In the diisopropyl ether production process, the distallation step for the separation of aqueous IPA recovered from the DIPE extraction operations is modified to avoid carrying out the distillation under conditions that yield IPA-water azeotrope providing lower overall process cost. The determination has been made that the overhead and bottom streams form an aqueous IPA fractionation process operated under off-azeotrope conditions in DIPE production can be recycled, respectively, to the DIPE reactor and extractor operations. Recycling the water and IPA overhead mixture eliminates the requirement for adding fresh water to the DIPE reactor. Returning the water and IPA bottom stream to the extractor reduces the requirement for distilled water addition to the extraction step. As a consequence, a less complex and costly aqueous IPA separation process is implemented.