Cities Service Company

Ralph Levine

Jerome R Olechowski

A process for the recovery of isobutylene as tertiary butyl alcohol from a stream of C.sub.4 hydrocarbons comprising contacting the stream with an aqueous acid solution comprising from 50 to 80 wt % hydrocarbyl sulfonic acid, recovering from the resultant mixture an aqueous acid phase containing tertiary butyl alcohol and recovering from the acid phase the product tertiary butyl alcohol.

Process for the preparation of tertiary butyl alcohol

Tertiary butyl alcohol is dehydrated in the presence of para-toluene sulfonic acid catalyst and xylene which forms an azeotrope with the water of hydration. Isobutylene and water, formed by the dehydration reaction, along with xylene, are removed as a vapor fraction. Xylene serves a dual purpose, acting as a solvent for paratoluene sulfonic acid so that this catalyst can contact the tertiary butyl alcohol feed, and also acting as an azeotrope forming agent to remove water as it is formed and to promote the dehydration reaction.

Dehydration of tertiary butyl alcohol

Tertiary butyl alcohol, containing some water, is dehydrated to isobutylene in the presence of a catalyst and a hydrocarbon which forms an azeotrope with water. Isobutylene, water, and the hydrocarbon are passed through a condenser to a phase separator from which isobutylene is recovered, preferably as a vapor phase, hydrocarbon is recycled to the dehydration zone, and a water phase removed from the process. The alcohol feed point location is the phase separator. A significant fraction of water contained in the tertiary butyl alcohol feed can be removed inexpensively, by phase separation, in the separator, to minimize the amount of water entering the dehydration zone.

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Freehold, NJ, United States of America

Ralph Levine