US Patent 7906685 Process for producing cyclohexylbenzene

In a process for producing cyclohexylbenzene, benzene and hydrogen are fed to at least one reaction zone. The benzene and hydrogen are then contacted in the at least one reaction zone under hydroalkylation conditions with a catalyst system comprising a molecular sieve having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom, and at least one hydrogenation metal to produce an effluent containing cyclohexylbenzene. The ratio of the total number of moles of hydrogen fed to said at least one reaction zone to the number of moles of benzene fed to said at least one reaction zone is between 0.4 and 0.9:1.