The Hydrogenation Catalysts Prepared from Transition Metal Chloride and Triethylaluminum

Abstract

Abstract Catalysts composed of anhydrous iron(III) chloride, cobalt(II) chloride, or nickel(II) chloride plus triethylaluminum have been used for the hydrogenation of olefin. The catalytic activity has changed with the Al(C2H5)3/MCln ratio. The optimum ratios for the hydrogenation of styrene have been found to be 1–7 for the iron catalyst, 0.2–1 for the cobalt catalyst, and 0.3–2 for the nickel catalyst. Cyclohexane has been used satisfactorily as a solvent. Tetrahydrofuran could be used for the nickel catalyst, but its presence was unfavorable for the iron and cobalt catalysts. The gas evolved in the reaction of the transition metal chlorides with triethylaluminum has been found to be essentially ethane, and sluggish gas absorption was observed when the atmosphere was switched to hydrogen. Ethylbenzene was formed in the treatment of the catalyst with styrene under nitrogen; the amount increased considerably if the catalyst was pre-treated with hydrogen. Ethane was formed in the hydrogen-treatment of the reaction mixture of nickel chloride and triethylaluminum. On the basis of these results, it has been assumed that metal hydride has been formed by the hydrogenolysis of metal - ethyl bonds.