A process for the manufacture of alkylbenzenes wherein a feed of fresh and recycle benzene and fresh olefin are reacted in the presence of an alkylation catalyst in an alkylator having at least two reaction stages wherein each stage is adiabatic. Essentially all of the olefin is completely reacted in each stage of the alkylator. Fresh olefin is fed into each stage of the alkylator. Preferred alkylbenzenes which are produced by this process are ethylbenzene and cumene.
