GB625909A - Manufacture of polyhydroxy compounds - Google Patents

Abstract

Polyhydroxy compounds are produced by reacting a mixture of formaldehyde, carbon monoxide and hydrogen, the formaldehyde being initially present, at a pressure of not less than 200 atmospheres and at a temperature of from 80 to 300 DEG C. in the presence of a hydrogenating catalyst. Instead of formaldehyde compounds yielding it under the reaction conditions may be used, e.g. paraformaldehyde, reactive formals, trioxane, and N-methylol derivatives. The reaction products may be further treated with hydrogen to obtain increased yields of hydroxy compounds boiling in the range of the lower glycols, and glycerine. This subsequent hydrogenation may be conducted in the presence of a hydrogenation catalyst, e.g. copper chromite at superatmospheric pressure at a temperature of about 100 DEG to 300 DEG C. Specified hydrogenating catalysts for the main reaction are nickel, cobalt, manganese, iron, chromium, copper, platinum, molybdenum, palladium, zinc, cadmium, ruthenium and compounds thereof or combinations of these materials with each other or with inert supports, e.g. kieselguhr, pumice, or with promoters such as thoria and manganese. Preferred catalysts are cobalt-containing catalysts such as metallic cobalt, reduced sintered cobalt oxide, cobalt carbonyl and salts of cobalt. Preferred temperatures are 100 DEG to 200 DEG C. and pressures of 200 to 1500 atmospheres are preferred. The reaction may be effected in an inert reaction medium, e.g. an aliphatic ether or ester. In examples: (1) a mixture of paraformaldehyde, methyl formate and reduced sintered cobalt oxide is heated in a silver-lined shaker tube under a pressure of 500 to 700 atmospheres of a mixture of carbon monoxide and hydrogen, distillation of the resulting mixture yields a mixture of polyhydroxy compounds; (2) reaction is effected as in (1) but a pressure of 460 to 750 atmospheres is employed, the resulting product is freed from methyl formate and then hydrogenated in methanol solution in the presence of copper chromite at a temperature of 230 DEG C. under a pressure of 745 to 750 atmospheres. Distillation of the product yields fractions containing ethylene glycol and glycerol respectively; (3) a mixture of trioxane, distilled water and reduced sintered cobalt oxide are heated under a pressure of 550 to 640 atmospheres of a gas containing carbon monoxide and hydrogen and the resulting product distilled yielding polyhydroxy compounds; (4) a mixture of paraformaldehyde, methyl formate, and reduced sintered cobalt oxide is heated under pressure and a mixture of carbon monoxide and hydrogen is then injected and the heating continued under a pressure of 445 to 735 atmospheres. Distillation of the product gives a syrupy residue containing polyhydroxy compounds and unspecified oxygenated compounds. The molecular ratio of carbon monoxide to hydrogen used is preferably from 4 : 1 to 1 : 10 and in the examples about 1.5 to 2 moles of carbon monoxide is initially present per mole of formaldehyde.