Type of compound:
Aldehyde
Alcohol
Amine
Ketone
Identify an Unknown
1. Physical PropertiesMelting point or boiling point
2. Functional Group
Infrared spectrum
NMR Spectrum
Solubility
Classification Tests
3. Solid Derivative
Procedure
Distill your unknown and note the boiling point
If can’t distill or not enough sample use this technique.
Measure boiling point of liquids
Carbonyl Group (1650 - 1725 cm-1)?
Yes No
Aldehyde Ketone
NMR
Aldehyde Ketone
+ -
Alcohol Amine
Broad OH in IR
Yes NoAlcohol Amine
(Basic?)3700 - 4000 cm-1
Yes
Primary or Secondary
No
Tertiary
Functional Group
NH2NH
NO2
NO2
Aldehyde or ketone
2,4-dinitrophenylhydrazine test
+ NH2NH
NO2
NO2
2,4-dinitrophenylhydrazone
C
O
NH2R C
OH
NHR
NRC
Mechanism
Reagent: NaOH and I2 (NaOI)
CCH3
O
RI2, NaOH
RCOOH + CHI3Yellow
Iodoform Test
CCH3
O
RI2, NaOH
RCOOH + CHI3Yellow
CHCH3
OH
RI2, NaOH
RCOOH + CHI3Yellow
Iodoform Test
(NH4)2Ce(NO3)6 + ROH
(NH4)2Ce(NO3)5OR
+ HNO3
Ceric Nitrate Test for Alcohols
1. Odor
2. If not soluble in water they may dissolve in dilute aqueous acid (HCl).
3. Water solutions of amines are basic to litmus.
Amines
SO2Cl
Benzenesulfonyl Chloride
Hinsberg Test for Amines
Primary: Soluble. PPT if add HCl
Secondary: Insoluble
Tertiary: Tends not to react
Hinsberg Test for Amines
Aldehydes and Ketones
1. 2,4-dinitrophenylhydrazone
2. Semicarbazone
NH2NHC
O
NH2
semicarbazide
+ RC
O
R NNHCNH2CR
R
O
semicarbazone
Derivatives
O2N
O2N
C Cl
O
O2N
O2N
C OR
OROH
3,5-dinitrobenzoyl chloride
3,5-dinitrobenzoate
Alcohol Derivative
Primary and Secondary Amines
C
O
Cl + RNH2 C
O
NHR
Benzoyl Chloride Benzamide
SO2Cl + RNH2 SO2NHR
Benzenesulfonyl Chloride Benzenesulfamide
Amine Derivatives
B.p. =198-200o
DNP = 231-235o
Sample Unknown
Data table
C
O
CH3
acetophenone
Acetophenone
B.p. = 80 - 85o
3,5-dinitrobenzoate = 119 - 121o
Sample Unknown
Data table
CCH3 CH3
H
OH
isopropyl alcohol
i-PrOH
B.p = 106o
3,5-dinitrobenzoate 85o
Sample Unknown
Data Table
CH2OHCH
CH3
CH3
isobutyl alcohol
Isobutyl alcohol
B.p. = 160o
3,5-dinitrobenzoate: 108-110o
Sample Unknown
Data Table
OH
H
cyclohexanol
cyclohexanol
B.p. = 155-157o
2,4-DNP = 158 - 160o
Sample Unknown
Data Tables
O
cyclohexanone
cyclohexanone
B.p. = 180 -183o
Benzenesulfonamide 110 - 112o
Benzamide 160 - 163o
NH2
aniline