Process for the cyclodimerization of 1,3-butadienes to 4-vinylcyclohexenes
AssigneeThe Dow Chemical Company
InventorsRonald W. Diesen, Kenneth A. Burdett, Ravi S. Dixit, Stanley S. T. King
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Abstract
A process for the cyclodimerization of 1,3-butadienes to 4-vinylcyclohexenes. The process involves contacting butadiene with a copper (I)-aluminosilicate zeolite prepared by (a) an impregnation method, or (b) heating a solid mixture of a copper salt and the zeolite, or (c) contacting vapors of a copper salt with the zeolite. The catalysts exhibit long life and good activity in the claimed process. The impregnated Cu(I)-catalyst is claimed.
Claims22
A process for the cyclodimerization of 1,3-butadiene or substituted 1,3-butadiene to 4-vinylcyclohexene or a substituted derivative thereof, the process comprising contacting 1,3-butadiene or a substituted 1,3-butadiene with a catalytic amount of a copper(I)-aluminosilicate zeolite wherein the zeolite is selected from the group consisting of faujasites, mordenite, zeolite L, zeolite .OMEGA., and zeolite beta, and wherein the zeolite has a framework silica to alumina molar ratio of at least about 15, the catalyst being prepared by:
- I) impregnating the aluminosilicate zeolite with a solution of a copper(II) salt, calcining the copper(II)-impregnated zeolite under conditions sufficient to remove the anion of the copper(II) salt, and reducing the calcined copper(II)-impregnated zeolite under conditions such that a portion of the copper (II) ions are converted to copper(I);
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- II) heating a solid mixture containing a copper salt and the aluminosilicate zeolite in the absence of liquid solvent;
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- III) contacting vapors of a copper salt with the aluminosilicate zeolite;
- the contacting of the butadiene and the copper(I)-zeolite occurring under reaction conditions such that 4-vinylcyclohexene or a substituted derivative thereof is formed.
A process for the cyclodimerization of 1,3-butadiene to 4-vinylcyclohexene, the process comprising contacting 1,3-butadiene in the liquid phase with a catalytic amount of a copper(I)--faujasite zeolite having a framework silica to alumina molar ratio of at least about 15, the catalyst being prepared by (a) impregnating the aluminosilicate zeolite with a solution of a copper (II) salt, (b) calcining the copper(II)-impregnated zeolite under conditions sufficient to remove the anion of the copper(II) salt, and (c) reducing the calcined copper(II)-impregnated zeolite with propylene or butene under conditions such that a portion of the copper(II) ions are converted to copper(I);
- the contacting of butadiene and the copper(I)-zeolite occurring at a temperature between 80.degree. C. and 150.degree. C., a pressure between 100 psig and 1000 psig, and a weight hourly space velocity between 0.1 hr.sup.-1 and 10 hr.sup.-1, such that the rate of formation of 4-vinylcyclohexene is at least about 0.5 (mole-hr).sup.-1 and the half-life of the catalyst is at least about 500 hours.
Dependencies are inferred from the claim text.