Selective hydrogenation of alpha-methyl-styrene to cumene

In a process comprising selective hydrogenation of AMS in a feed stream comprising up to 6 weight percent AMS in cumene over a supported noble group metal catalyst in the presence of hydrogen to obtain a cumene product comprising less than 750 ppmw AMS, the improvement comprising:

• contacting the feed stream in the presence of hydrogen with supported nickel catalyst in a fixed bed upstream from the supported noble group metal catalyst to convert from 70 to 95 percent of the AMS to cumene in an intermediate stream;
• supplying the intermediate stream with hydrogen to a downstream fixed bed comprising the supported noble group metal catalyst to obtain a stream of the cumene product.

Apparatus for selective hydrogenation of alpha-methyl-styrene (AMS) to cumene, comprising:

• reactor means for contacting a feed stream comprising AMS in cumene with nickel in the presence of hydrogen in a first fixed bed catalytic reaction zone for converting from 70 to 95 percent of the AMS to cumene;
• reactor means for contacting effluent from the first zone with a noble group metal in the presence of hydrogen in a second fixed bed catalytic reaction zone to convert AMS in the first zone effluent for obtaining a net reactor effluent comprising cumene essentially free of AMS.