DE2716132

In the epoxidation of propylene with tertiary butyl hydroperoxide to form propylene oxide, a by-product, tertiary butyl alcohol is formed. This alcohol can be dehydrated to form isobutylene which can be sold as a product or hydrogenated, followed by oxidation, and the resulting hydroperoxide reacted with propylene to produce propylene oxide and tertiary butyl alcohol for recycle. In this process, the operation of the tertiary butyl alcohol vaporizer is substantially improved by increasing the quantity of liquid purge to at least 15 weight percent of the input. Under such operating conditions, the organic content of the waste water effluent from the entire plant is reduced, fouling of the vaporizer heat transfer surfaces is minimized thereby increasing the on-stream time between cleanings by as much as 2-3 times the normal, and deposits are more easily removed from the vaporizer when it is shut down for cleaning.