Method for production of aklylhalosilanes

In a method for production of alkylhalosilanes by reaction between elemental silicon and an alkylhalide at elevated temperatures in the presence of a copper-based catalyst, the improvement comprising adding a separate aluminium promoter in the form of a solid metallic aluminium, or a solid aluminium alloy, or a solid aluminium containing silicon alloy or a solid aluminium containing compound or mixtures thereof to the reactor at the start of the reaction in an amount between 0.01 and 1% by weight calculated as aluminium based on the weight of silicon supplied to the reactor, said aluminium promoter being added as a separate component from said silicon, said alkylhalide, and said copper-based catalyst;

• and maintaining the amount of aluminium promoter in the reactor during the reaction at between 0.01 and 1% by weight silicon in the reactor.