GB729841A - Elimination of colour-forming impurities from 1,4-butanediol - Google Patents

Abstract

A process for treating technical 1,4-butanediol which is substantially free of unsaturated impurities which contains impurities developing a dark colour on treatment with concentrated hydrochloric acid, for removing such colour-forming materials therefrom substantially without decreasing its butanediol content, comprises treating an aqueous solution containing from 20 per cent to about 60 per cent by weight of said technical butanediol with hydrogen in the presence of a nickel-containing hydrogenation catalyst at a temperature in the range of 150 DEG to 170 DEG C. and a pressure in the range of 50 to 500 atmospheres for a time in the range of about 1 to 10 hours and recovering the 1,4-butanediol as a product which does not develop colour in 30 minutes after mixing with concentrated hydrochloric acid. The starting material may be prepared by catalytic hydrogenation of butynediol obtained by reacting acetylene and formaldehyde. In examples: mixtures of 1 : 4-butanediol with water are hydrogenated using a Raney nickel catalyst in an autoclave at elevated pressures (1); in similar processes Raney nickel and nickel, copper and manganese supported on a siliceous carrier are employed as catalysts (2); in a similar process a catalyst comprising nickel, copper and manganese supported on silica activated by heating in hydrogen is employed (3); 1,4-butanediol, prepared by hydrogenating at elevated temperature and pressure using the catalyst employed in (3), the 2-butyne-1,4-diol solution obtained by reacting acetylene and aqueous formaldehyde diluted with a recycle liquid, by passing the mixture downward over a copper, bismuth acetylide catalyst supported on granular silica gel at elevated temperature and pressure, is hydrogenated at higher temperature and pressure.