Patent ID: 7432407

Claim:
A process for the hydroisomerization of C 4 -C 6 -olefins, comprising: hydroisomerizing a hydrocarbon feed which is (1) a mixture of C 4 -C 6 -olefins or (2) an olefinic cut containing C 4 -C 6 -olefins, said feed containing from 0.1 to 5% of polyunsaturated hydrocarbons, the mixtures (1) and (2) containing only sulfur compounds that can be separated from the mixed olefin product obtained by distillation or which on hydroisomerization give rise to sulfurous compounds which can be separated from the olefins by distillation, wherein the mixtures of C 4 -C 6 -olefins or the olefinic cut contains olefins having terminal double bonds which are hydroisomerized to olefins that contain internal double bonds and wherein the polyunsaturated hydrocarbons in the hydrocarbon feed are simultaneously hydrogenated to monoolefins with an amount of hydrogen ranging from 1 to 4 times the stoichiometric quantity of hydrogen required to selectively hydrogenate the polyunsaturated hydrocarbons to the corresponding monoolefins, over a catalyst comprising an element of the eighth transition group of the Periodic Table in the presence of at least one added sulfur compound which contains at least 4 carbon atoms, thereby producing a mixed C 4 -C 6 -olefin product in which the quantitative ratio of the C 4 -C 6 -olefins containing internal double bonds to the C 4 -C 6 -olefins containing terminal double bonds is at its thermodynamic equilibrium value at a reaction temperature ranging from 30 to 150° C., which in the case of the ratio of 2-butene to 1-butene ranges from 18:1 to 16:1.