ORGANOALUMINIUM COMPOUNDS .15. MECHANISM OF EXCHANGE REACTION BETWEEN LEWIS-BASE COMPLEXED (CH3)2AIX AND (CH3)2AIY

Kinetic studies have beenmade by proton magnetic resonance spectroscopy of exchange reactions between trimethylaluminiumand dimethylaluminium bromide, trimethylaluminiumand dimethylaluminium chloride, trimethyl-aluminium and dimethylphenylaluminium, and (iv)dimethylaluminiumchloride and dimethylaluminium bromide. An excess of anisole waspresent in all four cases. In reactions (i), (ii), and (iii) the exchange rateswere strongly dependent upon excess anisole, but that of(iv) was only slightly dependent. The exchange between dimethylaluminiumchloride and dimethylaluminium bromide was also studied using an excess ofether and no dependence of rate upon excess ether was found. It is proposed that: (a)for (i), (ii), and (iii) removal of base from one of the organoaluminiumcompounds occurs prior to exchange; (b) exchange between dimethylaluminiumchloride and dimethylaluminium bromide in the presence of ether proceedswithout loss of base from either organoaluminiumcomplex; (c) for reaction (iv) exchange occurs partly with and partly withoutprior loss of base. © 1968 CSIRO. All rights reserved.