METHOD OF PROCESSING ISOBUTENE-CONTAINING HYDROCARBON MIXTURE Russian patent published in 2008 - IPC C07C11/09 C07C41/06 C07C43/04 

FIELD: petrochemical processes.

SUBSTANCE: invention is directed to processing of isobutene-containing hydrocarbon mixture preferably containing C₄-hydrocarbons, which processing comprises interaction of isobutene contained therein with methanol in presence of acidic solid catalyst in one or several zones of synthesis of methyl tert-butyl ether followed by distilling off unreacted C₄-hydrocarbons from reaction mixture, withdrawing, as more high-boiling residue, stream containing methyl tert-butyl ether, which is fully or partially supplied to ether decomposition zone, decomposing methyl tert-butyl ether in presence of high-acid solid catalyst, distilling off reaction products of stream preferably containing isobutene, methanol , and minor portion of non-decomposed methyl tert-butyl ether, withdrawing the rest of more high-boiling product containing predominantly methyl tert-butyl ether from the system or recycling it to ether decomposition zone, rectifying distilled-off stream predominantly containing isobutene, methanol, and minor portion of non-decomposed methyl tert-butyl ether, wherein stream mainly containing isobutene is distilled off and more highly boiling residue containing methanol and ether is subjected to additional rectification at lower pressure, recycling bottom residue containing mostly methanol to ether synthesis zone and distillate to distillation zone next after decomposition zone, recovering methanol by water extraction from mainly isobutene-containing stream, freeing washed isobutene stream from dimethyl ether by rectification, wherein stream containing dimethyl ether and isobutene is withdrawn as distillate and purified isobutene is recovered as more high-boiling bottom residue or, in case of heteroazeotropic drying of isobutene jointly with removal of dimethyl ether, stratifying resulting distillate and discharging water and hydrocarbon streams while recovering purified isobutene as more high-boiling bottom residue. Process is characterized by that decomposition of methyl tert-butyl ether is conducted at pressure assuring liquefied state of substances and temperature 60-120°C, stream obtained as distillate of rectification of washed out isobutene stream and containing dimethyl ether and isobutene or hydrocarbon stream containing dimethyl ether and obtained after stratification of distillate of heteroazeotropic drying of isobutene is recycled to methyl tert-butyl ether decomposition zone.

EFFECT: reduced formation of dimethyl ether and increased productivity of plant.

2 dwg, 9 tbl, 9 ex