co precipitation method and reported cyclohexane oxidation at 273 K using TBHP as oxidant. 69.2
selectivity to cyclohexanol and cyclohexanone at 23 conversion of cyclohexane. Oxidation of
cyclohexane is one of the important bulk processes for the production of polyamide fibres and plastics,
such as nylon 6 and nylon 6,6.
2.1.5 Alkylation
Alkylation reactions are of great interest in the petrochemical industry as they lead to several
commercially important alkyl aromatics. Cumene is
one such
alkyl aromatic
produced by
isopropylation of
benzene. The
commercial importance of cumene is felt by the world’s growing
phenol demand, 90 of which is met through cumene. In the cumene route for the production of
phenol, acetone is produced as a low value by product. Barman et al. [119] synthesised cumene
with 100 selectivity, by reductive alkylation of benzene with acetone in the presence of a
bifunctional catalyst system comprising a solid acid material, H mordenite HM, as alkylation
functional
and nano copper
chromite as
hydrogenation functional, eqn. 18. C
6
H
6
+ CH
3
COCH
3
+ H
2
→ C
6
H
5
CHCH
3 2
+ H
2
O 18
Copper chromite has been reported as a catalyst for the reductive N alkylation of aniline with
acetone [120,100]. Pillai [121] prepared different aliphatic secondary amines by reductive alkylation
of methylamine and ethanolamine with carbonyl compounds over copper chromite catalyst. Almost
100 selectivity was observed in all cases. Under optimum conditions of reaction the yield of N
isopropylaniline was 91 and that of N benzyl ethanolamine was 94.
2.1.6 Cyclization
Nitrogen containing heterocyclic compounds are pharmaceutically important [122,123]. Intensive
attention was concentrated on the manufacture of this type of compounds over a half century. Bai et
al. [124] employed Cu Cr Feγ Al
2
O
3
catalysts for the
intramolecular cyclization
of N 2
hydroxyethyl ethylenediamine to
piperazine which showed excellent activity, selectivity and
long service life under the optimum reaction conditions eqn. 19. Further they reported that
satisfactory results were obtained for cyclizations of other alkanolamines, such as N 2 hydroxyethyl
1,2 diaminopropane and 5 amino 1 pentanol. 2C
2
H
2
NH
2 2
→ C
4
H
4
NH
2
19 Ethylene diamine Piperazine
Moss and Bell [125] used Ni Cu Cr oxide for the amination of ethanolamine to a mixture of
ethylenediamine and cyclic product, piperazine. They found that addition of water increased the
selectivity of a Ni Cu Cr oxide catalyst to the cyclic product. Wang et al. [6] found that the Cu Cr Ba
Al
2
O
3
catalyst was suitable for highly selective synthesis of homopiperazine. Cu
is believed to be the active site of the catalyst and the addition of
Ba to the Cu based catalyst improves the dispersion of copper and prevents it from sintering.
The cyclization
of N β hydroxyethyl 1,3
propanediamine to homopiperazine proceeded with more than a 90 yield under optimum reaction
conditions.
2.2 Hydrogen production
Hydrogen is used in massive quantities in the petroleum and chemical industries [126]. In a
petrochemical plant, hydrogen is used for hydrodealkylation,
hydrodesulfurization, and
hydrocracking, all methods of refining crude oil for wider use. Ammonia synthesis plants accounted for
40 of the worlds consumption of H2 in making fertilizer. In the food industry, hydrogen is used to
hydrogenate oils or fats, which permits the production of margarine from liquid vegetable oil.
Hydrogen is used to produce methanol and hydrochloric acid, as well as being used as a
reducing agent for metal ores. Since H2 is the least dense of gases, meteorologists use hydrogen to fill
their weather balloons. The balloons carrying a load of instruments float up into the atmosphere,
for recording information about atmospheric conditions.
Hydrogen has the highest combustion energy release per unit of weight of any commonly
occurring material eqn. 20. H
2
g + 12O
2
g → H
2
Ol ∆H = 286 kJmol 20
This property makes it the fuel of choice for upper stages of multi stage rockets. Much has been
said about hydrogen being the energy carrier of the future due to its abundance and its non
polluting combustion products. When it is combusted, heat and water are the only products.
The use of hydrogen as a fuel for fuel cell powered vehicles can greatly reduce green house gas
emissions from internal combustion engines. Moreover, development of affordable hydrogen fuel
Copyright © 2011, BCREC, ISSN 1978 2993
cells will help reduce the nation’s dependence on foreign oil, leading to an increased national energy
security. Thus, hydrogen offers a potentially non polluting,
inexhaustible, efficient,
and cost
attractive cleanest fuel for today’s rising energy demands [127].
Hydrogen is not found in free state but it is abundantly available in nature as compounds of
oxygen water or carbon alcohols, hydrocarbons, carbohydrates, etc.. Energy must be supplied to
generate hydrogen
from either
water or
carbonaceous materials. Thus, note that hydrogen is not an energy source, as energy is needed to
produce it 21. As an energy carrier, hydrogen is the most attractive option with many ways to
produce and utilize it [128].
H
2
O + energy → H
2
+ 0.5O
2
21 Processes using copper chromite as catalysts for
the production of hydrogen are as follows: a. From water splitting
Photo electrolysis of water Sulphur based thermo chemical water
splitting cycles b. Catalytic conversion of alcohols
Dehydrogenation of alcohols Decomposition of methanol
Reforming of alcohols Methanol reforming
Ethanol reforming c. Water gas shift reaction
2.2.1 From water splitting 2.2.1.1 Photo,electrolysis of water
