The metathesis process is carried out in a reaction distillation column for: (A) for the production of propylene from the metathesis of 2-butene and ethylene; (B) for the production of detergent range olefins from the metathesis of C15 and heavier olefins with C9 and lighter olefins; (C) for the production of 2-methyl-2-butene and propylene from the metathesis of 2-butene and isobutylene and (D) for the production of tetramethylethylene from the metathesis of isobutylene with itself and/or the reaction of diisobutylene with the ethylene produced to produce neohexene.