ppt

1. HYDROGENATION OF BENZENE
“The secret of getting ahead is getting started.” – Mark Twain

2. Background information
about hydrogenation
Hydrogenation of
benzene
Types of
hydrogenation
. Catalytic
hydrogenation
Birch
reduction
Applications in
petrochemicals
TO BE
DISCUSSED?

3. Why we are
studying this
topic?
Why we are discussing this
topic?

4. Hydrogenation is a
chemical reaction
between molecular
hydrogen (H2) and
another compound or
element
Hydrogenation
Must be
unsaturated
Conditions
Catalysts
Ni, pt, pd
Specific
temperature

5. RATE
DETERMININ
G
FACTORS
Temperature
Pressure
Catalyst
Simplest
Produce high yield
Clean product
Use commercially
Not use large volume of water
WHY WE USE
HYDROGENATION
Thermal
decomposition
Partial
oxidation
Steam
Reforming
From catalytic
Reforming

6. M
E
C
H
A
N
I
S
M

7. HYDROOGENATION OF
BENZENE

8. INTRODUCTION
 Example of addition reaction of benzene
 Occur under drastic condition
 Exothermic in nature
 Reaction always furnished in three steps
Conditions
P: 1500 atm 100psi
Agitated speed

9. S
T
A
B
I
L
I
T
Y

10. TYPES
2
1
 Complete Hydrogenation
 Control hydrogenation
CATALYTIC
HYDROGENATION
BIRCH
REDUCTION
Colourless liquid
Insoluble in water
Soluble in
hydrocarbons
Thermodynamically
stable
Pt,pd,Rh J.phys.chem..,1931,..35(8).2219-2225
DOI: 10.1021/J50326a005

11. Take place in catalytic
reforming that increase its
octane number
OXIDATION
Ketone + Alcohol
KA Oil
Caprolactam
Adipic acid
For nylon 6,6
95°C-120°C
10atm
95% yield

12. Caprolactam is an organic compound
with the formula (CH₂)₅C(O)NH. This
colourless solid is a lactam of caproic
acid. Global demand for this compound is
approximately five million tons per year.
Adipic acid or hexanedioic acid is the
organic compound with the formula
(CH2)4(COOH)2. From an industrial
perspective, it is the most important
dicarboxylic acid:
12

13. High conversion rate; easy for
industrialization
High reaction rate
High specificity
High energy consumption& safety
cost
Low conversion efficiency & more
difficult to achieve product
catalyst separation
Limited catalysts explored
CATALYTIC
HYDROGENATION
ADVANTAGES DISADVANTAGES

14. Hydrocarbon
feed enters the
column at 45
stage
Three
product
streams
Consist of 70
trays (condenser+
boiler)
Hydrogen enter
above hydrocarbon
feed stage & below
reactive zone
Control of benzene hydrogenation via RD
Feed
components
weight
butane 0.01
pentane 0.08
hexane 0.01
benzene 0.08
Liquid product that contain
heavier hydrocarbons+
benzene
Distillates
result from
reaction of
H2+benzene
Separation+ Reaction Contain most of
unreactive
hydrogen
Feed composition

15. THE BIRCH REDUCTION
Benzene can be reduced to 1,4-cyclohexadiene by
treating it with an alkali metal (sodium, lithium, or
potassium) in a mixture of liquid ammonia and an
alcohol. This reaction is called the Birch reduction.
Catalyst e-
rich system
NH3 e-
donator
C2H5OH
provide-H
Australian chemist,
A. J. Birch.
1,4-cyclohexadene

16. M
E
C
H
A
N
I
S
M

17. S
U
B
S
T
I
T
U
T
I
O
N
E
F
F
E
C
T
EWG
EDG
Electron-donating groups destabilize a negative
charge (when compared to simple benzene) through
conjugation and this effect would be strongest at the
ipso and para positions.
Electron-withdrawing groups stabilize electron
density at the ipso and para positions through
conjugation and so the negative charge will mainly
be found in these positions; subsequent protonation
occurs para

18. 01
02
06
05
03
04
Applications
 Maleic anhydride
 Styrene
 Paint thinner
 LABSA
 Caprolectum  Insecticides

19. Did you know
about
hydrogenated oil?

20. FOODS TO
AVOID
Breakfast cereals
Margarine
Fried food
(especially fast food)
Frozen pizza
Crackers

21. HYDROGENATION OF
BENZENE
Catalytic
Hydrogenation
Birch Reduction
Control
Hydrogenation
Complete
Hydrogenation
Cyclohexanol Cyclohexanone
KA oil
Caprol
ectum
Adipic
acid
Nylon
Nylon6,6
Cyclohexene
SUMMARY
Substitution
effect
EDG EWG
1,4-cyclohexadiene
Use as a very effective
hydrogen donor for
catalytic hydrogenation
Cyclohexane

22. 22
REFERENCES:
1. H. S. Taylor, J. Am. Chem. Soc. 60, 627 (1938). Google
ScholarCrossref
2. G. H. Burrows and C. Lucarni, J. Am. Chem. Soc. 49, 1157 (1927).
Google ScholarCrossref
3. V. R. Zharkov and A. V. Frost, J. Gen. Chem. U.S.S.R. 2, 534 (1932).
Google Scholar
4. Beckett, Freeman, and Pitzer, J. Am. Chem. Soc. 70, 4227 (1948).
Google ScholarCrossref, ISI

23. 23
Once we accept our limits, we go beyond them.