126
alkylation of benzene with cyclohexene takes place on the acid site to produce CHB,
as shown in Fig. 9.
During the reaction, side products like cyclohexane, dicyclohexylbenzene
(DCHB), and methyl cyclopentane are reported to form, which affect the selectivity
of CHB. It is further reported that formation of bicyclohexyl also takes place by
hydrogenation of CHB under severe operating conditions [123, 127]. The literature
reports the use of several bifunctional catalyst recipes based on metals like Ni, Co,
Zn, Pd, Pt, Ru, Rh, Re, and Sn supported on SiO 2 , Al 2 O 3 , and zeolites like MOR,
Beta, 13X, and MCM-22 for benzene hydroalkylation [120–122, 128, 129]. The
production of CHB as a side product was first reported during the hydrogenation of
benzene using nickel catalyst in the presence of phosphoric anhydride [130].
Subsequently, production of CHB was reported on solid catalysts through hydrogenation of benzene using alkali metal supported on Al 2 O 3 as a catalyst and group VIII
metal deposited on acid function like SiO 2 -Al 2 O 3 , AlCl 3 , and BF 3 [126, 131]. Since
then, several research articles and patent by prominent industrial companies like
Shell, Phillips Petroleum, Universal Oil, Texaco, Total, and Exxon Mobil have been
published/filed for the production of CHB [132–135].
The effect of catalyst pretreatment and operating conditions on the catalyst activity were studied for hydroalkylation of benzene on a series of nickel-supported silica-alumina catalysts in batch reactor [136]. This study reported that selectivity of
CHB is proportional to the quantity of acid sites, and silica-alumina with 42 wt% of
alumina was the best support for the hydroalkylation reaction due to higher acidity
of the support . The author also studied the effect of catalyst metal content on the
hydroalkylation selectivity and activity. The activity of the catalyst increased with
nickel content; however, CHB selectivity decreased due to higher hydrogenation
Fig. 9 Benzene hydroalkylation pathway for CHB
S. M. Pai et al.
alkylation of benzene with cyclohexene takes place on the acid site to produce CHB,
as shown in Fig. 9.
During the reaction, side products like cyclohexane, dicyclohexylbenzene
(DCHB), and methyl cyclopentane are reported to form, which affect the selectivity
of CHB. It is further reported that formation of bicyclohexyl also takes place by
hydrogenation of CHB under severe operating conditions [123, 127]. The literature
reports the use of several bifunctional catalyst recipes based on metals like Ni, Co,
Zn, Pd, Pt, Ru, Rh, Re, and Sn supported on SiO 2 , Al 2 O 3 , and zeolites like MOR,
Beta, 13X, and MCM-22 for benzene hydroalkylation [120–122, 128, 129]. The
production of CHB as a side product was first reported during the hydrogenation of
benzene using nickel catalyst in the presence of phosphoric anhydride [130].
Subsequently, production of CHB was reported on solid catalysts through hydrogenation of benzene using alkali metal supported on Al 2 O 3 as a catalyst and group VIII
metal deposited on acid function like SiO 2 -Al 2 O 3 , AlCl 3 , and BF 3 [126, 131]. Since
then, several research articles and patent by prominent industrial companies like
Shell, Phillips Petroleum, Universal Oil, Texaco, Total, and Exxon Mobil have been
published/filed for the production of CHB [132–135].
The effect of catalyst pretreatment and operating conditions on the catalyst activity were studied for hydroalkylation of benzene on a series of nickel-supported silica-alumina catalysts in batch reactor [136]. This study reported that selectivity of
CHB is proportional to the quantity of acid sites, and silica-alumina with 42 wt% of
alumina was the best support for the hydroalkylation reaction due to higher acidity
of the support . The author also studied the effect of catalyst metal content on the
hydroalkylation selectivity and activity. The activity of the catalyst increased with
nickel content; however, CHB selectivity decreased due to higher hydrogenation
Fig. 9 Benzene hydroalkylation pathway for CHB
S. M. Pai et al.