Method for producing 2,3-dimethyl-1-butene and 2,3-dimethyl-2-butene via dimerisation and isomerisation of propene

摘要

A method for producing 2,3-dimethylbutene-1 (DMB-1) and 2,3-dimethylbutene-2, (DMB-2), comprises the steps of

(a) dimerizing propylene in a propylene-dimerization step using a nickel complex catalyst as described below as a propylene-dimerization catalyst having propylene-dimerization activity and selectivity for DMB-1 ;

(b) rectifying the resulting reaction solution to obtain 2,3-dimethylbutene-1 as a distillate and a distillation residue containing 2,3-dimethylbutene-1 in a 2,3-dimethylbutene-1 distillation step,

(c) allowing the DMB-1 distillation residue to contact with sulfuric acid, sulfonic acid such as a strong acidic ion exchange resin with sulphonic acid functional groups or heteropolyacid, such as silicotungstic acid, to isomerize 2,3-dimethylbutene-1 in said distillation residue into 2,3-dimethylbutene-2 in an isomerization step, and

(d) rectifying the resulting isomerization reaction solution to obtain 2,3-dimethylbutene-2 in a 2,3-dimethylbutene-2 distillation step, wherein said nickel complex catalyst comprises

(A) at least one nickel compound,

(B) a trialkylaluminum,

(C) a trivalent phosphorus compound, PR1R2R3, where R1,R2,R3 are the same or different and independently represent a phenyl group which may be substituted with an alkyl or alkoxy group ; an alkyl group ; a cycloalkyl group or an aralkyl group

(D) a fluorinated isopropanol or a halogenated phenol, of formula (2) : where x1 to x5 are the same or different and independently represent halogen or hydrogen atom and at least one x1 to x5 is a halogen atom, and

(E) at least one sulfur compound selected from a sulfonic acid and a a dialkylsulfuric acid. The distillation residue from step (b) comprising 2,3-dimethyl-1-butene may be subjected to a further cycle of distillation, isomerisation in contact with sulphuric acid, sulphonic acid or heteropolyacid and distillation of the isomerised product.