In a process for producing phenol and cyclohexanone, a cleavage feed containing greater than 40 wt % and no greater than 95 wt % cyclohexyl-1-phenyl-1-hydroperoxide, and at least 5 wt % and less than 60 wt % cyclohexylbenzene is mixed with at least phenol, cyclohexanone, water, and sulfuric acid to produce a cleavage reaction mixture containing from 15 wt % to 50 wt % phenol, from 15 wt % to 50 wt % cyclohexanone, from 1 wt % to 10 wt % cyclohexyl-1-phenyl-1-hydroperoxide, from 5 wt % to 60 wt % cyclohexylbenzene, from 0.1 wt % to 4 wt % water, and from 10 wppm to 1000 wppm sulfuric acid. The cleavage reaction mixture is then reacted at a temperature from 30° C. and to 70° C., and a pressure of at least 1 atmosphere for a time sufficient to convert at least 50% of said cyclohexyl-1-phenyl-1-hydroperoxide in said cleavage reaction mixture and produce a cleavage effluent containing phenol and cyclohexanone.