Simulation study of direct hydration of cyclohexene to cyclohexanol using isophorone as cosolvent

- Using isophorone as cosolvent for direct hydration of cyclohexene to cyclohexanol.
- The reactive distillation process is feasibility when Da numbers is below 0.07.
- Conceptual design was presented.
- The process was verified by the simulating with the Aspen Plus software.

Cyclohexanol is an important intermediate in the production of adipic acid and ε-caprolactame, and these in turn are used as intermediates for the production of nylons, plasticizers, and pesticides. Traditionally, cyclohexanol is obtained from the oxidation of cyclohexane, however, the process suffer lots of drawbacks including the low selectivity of cyclohexanol, high energy requirement, the explosion risk, and numerous by-products formations. In this paper, a process simulation of reactive distillation using isophorone as cosolvent for the direct hydration of cyclohexene to cyclohexanol was performed. Results showed that the novel process not only got rid of drawbacks owned by the traditional oxidation method, but also improved the conversion and reaction rate of the reactants greatly. Process simulation results also demonstrated that with the increasing Damköhler number (Da), a reactive azeotrope emerged when Da numbers exceeded a critical value of 0.07. Therefore, the reactive distillation could only be practical when Da numbers is below 0.07. During the simulation, the cyclohexene conversion increased with excess water and cosolvent isophorone in the reactive distillation column. Finally, a high-purity cyclohexanol product (99.9 mol.%) can be obtained using a decanter and two distillation columns for reactive distillation, with a high cyclohexene conversion of 99.14%, and the isophorone purity well fitted for recycling, and the energy consumption was studied.