GB708488A - Improvements in or relating to aluminium and/or aluminium oxide coated metals - Google Patents

Abstract

Aluminium alcoholates may be prepared from methanol, ethanol, isopropanol, butanol, tert.-butanol, hexanol, isohexanol, heptanol, tert.-octanol, 2-ethyl-hexanol, 2 : 5-dimethyl heptanol, dodecanol, tetradecanol, penta-decanol, octadecanol, cyclohexanol, methylcyclohexanol, furfuryl alcohol, benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, glycerol, sorbitol and mannitol. Aluminium phenates may be prepared from phenol, o-cresol, m-cresol, p-cresol, commercial cresol mixtures, the xylenols a - and b -naphthols, resorcinol and pyrogallol. Alcoholates may also be prepared from mixtures of alcohols obtained by hydration of mixtures of olefins obtained in cracking petroleum fractions, or by reaction of such olefins with carbon monoxide and hydrogen in the Oxo process. Alcoholates may be prepared from aluminium powder or turnings heated under reflux with excess of the alcohol. Or the calculated amount of alcohol may be used with an inert solvent such as benzene, toluene or xylene. The aluminium may be activated by the addition of iodine or mercuric chloride. The alcoholates (excepting the methoxide) may be purified by distillation under reduced pressure. Aluminium ethoxide may be prepared using aluminium powder, xylene and absolute alcohol with mercuric chloride and iodine. Aluminium phenates may be prepared similarly by reacting aluminium with a phenol in a solvent.ALSO:A process for the protection of aluminium and/or aluminium oxide coated metals comprises applying to the surface thereof a p fluid consisting of, or containing, an aluminium alcoholate or phenate. The alcoholates may be prepared from mono-hydric, di-hydric or poly-hydric alcohols, which may be saturated or unsaturated, aliphatic, cyclic, alicyclic, heterocyclic or aromatic, such as methanol, ethanol, isopropanol, butanol, tert-butanol, hexanol, isohexanol, heptanol, tert.-octanol, 2-ethyl-hexanol, 2 : 5- dimethyl heptanol, dodecanol, tetradecanol, pentadecanol, octadecanol, cyclohexanol, methylcyclohexanol, furfuryl alcohol, benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, glycerol, sorbitol, or mannitol. The preferred alcohols are saturated aliphatic alcohols containing not more than 4 carbon atoms. The phenate may be prepared from mono-hydric, dihydric or poly-hydric phenols which may be mono-cyclic or poly-cyclic, such as phenol, o-cresol, m-cresol, pcresol, xylenols alpha and b naphthols, resorcinol or pyrogallol. The alumminium alcoholate may, if sufficiently volatile, be applied as a vapour by vacuum evaporation, or the undiluted liquid compound may be brushed or sprayed on the surface. Preferably the compound is applied in solution in a volatile solvent of low surface tension, such as benzene toluene, xylenes, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, diethyl ether or di-isopropyl ether. The solution may be brushed or sprayed on. The aluminium compound decomposes in pores in the coating to form aluminium hydroxide or alumina, which acts as a barrier and enhances the protection afforded by the coating.