Lecture 9 Organic Chemistry and Polymerization

8/13/2019 Lecture 9 Organic Chemistry and Polymerization

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Organic Chemistry I:Formulas, Names,

and Properties


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Chapter Goals

Saturated Hydrocarbons1. Alkanes and Cycloalkanes2. Naming Saturated Hydrocarbons

Unsaturated Hydrocarbons 3. Alkenes4. Alkynes

Aromatic Hydrocarbons5. Benzene6. Other Aromatic Hydrocarbons7. H drocarbons: A Summar


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Chapter Goals

Functional Groups8. Organic Halides9. Alcohols and Phenols10.Ethers11.Aldehydes and Ketones12.Amines13.Carboxylic Acids14.Some Derivatives of Carboxylic Acids15.Summary of Functional Groups


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Chapter Goals

Fundamental Classes ofOrganic Reactions

16.Substitution Reactions17.Addition Reactions18.Elimination Reactions19.Polymerization Reactions


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Saturated Hydrocarbons Hydrocarbons are chemical compounds

that contain only C and H atoms. Saturated hydrocarbons contain only

single or sigma ( ) bonds. There are no double or triple bonds in these

compounds.

The primary source of hydrocarbons ispetroleum and natural gas.


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Alkanes and Cycloalkanes The simplest saturated hydrocarbons are

called alkanes. Methane, CH 4, is the simplest alkane. The alkanes form a homologous series.

Each member of the series differs by aspecific number and kind of atoms.

C

H

HH

H or CH 4


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Alkanes and Cycloalkanes

The alkanes differ from each other by a CH 2 ormethylene group.

All alkanes have this general formula.CnH2n+2

For example ethane, C 2H6 , and propane, C 3H8 , are the next two family members.


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Isomers are chemical compounds thathave the same molecular formulas but

different structures. Two alkanes have the molecular formulaC4H10.

They are a specific type of isomer calledstructural isomers .


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Three alkanes have the formula C 5H12. There are three structural isomers of pentane.

CH3CH2

CH2

CH2

CH 3

n-pentane


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CH3CH2

CH2

CH2

CH 3 CH3CH C

H2

CH 3

CH 3

n-pentane 2-methylbutane


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There are five isomeric hexanes, C 6H14.You draw them!

CH3 C

H2

CH2

C

H2

CH2

CH 3

n-hexane


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There are five isomeric hexanes, C 6H14.

CH3CH2

C

H2

CH2

C

H2

CH 3CH3

CH C

H2

CH2

CH 3

CH 3

n-hexane 2-methylpentane


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CH3CH2

C

H2

CH2

C

H2

CH 3CH

3

CH C

H2

CH2

CH3

CH 3

CH3CH2

CH C

H2

CH 3CH 3

n-hexane 2-methylpentane 3-methylpentane


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CH3CH2

CH2

CH2

CH2

CH 3CH3

CH C

H2

CH2

CH 3

CH 3

CH3CH2

CH C

H2

CH 3

CH 3

CH3

CCH2 CH 3

CH 3

CH 3


2,2-dimethylbutane


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CH3CH2

C

H2

CH2

C

H2

CH 3CH

3

CH C

H2

CH2

CH3

CH 3

CH3CH2

CH C

H2

CH 3CH 3

CH3C

C

H2 CH 3

CH 3

CH 3CH

3

CH C

H CH 3

CH 3

CH 3


2,2-dimethylbutane 2,3-dimethylbutane


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The number of structural isomers increasesrapidly with increasing numbers of carbonatoms.

The boiling points of the alkanes increase withmolecular weight.


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Cyclic saturated hydrocarbons are calledcycloalkanes . They have the general formula C nH2n.

Some examples are:

CH2

CH2

CH 2CH2

CH2

cyclopentane


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Some examples are:

CH2

CH2

CH 2CH2

CH2CH2

CH2 CH2

CH 2

CH 2CH2

cyclopentane cyclohexane


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Some examples are:


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Naming Saturated Hydrocarbons

The International Union of Pure and Applied Chemistry(IUPAC) names for the first 12 "straight-chain" or "normal"alkanes are given in this table.

Number of carbonatoms in chain Name

1 Methane

2 Ethane

3 Propane4 Butane

5 Pentane

6 Hexane


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Number of carbonatoms in chain Name

7 Heptane8 Octane9 Nonane

10 Decane11 Unidecane12 Dodecane



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Other organic compounds are named asderivatives of the alkanes.

Branched-chain alkanes are named by thefollowing rules.

1. Choose the longest continuous chain ofcarbon atoms which gives the basic name orstem.


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2 Number each carbon atom in the basic chain, starting atthe end that gives the lowest number to the first group

attached to the main chain (substituent).3 For each substituent on the chain, we indicate the

position in the chain (by an Arabic numeric prefix)and the kind of substituent (by its name).

The position of a substituent on the chain is indicated by thelowest number possible.

The number precedes the name of the

substituent.


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4 When there are two or more substituents of a given kind,use prefixes to indicate the number of substituents.

di = 2, tri = 3, tetra = 4, penta = 5, hexa = 6, hepta = 7, octa =8, and so on.

5 The combined substituent numbers and names serve as a prefix for the basic hydrocarbon name.

6 Separate numbers from numbers by commas andnumbers from words by hyphens.

Words are "run together".


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Alkyl groups (represented by the symbol R) arecommon substituents. Alkyl groups are fragments of alkanes in which one

H atom has been removed for the connection to themain chain.

Alkyl groups have the general formula C nH2n+1 . In alkyl groups the -ane suffix in the name of the parent

alkane is replaced by -yl. A one carbon group is named methyl . A two carbon group is named ethyl .

A three carbon group is named propyl .


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Unsaturated Hydrocarbons

The three classes of unsaturatedhydrocarbons are:

1. alkenes and cycloalkenes, C nH2n 2. alkynes and cycloalkynes, C nH2n-2 3. aromatic hydrocarbons


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Alkenes

The simplest alkenes contain one C=C bond permolecule. The general formula for simple alkenes is C

nH

2n.

The first two alkenes are: ethene, C 2H4


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Alkenes

The simplest alkenes contain one C=C bond permolecule. The general formula for simple alkenes is C nH2n.

The first two alkenes are: and propene, C 3H6


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Alkenes

Each doubly bonded C atom is sp 2 hybridized. The sp 2 hybrid consists of:

two bonds (single bonds) and one and one p bond (double bond)


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Alkenes

The systematic naming system for alkenes uses thesame stems as alkanes.

In the IUPAC system, the -ane suffix for alkanes is

changed to -ene. Common names for the alkenes have the same stem but use

the suffix -ylene is used.

In chains of four or more C atoms, a numerical prefixshows the position of the lowest-numbered doubly

bonded C atom. Always choose the longest chain that contains the C=C

bond.


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Alkenes

Polyenes contain two or more double bonds permolecule.

Indicate the number of double bonds with suffixes:

-adiene for two double bonds. -atriene for three double bonds, etc.

The positions of the substituents are indicated as foralkanes.

The position of the C=C bond(s) is/are given thelowest number(s) possible.


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Alkenes

CC

CC

CC

H

H H

H

H

H

H

H

H

H

1,3-hexadiene


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Alkenes

CC

CC

CCH

H H

H

H

H

H

H

1,3,5-hexatriene

CC

CC

CCH

H H

C

C

H

H

H

H

H H

H

HH

2,3-dimethyl-1,3,5-hexatriene

CC

CC

CC

H

H H

H

H

H

H

H

H

H

1,3-hexadiene


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Cycloalkenes

Cycloalkenes have the general formula C nH2n-2 . Examples are: cyclopentene

C C

CC

C

HH

H

HH

H

H

H


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Cycloalkenes

cycloheptene

C C

CCC

C

CH

HH

H H

HHH

HHHH


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Alkynes

Alkynes contain C C bonds. The simplest alkyne is C 2H2, ethyne, or acetylene.

Alkynes with only one C C bond have the formula

CnH2n-2 . Each carbon atom in a C C bond is sp hybridized.

Each sp hybrid contains two bonds and two p bonds. The carbon atom will have one single bond and one

triple bond.


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Alkynes

Alkynes are named like the alkenes exceptthat the suffix -yne is used with thecharacteristic stem The alkyne stem is derived from the name of the

alkane with the same number of carbon atoms.


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Alkynes

Acetylene burns in a highly exothermic reaction The combustion produces temperatures of about 3000C. Acetylene is used in cutting torches for welding.

Alkynes are very reactive The two p bonds are sights of special reactivity.

Addition reactions, such as hydrogenation, are common.

g2g2g2g22 OH2CO45OH2C

g62g2g22 HC2HHC


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Hydrocarbons: A Summary

Carbon AtomHybridization C uses C forms Example

sp 3

tetrahedral 4 sp 3 hybrids4

bonds CH 4

sp 2

trigonal planar3 sp 2 hybrids& 1p orbital

3 bonds

1 p bondC2H4

sp linear 2 sp hybrids &2 p orbitals

2 bonds

2 p bonds

C2H2


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Aromatic Hydrocarbons

Historically, aromatic was used to describe pleasant smelling substances.

Now it refers to benzene, C 6H6, and derivativesof benzene. Other compounds that have similar chemical

properties to benzene are also called aromatic.


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Benzene

The structure of benzene, C 6H6, is:


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Other Aromatic Hydrocarbons

Coal tar is the common source of benzene andmany other aromatic compounds.

Some aromatic hydrocarbons that containfused rings are:

napthalene


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phenanthrene

CC

CC

C

CC

C

CC

C

CCC

H

H

H

H H

H

H

H

H

H


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Many aromatic hydrocarbons contain alkylgroups attached to benzene rings (as well as toother aromatic rings).

The positions of the substituents on benzenerings are indicated by the prefixes: ortho- ( o-) for substituents on adjacent C atoms

meta- ( m-) for substituents on C atoms 1 and 3 para- ( p-) for substituents on C atoms 1 and 4


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Functional Groups

Functional groups are groups of atoms thatrepresent potential reaction sites.

Compounds that contain a given functionalgroup usually undergo similar reactions.

Functional groups influence physical properties as well.


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Organic Halides

A halogen atom may replace almost any hydrogenatom in a hydrocarbon.

The functional group is the halide (-X) group.

Examples include: chloroform, CHCl 3

CCl Cl

Cl

H


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Organic Halides

1,2-dichloroethane, ClCH 2CH 2Cl

C CH

Cl

H

H

Cl

HH

CHH

H
http://localhost/var/www/apps/conversion/tmp/scratch_4/MEDIA/PDBs/1,2-dichloroethane.pdbhttp://localhost/var/www/apps/conversion/tmp/scratch_4/MEDIA/PDBs/1,2-dichloroethane.pdb


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Organic Halides

para-dichlorobenzene

Cl

Cl


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Alcohols and Phenols

The functional group in alcohols and phenols isthe hydroxyl (-OH) group.

Alcohols and phenols can be consideredderivatives of hydrocarbons in which one ormore H atoms have been replaced by -OHgroups.

Phenols are derivatives of benzene in which oneH has been replaced by replaced by -OH group.


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Ethyl alcohol (ethanol), C 2H5OH, is the mostfamiliar alcohol.


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Phenol, C 6H5OH, is the most familiar phenol.

OH


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Alcohols are considered neutral compounds because they are only very slightly acidic. Alcohols can behave as acids but only in the presence

of very strong bases. Phenols are weakly acidic.

K a 1.0 x 10 -10 for phenol

Although phenols are very weakly acidic, theyare also very corrosive.


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Alcohols can be classified into three classes:1. Primary (1) alcohols like ethanol have the -

OH group attached to a C atom that has one bond to another C atom.

CH3CH2

OH


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2. Secondary(2) alcohols have the OH groupattached to a C atom that has bonds to 2 otherC atoms.

For example,2-propanol:

CH3

CHCH3

OH


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3. Tertiary (3) alcohols have the OH groupattached to a C atom that is bonded to 3 otherC atoms.

For example, 2-methyl-2-propanol

CH3 C CH 3

OH

CH 3


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The stem for the parent hydrocarbon plus an -ol suffix is the systematic name for an alcohol.

A numeric prefix indicates the position of the -OHgroup in alcohols with three or more C atoms.

Common names are the name of the appropriate

alkyl group plus alcohol.


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Alcohols are named using the stem for the parenthydrocarbon plus an -ol suffix in the systematicnomenclature.

A numeric prefix indicates the position of the -OH groupin alcohols with three or more C atoms. Common alcohol names are the name of the appropriate

alkyl group plus the word alcohol.

CH 2C

H 2

CH 2

C

H 2

CH 3OH

CH 3CH C

H 2

CH

2

CH 3

OH

1-pentanol1-pentyl alcohol


CH 2C

H 2

CH 2

C

H 2

CH 3OH


CH 2C

H 2

CH 2

C

H 2

CH 3OH

CH 3CH C

H 2

CH

2

CH 3

OH

CH 3C

H 2

CH C

H 2

CH 3OH





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There are several isomeric monohydric acyclic(contains no rings) alcohols that contain morethan three C atoms.

There are four isomeric four-carbon alcohols.


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There are eight isomeric five-carbon alcohols.You do it!

CH 2

CH 2

CH 2

CH 2

CH 3OH

CH 3CH C

H 2

CH 2

CH 3

OH

CH 3CH 2

CH C

H 2

CH 3OH

1-pentanol 2-pentanol 3-pentanol

CH 2

CH C

H 2

CH 3OHCH 3

CH 3 C CH 2CH 3

CH 3

OHCH 3

CH C

H CH 3

OH

CH 3

2-methyl-1-butanol 2-methyl-2-butanol 3-methyl-2-butanol

CH 3CH C

H 2

CH

2

CH 3

OH

3-methyl-1-butanol

CH 3 C CH 2CH 3

CH 3 OH

2,2-dimethyl-1-propanol


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Polyhydric alcohols contain more than one -OHgroup per molecule.

CH2CH CH 2

OH

OH

OH

CH2

CH C

H CH C

H CH 2OHOH

OH

OH

OH

OH

glycerin sorbitol


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Phenols are usually called by their common(trivial) names.

OH

OH

resorcinol


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OH

OH

OH

CH 3

resorcinol o-cresol


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OH

OH

OH

CH 3

OH

CH 3

resorcinol o-cresol m-cresol


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OH

OH

OH

CH 3

OH

CH 3

OH

CH 3resorcinol o-cresol m-cresol p-cresol


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Because the -OH group is quite polar, the properties ofalcohols depend upon the number of -OH groups permolecule and the size of the organic group.

The boiling points of monohydric alcohols increase withincreasing molecular weight.

The solubility of monohydric alcohols in water decreasewith increasing molecular weight.

Polyhydric alcohols are more soluble in water because ofthe two or more polar groups (-OH).


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Ethers

Ethers may be thought of as derivatives of waterin which both H atoms have been replaced by

alkyl or aryl groups.

HO

H

water


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Ethers



HO

H CH3O

H

water an alcohol


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Ethers



HO

H CH3O

H CH3O

CH 3

water an alcohol an ether


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Ethers

Ethers are not very polar and not very reactive. They are excellent solvents.

Common names are used for most ethers.


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Aldehydes and Ketones

The functional group in aldehydes and ketones isthe carbonyl group.

O

R2R1 or H

carbonyl group


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Except for formaldehyde, aldehydes have one Hatom and one organic group bonded to a carbonylgroup.


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Ketones have two organic groups bonded to acarbonyl group.


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Common names for aldehydes are derived fromthe name of the acid with the same number of Catoms.

IUPAC names are derived from the parenthydrocarbon name by replacing -e with -al .

C

O

CH2

CH2

CH2

CH3 H

pentanal or pentyl aldehyde


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C

O

CH2

CH2

CH2

CH3 HC

O

C

CH3

CH3

CH 3

H


2,3-dimethylproponal or 2,3-dimethylpropionaldehyde


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C

O

CH2

CH2

CH2

CH3 HC

O

CCH3

CH3

CH 3

HC

O

H


2,3-dimethylproponal or 2,3-dimethylpropionaldehyde

benzanal or benzyl aldehyde


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The IUPAC name for a ketone is the characteristicstem for the parent hydrocarbon plus the suffix -one.

A numeric prefix indicates the position of thecarbonyl group in a chain or on a ring.

C

O

CH2

CH2

CH2

CH3 CH 3

2-hexanone or methyl pentyl ketone


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C

O

CH2

CH2

CH2

CH3 CH 3


CH3CH2

CH2

CCH2

CH 3

O

3-hexanone or ethyl propyl ketone


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C

O

CH

2

CH2

CH

2

CH3 CH 3


CH3CH2

CH

2

CCH

2

CH 3

O

3-hexanone or ethyl propyl ketone

CCH 3O

acetophenone or methyl phenyl ketone


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Many aldehydes and ketones occur in nature.

CHCH

COH

cinnamaldehyde

O

CH 3

CH 3 OH

testosterone


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Amines

Amines are derivatives of ammonia in which oneor more H atoms have been replaced by organicgroups (aliphatic or aromatic or a mixture of

both). There are three classes of amines.

H

N

HH

ammonia


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Amines



HN

H

H

CH3N

H

H

ammonia primaryamine


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Amines



HN

HH

CH3N

HH

CH3N

HCH 3

ammonia primaryaminesecondary

amine


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Amines



HN

HH

CH3N

HH

CH3N

HCH 3

CH3N

CH 3CH 3

ammonia primaryaminesecondary

aminetertiaryamine


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Amines

Aniline is the simplest aromatic amine. It ismuch less basic than NH 3.

Aniline is a very important industrial chemical.


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Amines

Heterocylic amines have one or more N atomsin a ring structure.

Many are important in living systems.

Npyridine

A i


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Amines



Npyridine

N

N

pyrimidine

A i


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Amines



Npyridine

N

N

pyrimidine

N

N

N

N

purine

C b li A id


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Carboxylic Acids

Carboxylic acids contain the carboxyl functionalgroup.

The general formula for carboxylic acids is: R represents an alkyl or an aryl group

COH

O

R1

COH

O

C b li A id


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Carboxylic Acids

IUPAC names for a carboxylic acid are derivedfrom the name of the parent hydrocarbon. The final -e is dropped from the name of the

parent hydrocarbon The suffix -oic is added followed by the word

acid.

Many organic acids are called by their common(trivial) names which are derived from Greek orLatin.

C b li A id


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Carboxylic Acids

Positions of substituents on carboxylic acid chainsare indicated by numeric prefixes as in othercompounds Begin the counting scheme from the carboxyl

group carbon atom. They are also often indicated by lower case Greek

letters.

= 1 st C atom = 2 nd C atom = 3 rd C atom, etc.

C b li A id


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Carboxylic Acids

CH C

OH

O

CH3

CH3

2-methylpropanoic acid or

-methylpropanoic acid

C b li A id


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Carboxylic Acids

CH C

OH

O

CH3

CH3

2-methylpropanoic acid or

-methylpropanoic acid

CH3CH C

H2

COH

OCH 3

3-methylbutanoic acid or

-methylbutanoic acid

C b li A id


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Carboxylic Acids

CH C

OH

OCH3

CH 3

2-methylpropanoic acid or -methylpropanoic acid

CH3CH C

H2

COH

OCH 3

3-methylbutanoic acid or -methylbutanoic acid

CH3 CH C

H2

CH2

COH

O

CH 3

4-methylpentanoic acid or -methylpentanoic acid

C b li A id


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Carboxylic Acids

Dicarboxylic acids contain two carboxyl groups permolecule.

OHC C

OHO

O

oxalic acid

Nomenclature of Carboxylic


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yAcids Dicarboxylic acids contain two carboxyl groups per

molecule.

OHC C

OHO

OOH C C

H2

C OH

O O

oxalic acid malonic acid

Nomenclature of Carboxylic


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yAcids Dicarboxylic acids contain two carboxyl groups per

molecule.

OHC C

OHO

OOH C C

H2

C OH

O O

OH C CH2

C

H2

C OH

O

O

oxalic acid malonic acid succinic acid


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Carboxylic Acids Aromatic acids are usually called by their

common names. Sometimes, they are named as derivatives of

benzoic acid which is considered to be the"parent" aromatic acid.

C b li A id


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Carboxylic Acids

OOHOOH

Clbenzoic acid p-chlorobenzoic acid

Carbo lic Acids


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Carboxylic Acids

OOHOOH

Cl

OOH

CH 3

O

OH

O

OH

benzoic acid p -chlorobenzoic acid

p -toluic acid phthalic acid

Carboxylic Acids


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Carboxylic Acids

Acid strengths of simple carboxylic acids varylittle with chain length.

However, substituents on a carbon atom in thechain can cause large variations in acidstrengths .

Carboxylic Acids


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Carboxylic Acids

COH

O

H

CH 3C

OH

O

OHC

CH 2

CH 3

O

Compound Name K a

formic acid

acetic acid

propionic acid

1.8 x 10 -4

1.8 x 10 -5

1.4 x 10 -5

Carboxylic Acids


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Carboxylic Acids

CH 2

COH

O

Cl

Compound Name K a

monochloroacetic acid 1.5 x 10 -3

CH 3C

OH

Oacetic acid 1.8 x 10 -5

CH C

OH

O

Cl

Cl dichloroacetic acid 5.0 x 10 -2

CC

OH

O

Cl Cl

Cltrichloroacetic acid 2.0 x 10 -1

Carboxylic Acids


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Carboxylic Acids

The -OH group in the carboxyl group ofcarboxylic acids, is displaced in many of theirreactions.

The non -OH portion of a carboxylic acid is calledan acyl group.

R1 C OH

O

R1 C

O

carboxyl group acyl group

Some Derivatives of


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Carboxylic Acids Four important classes of compounds contain

acyl groups They are all considered to be derivatives of

carboxylic acids. In these structures R's may represent either


Some Derivatives of


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Carboxylic Acids

R1C

OC

R1

O O

R1C

Cl

O

acid anhydride acid chloride

Some Derivatives of


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Carboxylic Acids

R1C

OC

R1

O O

R1C

Cl

O

R1 C O R2

O

R1 C NH2

O

acid anhydride acid chloride

ester amide

Some Derivatives of


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Carboxylic Acids Acid anhydrides are related to their parent acids as

follows: The word anhydride means without water.

CH3C

OH

O2

CH3 O CH 3

O O

+ H2O

acetic acid acetic anhydride

Some Derivatives of


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Carboxylic Acids Acyl halides are much more reactive, and more

volatile, than their parent acids. They react with water to form their parent acids and a

hydrohalic acid.

CH3C

Cl

O

CH3 OH

O

+ HCl

acetyl chloride acetic acid

H2O+

Some Derivatives of


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Carboxylic Acids Acyl halides are prepared by reacting their parent

acids with PCl 3, PCl 5, or SOCl 2. The more volatile acid halide is then distilled out of

the reaction mixture.

OOH

+ PCl 5

OCl

benzoic acid benzoyl chloride

Some Derivatives of


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Carboxylic Acids Esters are prepared by heating a carboxylic acid with

an alcohol in the presence of a small amount of aninorganic acid. The reaction mixture will contain some ester and water, as

well as unreacted acid and alcohol.

CH3C

OH

OCH2

OHCH3+

H2SO 4

CH3C

OCH2

CH 3

O+ H2O

ethanoic acid or acetic acid

ethanol or ethyl alcohol

ethyl ethanoate or ethyl acetate

Some Derivatives of


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Carboxylic Acids

Esters are usually called by their common names. Many simple esters occur naturally and have pleasant

odors. Esters are frequently used in fragrances and as artificial

flavors.

CH2

CO

CH2

CH 3

O

CH2

CH3

ethyl butanoate or ethyl butyrateodor of pineapples

CH3 OCH2

CH2

CH2

CH2

CH2

CH2

CH2

CH 3

O

octyl ethanoate or octyl acetate odor of oranges

Some Derivatives of


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Carboxylic Acids Fats are solid esters of glycerol and (mostly) saturated

acids at room temperature. Oils are liquid esters of glycerol and primarily

unsaturated acids at room temperature. The "acid" parts of fats and oils usually contain even

numbers of C atoms in naturally occurring fats and oils. 16 and 18 carbon chains are the most commonly found

chain sizes in nature.

Some Derivatives of


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Carboxylic Acids

Some acids that are found (as their esters) in fatsand oils include:

CH3CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

COH

O

palmitic acid CH 3(CH 2)14 COOH

Some Derivatives of


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Carboxylic Acids

Stearic acid is often found in beef fat.

CH3CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

C

OH

O

stearic acid CH 3(CH 2)16 COOH

Some Derivatives of


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Carboxylic Acids

Triglycerides are the triesters of glycerol. The common name for triglycerides is tri (acid

stem) plus an -in suffix. For example, tripalmitin.

Some Derivatives of


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Carboxylic Acids Waxes are esters of long chain fatty acids and

alcohols other than glycerol. Commonly, waxes are derived from

monohydric alcohols. Beeswax and carnauba wax are esters of myricyl

alcohol, C 30H61OH.

Some Derivatives of


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Carboxylic Acids

Carnauba wax is often used in car waxes.

carnauba wax

C

O

OC 25 H51C 30 H61

Some Derivatives of


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Carboxylic Acids

Dihydric alcohols (2 OHs per molecule) can reactwith dicarboxylic acids (2 COOHs per molecule) toform polyesters .

Ester linkages are formed at both ends of bothmolecules to give polymeric esters with very highmolecular weights.

COH

C

OH

O

O

+ CH2

CH2

OHOH

terephthalic aciddicarboxylic acid

ethylene glycoldihydric alcohol

Some Derivatives of


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Carboxylic Acids

CO

CO

O

O

CH2 CH 2

O

*

*n

dacron

Some Derivatives of


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Carboxylic Acids

Amides are derivatives of organic acids and primaryor secondary amines.

The functional groups of amides are:

CN

OR2

H

R1C

N

OR2

R3

R1or C

N

OH

H

R1 or

Some Derivatives of


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Carboxylic Acids

Amides are also named as derivatives of carboxylicacids.

The suffix -amide is substituted for -ic acid or -oicacid .

CN

O

H

H

CH3

CNH2O

ethanamide or acetamide

benzamide

Some Derivatives ofb l d


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Carboxylic Acids

When an aryl or alkyl substituent is present on the Natom, the letter N and the name of the substituent are

prefixed to the name of the unsubstituted amide.

CN

O

CH 3

H

CH3

CNO

CH 3

CH2CH

3

N -ethylethanamide or N-ethylacetamide

N -ethyl- N -methylbenzamide

Some Derivatives ofb l d


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Carboxylic Acids

Acetaminophen Tylenol - is an amide.

Summary of thei l G


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Functional Groups

A summary of the functional groups is:


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Substitution Reactions


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Subst tut o eact o s

In a substitution reaction an atom or group ofatoms attached to a carbon atom is replaced(substituted for) by another atom or group of

atoms. There is no change in the degree of saturation

at the reactive carbon atom.

Halogenation reactions are an important classof substitution reactions. Chlorine reacts with alkanes in free radical

chain reactions (also substitution reactions).



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Free radical chain reactions The halogenation of methane is one example.

heat or uv light

Cl

.2

free radicals

Cl Cl



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Cl

.+ H C

H

H

. + Cl

HH C H

H

H

heat or uv light

free radicals

Cl Cl

2 Cl

.

methyl radical



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H C

H

H

. + Cl Cl

+ Cl .H C

H

H Cl

methyl radical

Cl

.+ H C

H

H

. + Cl

HH C H

H

H

heat or uv light

free radicals

2 Cl

.Cl Cl

methyl chloride



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Free radical chain reactions Many substitution reactions of alkanes produce

more than one product.

C ClH

H

H

+ Cl Cl CH

H

ClCl + HCl



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C ClH

H

H

+ Cl Cl CH

H

ClCl + HCl

CH

H

ClCl + Cl Cl CH

Cl

ClCl + HCl



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HCl

C

H

ClClCl + Cl Cl C

Cl

ClClCl + HCl

C

H

H

ClCl + Cl Cl CH

Cl

ClCl +

C ClH

H

H

+ Cl Cl CH

H

ClCl + HCl



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Nitration reaction of an aromatic hydrocarbonreplaces an H atom attached to an aromatic ringwith a nitro, -NO 2, group.

+ 2H SO 4HNO 2

NO2

Addition Reactions


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An addition reaction involves an increase inthe number of groups attached to carbon. The degree of saturation of the molecule is

increased.

C CH

H H

H

+ Cl C CH

Cl

H

HH

Cl

2

Addition Reactions


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Hydrogenation is a very important kind of addition reaction. Hydrogenation is used to convert unsaturated fats and oils to

saturated fats or oils.

C CH

H H

H+ H C CH

H

HHH

H2

Elimination Reactions


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An elimination reaction involves the removalof groups attached to carbon. The degree of unsaturation increases.

C CCH3 CH 3

HH

CH3

CH CH

Br Br

CH 3

Zn in

acetic acidor ethanol

C CCH3 H

CH 3H

+ ZnBr 2

mixture of cis & trans -2-butene

+

Elimination Reactions


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Dehydration is an important kind ofelimination reaction.

concentrated

2H SO 4

C CH H

HH

HCH CH

OHH

H+ H O2

Polymerization Reactions


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A polymer is a large molecule that consists ofa high-molecular weight chain of smallmolecules.

The small molecules that have been joined to formthe polymer are called monomers .

Synthetic polymers are a relatively new class

of molecules. The first one, bakelite, was discovered in 1909. Nylon, which is still extensively used, was

discovered in 1930s.



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Addition polymerization is a large commercial process in the United States.

Polyethylene is the addition polymer made inthe largest quantities in the United States. Polyethylene is used to make Coke bottles, plastic

bags, etc.



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Addition polymerization Polyethylene formation

CH2 CH 2n

ethylene

catalyst* CH 2 CH 2 *n

polyethylene



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Addition polymerization Teflon is the material used in nonstick frying pans

and other kitchen utensils.

C CF

F F

Fn

catalystC CF

F F

F** n

polytetrafluoroethylene or Teflon

tetrafluoroethylene

heat



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Formation of rubber Natural rubber is a polymer made of isoprene (2-

methyl-1,3-butadiene) units that form a uniquestereoisomeric structure.

2n

natural rubber isoprene

CH2

C CH

CH2

CH3

CH 2C

CHCH2

CH 2C

CHCH 2

*

CH 3 CH 3

*n



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Vulcanization of rubber Natural rubber is a sticky, soft compound when

heated which limited its commercial potential.

Charles Goodyear discovered in 1839 that heatingrubber with sulfur removed the stickiness andmade the substance elastic. This is the basis of modern tire production.

Vulcanization provides disulfide cross-linking bonds between the isoprene units.


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Copolymers

3

styrenebutadiene

C CC C

H

H

H

H H

H CCH

H

H

+



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CH 2C

C

CH2 CH 2C

CCH2 CH 2

CCH2

CCCH 2

*

*

H

H

H

H

H H

H

n

Styrene - butadiene rubber (SBR)



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Condensation Polymers Condensation polymers occur when two molecules

react and eliminate a small molecule.

Molecules eliminated commonly are water and HCl. Important condensation polymers include nylon,

dacron, and kevlar.

Dacron is used in clothing to make it wrinkle free. Blood does not clot in contact with dacron thus it isused in artificial arteries.



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Condensation Polymers Dacron formation

terephthalic acidethylene glycol

CH2

CH2

OHOH

COOH

O OH

+



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CO OC

OOC

H2CH2

CH2

O HCH2

OH n

Dacron is a polyester

+ H2O



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Condensation Polymers Nylon was first made by Wallace Carothers in

the 1930s. Nylon is widely used in a variety of commercial

products including stockings, rope, guitar strings,fire-proof clothing.



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Condensation Polymers Nylon 66 formation

OHC

CH2

CH2

CH2

CH2

COH

O

O

NH2CH2

CH2

CH2

CH2

CH2

CH2

NH2+

adipic acid hexamethylene diamine



155/155

+ H2ONH2C

CH2

CH2

CH2

CH2

CNH

CH2

CH2

CH2

CH2

CH2

CH2

NH

COH

O

O

O

n

Nylon is a polyamide

Documents

Lecture 9 Organic Chemistry and Polymerization