Hydride Transfer Reactions catalysed by Metal Complexes

Abstract

IN the course of an investigation of the catalytic action of certain metal complexes in hydride transfer reactions it was observed that rhodium chloride catalysed the dehydrogenation of isopropanol to acetone. During the reaction rhodium metal was precipitated, and it was found that the rate of dehydrogenation decreased as rhodium was removed from solution. For example, when a 100 ml. solution of isopropanol containing 0.0076 M rhodium trichloride, 0.094 M lithium chloride and 0.29 M hydrochloric acid was refluxed, 216 ml. of gas were evolved after 1 h and 303 ml. after 2 h. A sample of gas taken 1 h after the commencement of the reaction consisted of 97 per cent hydrogen, 1.4 per cent isopropyl chloride, and small amounts of acetone, isopropanol, di- isopropyl ether and propane (all less than 1 per cent). A total of 0.017 mole of hydrogen was evolved, and about 0.013 mole of acetone was formed in the reaction solution.