125
commercial production of CHB will depend on the development of efficient catalysts and economical process.
1.2.2 Conventional Process for Synthesis of CHB
The conventional route for production of CHB is direct alkylation of benzene with
cyclohexene in the presence of aluminum chloride or sulfuric acid as catalysts. This
route not only offers low selectivity (around 44%) for CHB but also uses catalysts
that are hazardous in nature [125, 126]. Hence, it is essential to look for alternate
environmentally benign routes to overcome the hazards associated with the conventional route.
1.2.3 Alternative Route for Hydroalkylation of Benzene
Hydroalkylation of benzene involving partial hydrogenation of benzene followed
by alkylation of benzene is a potential alternative route for CHB synthesis [123,
127]. Bifunctional catalysts are required for hydroalkylation reaction where cyclohexene is produced by partial hydrogenation of benzene on metal sites and
Fig. 8 Synthesis of phenol from CHB
Emerging Trends in Solid Acid Catalyst Alkylation Processes