GB654408A - Improvements in the manufacture of aluminium alkoxides - Google Patents

Abstract

Aluminium alkoxides are obtained by reacting vapours of alcohols containing not more than four carbon atoms with heated aluminium-bearing materials in the presence of a catalyst as defined below, the temperature to which the aluminium-bearing material is heated being such that the aluminium alkoxides are formed in the vapour phase. The catalyst is defined as anhydrous cupric chloride or a substance which is known to catalyse the reaction in the known methods for producing aluminium alkoxides from aluminium and an alcohol, but which will not volatilize at the reaction temperature. The alcohol may be normal, secondary, iso or tertiary. The aluminium-bearing materials are preferably comminuted and include both pure and impure aluminium as well as aluminium alloys and mixed alloy scrap. The alcohol vapour is preferably carried forward in a stream of nitrogen or hydrogen and the process can be carried out in a continuous manner, the alcohol vapour being passed in counter - current to the aluminium - bearing material as this is advanced through the reaction space. The reaction may be carried out under reduced pressure, atmospheric pressure or higher pressure. The alkoxide vapour formed may be hydrolysed to hydrate of alumina, e.g. by blowing steam into the vessel into which the vapour or smoke is delivered from the reaction space. The alcohol liberated can be recovered by distillation and returned to the process. In an example, a finely divided aluminium-copper alloy mixed with anhydrous cupric chloride is fed into one end of a reaction vessel heated to 200-300 DEG C. and passed through the vessel by a helical screw device. Ethyl alcohol vapour at atmospheric pressure and carried in a stream of nitrogen is passed counter-current to the metal, the rates of feed being controlled so that pure aluminium ethoxide distils over at the outlet end of the vessel. The Provisional Specification is not restricted to alcohols containing up to four carbon atoms but refers to the use of alcohols generally.ALSO:Hydrate of alumina is obtained by hydrolysing the aluminium alkoxide vapour obtained by reacting the vapour of an alcohol containing up to four carbon atoms with heated aluminium-bearing material in the presence of a catalyst the temperature to which the aluminium-bearing material is heated being such that the aluminium alkoxide is formed in the vapour phase (see Group IV (b)). The hydrolysis may be effected by blowing steam into the vessel into which the alkoxide vapour is delivered from the reaction space. The Provisional Specification is not restricted to the use of alcohols containing up to four carbon atoms but refers to alcohol vapours generally.