GB954197A - Recovery of tertiary olefins - Google Patents

Abstract

Primary-tertiary ethers, are obtained in the separation of C4-C7 tertiary from other monoolefins by reacting the tertiary olefin with a C1-C6 primary alcohol. The reaction is effected at 100-350 DEG F., and 0-5,000 p.s.i.g. in the liquid phase with an alcohol to tertiary olefin mol ratio of 0.1-100 using as catalyst an anion exchange resin. The tertiary olefin may be isobutylene, an isoamylene, isohexylene, isoheptene or 1-methyl-cyclopentene. The alcohol may be mono-or polyhydric and in preferably methanol or ethanol. The catalyst may contain sulphonic acid groups on a resin such as phenol-formaldelyde, coumarone-indene-cyclopentadiene, coumarone-indene-furfural, cyclopentadiene-furfural, coumarone-indene-cyclopentadiene-furfural or styrene-divinyl-benzene or on coal. In batch processes 0.5-50% by wt. of catalysts based on reactants is used and in continuous processes a WHSV of 0.1-100 based on hydrocarbon feed is used.ALSO:Tertiary olefins of 4-7 carbon atoms are separated from other close-boiling hydrocarbons by selectively reacting the tertiary olefins with a C1-C6 primary alcohol to form the corresponding ether, separating unreacted hydrocarbons and decomposing the ether to recover the olefins by contact with a solid phosphoric acid catalyst or a solid polystyrene sulphonic acid resin catalyst at 100-400 DEG F. Tertiary olefins which may be separated are isobutylene, isoamylenes, isohexylenes, isoheptenes and cyclic olefins such as 1-methyl-cyclopentene. The alcohol may be mono- or poly-hydric, is preferably methanol or ethanol and is employed in a mol ratio to tertiary olefin of 0.1-100, preferably 1-10. The temperature may be 100-350 DEG F. and pressure 0-5000 p.s.i.g., liquid phase being maintained. The catalyst used to form the ether is an organic hydrogen ion exchange resin bearing SO3H functional groups based on coal or polymers such as phenol-formaldehyde, coumarone - indene - cyclopentadiene, coumarone-indene - furfural, coumarone - indene - cyclopentadiene - furfural, cyclopentadiene - furfural or styrene - divinyl benzene. In batch processes 0.5-50% by weight of the reactants of catalyst is used and in continuous processes a WHSV of 0.1-100 based on hydrocarbon feed is used. Separation of excess alcohol from the ether is not necessary, an ether-alcohol azeotrope separated by distillation may be passed to the decomposition. The pressure may be 1/25 -25 atmospheres and the amount of catalyst may be 1-25% by weight of ether in batch processes or a WHSV of 0.5-10 may be used in continuous processes.