GB832141A - Hydrogenation catalyst and its use in partial hydrogenation of 1,4-butynediol - Google Patents

Abstract

A hydrogenation catalyst is prepared by treating a liquid dispersion or solution containing a copper compound and metallic palladium with a reducing agent (preferably hydrogen or hydrazine, but also e.g. hydroxylamine) so as to deposit metallic Cu on the Pd, the latter preferably being supported on an inert carrier such as carbon (preferably charcoal), aluminium or silica. It is preferred to use an aqueous solution of a Cu salt, particularly the acetate, but also e.g. the sulphate, chloride, nitrate, cyamide, formate, carbonate or oxide, in dispersion or solution. The catalyst is preferably utilized for the conversion of 1 : 4-butynediol to 1 : 4-butenediol: it is stated that the catalyst may be used also for converting nitro-compounds to amines, ethylenic to saturated compounds, carbonyl compounds to alcohols and particularly acetylenic to ethylenic compounds. U.S.A. Specification 2,319,707 is referred to.ALSO:1 : 4-Butynediol is converted to 1 : 4-butenediol by use of a catalyst prepared by treating a liquid dispersion or solution of a copper compound and metallic palladium with a reducing agent (e.g. hydrogen, hydrazine or hydroxylamine) to deposit metallic Cu or the Pd. Preferred conditions for the conversion are (a) use of 1 equivalent of H2; (b) about room temperature-100 DEG C., particularly about 40-75 DEG C.; (c) about 1-20, particularly about 3-10 atm. In an example, a catalyst slurry prepared from 5% Pd on charcoal, and aqueous Cu acetate at 40 DEG C. under 75 p.s.i.g. of H2 was used to hydrogenate three successive portions of 38.3% aqueous butynediol at 40 DEG C. and 75 p.s.i.g., each reaction being stopped when 95% of 1 equivalent of H2 had been added (5 hours). Each one gave 87-88% total diols, over 90% thereof being recovered as butenediol. U.S.A. Specification 2,319,707 is referred to.