Isobutylene, High-Purity, by Phenol Alkylation

High-purity isobutylene is utilized in the production of butyl rubber and polyisobutylene. lsobutylene is commonly separated and isolated from mixed C4 streams (from olefin plants and catalytic crackers) via acid extraction (with sulfuric acid) or chemical conversions (through reactions with water or methanol). A process for production of high-purity isobutylene by selectively alkylating phenol to a mixture of tertiary-butyl-phenols (TBPs) , removing the normal C4s, then dealkylating TBP to release isobutylene is developed and discussed in this review.

SRI estimates the investment and production costs are in the same range with those for high-purity isobutylene production via acid extraction, dehydration of tertiary-butyl alcohol, and cracking of methyl tertiary-butyl ether on the same cost and isobutylene production bases.