Oxidation of cyclohexanol or preparation of adipic acid

Oxidation of cyclohexanol to adipic acid using 50% HNO3 and NH4VO3 as catalyst

1. CPP-1.5 (1.1) Practical Organic Chemistry

DOS & R in Organic Chemistry, TUT Page 1







Prepared By
Dr. Krishnaswamy G
Faculty
DOS & R in Organic Chemistry
Tumkur University
Tumakuru

2. CPP-1.5 (1.1) Practical Organic Chemistry

DOS & R in Organic Chemistry, TUT Page 2


Oxidation of Cyclohexanol or Preparation of Adipic
acid from cyclohexanol
AIM:
To prepare Adipic acid from cyclohexanol by oxidation.
PRINCIPLE:
Adipic acid is a dicarboxylic acid with IUPAC name Hexane-1,6-dioic
acid with the formula (CH2)4(COOH)2. Fromm an industrial perspective,
it is the most important dicarboxylic acid used as monomer for the
production of nylon by polycondensation reaction with hexamethylene
diamine forming 6, 6,-nylon. Hence, the purpose of this experiment is to
synthesize Adipic acid through oxidation of cyclohexanol using 50%
nitric acid in presence of catalyst ammonium metavanadate.
CHEMICALS REQUIRED:
Cyclohexanol, Concentrated nitric acid, Ammonium metavanadate.
APPARATUS:
Conical flask, Thermometer, Beaker, Funnel, Measuring cylinder, Filter
paper.


PROCEDURE:

3. CPP-1.5 (1.1) Practical Organic Chemistry

DOS & R in Organic Chemistry, TUT Page 3


 In a 250 mL round bottom flask or conical flask 15 mL of 50%
HNO3 was placed and the acid solution was heated on water bath
nearly to 65-70
o
C.
 A pinch of ammonium metavanadate (~0.05 g) was added to hot
acid solution.
 1 mL of cyclohexanol was added dropwise to the acid solution
maintaining the temperature at 65-70
o
C.
 The reaction progress was indicated by the evolution of brown gas
i.e. oxides of nitrogen.
 After complete addition of cyclohexanol, maintain the temperature
for 10 more minutes till evolution of brown gas ceases.
 The reaction mixture was cooled to lab temperature and was then
placed in an ice bath. Crystallization of Adipic acid takes place as
light yellow/white crystals.
 The light yellow/white crystals were then collected by filtration
and washed with cold 50% HNO3. (Do not wash with excess)
 The light yellow/white crystals were then dried and weighed.
Calculate the yield and obtain melting point.
REACTION: OH
COOH
COOH
50 % HNO
3
Cat. NH
4VO
3
65-70
o
C

CALCULATIONS:

4. CPP-1.5 (1.1) Practical Organic Chemistry

DOS & R in Organic Chemistry, TUT Page 4


Compound Amount
Molecular
Weight
Moles Equivalent
Cyclohexanol 1 mL
100.1
D = 0.96 g/cm
3

- -
50 % HNO3 15 mL - - -
NH4VO3
Pinch
(~0.05g)
- - -
THEORETICAL CALCULATION:
100.1 g of cyclohexanol gives 146.14 g of Adipic acid
1 g of cyclohexanol will forms X g of Adipic acid
Theoretical yield =
Practical yield =
% Yield = (Practical yield) / (Theoretical yield) X 100
CHEMICAL TESTS:
Reaction with NaHCO3
Cyclohexanol: No evolution of gas (-Ve)
Adipic Acid: Evolution of gas (+Ve)
Litmus test:
Cyclohexanol: Blue litmus remain to blue and red litmus remain to red
(Neutral)
Adipic Acid: Blue litmus remain turns to red and red litmus remain to
red (Acidic)

5. CPP-1.5 (1.1) Practical Organic Chemistry

DOS & R in Organic Chemistry, TUT Page 5


MECHANISM: OH
50 % HNO
3
OH
2
NO
3
-H
2O
O
N
O
O
H
O
HNO
2
HNOH
2O
OHO
N
O
NOH
O
O
COOH
COOHVO
3
H
2O
Keto-Enol tautomerism
H
O
-HNO
2
Oxidation

6. CPP-1.5 (1.1) Practical Organic Chemistry

DOS & R in Organic Chemistry, TUT Page 6


REPORT:
Structure
and name
of the
compound
Theoretical
yield
Practical
yield
Percentage
yield
Theoretical
Melting
point
Experimental
Melting
point
COOH
COOH
Adipic acid

152
o
C

REFERENCES:
1. https://www.scribd.com/doc/114328909/Oxidation-of-
Cyclohexanol-to-Adipic-Acid.
2. Organic Syntheses, Coll. Vol. 1, p.18 (1941); Vol. 5, p.9 (1925).
3. https://www.academia.edu/31380866/PREPARATION_OF_ADIP
IC_ACID_FROM_CYCLOHEXENE_Chem_126_4.doc .