Patent GB-703100-A (GB)
Title: Improvements in or relating to selective hydrogenation of oxo-process aldehydes
Inventor: BURNEY DONALD EUGENE
IPC: C07C29/141
Filed: 1951-06-19
Abstract: A process for selectively hydrogenating aldehydes to yield alcohols in a mixture containing aldehydes and olefines obtained by subjecting a secondary olefine-tertiary olefine copolymer to reaction with carbon monoxide and hydrogen under the conditions of the Oxo-synthesis and in the presence of a carbonylation catalyst comprises contacting the mixtures with hydrogen at about 150-700 DEG F., at a pressure above about 500 lbs. per sq. in., and with a liquid space velocity between about 0.1 and 5.0 volumes of charging stock per gross volume of catalyst zone per hour in the presence of a cobalt catalyst.  Specified copolymers are those of propylene, 1-butene, 2-butene, or a secondary amylene, with isobutylene, 2-methyl-1-butene or 2-methyl-3-butene.  The copolymers may be made by acid treatment, e.g. with sulphuric acid, phosphoric acid, hydrogen fluoride, copper pyrophosphate, boron fluoride, silica alumina or acid-treated bentonite. Pressures specified are about 500-4,000 lbs. per sq. in. Unreacted olefines may be recycled.  The hydrogenation may be effected batchwise in autoclaves, with cocurrent flow at about 350-600 DEG  F., or in countercurrent but is preferably effected by trickling the mixture downwards over a pelleted catalyst in a continuous atmosphere of hydrogen at about 350-600 DEG  F., about 500-1,500 lb. per sq. in., and with a liquid space velocity of about 0.2-2.0 per hour.  Many hydrogenation catalysts containing metallic cobalt are specified all of conventional type. Preferred are supported catalysts containing about 5-15 per cent. of cobalt. Before hydrogenation cobalt carbonyl and carbon monoxide is preferably removed from the mixture.  The hydrogen used for hydrogenation preferably contains less than about 2 per cent. of carbon monoxide and should be substantially free from catalyst poisons such as hydrogen sulphide.  Separation of the final product into alcohols, olefines and saturated hydrocarbons may be accomplished by conventional means, many of which are specified.  The alcohols in the mixture may be esterified, e.g. with boric acid or phthalic anhydride, the esters separated and alcohols regenerated. The mixture may be dehydrated, e.g. over an alumina catalyst at 700-900 DEG  F., to give an olefinic charging stock containing olefines of one more carbon atom than those originally used.  Liquid diluents may be present, those specified being aliphatic, aromatic and naphthenic hydrocarbons, ethers, alcohols, especially lower aliphatic alcohols, benzyl alcohol and tetrahydrofurfuryl alcohol. In an illustration of suitable apparatus lay-out for batch operation olefine copolymer is treated with carbon monoxide and hydrogen in approximately 1 : 1 mol. ratio at around 350 DEG  F. and approximately 200 atoms in the presence of a catalyst comprising 3 to 5 per cent. cobalt on kieselguhr, the reaction products are purged of carbon monoxide by treatment with hydrogen at 375-425 DEG  F. and finally hydrogenated at about 500-1,500 lb. per sq. in.  In an illustration of a continuous process olefine charging stock is treated at about 100-300, preferably 200, atmos., and about 200-500 DEG , preferably about 325-375 DEG  F. with an equimolar mixture of carbon monoxide and hydrogen.  The rate of injection of copolymer is about 0.05-10, preferably about 0.5-2, vols. per hour per unit vol. of reaction zone and the catalyst comprises metallic cobalt on an inert silicious material or metal carbonyls or salts added with the charging stock.  The liquid products, in part recycled for temperature control, and optionally treated for removal of catalyst and carbon monoxide, are hydrogenated at around 800 lb. per sq. in. and around 550 DEG  F.  Products of hydrogenation are separated by fractionation.  In examples (1)-(5) products from the carbonylation step of Oxo processes in which n-butylene-iso-butylene codimers are used are hydrogenated at pressures ranging from 750-850 lb. per sq. in. and temperatures of 380-600 DEG  F. in the presence of metallic cobalt on "Filtros," and in (6) a C7 fraction from a propylene-butylene copolymer is carbonylated, the products washed at 80 DEG  F., with aqueous sulphuric acid, steam distilled and the distillate hydrogenated over cobalt on pumice at 375 DEG  F. and 3,000 lb. per sq. in.  The alcohol products may be oxidized to aldehydes or acids, reacted with ammonia to form amines, with other amines to form mixed amines, dehydrated to olefines, and ethers, to alkylate aromatics, and esterified.  Esters specified being phthalates, phosphates, sebacates, adipates, stearates, citrates, sulphates, acrylates and methacrylates of mixed octyl and nonyl alcohols.