Patent ID: 7439410

Claim:
An alkylation process comprising: a) producing an alkylate and forming a first C 3 -minus paraffin from isobutane and a C 3 -C 4 olefin, and forming an alkylate-containing stream comprising the alkylate, isobutane, and the first C 3 -minus paraffin; b) separating by distillation in a first distillation zone the alkylate from isobutane and the first C 3 -minus paraffin; c) recycling at least a portion of the isobutane separated in step b) to step a), wherein steps a), b), and c) define a flow cycle loop; d) at least intermittently withdrawing a purge comprising the first C 3 -minus paraffin from at least one point in the flow cycle loop; e) producing isobutane and forming a second C 3 -minus paraffin from normal butane, and forming an isomerate stream comprising isobutane and the second C 3 -minus paraffin; f) separating by distillation in a second distillation zone isobutane from the first C3-minus paraffin and the second C 3 -minus paraffin; and g) passing at least a portion of the isobutane separated in step f) to at least one point in the flow cycle loop; wherein the C 3 -C 4 olefin is a first C 3 -C 4 olefin, wherein the purge comprises hydrogen chloride, and wherein the process further comprises reacting at least a portion of the hydrogen chloride in the purge with a second C 3 -C 4 olefin in a treating zone to produce a C 3 -C 4 chloroparaffin, separating by the distillation in step f) the C 3 -C 4 chloroparaffin produced in the treating zone from the first C 3 -minus paraffin and the second C 3 -minus paraffin, and passing at least a portion of the C 3 -C 4 chloroparaffin separated in step f) to at least one point in the flow cycle loop.