Acceptor properties of metal halides. Part IV. Group III halides as catalysts for the racemisation of α-methylbenzyl chloride in diethyl ether

Abstract

The catalytic efficiencies of boron chloride, boron fluoride, aluminium chloride, and gallium chloride in the racemisation of α-methylbenzyl chloride in diethyl ether have been compared kinetically at 25°. Gallium chloride has also been studied at 5 and 15°. With aluminium and gallium chlorides, and with boron fluoride, a simple first-order dependence of rate upon catalyst concentration is found. The catalytic efficiencies are in the order GaCl₃ > AlCl₃ > BF₃. Qualitative results with boron chloride indicate that its efficiency is approximately the same as that of boron fluoride. The mechanism of racemisation is discussed in the light of these results.