic forces and hydrogen bonds.
The reaction can be made to process by using catalytic amount of crown
ether, 18-crown-6.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 46
Illustration 13:
Explain why
O is much more soluble than furan in water.
Solution:
THF is more soluble than furan. In THF, in contrast to furan the electron
pairs are available for H-bonding with water which makes it more
soluble in water.
Exercise 10:
What chemical methods can be used to distinguish between the following
pairs of compounds?
(a) Ethoxy ethanol and methyl isopropyl ether.
(b) Butyl iodide and butyl ethyl ether.
(c) Ethyl propyl ether and ethyl allyl ether.
Exercise 11:
Ether A cleaves much faster than B with conc. HI. Explain.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 47
H3CO C2H5
HBr
Br C2H5
3CH OH
(A)
H3CO
HBr
OH
3CH Br
(B)
PHENOL
These are organic compounds a hydroxyl group attached directly to a
benzene ring.
OH
Phenol or carbolic acid
OH
CH3
(o , p , m)
Cresol
Preparation
Industrial Method
(i) From chloro benzene (Dow’s process)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 48
Chlorobenzene is heated with NaOH at 673 K and under pressure of 300 atm
to produced sodium phenoxide which on acidification yields phenol.
Cl
NaOH/ 623K
300 atm p
ONa
H
OH
(ii) Cumene Process
Cumene obtained from propene & benzene cumene on air oxidation followed
by acidification with H2SO4 gives phenol & acetone.
0
3 4
250 C
H PO
HC
CH3
CH3
H3C CH CH2
Cumene
O2
95 - 1350
C O OH
CH3
CH3
CH3 C CH3
O
OH
Cumene hydroperoxide
H, H 2O 50-900C
(iii) From benzene sulphonic acid
It is fused with NaOH gives sodium salt of phenol.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 49
2H O /HNaOH
6 5 3 6 5 3 6 5 6 5FusionC H SO H C H SO Na C H ONa C H OH
(iv) From benzene diazonium chloride
This gives Ar SN1 reaction with H2O to form phenol.
N N Cl
2H O/H
Δ
OH
N2
Illustration 14:
Starting from 1-methyl cyclohexene, prepare the following:
(a) CH3
H
OH
OH
(b) CH3
OH
Solution:
(a) CH3
H
OH
OH
CH3
4
2
i KMnO
ii H O
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 50
(b) CH3
OH
CH3
2H O/H
Exercise 12:
Starting from 1-methyl cyclohexene, prepare the following:
(a) CH3
H
OH
OH
(b) CH3
OH
OH
OH
PHYSICAL PROPERTIES
Phenol is needle shaped solid, soon liquefies due to high hygroscopic nature.
It is less soluble in water, but readily soluble in organic solvents.
Phenol has high boiling point due to presence of hydrogen bonding.
Acidity of phenol
Phenol is weak acid. It reacts with aqueous NaOH to form sodium phenoxide,
but does not react with sodium bicarbonate.
The acidity of phenol is due to the stability of the phenoxide ion, which is
resonance stabilized as shown below:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 51
O O O O
(I)(II) (III)
O
(V)(IV)
In substituted phenols, the presence of electron withdrawing groups at ortho
and para positions such as nitro group, stabilizes the phenoxide ion
resulting in an increase in acid strength. It is due to this reason that
ortho and para nitro phenols are more acidic than phenol.
On the other hand, electron releasing groups such as alkyl group, do not
favour the formation of phenoxide ion – resulting in decrease in acid
strength.
For example: (cresol are less acidic then phenol)
Exercise 13:
Arrange each group of compounds in order of decreasing acidity:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 52
OH
NO2
(a)
OH
CH3
OH OH
, , ,
(b)
OH
NO2
OH
NO2
OH
NO2
NO2
OH
Cl
, , ,
CHEMICAL REACTIONS
(A) Reaction due to breaking of O – H bond
Phenol is more reactive than alcohol for this reaction because phenoxide ion
is more stable than the alkoxide ion.
R O H R O H
O H O
H
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 53
Reactions of phenol due to breaking of O H bond are given
below:
O H
Alcoholic
FeCl3
NaOH
(CH3)2SO4
NaOH
O Fe
3
blue or violet colour (test for phenolic group).
ONa
dry ether
CH2N2
O CH3
H2O
Anisole
O CH3
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 54
Acylation
OH
R C Cl
O
or
R C O
O
C R
O
O C R
O
/ Pyridine
Phenyl esterpyridine
Fries rearrangement
Phenolic esters are converted in to o– and p–hydroxy ketones in the
presence of anhydrous AlCl3. Generally low temperature favours the
formation of p–isomer and higher temperature favour the o-isomer.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 55
O C CH3
O1600C
600C
OH
COCH 3
OH
COCH 3
(B) Reactions due to breaking of carbon- Oxygen bond
Nucleophilic substitution reaction
Phenols are less reactive than aliphatic compound because:
(i) –OH group is present on sp2 hybridised carbon. This makes C–O
bond stronger.
(ii) ‗O‘ is more electronegative than halogens. This also makes C–O
bond stronger than C–X.
(iii) There is some double bond character between carbon and
oxygen due to the resonance. This also makes C–O bond
stronger.
However it give SN under drastic condition.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 56
OH
NH2
NH3/Anhy ZnCl2
3000C
Cl
SH
PCl / Δ5
2P S / Δ
5
O P
3
(C) EAS in Phenol:
It is strong activating group.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 57
OH
OH
NO 220 % HNO3
250C
OH
Br Br
Br
3Conc. HNO
2 2Br /H O
2 4H SO / Δ
2 3or Br / CH COOH
2 2Br / CS
2 4or Br / CCl
OH
SO3H
2 4H SO
Δ
OH
R3R X Anhy AlCl
Δ
OH
SO3H
OH
Br
OH
Br
OH
O2N NO 2
NO 2
2, 4, 6, tri nitro phenol
OH
NO 2
o-nitro phenol
p-nitro phenol
(picric acid)
2, 4, 6, tri bromo phenol
p-bromo phenol
o-hydroxy benzene sulphonic acid
p-hydroxy benzene sulphonic acid(Major)
o-alkyl phenol
o-bromo phenol
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 58
OH
OH
NO
HNO2
OH
CHO
3i CHCl / alc KOH
2ii H O /H
4ii CCl / alc KOH Δ
2ii H O /H
OH
COOH2i CO /NaOH
ii H
OH
CH2OH
2CH O
OH
COOH
O
N OH
OH
R
2 4ROH/H SO
Coupling reaction OH mild
ReimerTiemann reaction
ReimerTiemann reaction
0120 C, 7 atm
OH
CH2OH
OH
COOH
Major
Salicylic acid
Major product
OH
CHO
N NCl
OHN N
p hydroxy azo benzene Azodye
p nitroso phenol
Kolbe 's reaction
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 59
MERCURATION
Mercuric acetate cation. [HgOAC]+ is a weak electrophile which substitutes in
ortho and para position of phenol. Usually donating product is O–
acetoxy mercuriphenol. The mercuric compound can be converted to
iodophenol.
OH
3 2Hg OCOCH
Reflux
OH
HgOCOCH 3
Aq. NaCl
OH
HgCl
OH
I
I2/CHCl 3
Miscellaneous reaction
(i) Reaction with Zn dust
OH
Zn Δ ZnO
Dust
(ii) Oxidation
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 60
OH
O
O
p - benzoquinone
(brow n in colour)
OH
OH
K2S2O8/OH
Elbs oxidationp - quinol
h ν
(iii) Condensation with phthalic anhydride
C
C
O
O
O
2 4
2
Conc. H SO
Δ H O
C
C
O
O
OHOH
OH
H
OH
H
Penolphthalein
(Acid base indicator)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 61
Exercise 14:
Discuss the product formed in the bromination of p-phenol sulfonic
acid.
Mechanism of some important reactions
1. Reimer Tieman reaction
OH
3i CHCl , OH
ii H
CHO
OH
The electrophile is the dichloro carbene: CCl2, formation of carbene is an
example of -elimination.
(i)
OH H C Cl
Cl
Cl
-HClCCl 2
(ii) OH
OH
O
2CCl
Ar SE
O
CCl 2
H
O
CHCl 2
o (dichloro methyl) Phenoxide ion
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 62
(iii) O
HC
Cl
Cl
OH
O
C
H
O
Cl
H
O
C
O
HH
OH
CHO
2. Kolbe’s reaction
OH
NaOH CO2
0i 120 C, 7 atm
ii H
OH
COOH
Mechanism
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 63
OH O Na
NaOH
C O
O
(More reactive for Ar SE)
O
C
O
O Na
H
OH
C O Na
O
OH
COOH
Salicylic acid
H2O/H
Illustration 15:
How will you convert?
(i) phenol to aspirin (ii) phenol to salol.
(iii) phenol to oil of winter green. (iv) phenol to benzoic acid.
Solution:
(i) OH
02i NaOH/ CO , 120 C
4 7 atm ii H
OH
COOH3 2
CH CO O
H
O
COOH
COCH 3
Aspirin
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 64
(ii) OH
COOH
OH
CO O
OH
H
Salol
OH
02i NaOH/ CO , 120 C
7 atm P ii H
(iii) OH OH
COOH3CH OH
H
OH
COOCH 3
Oil of w inter green
02i NaOH/ CO , 120 C
7 atmP ii H
(iv) OH OH
COOHZn dust
COOH02i NaOH/ CO , 120 C
7 atm P ii H
Illustration 16:
What product would you expect in the following reaction? Explain.
OH
CH3
3CHCl , KOH?
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 65
Solution:
3 2CHCl aq. KOH : CCl
O
CH3
2CCl
O
CH3CCl 2
2H O
O
CH3CHCl 2
It is an ‗abnormal‘ product formed in the Reimer-Tiemann reaction when the
dienone cannot tautomerize to regenerate a phenolic system.
Illustration 17:
How would you distinguish between the following pairs?
(a) Phenol and cyclohexanol
(b) Ethyl alcohol and methyl alcohol
Solution:
(a) Phenol gives coloration with FeCl3 solution
(b) Ethyl alcohol responds to the iodoform test
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 66
Exercise 15:
How would you distinguish between the following pairs?
(a) 2-Pentanol and 3-pentanol
(b) 1-Propanol and phenol
Exercise 16.
Offer explanation for the following observations:
(a) Why is phenol unstable in the keto-form?
(b) The following dehydration is extremely facile:
CH3
O
H
OH
CH3
O
(c) Why does thionyl chloride provide alkyl chlorides of high purity?
(d) 2-Methyl -2- pentanol dehydrates faster than 2 – methyl – 1 –
pentanol.
(e) Phenol is acidic but ethyl alcohol is neutral.
(f) Ethanol responds to Iodoform test but tert- butanol does not.
(g) A tertiary alcohol reacts faster than a primary alcohol in the
Lucas test.
Exercise 17:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 67
How will you effect the following conversion?
(a) OH O
(b) C2H5OH CH3CH2CH2OH
Exercise 18:
How will you effect the following conversion?
(a) OH
(b) CH CH2 CH2CH2OH
(c) OH
CH3 CH3 (d) OH
OH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 68
Exercise 19:
Write mechanism
CH2OH
H Cyclohexene
Some Commercially Important Alcohols And Phenols
(i) Methanol: Methanol is also called wood spirit since originally it was
obtained by destructive distillation of wood. Now a days it is prepared
by catalytic hydrogenation of water gas.
3CuO ZnO CrO
2 3573 673K, 200 300KCO 2H CH OH
Uses:
It is largely used as:
(a) a solvent for paints, varnishes and celluloids.
(b) for manufacturing of formaldehyde.
(c) for denaturing ethyl alcohol, i.e. to make it unfit for drinking
purpose. Denatured alcohols is called methylated spirit.
(d) in manufacture of perfumes and drugs.
(ii) Ethanol: Ethanol is mainly prepared by hydration of ethene formation
of carbohydrates gives only 95% alcohol the rest being water. This is
called rectified spirit.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 69
Uses:
It is largely used as an
(a) antiseptic.
(b) solvent for paints, lacquers, varnishes, dyes, cosmetics,
perfumes, tinctures, cough syrups etc.
(c) As an important starting material for manufacture of ether,
chloroform, Iodoform etc.
(d) As an important beverages.
(e) As power alcohol a mixture of 20% absolute alcohol and 80%
petrol (gasoline) with benzene or tetralin as a co-solvent.
(f) As an antifreeze in automobile radiators.
(iii) Absolute alcohol: Absolute alcohol is 100% ethanol prepared from
rectified spirit 95.5% alcohol as follows:
In laboratory absolute alcohol is prepared by keeping the rectified spirit in
contact with calculated amount of quick lime for few hours and then
refluxing and distilling it.
Phenol or Carbolic Acid
Uses
(i) As an antiseptic and disinfectant in soaps and lotions.
(ii) In manufacture of drugs like, aspirin, salol, salicylic acid,
phenacetin.
(iii) In the manufacture of bakelite.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 70
(iv) In the manufacture of picric acid, phenolphthalein, azo
dyes.
(v) As a preservative for ink.
Ethylene Glycol: Ethane 1, 2 diol
Preparation: Lab preparation by hydroxylation.
(i) CH2
CH2
34 2
Cold dilute alkaline
2KMnO 4H O
CH2OH
CH2OH
22MnO 2KOH3
Manufacture
CH2
CH2
2O / Ag
575K
H2C
H2CO
2H O/473K
hydrolysis
CH2OH
CH2OH
Ethylene epoxideor oxirane
Physical properties:
It is highly viscous because of the presence of two OH bond it undergoes
extensive intermolecular H-bonding. Same reason owes to high
solubility in water and high boiling point.
Chemical properties
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 71
Reaction with sodium
(i)
2
Na, 323K
1H2
CH2ONa
CH2OH
CH2OH
CH2OHMonosodium glycolate
2
Na, 433K
1H2
CH2ONa
CH2ONa
Disodium glycolate
(ii) 52PCl
CH2Cl
CH2Cl
CH2OH
CH2OH
32POCl 2HCl
(iii) 22SOCl
CH2Cl
CH2Cl
CH2OH
CH2OH
22SO 2HCl
Ethylene dichloride
(iv) 2
HCl, 433K
H O
CH2Cl
CH2OH
CH2OH
CH2OH
Ethylene chlorohydrin
2
HCl, 473K
H O
CH2Cl
CH2Cl
Ethylene dichloride
(v)
p toulenesulphonic acid
RCH O
H2C
H2C
CHRCH2OH
CH2OH
2H O
Cyclic acid
(vi) Oxidation: Ethyelene glycol upon oxidation gives different
products with different oxidising agents. For example.
(a) O
CH2OH
CH2OH
CHO
CH2OH
O
COOH
CH2OH
Glycolaldehyde Glycollic acid
CHO
CHO
COOH
CHOGlyoxal
O
Glyoxalic acid
O
COOH
COOH
Oxalic acid
(b) With periodic acid HIO4 or lead tetra acetate.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 72
4HIO
CH2OH
CH2OHIodic acid
2 3H O HIOHCHO
HCHO
Also called malapride reaction.
3 4
2 CH COO Pb
CH2OH
CH2OH
3 3 22CH COOH CH COO Pb
HCHO
HCHO
Dehydration
(a) 773K
H2C
H2C
OCH2OH
CH2OH
2H O
(b) 2
2
ZnCl
H O
CH2
CHOH
CH2OH
CH2OH
Vinyl alcohol
Tautomerize
CH3
CHO
(c) 2 4conc. H SO
distill
CH2
CH2
O
CH2
CH2
O
CH2OH
CH2OH
2 22H O
1, 4 dioxane
(d) 3 4conc. H PO
distill
CH2
CH2
O
CH2OH
CH2OHCH2OH
CH2OH
2 2H O
Diethylene glycol
Uses
(a) As a solvent.
(b) Antifreeze in the radiators of cars and aeroplanes.
(c) In manufacture of terylene and other polyester.
Exercise 20:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 73
How would you convert cyclohexane to 1, 6 – hexanediol?
Glycerol (Propane 1, 2, 3 triol)
One of the most important trihydric alcohol.
Preparation:
(i) By Saponification of oils and fats.
H2C
HC
H2C
O
OCOR 2
OCOR 3
COR 1
3NaOH
CH2OH
CHOH
CH2OH
R1COONa
R1COONa
R1COONa
Sodium salt of fatty acid (soap)
(ii) From Propylene
2 32
2 2
aq.Na COCl , 773K
3 2 2 2 2 2HCl 423K, 12 atmAllyl chloride Allyl alcohol
HOCl Cl OH aq. NaOH
2 2 2 2trans Cl H O NaClglycerol
glycerol m
CH CH CH Cl CH CH CH HO CH CH CH
HOCH CHOH CH Cl CH OH CHOH CH OH
onochlorohydrin
(iii) Synthesis from its elements
3 3
2 4
Na in liq. NH CH IElectric ore
2 Berthelets synthesis 196 K NaI
H /Pd BaSO
3 3 2Lindlar 's catalystPr opyne Pr opylene
2C H CH CH Na C CH
H C C CH CH CH CH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 74
Physical Properties
Highly viscous due to three –OH group due to which it undergoes extensive
intermolecular H-bonding.
Chemical Properties
(i) It undergoes reaction of both secondary and primary alcoholic group.
CH2OH
CHOH
CH2OH
2
Na, room temperature
1H2
CH2ONa
CHOH
CH2OH
Na, room temperature
CH2ONa
CHOH
CH2ONa
monosodium glycerolate , 'disodium glycerolate
(ii)
CH2OH
CHOH
CH2OH
CH2Cl
CHOH
CH2OH
CH2OH
CHCl
CH2OH
CH2Cl
CHCl
CH2OH
CH2Cl
CHOH
CH2Cl
HClgas
2383K, H O 2gas, 383 K, 2H O
Excess of HCl
Glycerol
monochlorohydrin
Glycerol
monochlorohydrin
Glycerol
, dichlorohydrin
Glycerol
, dichlorohydrin
Excess of dry HCl gas, 383 K
2H O
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 75
To replace the third hydroxyl group in either of two dichlorohydrins, PCl5 or
PCl3 is fused.
(iii) CH2OH
CHOH
CH2OH
23H O3HI
CH2I
CHI
CH2I
Unstable
2I
CH2
CH
CH2I
HI
Markonikof 's addition
CH3
CHI
CH2I
1, 2 diiodopropane
2I
CH3
CH
CH2
HI
CH3
CHI
CH3
Isopropyl iodide
3. Reaction with concentrated nitric acid:
H2C
HC
H2C
OH
OH
OH
HO
HO
HO
NO2
NO2
NO2
Glycerol
3 2 4Conc HNO Conc. H SO
283 298K
H2C
HC
H2C
O
O
O
NO2
NO2
NO2
3H2O
Glyceryl trinitrate Noble'soil
Nitroglycerine
A mixture of glyceryl trinitrate and glyceryl dinitrate absorbed on Kieselguhr
is called dynamite.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 76
4. Reaction with KHSO4 – Dehydration.
H
C
C
C
H
H
OH
H OH
H
OH
Glycerol
4
2
KHSO , 473 503K
2H OC
CH2
CHOH
(unstable)
Tautomerises CH
CH2
CHO
Acrolein
or Prop- 2-en-1-al
5. Oxidation.
CH2OH
CHOH
CH2OH
Glycerol
[O]
CHO
CHOH
CH2OH
Glyceraldehyde
[O]
COOH
CHOH
CH2OH
Glyceric acid
[O]
CH2OH
C
CH2OH
O
Dihydroxyacetone
[O]
COOH
CO
COOHMesoxalic acid
COOH
CHOH
COOH
Tartromic acid
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 77
(i) With dil. HNO3, a mixture of glyceric acid and tartronic acid is
produced.
(ii) With conc. HNO3, mainly glyceric acid is obtained.
(iii) With bismuth nitrate, only mesoxalic acid is formed.
(iv) Mild oxidising agents like bromine water, sodium hypobromite
(Br2/NaOH) and Fenton‘s reagent (H2O2 + FeSO4) give a mixture
of glyceraldehyde and dihydroxyacetone. The mixture is called
glycerose.
(v) With periodic (HIO4) acid.
CH2OH
CHOH
CH2OH
42HIO
Glycerol
HCHOFormaldehyde
HCOOHFormic acid
HCHO
Formaldehyde
3 2Iodic acid
2HIO H O
(vi) With acidified potassium permanganate.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 78
CH2OH
CHOH
CH2OH
4
Acidified
KMnOO
Glycerol
COOH
COOH
Oxalic acid
2 2CO 3H O
6. Reaction with phosphorous halides.
CH2OH
CHOH
CH2OH
53PCl
Glycerol 1, 2, 3 - trichloropropane
CH2Cl
CHCl
CH2Cl
(Glyceryl trichloride)
33HCl 3POCl
7. Reaction with monocarboxylic acids. Glycerol reacts with
monocarboxylic acids to form mono-, di- and tri- ester depending upon
the amount of the acid used and the temperature of the reaction. An
excess of the acid and high temperature favour the formation of
tri-esters. For example, with acetic acid, glycerol monoacetate,
diacetate and triacetate may be formed.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 79
CH2O.COCH 3
CHOH
CH2OH
Glycerol monoacetate
CH2O.COCH 3
CHOH
CH2O.COCH 3
Glycerol diacetate
CH2O.COCH 3
CHO.COCH 3
CH2O.COCH 3
Glycerol triacetate
8. Acetylation. When treated with acetyl chloride, glycerol forms
glycerol triacetate.
CH2OH
CHOH
CH2OH
33CH COCl
Glycerol Glycerol triacetate
CH2OCOCH 3
CHOCOCH 3
CH2OCOCH 3
3HCl
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 80
9. Reaction with oxalic acid
(i) H2C
CHOH
CH2OH
OH
Glycerol
H OOC COOHOxalic acid
2
383K
H O
H2C
CHOH
CH2OH
OOC COO H
Glyceryl monoxalate
2
Heat
CO
H2C
CHOH
CH2OH
OOCH
Glyceryl monoformate
HOH, hydrolysis
From water of crystallization
CH2OH
CHOH
CH2OH
Glycerol
HCOOH
Formic acid
(ii) CH2O H
CHO H
CH2OH
2
503K
2H O
Glycerol
CO
CO
HO
HO
Oxalic acid
H2C
HC
CH2OH
OOC
OOC
Glyceryl dioxalate
(Dioxalin)
2
503K
2H O
CH2
CH
CH2OH
Allyl alcohol
Uses:
Glycerol is used:
1. In the preparation of nitroglycerine used in making dynamite.
Nitroglycerine is also used for treatment of angina pectoris.
2. As an antifreeze in automobile radiators.
3. In medicines like cough syrups lotions etc.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 81
4. In the production of glyptal or alkyl resin (a cross – linked
polyester obtained by the condensation polymerization of
glycerol and phthalic acid) which is used in the manufacture of
paints and lacquers.
5. In making non-drying printing inks, stamp colours, shoes
polishes etc.
6. In the manufacture of high class toilet soaps and cosmetics since
it does not allow them to dry due to its hydroscopic nature.
7. As a preservative for fruits and other eatables.
8. As a sweetening agent in beverages and confectionary.
Exercise 21:
How does glycerol react with a. HI, b. (COOH)2 and c. conc HNO3?
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 82
ANSWER TO EXERCISES
Exercise 1:
(i) CH3 OH
HgOAC
HA =
CH3 OH
B =
(ii) A = CH3CH2CH2OH
B = CH3OH
Exercise 2:
(i)
RCO 2Et + OH
byfollowed
3MgBr MgBr
R
OH
RR
-H2O
H2/Pd
(ii) The R– (carbanion) pulls acidic hydrogen from OH group making
it an acid-base reaction instead of usual nucleophilic addition
reaction. On further hydrolysis it produces reactant. But in the
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 83
second case you have two moles of RMgX that completes the
reaction because there are two R– for two different sites.
Exercise 3:
CH3
CH CH3
OH
H
CH3
CH CH3 ring
Expansion
CH3
CH3
H
CH3
CH3
H
Exercise 4:
(a) (iii) > (ii) > (i) > (iv)
(b) (i) > (ii) > (iii)
Exercise 5:
(i) Only (c) and (d) gives iodoform test.
(ii) O
OH
O
(A) =
OH
OH
OH
(B) =
Exercise 6:
(a) 6 5 2 6 5 3 6 5 33 2C H CCH OH C H CHOHCH C H C(OH)CH
(b) (i) No reaction
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 84
(ii) 6HCOOH
(iii) RCHO + R CHO + NH3
Exercise 7:
(i)
A = C C
CH3
O
Ph
CH3
Ph
(ii)
A = C C
CH3
O
Ph
CH3
Ph
Here phenyl migration takes
place.
Here methyl migration
takes place.
Exercise 8:
Considering the reactions of C5H10O2, it is likely that C6H5NHNH3, I2,
NaOH will react only with a keto group while CH3COCl and oxidation
are reactions of an alcohol. Therefore two isomeric structures are
possible for the original compound.
CH3 C
O
CH2CH2CH2OH and CH3 C
O
CH2CH2OH
CH3
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 85
Exercise 9:
X =
O
, w – halo alcohols undergoes
intramolecular Williamson
ether.
Y = O
Synthesis in the presence of NaOH
by NS 2 reaction.
Exercise 10:
(a) Ethoxyethanol give the Iodoform test.
(b) Butyl iodide with AgNO3 yields AgI precipitate.
(c) Ethyl allyl ether decolorize bromine water.
Exercise 11:
The cleavage reaction of an ether by HI is initiated by protonation of
the ether oxygen.
O
I 1 2Attack byeither SN or SN
H CH3
(B)
In the second step the attack by Br has to take place by SN1 or SN2
process. Since the system B is rigid either attack is very slow. The
ether A does not pose such a problem
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 86
Exercise 12:
(a)
CH3
H
OH
OHCH3
4
3
i OsO
ii NaHSO
(b) CH3
O
CH3
6 5 2C H CO OH 2H O
H
OHCH3
OH
H
Exercise 13:
OH
NO 2
(a)
OH
CH3
OH OH
> > >
(b)
OH
NO2
OH
NO2
OH
NO2
NO2
OH
Cl
> > >
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 87
Exercise 14:
A phenol is highly reactive towards electrophilic substitution.
Treatment of phenol with aqueous solution of bromine results in the
replacement of every hydrogen ortho and para to the OH group, and
it even cause the displacement of the sulfonic group to yield
tribromophenol.
OH
SO3H
23Br
OH
Br
BrBr
2 43HBr H SO
Exercise 15:
(a) 2-Pentanol responds to the Iodoform test
(b) Phenol gives coloration with FeCl3 solution
Exercise 16:
(a) Phenol loses the aromatic stabilization in the keto form.
(b) The alkene formed is more stable due to resonance.
(c) Because the other products during the reaction of thionyl
chloride with alcohols are gaseous.
(d) 2-Methyl-2-pentanol yield a stable alkene
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 88
(e) The phenoxide ion formed from phenol is stabilized by
resonance.
(f)
Ethanol contains the H C
H
CH3
OH grouping
(g) A tertiary alcohol form a stable tertiary carbonation.
Exercise 17:
(a) OH OH
2H ,
Na2 2 7Na Cr O
H ,
O
(b) 5 2HPCl HNOKCN
2 5 2 5 2 5 2 5 2 2 2 5 2C H OH C H Cl C H CN C H CH NH C H CH OH
Exercise 18:
(a) 2 4
0
H SO
160
SO3H
NaOH
SO3 Na
H
OH
(b) HBr aqueous OH
6 5 2 6 5 2 2 6 5 2 2PeroxideC H CH CH C H CH CH Br C H CH CH OH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 89
(c) CH3
OH OH
CH3
2H /Ni
2
H ,
H O
CH3
(d) OH
H HOCl
OH
Cl
2
H ,
H O
Cl
aq. KOH
OH
Exercise 19:
CH2OH
2
H ,Δ
H O
CH2
ring expansion H
Exercise 20:
3 4O NaBH
2 6HO CH OH
Exercise 21:
See the text.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 90
MISCELLANEOUS EXERCISES
Exercise 1: Write a note on: (a) Oxo process (b) absolute alcohol
Exercise 2: What happens when?
(a) ethanol vapours are passed over alumina at 600 K,
(b) excess of ethanol is heated with conc.H2SO4 at 413K,
(c) phenol is treated with acetyl chloride?
Exercise 3: How is glycerol prepared from fats and oils? Why it is
highly viscous? Give its uses?
Exercise 4: Discuss the following reactions:
(a) Reimer and Tiemann reaction
(b) Kolbe‘s reaction
Exercise 5: Complete the following by putting structures of A, B, C, D.
3 3KOH als.PBr NHHBr
3 2 2CH CH CH OH A B C D
Complete the following.
Exercise 6: Compete the following by drawing correct structures.
SO3H2 4 2
i fuse withNaOHfu min g
H SO ii H O / H.................. ..................
Exercise 7: How the sugar is converted to ethanol?
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 91
Exercise 8: Write the structure of organic compounds A to F in the
following sequence of reactions:
OH
3 32 2 2
2 4
HNO H OBr H / V Pt HNOZn
H SO HClA B C D E F
Exercise 9: Predict the products of the following reactions:
(a)
2 5C H O Na
Br
(b) HBr
3 2 6 55CH CH O C H
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 92
ANSWER TO MISCELLANEOUS EXERCISES
Exercise 1:
(a) Oxo process: It is used for the preparation of alcohols. When alkenes
are treated with carbon monoxide and hydrogen in presence of
octa-carbonyl dicobalt at high temperature and pressure, aldehyde are
formed, which on reduction with H2/Ni give alcohols.
4 2 2CO Co H /Ni
2 2 2 3 2 3 2 2High temp.Ethene Propanal 1 propanoland pressure
CH CH CO H CH CH CHO CH CH CH OH
(b) Absolute alcohol: 100% ethanol is known as absolute alcohol. 95.6%
alcohol and 4.4% water form azeotropic mixture and boil at same
temperature. To prepare absolute alcohol, rectified spirit (95%
alcohol) and benzene mixture is fractionally distilled. The first fraction
obtained at 331.8 K contains the azeotropic mixture of total water
(7.5%) some alcohol (18.5%) and maximum benzene (74%). The
second fraction, which is an azeoptroopic mixture of remaining
benzene (nearly 68%) and some alcohol (32%) is obtained at 341.2 K.
The third and last fraction consists of absolute alcohol which is
obtained at 351K.
Exercise 2:
(a) Dehydration with take place and ethylene is formed.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 93
2 3Al O
3 2 2 2 2600KEtheneEthanol
CH CH OH CH CH H O
(b) Diethylether is formed.
2 4Conc. H SO
2 5 2 5 2 5 2413KEthoxy Ethane
2C H OH C H OC H H O
OH
Phenol
3Acetyl chloride
CH COCl
O COCH 3
Phenyl acetate
HCl
(c) Phenylethanoate is formed.
Exercise 3:
Glycerol is prepared by the Saponification of oils and fats i.e., hydrolysis of
oils and fats with NaOH. Fats and oils are the esters of glycerol and
higher fatty acids i.e. glycerides of fatty acids.
Glycerol is very viscous with extensive intermolecular hydrogen bonding.
Glycerol molecule contains three OH groups which form extensive
hydrogen bonding. Hence the intermolecular forces are very high and
molecules are highly associated. Due to this reason it is very viscous
and posses high boiling point (563K).
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 94
H2C
HC
H2C
O
O
O
COR
COR'
COR"
3NaOH
H2C
HC
H2C
OH
OH
OH
RCOONa
RCOONa
RCOONa
(Oil and fats) Glycerol Sodium salt of fatty acids (soaps)
Uses:
(i) Used in the preparation of nitroglycerine which is main
constituent of dynamite.
(ii) Used as antifreezing agent in automobile radiators.
(iii) Used as a sweetening agent in confectionery and beverages.
Exercise 4:
(a) Reimer and Tiemann reaction: When phenol is refluxed with
chloroform and sodium hydroxide at 340 K followed by hydrolysis,
gives o-hydroxy benzaldehyde (main product) and p-hydroxy
benzaldehyde (minor product). This reaction is known as Reimer and
Tiemann reaction.
OH
Phenol
4CCl
340K
OH
COONa
2H O/H
OH
COOH
2-Hydroxybenzaldehyde (Salicyldehyde)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 95
OH
Phenol
4CCl /NaOH
340K
OH
COONa
2H O/H
OH
COOH small amount of 4-hydroxy benzoic acid is also formed
2-Hydroxy benzoic acid (Salicylic acid)
If CCl4 is used in place of CHCl3 the main product will be salicylic acid.
(b) Kolbe’s Reaction: When sodium phenoxide is treated with carbon
dioxide under pressure (4 to 7) and at 400 K, sodium salicylate is
formed which on acidic hydrolysis gives salicylic acid. This reaction is
known as Kolbe‘s reaction.
OH
Phenol
4 7 atm
2 400KCO
OH
COONa
2H O/H
OH
COOH
Salicylic acid(Major product)
Exercise 5:
3KOH alc.PBr
3 2 2 3 2 2 3 21 Propanol 1 Bromopropane Propene B
A
CH CH CH OH CH CH CH Br CH CH CH
HBrCH3 CH
Br
CH3
NH3CH3 CH CH3
NH2
2-Propanamine(D)
2-Bromopropane(C)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 96
Exercise 6:
SO3H2 4
fuming
H SO
SO3H
SO3H
2
i fuse with NaOH
ii H O/H
OH
OH1, 3 - Dihydroxy benzene
Exercise 7:
Molasses, which is the main source of sugar is treated with yeast. The
enzymes present in yeast ferment the sugar and ethanol is obtained.
Sugar is converted to glucose and fructose by the invertase enzyme.
Glucose is further converted to ethanol by the zymase enzyme.
Invertase Zymase
12 22 11 2 6 12 6 6 12 6 2 5 2Sugar Glucose Frucot se Ethanol
C H O H O C H O C H O 2C H OH 2CO
Exercise 8:
OH
Zn 3
2 4
HNO
H SO
NO 2
2Br
NO 2
Br
Sn /HCl
Phenol Benzene
[A]
Nitrobenzene
[B]m-Nitro
(bromobenzene)[C]
NH2
Brm-Bromo
Aniline[D]
N2Cl
Br
m-BromoBenzenediazonium
[E]
3H O 2HNO
HCl
OH
Brm-Bromophenol
[F]
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 97
Exercise 9:
(a) OC2H5
(b) 3 2 2 6 54CH CH CH Br C H OH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 98
SOLVED PROBLEMS
Subjective:
Board Type Questions
Problem 1:
What happens when?
(i) Vapours of ethanol are passed over heated alumina at 523 K.
(ii) Ethyl bromide is heated with dry silver oxide.
(iii) Methyl magnesium bromide is treated with methoxy chloro
methane.
(iv) Ethyl alcohol is heated with diazomethane in presence of HBF4.
(v) 2 methyl propene is heated with methanol in the presence of dil.
H2SO4.
Solution:
(i) Diethyl ether is formed.
2 30
Al O
3 2 2 3 3 2 2 3 2350 CCH CH OH H O CH CH CH CH O CH CH H O
(ii) C2H5 Br
C2H5 Br
Ag2O H5C2 O C2H5 2AgBr
diethyl ether
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 99
(iii) Ethyl methyl ether is formed.
CH3 O C2H5Mg
Cl
Br
dry
etherH3C O CH2Cl CH3MgBr
(iv) Ethyl methyl ether is formed
4HBF
3 2 2 2 3 2 3 2dim ago methane
CH CH OH CH N CH CH O CH N
(v) Tertiary – butyl methyl ether
CH3 C
CH3
CH2 H O CH3
H2SO4 CH3 C
CH3
CH3
O CH3Methyl ter - butyl ether
Problem 2:
Why phenol has smaller dipole moment than methanol?
Solution:
In case of phenol, the electron withdrawing inductive effect of oxygen
is opposed by electron releasing resonance effect. Hence, phenol has
smaller dipole moment. In case of methanol only electron withdrawing
inductive effect is operative. Hence, it has higher dipole moment.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 100
Problem 3:
Why di tert – butyl ether can not be obtained by Williamson‘s method?
Solution:
In order to prepare the above ether the reagents to be used are
tert–butyl bromide and tert–butoxide. Since the tertiary bromide
prefers to under go elimination, therefore, major product of the
reaction shall be iso butylene and not di tert – butyl ether.
CH3 C
CH3
CH3
Br Na O C
CH3
CH3
CH3CH3 C
CH3
CH2 CH3 C
CH3
CH3
OH NaBr
30 bromide tert- butoxide
Problem 4:
Identify the product in the following reaction
OH
OH 2
3
ClCH COCl
POClA 3 2CH NH B 4i KMnO / OH
ii HC Zn dust D
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 101
Solution:
A =
OH
COCH 2Cl
OH
B =
OH
COCH 2NHCH 3
OH
C =
OH
COOH
OH
D =
COOH
Problem 5:
Write the various product when ethanol reacts with sulphuric acid in suitable
conditions.
Solution:
C2H5OH 2 4H SO
383KC2H5HSO 4
C2H5OC2H5
CH2 CH2
H2SO4/ 413 K
H2SO4/ 443 K
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 102
IIT Level Questions
Problem 6:
Give products expected when each of the following diols are reacted with
periodic acid HIO4 .
(a) HO CH2 CH
OH
CH2 C6H5
(b) OH
C
H
OH
Solution:
(a) C O
H
H
H C
O
CH2 C6H5
(b)
O
CH O
Problem 7:
Effect the following conversion
(a) CH2OH CH2OH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 103
(b) CH3OH
CH2CH2OH
Solution:
(a) CH2OH CH2
H ring
Expansion
H2O
OHK2Cr2O7
O
Ph 3P CH2
CH2
HBO
CH2OH
(b)
CH3OH 5PClCH3Cl
Anhy AlCl 3
CH3
NBS
CH2Br
Mg dry ether
CH2MgBr
3
HCHO
H O
CH2CH2OH
Problem 8:
Postulate a mechanism for the following reactions:
CH3
OH
H
O
Solution:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 104
OH
OH
H
-H2OOH
ring expansion
O H
-H
O
Problem 9:
Conversion
(a) H
OH
H
D
(b) CH2 CH2 O O
Solution:
(a) H
OH
H
Br
PBr 3
Pyridine
Mg/dry ether
H
MgBr
D2O
H
D
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 105
(b) CH2 CH2
MnO 4
KOHHOH 2C CH2OH
H
-H2OOH CH2
CH2
O
CH2CH2OH
2H , Δ, H OIntrmoleculadehydration
O O
Problem 10:
Identify the products in the following reaction sequence.
CH3
OH
3i CHCl
ii KOH, HA 4LiAlH
B 3CH COOH
HC
Solution:
A =
CH3
OH
CHO
B =
CH3
OH
CH2OH
C =
CH3
OH
CH2 O C CH3
O
Problem 11:
Distinguish between each pair of compounds by a simple test.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 106
(a) (CH3)2CHOH and (CH3)2CHSH
(b) CH3CH2CH2OH and (CH3)2CHOH
Solution:
(a) The thiol gives a precipitate with heavy metal cations like
2 2 2Hg , Pb and Cu
(b) (CH3)2CHOH (2 alc) gives a yellow precipitate of CHI3 with
I2/OH (iodoform test)
Problem 12:
Write mechanism of the following reaction
OH
OH
H3O
O
Solution:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 107
OH
OH
O
O H
O
H
Problem 13:
Compound (A) C6H14O is insoluble in water and gives negative Lucas test. On
treatment with conc. H2SO4 followed by hydrolysis it gives only one
compound (B) (C3H8O). Compound (B) is soluble in water and gives
red colour with ceric ammonium nitrate. (B) gives yellow precipitate
(C) and compound (D) on treatment with I2/Na2CO3 followed by
acidification. Identify the compound A, B, C and D. Give the reasons.
Sol.
A = O
CH3
CH3
C CH3
CH3
H
B =
CH3OH
CH3
C = CHI3 D = CH3COOH
Problem 14:
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 108
Explain the low a boiling point and decreased water solubility by
o–nitro phenol and o–hydroxy benzaldehyde as compared with this m
and p–isomers.
Solution:
Intramolecular H-bonding (chelation) in the o-isomers inhibits intermolecular
attraction, lowering the boiling point and reduces
H-bonding with H2O, decreasing water solubility. Intramolecular
chelation cannot occurs in m – and p – isomers.
O
N O
H
O
o - nitro phenol
O
C O
H
H
o - hydroxy benzaldehyde
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 109
Objective:
Problem 1:
When ether is exposed to air for some time an explosive substance is
produced
(A) peroxide (B) TNT
(C) oxide (D) super oxide
Solution:
(A) Peroxide
Problem 2:
What is the major product obtained when phenol is treated with
chloroform and aqueous alkali?
(A) OH
CHO
(B) OH
CHO
(C) CHOOH
(D) OH
COOH
Sol.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 110
(A) Salicyldehyde
Problem 3:
CH3 C CH2
CH3
O
182H O
HA, A is
(A)
CH3 C
CH3
OH
CH2
OH18
(B)
CH3 C
CH3
OH
CH2
OH18
(C) Both (D) none
Solution:
Stability of carbocation is 3 > 2 > 1
(A)
Problem 4:
Organic acid without a carboxylic acid group is ……………………..
(A) ascorbic acid (B) vinegar
(C) oxalic acid (D) picric acid
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 111
Solution:
Picric acid is a phenol i.e. 2, 4, 6 tri nitro phenol
(D)
Problem 5:
The product of the following reaction
CH3 CH23
2 2
i BH / THF
ii H O ,OH
(A) 1 – pentanol (B) 2 – pentanol
(C) pentane (D) 1, 2 – pentane diol
Solution:
Anti Markowvnikov product.
(A)
Problem 6:
Product in the reaction
3CH INaOH NaOH
2 5 aqC H Br A B C will be
(A) propane (B) ethyl iodide
(C) butanol (D) methoxy ethane
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 112
Solution:
3Na/CH INaOH
2 5 2 5 2 5 3aq William son's synthesisC H Br C H OH C H OCH
(D)
Problem 7:
Phenol can be distinguished from alcohol with
(A) Tollen‘s reagent (B) Schiff‘s base
(C) Neutral FeCl3 (D) HCl
Solution:
Phenol gives violet colour with neutral FeCl3.
(C)
Problem 8:
Tert – butyl methyl ether on heating with HI of one molar concentration
gives
(A) CH3OH + (CH3)3C I (B) CH3I + (CH3)3COH
(C) CH3I + (CH3)3CI (D) none of these
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 113
Solution:
HI
3 3 3 33 3CH C O CH CH OH CH C I
(A)
Problem 9:
Which of the following is the strongest acid?
(A) OH
NO2
(B) OH Cl
(C) NO2OH
(D) OH
NO2
Solution:
Due to greater electron withdrawing effect of NO2 group than Cl atom
nitrophenols are stronger acids than p–chloro phenol among nitro
phenols P nitro phenol is the strongest acid.
(C)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 114
Problem 10:
Phenol is heated with phthalic anhydride in presence of conc. H2SO4.
The product is
(A) Phenolphthalein (B) bakelite
(C) salicylic acid (D) fluorescein
Solution:
Phenolphthalein
(A)
Problem 11:
An organic compound X of molecular formula C4H10O undergoes
oxidation to give a compound Y of molecular formula C4H8O2. X could
be
(A) CH3CH2CH2CH2OH (B) CH3CH2CH(OH)CH3
(C) (CH3)2CHCH2OH (D) (CH3)3COH
Solution:
(A) & (C)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 115
Problem 12:
Which of the following methods is/are not the industrial methods to
prepare methanol?
(A) catalytic reduction of carbon monoxide in presence of ZnO-
Cr2O3.
(B) reacting methane with steam at 900 C with a Ni catalyst.
(C) reducing formaldehyde with lithium aluminium hydride.
(D) reacting formaldehyde with aqueous sodium hydroxide solution.
Solution:
(B), (C) & (D)
Problem 13:
Which of the following reagent (s) or test (s), can be used to
distinguish 2 methyl propanol and 2-methyl propanol–2?
(A) I2/NaOH (B) HCl/anhyd. ZnCl2
(C) Victor-Meyer test (D) oxidation with Cu at 573 K
Solution:
(B), (C) & (D)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 116
Problem 14:
Phenol has higher pka value than
(A) acetic acid (B) p-methoxy phenol
(C) p-nitrophenol (D) ethanol
Solution:
(A) & (C)
Problem 15:
Which of the following reactions can be used to prepare methyl phenyl
ether?
(A) reacting sodium phenoxide with methyl chloride
(B) reacting phenol with diazomethane (CH2N2)
(C) reacting sodium methoxide with chlorobenzene
(D) reacting C6H5OMgCl with chloromethane
Solution:
(A) & (B)
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 117
Fill in the Blanks
Problem 16:
Williamson‘s synthesis involves the reaction of an………………..with
an……………….
Solution:
Alkyl halide, alkoxide
Problem 17:
An ether is more volatile than alcohol having the same formula due to
absence of………………..
Solution:
Intermolecular hydrogen bonding
Problem 18:
Anisole reacts with HI to form……………………
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 118
Solution:
Methyl iodide and phenol
Problem 19:
Power alcohol is a mixture of absolute alcohol and…………….in the
ratio…………….
Solution:
Petrol, 20 : 80
Problem 20:
Glycerol on reaction with potassium hydrogen sulphite and heat yields
a product which…………to form acraldehyde.
Solution:
Tautomerise
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 119
Problem 21:
Phenol on exposure to air produces a………………..coloured product
known as……………………..
Solution:
Red, phenoquione
True and False
Problem 22:
t-butyl alcohol reacts less rapidly with metallic sodium than the
primary alcohol.
Solution:
True
Problem 23:
o-nitro phenol is more soluble in water than p-nitrophenol.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 120
Solution:
False
Problem 24:
2-methyl – 2- propanol gives cloudiness with HCl and ZnCl2
immediately at room temperature.
Sol:
True
Problem 25:
The hydroboration oxidation process gives product corresponding to
Markonikov‘s addition of water to the carbon – carbon double bond.
Solution:
False
Problem 26:
p-amino phenol has higher pka value than phenol.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 121
Solution:
True
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 122
ASSIGNMENT PROBLEMS
Subjective:
Level–O
1. Write all the canonical forms of phenol.
2. Account for the following:
(i) When HI react with methyl phenyl ether, phenol and methyl
iodide are formed and not methyl alcohol and iodobenzene?
(ii) An ether would posses a dipole moment even if the alkyl groups
present in it are identical.
3. O – nitro phenol is less soluble in water than p – nitro phenol. Why?
4. 3, 3 – dimethyl butane 2 – ol loses a molecule of water in the presence
of concentrated sulphuric acid to give tetra methyl ethylene as a major
product.
Suggest a suitable mechanism.
5. Complete the following sequences of reactions by supplying X, Y and
Z:
(a) 3 2PBr ClNa
3 3Ether heatX Y CH CH Z
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 123
(b)
X 2H O/HCH3 CH CH3
OH
Cu/ 573KY
(i) C2H
5MgI
(ii) H2O/H+
Z
6. How will you convert phenol to salol?
7. Name the reagents used in the following reactions:
(i) Benzyl alcohol to benzoic acid.
(ii) Phenol to 2, 4, 6 tribromo phenol.
(iii) Ethanol to ethanol
(iv) Ethene to ethane – 1, 2 diol.
8. Arrange the following set of compound in order of their increasing
boiling points.
(a) Pentan–1–ol, butan–1–ol, butan–2–ol, ethanol, propan–1–ol,
methanol.
(b) Pentan–1–ol, n–butane, pentanal, ethoxyethane.
9. Arrange the following compounds in increasing order of their acid
strength:
Propan–1–ol, 2, 4, 6–trinitrophenol, 3–nitrophenol, 3, 5–dinitrophenol,
phenol, 4–methyl phenol.
10. (a) Explain why a non symmetrical ether is usually prepared by
heating a mixture of ROH and R OH in acid.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 124
(b) Would you get any di-tert-butyl ether from this reaction?
Explain.
11. How the following conversion carries out?
(i) Propane Propan–2–ol
(ii) benzyl chloride benzyl alcohol
(iii) Ethyl magnesium chloride propanol–1
(iv) Methanol to Ethanol
12. Identify the major products in the following reactions.
(i) NO 2
OCH 3
3
2 4
HNO
H SOA
(ii) OH
CH3
2Br
waterB
13. Give one test to distinguish
(a) Ethanol and methanol
(b) Phenol & Benzyl alcohol
14. Compound (A) C7H8O is insoluble in water and dilute NaHCO3 but
dissolve in dilute NaOH solution. On treatment with Br2 water it readily
gives a precipitate of C7H5OBr3. Write down the structure of the
compound.
15. Give the mechanism of Reimer Tiemann reaction on phenol.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 125
Level – I
1. Write the product of the following reactions
CH3
3i BH
ii OxidationA
2. Write the product A & B
CH CH CHO
A
B
H2/Pt
NaBH 4
3. Write the product A & B
CH3
4
Cold
alkaline KMnOA 2 3Cr O
ACOHB
4. Convert nitro benzene to m – nitro phenol.
5. An unknown compound A (C4H10O2) reacts with sodium metal to
liberate hydrogen gas. A is inert towards periodic acid, it react with
CrO3 to form B (C4H6O3). Identify A and B.
6. Convert
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 126
OH
to
CH3
OH
Write mechanism of above conversion.
7. Identify compounds A – D in the following reaction.
CHC 6H5
3
2
i O
ii Zn/H OA B
dil. NaOH
2aq. ethanolA B C H O
3
2
i O
ii Zn/H OC D A
2H /PtD
OH
OH
8. Give mechanism of the following reaction
4
3
i CCl NaOH/Δ
ii H O
OH
COOH
OH
9. Identify the product in the given reaction
1 equiv
H CH3
BH3/THFA
H2O2 OHB
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 127
10.
O
Conc. H2SO4
ΔX
H2OY
Identify X and Y.
11. Identify A & B
N
H
CHCl 3OH
A B
Pyrole
12. Give a simple test that distinguish between the compounds.
(a) Allyl and n – propyl alcohol.
(b) Benzyl methyl ether and benzyl alcohol.
13. How will you synthesize?
CH3
from phenol
14. An organic compound (A) gives positive Libermann reaction and on
treatment with CCl4/KOH followed by hydrogenation gives (B). B on
reduction gives (C) C7H8O2. (B) react with (CH3CO)2O/CH3COOH give a
pain reliever (D). Identify A to D.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 128
15. Provide suitable mechanism
CH3
OH CH3
Level – II
1. An ester A (C4H8O2) on treatment with excess of methyl magnesium
bromide followed by acidification gives an alcohol (B) as the sole
organic product. Alcohol (B) on oxidation with NaOCl followed by
acidification gives acetic acid.
Deduce the structure of A and B and show the reactions involved.
2. Propose a mechanism for the following reaction.
(a)
Me Ph
Me
OH
Ph
OH
O C
Me
C
Ph
Me
Ph
(b) OH
OH
O
3. Give products
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 129
CH3 C
CH3
CH3
O CH3
Anhydrous HI
ether I
Conc. HI
( 2 )
A B
C D
4.
CH(OH)Me
Me
HA [ C9H16]
A on ozonolysis gives nonane – 2, 8 dione. What is A and how is it
formed?
5. An organic compounds (P) having molecular formula C5H10O treated
with dilute H2SO4 gives two compounds Q & R both gives positive
iodoform test. The reaction of C5H10O with dilute H2SO4 gives reaction
1015 times faster than ethylene. Identify organic compound of
Q & R. Give the reason for the extra stability of P.
6. Complete the following reaction.
OH
NO 2
i OH
ii Et BrA
Zn /HClB
20
NaNO
HCl, 50 CC
C6H5OH
DLiAlH 4
(F)(E)
Soluble in NaOH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 130
7. (a) Diphenyl ether is not very easily prepared using Williamsons
sysnthsis. Provide an useful synthetic route for the same.
(b) When phenol is treated with Br2 presence of H2O. 2, 4, 6 tri
bromo phenol is obtained whereas on treatment with Br2 in
presence of CCl4. p–bromo phenol is obtained. Explain.
8. Write mechanistic step of the following reaction?
CH2OH
H
9. Compound (A) gives positive Lucas test in 5 minutes when 6.0 gm of
(A) heated with Na metal, 1120 ml of H2 is evolved at STP. Assuming
(A) to contain one of oxygen per molecule, write structural formula of
(A). Compound (A) when heated with PBr3 gives (B) which when
treated with benzene in presence of anhydrous AlCl3 gives (C). What
are (A), (B) and (C)?
10. Carry out the following conversion.
OH
to
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 131
11. Treatment of compound (A) C8H10O with chromic acid & pyridine gives
(B) C8H8O. Treatment of (B) with two equivalent Br2 yields (C)
C8H6OBr2 which on treatment with caustic soda followed by
acidifications gives a compound (D) C8H8O3. (D) liberates CO2 on
treatment with NaHCO3 and is resolvable.
12. Compound X, Y and Z are isomeric alcohol with formula C5H12O. X and
Y react with chromic acid solution, Y forming an acid A. The three
isomers react with HBr with decreasing relative rates of Z > X >> Y,
all giving the same C5H11Br (B) in varying yields. X alone can be
oxidised by I2/OH to C. Write the structure of X, Y, Z with proper
explanations.
13. Predict the product (s) and write the mechanism of each of the
following reactions
(a)
O CH3
1mole
HI (A)
(b)
O CH3
Excess HI
Δ(B)
14. Find product
(a)
CH3 C
CH3
CH2 MeOHH2SO4
(A)
(b) OH
H(B)
OH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 132
(c)
RCOOEt (H2C)5
MgBr
MgBr
H3OC
H2/NiD
(d)
C
CH2OH
CH2OH
O 2IO 4 E F
15. (Z) C6H14O 2 4Δ /H SO(A) C6H12
HClB C
C6H13Cl
Balc. KOH
D (Isomer of A)
DO3/H2O
E
(Given negative test with Fehling solution
but responds to iodoform)
AO3/H2O
F G
(both give positive Tollen‘s test but do not
give iodoform test)
Conc. NaOHF G HCOONa a primary alcohol
Identify A to G and Z.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 133
Objective:
Level–I
1. Which one of the following has the maximum acidic strength?
(A) Phenol (B) o-nitro phenol
(C) p-methyl phenol (D) o, p-dinitro phenol
2. The boiling point to isomeric alcohols follows the order
(A) primary > secondary > tertiary
(B) tertiary > secondary > primary
(C) secondary > tertiary > primary
(D) all have same boiling point
3. A mixture of benzoic acid and phenol may be separate by treatment
with
(A) NaHCO3 (B) NaOH
(C) NH3 solution (D) KOH
4. In the lucas test of alcohols, appearance of cloudiness is due to the
formation of
(A) aldehyde (B) ketone
(C) acid chloride (D) alkyl chloride
5. The dehydration of 1 – butanol gives
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 134
(A) 1 – butene as the main product
(B) 2 – butene as the main product
(C) equal amounts of 1 – butene and 2 – butane
(D) 2 – methyl propane
6. Ethyl alcohol is obtained when ethyl chloride is boiled with
(A) alc. KOH (B) aq. KOH
(C) AlCl3 (D) H2O2
7. The number of methoxy groups in a compound can be determined by
treating with
(A) Na2CO3 (B) NaOH
(C) HI and AgNO3 (D) CH3COOH
8. Diethyl ether absorbs oxygen to form
(A) red coloured sweet smelling compound
(B) CH3COOH
(C) ether peroxide
(D) ether suboxide
9. Which of the following compounds is oxidised to prepare methyl –
ethyl ketone?
(A) 2 – propanol (B) 1 – butanol
(C) 2 – butanol (D) 2 methyl 2 propanol
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 135
10. Order of reactivity of HX towards ROH is
(A) HI > HBr > HCl (B) HBr > HI > HCl
(C) HCl > HI > HBr (D) HI > HCl > HBr
11. Glycerol has
(A) one 1 and one 2 alcoholic groups
(B) one 1 and two 2 alcoholic groups
(C) two 1 and one 2 alcoholic groups
(D) two 2 alcoholic group
12. Ethyl iodide reacts with moist silver oxide to produce
(A) ethane (B) propane
(C) ethyl alcohol (D) diethyl ether
13. Reaction of tertiary butyl alcohol with hot Cu at 350 C produces
(A) butanol (B) butanal
(C) 2 – butene (D) 2 methyl propene
14. 1 alcohol can be converted to aldehyde by using the reagent
(A) pyridinium chloro chromate
(B) potassium di chromate
(C) potassium permanganate
(D) all of above
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 136
15. Reaction of ethanol with H2SO4 and suitable conditions can lead to the
formation of
(A) C2H5HSO4 (B) ethene
(C) ethoxy ethane (D) all of them
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 137
Level – II
1. 2 – phenyl propene on acidic hydration gives
(A) 2 – phenyl – 2 propanol (B) 2 phenyl – 1 – propanol
(C) 3 – phenyl – 1 – propanol (D) 1 – phenyl – 2 – propanol
2. The order of reactivity of phenyl magnesium bromide with the
following compound is
O
Me Me
(I)
O
Me H
(II)
O
Ph Ph
(III)
(A) II > III > I (B) I > III > II
(C) II > I > III (D) all react with the same rate
3. Which one is the stronger base?
(A) CH3CH2O (B) CF3CH2O
(C) both of equal strength (D) can not say
4. The acidic character of 1 , 2 , 3 alcohols H2O and RC CH is in the
order
(A) H2O > 1 > 2 > 3 > RC CH
(B) RC CH > 3 > 2 > 1 > H2O
(C) 1 > 2 > 3 > H2O > RC CH
(D) 3 > 2 > 1 > H2O > RC CH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 138
5. Choose the correct statement (s) for the reaction
OCOCH 33 2AlCl / CS
heatCOCH 3
OHOH
COCH 3
(a)
(b)
(A) (b) is formed more rapidly at higher temperature
(B) (b) is more volatile than (a)
(C) (a) is more volatile than (b)
(D) (a) is formed higher yields at lower temperature
6. Predict the major product
O
Excess HI
(A) HO CH2 CH2 CH2 CH2 I
(B) HO CH2 CH2 CH2 CH2 OH
(C) I CH2 CH2 CH2 CH2 I
(D) no reaction
7. Dipole moment of CH3CH2CH3, CH3CH2OH and CH3CH2F is in order
(I) (II) (III)
(A) I < II < III (B) I > II > III
(C) I < III < II (D) III < I < II
8. 3 – methyl – 3- hexanol can be prepared by
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 139
(A) CH3MgI and 3 – hexanone, followed by hydrolysis
(B) C2H5MgI and 2 – pentanone, followed by hydrolysis
(C) C3H7MgI and 2 – butanone, followed by hydrolysis
(D) any of the method above
9. 3H O
4 8 2 3 4 102 parts
Ester (A)C H O CH MgBr B C H O
Alcohol B reacts fastest with Lucas reagent. Hence A and B are
(A)
CH3 C
O
O C2H5 ,(CH3)3COH
(B)
H C
O
O C3H7 ,(CH3)2CHOH
(C)
CH3 C
O
O C2H5 ,(CH3)2CHOH
(D)
H C
O
O C3H7 ,(CH3)3COH
10. Vinyl carbinol is
(A) HO CH2 CH = CH2 (B) CH3C(OH) = CH2
(C) CH3 CH = CHOH (D) 3 2CH CH CH OH
11. The reaction of elemental sulphur with Grignard reagent followed by
acidification leads to the formation of
(A) mercaptan (B) sulphoxide
(C) thio ether (D) sulphonic acid
12. Conversion of chloro benzene into phenol by Dow‘s process is an
example of
(A) free radical substation (B) nucleophilic substitution
(C) electrophilic substitution (D) rearrangement
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 140
13. For the preparation of tert-butyl methyl ether by Williamson‘s method
the correct choice of reagents is
(A) methoxide and tert – butyl bromide
(B) methanol and 2 – bromobutane
(C) 2 – butanol and methyl bromide
(D) tert-butoxide and methyl bromide
14. Allyl alcohol is obtained when glycerol reacts with the following at
260 C
(A) formic acid (B) oxalic acid
(C) both (D) none
15. The correct decreasing order of acidic strength is
(A) C6H5OH > C6H5CH2OH > C6H5COOH > C6H5SO3H
(B) C6H5CH2OH > C6H5OH > C6H5SO3H > C6H5OH
(C) C6H5COOH > C6H5CH2OH > C6H5OH > C6H5SO3H
(D) C6H5SO3H > C6H5COOH > C6H5OH > C6H5CH2OH
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 141
ANSWERS TO ASSIGNMENT PROBLEMS
Subjective:
Level – O
1. Refer to text.
2. (i) In methyl phenyl ether.
The Ist step is protonation of ether to form phenyl methyl
oxonium ion.
O CH3
H
step 1
O CH3
H
I
step 2
OH
CH3I
Phenyl carbocation is highly unstable and bond between C6H5–O
is stronger than O–CH3 so I attacks on CH3 to form CH3I &
phenol.
(ii) Oxygen of ether is sp3 hybridised, therefore ethers have
tetrahedral geometry. Due to more electronegativity of oxygen
than carbon, C–O bonds of ether are polar in nature.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 142
O
R
R
1100C Net dipole moment
The two dipoles do not cancel each other hence the molecule
would posses dipole moment.
3. In O – nitro phenol there is intramolecular hydrogen bonding. This
inhibits its hydrogen bonding with water and reduces its solubility in
water.
O
N
H
O
O
4.
CH3 C
CH3
CH3
CH
OH
CH3
HCH3 C
CH3
CH3
CH
OH2
CH3
-H2O
CH3 C
CH3
CH3
CH CH3
1, 2 methyl shift
CH3 C
CH3
CH CH3
CH3
-HCH3 C
CH3
C CH3
CH3
tetra methyl ethylene
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 143
5. (a) X = CH3OH, Y = CH3Br, Z = CH3CH2Cl
(b)
X = CH3CH = CH2, Y = CH3COCH3, Z =
CH3 C
C2H5
CH3
OH
6. OH
2
3
Kolbe 's reaction
i CO 400K, OH
ii H O
OH
COOH
OH
H
OH
COO
Phenyl salicylate (salol)
7. (i) Alkaline KMnO4
(ii) Br2 water
(iii) P.C.C
(iv) 1% alkaline KMnO4
8. (a) Methanol < ethanol < propan–1–ol < butan–2–ol < butan–1–ol
< pentan–1–ol.
(b) n–butane < ethoxy ethane < pentanal < pentan–1–ol.
9. Propan–1–ol < 4 methoxyphenol < phenol < 3 nitro phenol < 3, 5–
dinitrophenol < 2, 4, 6–trinitrophenol.
10. (a) A mixture of three ethers, R–O–R, R–O–R and R –O–R is
obtained.
(b) Not–butanol does not solvate the 3 carbocation readily because
of steric hindrance.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 144
12. (i)
A =
O2N
NO 2
OCH 3
(ii)
A =
Br
OH
Br
CH3
13. (a) Iodoform test given by ethanol.
(b) Neutral FeCl3 test given by phenol.
14. OH
CH3
m - Cresol
15. CHCl 3
OHCCl 3
ClCCl 2
OH
OH
O
CCl 2
O
H
CCl 2
O
CHCl 2
O
CHO OH2
H2O
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 145
Level – I
1.
HCH3
OH
H
2. A = CH2CH2CH2CHO B = CH CH CH2OH
3.
A =
CH3
OH
OH
B =
CH3
OH
O
4. NO 2
3
2 4
funing HNO
Conc. H SO , Δ
NO 2
NO 2
4 2NH S
NH2
NO 2
NaNO 2/H2SO4
0 - 50C
N2 HSO 4
NO 2
2H O
Δ
OH
NO 2
5.
CH3 CH
OH
CH2 CH2 OHA =
CH3 C
O
CH2 COOHB =
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 146
6. OH
Hring
expansion
CH3
(Hydride shift)
CH3
OH
CH3
OH
-H2O
7.
C O
H
A =
O
B =
C
H
O
C =
O
O
D =
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 147
8. OH
OH
O
CCl 3
Cl
O
CCl 3
H
O
CCl 3
OH
O
COOH
OH
O
CO 2
OHH3O
OH
COOH
9.
A = BH2
H
H
CH3
B = OH
H
H
CH3
10. OH O SO3H(X) =
OH OH(Y) =
11.
N
H
CHO
A = B =
N
Cl
12. (a) Add Br2/CCl4 – Allyl decolourises orange colour
(b) Add small piece of Na.
H2 releases from alcohol.
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 148
13. OH
Zn
dust
Cl
O
AlCl 3
CH3
O
CH3
Zn(Hg)/HCl
14.
A =
OH
Phenol
B =
OH
COOH
Salicylic acid
C =
OH
CH2OH
C7H8O2
2 hydroxy benzyl alcohol
D =
OCOCH 3
COOH
Aspirin
15. OH
CH3
OH2
CH3
-H2O
H
CH3
CH3
-H
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 149
Level – II
1
. OH
CH3
CH3 H
H C
O
O C
CH3
H
CH3
(B)(A)
2
.
(a)
Me Ph
Me
OH
Ph
OH
H
Me
OH
Ph
Ph
Me
OH
Ph
Me
Ph
O
Me
H
Ph
Me
Ph
O
Me
Ph
Me
C-H
CH3 Ph
(b)
OH
OHH
OH2
OH
H-H2O
OH
O H-H
O
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 150
3.
CH3 C
CH3
CH3
O CH3
Anhydrous HI
ether ICH3 C
CH3
CH3
OHCH3I
Conc. HI
( 2 )CH3OH CH3 C
CH3
CH3
I
4. A Nonane 2, 8 dione (No loss of C)
H2C
CH2
CH2 CH2
CH2
C
C
CH3
CH3
O3/H2OH2C
CH2
CH2 CH2
CH2
C
C
CH3
CH3
O
O
CH(OH)Me
Me
HCH Me
Me
20 carbocation
1, 2 alkyl shift
(ring expansion)
Me
Me
Me
Me
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 151
5.
CH2 O CH3
CH3
(C5H10O)
C
CH3 O CH3
CH3
H
Highly stable carbocation
H2OCH3 O
CH3
(Q)
C2H5OH
(R)
C O
CH3
CH3
CH3
Stability by resonacne
6
.
A =
OEt
NO 2
B =
OEt
NH3 Cl
C =
OEt
N2Cl
D = N N
OEt
OH
F =
OH
NH2
E =
OEt
NH2
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 152
7. (a) OH
NaOH
O
X
O
O
Se/Δ
(b) H2O ionises phenol into the most reactive phenoxide anion and
hence tri substitution occurs. Moreover H2O can stabilizing the
arenium ion intermediate formed as well as the electrophile
Br+. Hence the rate of reaction is fast and hence
tri – substitution results. Hence the rate of the reaction is slow
and hence now substitution results.
8.
CH2OH
2
H
H O
CH2
H
H
H
ring expansion
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 153
9. (A) is secondary alcohol.
CnH2n+1OH = Molecular weight
Molecular weight of (A) = 6 11200
60 gm A1120
CnH2n+1OH = 60 (n = 3)
(A) C3H7OH
CH3 CH CH3
OH
CH3CH(OH)CH 3
(A)
PBr 3CH3CHBrCH 3
(B) Anhy AlCl 3
HC
CH3
CH3
(C)
10. OH
3
O
CrO
O
3 3Ph P CH Cl
t BuLi
CH2
2 2C H N , Δ
11. CHCH 3
OHA =
C CH3
O
B =
C CHBr 2
O
C =
CH COOH
OH
D =
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 154
12.
Br C
CH2
CH3
CH3
CH3
(B)
Hydride shift
Methyl shift
SN' displacement
CH3 CHCH(CH3)2
OH
(X)
I2/OH(CH3)2CHCOOH
(CH3)2CCH2OH
(Y)
(CH3)3C.CH2OH
(A)
(CH3)2.C(OH)CH2CH3
Oxidation
OxidNo Reaction
(Z)
13.
O CH3
1 mole HI
O CH3
H
OH CH3
I
OH CH3
I
(A)
(a)
O CH3 OH CH3
IH
OH2 CH3
I
SN2
I
I CH3
I
H2O
(B)
(b)HI
14. (a)
CH3 C
CH3
CH3
OCH 3
(b) CH3
C CH3
O
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 155
(c) R
(d)
R
E = 2HCHO + F = CO2
15. Z =
H2COH
D =
A =
E = CH3 C CH3
O
B =
CH3
CH3CH3
Cl CH3
F =
O
H
C =
Cl
G = HCHO
AISM-09/C/APE
askIITians Powered By IITians
Trans Web Educational Services Pvt. Ltd Website:www.askiitians.com Email. [email protected]
Tel: +91-120-4224242, +91-120-4224248
Page 156
Objective:
LEVEL - I
1. D 2. A 3. A
4. D 5. B 6. B
7. C 8. C 9. C
10. A 11. C 12. C
13. D 14. A 15. D
LEVEL - II
1. A 2. C 3. A
4. A 5. C 6. C
7. A 8. D 9. A
10. A 11. A 12. B
13. D 14. B 15. D