GB878120A - Improvements in the production of oligomers of 1, 3-dienes - Google Patents

Abstract

Oligomers of 1,3-dienes are obtained by contacting the diene with (a) a ferric halide or a titanium compound and (b) aluminium and optionally (c) an aluminium halide and/or a compound which forms a complex with aluminium halides. Suitable dienes are butadiene, isoprene, 2,3 - dimethylbutadiene-1,3, cyclohexadiene - 1,3, hexadiene - 1,3 and 2-propylbutadiene-1,3; butadiene yields mainly cyclododecatriene-1,5,9. The titanium compound may be the tetramethylate, tetraethylate, tetrapropylate, tetrabutylate, trichloride, tribromide, tetrachloride, or tetrabromide, diethoxy titanium dichloride, triethoxy titanium chloride, bis-cyclopentadienyl titanium dichloride, or a dialkyl titanium dihalide. Aluminium is used as a dust or a powder of grain size 0.01-2 mm. Aluminium chloride, bromide or iodide may be added or formed in situ from the aluminium and the corresponding halide or hydrogen halide. Suitable complex forming compounds are aliphatic, araliphatic or aromatic ethers, or thiothers, amines, alkali or alkaline earth metal halides, hydrides or cyanides, and the salts of alkali, alkaline earth or earth (Al, Si, Y or La) metals with organic acids e.g. aliphatic acids containing up to 4 carbon atoms. The mol ratio of titanium compound: aluminium: aluminium halide may vary from 1:300:300 to 1:10:10 or the titanium compound may be in excess. The amount of complexing agent used may vary between wide limits but if used together with an aluminium halide preferably the mol ratio of combined titanium compound and aluminium halide to complexing agent should be from 1:0.2 to 1:3. A solvent may be added such as benzene, toluene, xylene, ethylbenzene, cumene, chlorbenzene, heptane, cyclohexane, isooctane or cyclododecatriene in amounts of 0.2 to 0.5 times the amount of diene. The catalyst may be "developed" in the solvent for up to 10 hours. Atmospheric pressure is preferred but the pressure may be lower or increased, e.g. to 10 atmospheres when using low boiling feeds, and temperatures of -50 to 150 DEG C. may be used.ALSO:Oligomers of 1,3-dienes are obtained by contacting the diene with (a) a ferric halide or a titanium compound and (b) aluminium and optionally (c) an aluminium halide and/or a compound which forms a complex with aluminium halides. The titanium compound may be the tetramethylate, tetraethylate, tetrapropylate, tetrabutylate, trichloride, tribromide, tetrachloride, or tetrabromide, diethoxy titanium dichloride, triethoxy titanium chloride, bis-cyclopentadienyl titanium dichloride, or a dialkyl titanium dihalide. Aluminium is used as a dust or a powder of grain size 0.01-2 mm. Aluminium chloride bromide or iodide may be added or formed in situ from the aluminium and the corresponding halide or hydrogen halide. Suitable complex forming compounds are aliphatic, araliphatic or aromatic ethers, or thioethers, amines, alkali or alkaline earth metal halides, hydrides or cyanides, and the salts of alkali, alkaline earth or earth (aluminium, scandium, yttrium or lanthanum) metals with organic acids e.g. aliphatic acids containing up to 4 carbon atoms. The mol ratio of titanium compound: aluminium: aluminium halide may vary from 1:300:300 to 1:10:10 or the titanium compound may be in excess. The amounting p of complexing agent used may vary between wide limits but if used together with an aluminium halide preferably the mol ratio of combined titanium compound and aluminium halide to complexing agent should be from 1:0.2 to 1:3. A solvent may be added such as benzene, toluene, xylene, ethylbenzene, cumene, chlorobenzene, heptane, cyclohexane, isooctane or cyclododecatriene in amounts of 0.2 to 0.5 times the amount of diene. The catalyst may be "developed" in the solvent for up to 10 hours.