GB311788A - Improvements in the production of mono or polyhydric alcohols - Google Patents

Abstract

311,788. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). Dec. 2, 1927. Addition to 309,200. Alcohols.-In the process for the production of mono-and polyhydric alcohols by catalytic reduction with hydrogen of the condensation products of aldehydes or ketones or both described in the parent Specification, the condensing agent is removed from the condensation product prior to the reduction, either by precipitating the condensing agent with a suitable precipitant, such as sulphuric, oxalic or carbonic acid, or by purecipitating the condensation products, for instance in the form of saccharates, by adding metal oxides or hydroxides, especially alkaline earth oxides or hydroxides, or by extraction of the condensing agents or the condensation products with solvents such as water or alcohols. The condensing agents may be compounds of magnesium, barium, strontium, calcium, lithium, or lead, for instance the oxides, hydroxides, basic salts and salts with weak acids such as carbonates and formates and the catalysts for the reduction may be metals of the 1st and 8th groups of the periodic system, preferably with the addition of activators such as the oxides, hydroxides silicates and phosphates of the same or other elements, and preferably with a carrier such as kieselguhr or fullers' earth. In an example, a 3 per cent solution of formaldehyde is heated and stirred with lead hydroxide at 100‹ C. for an hour and after removing the undissolved lead hydroxide the dissolved lead is removed by adding dilute sulphuric acid; the filtrate is concentrated and reduced by hydrogen in presence of an activated nickel-kieselguhr catalyst, the products containing penta- and hexa-hydric alcohols together with glycol and glycerol. In another example, a 4 per cent solution of formaldehyde is heated and stirred with magnesia at 130‹ C. for 1¢ hours; the reaction mixture is concentrated to a syrup and the condensation product is extracted with alcohol, the solution being reduced with hydrogen at 25 atmospheres with a nickel-fullers' earth catalyst containing 40 per cent of nickel, which has been reduced in hydrogen at 450‹ C. The product is a mixture of polyhydric alcohols including glycol and glycerol, which are separated by distillation in vacuo.