GB908767A - Process for purifying and colour-stabilizing octanols and decanols prepared by aldolcondensation of aldehydes - Google Patents

Abstract

In a process of producing octanols or decanols by subjecting aliphatic aldehydes to the aldol condensation, dehydrating the aldols to obtain unsaturated aldehydes, and hydrogenating the unsaturated aldehydes to produce the desired alcohols, the hydrogenation product is distilled in a fractioning column operated at an absolute pressure below 200 mm. mercury, preferably between 10 and 50 mm., to remove aldehyde-impurities overhead, and the product is finally submitted to a distillation in which the desired purified alcohols are obtained as distillate. The purified alcohols are suitable for the manufacture of colourless esters for use as plasticizers. In Example 1, n- and iso-butyraldehyde are reacted together in the presence of aqueous 2% sodium hydroxide solution at 90 to 95 DEG C. The reaction mixture is distilled from the caustic and salts, and the distillate is hydrogenated in the presence of Raney nickel. The product is dried by stripping in a packed column, operating with a base temperature of 186 DEG C. The mixture of dry alcohols is then distilled in a 50-foot column, operating at an absolute pressure of 33 to 35 mm., from which aldehydes are withdrawn overhead. The alcohols are finally distilled in a packed column; and 2-ethyl-4-methyl-pentanol is obtained as distillate. This product reacts with phthalic anhydride to give a colourless ester. Example 2 relates to the production of mixed decanols starting from n-valeraldehyde and 2-methylbutyraldehyde.