Patent ID: 7579511

Claim:
A process for making cyclohexylbenzene, comprising: (a) contacting benzene and hydrogen in the presence of a first catalyst under hydroalkylation conditions sufficient to form a first effluent stream having cyclohexylbenzene, cyclohexane, methyl cyclopentane, and unreacted benzene; (b) supplying at least part of said first effluent stream to a first separation system to divide said first effluent stream part into a cyclohexane/methylcyclopentane-rich stream, a cyclohexane-rich stream, a benzene-rich stream, and a dicyclohexyl benzene-rich stream; (c) recycling at least part of the benzene-rich stream to the contacting step (a); (d) contacting the cyclohexane/methylcyclopentane-rich stream with a second catalyst that catalyzes dehydrogenation and exhibits low acidity under conditions sufficient to convert at least a portion of the cyclohexane to benzene and at least a portion of the methylcyclopentane to linear and/or branched paraffins to form a second effluent stream; and (e) recycling at least part of the second effluent stream to the contacting step (a).