Processes for the production of high purity isobutylene are disclosed. The processes may include supplying a mixed C4 feed stream to a catalytic distillation column, which may contain a butene isomerization catalyst. 1-butene is isomerized to 2-butene and concurrently in the catalytic distillation column the 2-butene is separated from the isobutane and isobutylene. The overheads fraction comprising the isobutane and isobutylene is then condensed in an overheads system and fed to a splitter, where the isobutane is separated from the isobutylene. The process further includes operating the catalytic distillation column at an overheads temperature greater than a bottoms temperature of the splitter, and heating a portion of the splitter bottoms stream via indirect heat exchange with at least a portion of the catalytic distillation column overheads fraction, thereby producing a heated bottoms stream (reboil vapor) fed to the splitter and a cooled overheads fraction.