Patent GB-651250-A (GB)
Title: Improvements in or relating to synthesis of alcohols from olefins, carbon monoxide and hydrogen
IPC: C07C45/50
Filed: 1948-12-31
Abstract: Olefines, carbon monoxide and hydrogen are reacted together in the presence of a carbonylation catalyst to form carbonyl compounds which are hydrogenated in a hydrogenation zone and the products distilled to remove and recover alcohols at least some of the bottoms from the distillation stage being hydrolysed to give more alcohols and carbonyl compounds.  The carbonylation and hydrogenation stages of the above process are effected by methods known in the art.  Thus olefines specified include straight and branched chain olefines and diolefines, olefine polymers, olefinic fractions from the hydrocarbon synthesis process, and those from thermal or catalytic cracking processes.  In general, olefines of 18-20 carbon atoms per molecule are preferred.  Carbonylation catalysts specified are salts of catalytically active metals, e.g. cobalt stearate, oleate or naphthenate and iron linoleate. Preferably about equal volumes of hydrogen and carbon monoxide are used and 1000-45,000 cubic feet of mixed hydrogen and carbon monixide (generally 2500-15,000) are used per barrel of olefine fed.  Pressures in the range of about 1500-4500 pounds per square inch gauge and temperatures of about 150-450 DEG F. are indicated. Hydrogenation catalysts mentioned include supported or unsupported metallic nickel, cobalt, sulphactive catalysts, e.g. tungsten, molybdenum and nickel sulphides and copper chromite. Hydrogenation temperatures mentioned are 150-450 DEG  F. with pressures of about 1500-4500 pounds per square inch gauge.  The bottoms remaining after the removal of unreacted hydrocarbons and alcohols have been found to contain acetals, e.g. up to 50 per cent which on hydrolysis yield additional alcohols and carbonyl compounds. The hydrolysis may be effected with dilute mineral acid or steam at elevated temperatures and the products separated and recycled to the hydrogenation stage.  In an illustration an olefine containing dissolved therein a conventional carbonylation catalyst in a concentration of 0.1-5.0, preferably about 1 per cent by weight of olefine is reacted with a gas mixture containing hydrogen and carbon monoxide in the approximate ratio of 0.5-2.0 vols. of the former to the latter at about 3000 pounds per square inch gauge and about 250-400 DEG  F.  Products are withdrawn, cooled and sent to a high-pressure separator where gases are removed, scrubbed of entrained catalyst and optically recycled to the reactor, a modification wherein a portion of the liquid product from the carbonylation zone containing dissolved catalyst is recycled to the reactor being described and claimed in Specification 647,363.  Liquid products are withdrawn to a low-pressure separator and freed from more metal carbonyls before passing together with unreacted olefines to a catalyst removal zone where they are treated with hydrogen containing gases optionally recovered from another stage in the process, preferably at about 200-450 DEG  F. to deposit catalyst metals, e.g. on inert packing and to liberate carbon monoxide which may be purged with hydrogen as described and claimed in Specification 629,915.  The mixed hydrogen and carbon monoxide may be methanized or used in the hydrogenation stage if a CO-insensitive catalyst is used therein, e.g. sulphactive catalysts.  Carbonyl products substantially free of catalysts are withdrawn and hydrogenated at 2500-4500 pounds per square inch gauge and about 300-500 DEG  F. depending on the conventional catalyst chosen and at a hydrogen rate of about 5000-20,000 normal cubic feet per bbl. of feed. Products and unreacted hydrogen are cooled, separated and the hydrogen preferably recycled to the hydrogenator.  Products are withdrawn via a low-pressure regenerator and sent to a still for removal of hydrocarbons, e.g. with a U.O.P. C7 olefine fraction as feed, the product boiling up to 340 DEG  F. is removed, and may be used as a gasoline blending agent, the bottoms being withdrawn and distilled for alcohol recovery.  Bottoms from the last still are sent to a hydrolyser, preferably made of acid-resistant material and equipped with an agitator where they are treated with a 10 per cent aqueous hydrochloric acid solution at 200-250 DEG  F. when after hydrolysis the products are withdrawn and the aqueous layer separated from an organic layer from which alcohols and aldehydes are recovered from less volatile polymeric products by steam distillation or by vacuum distillation preferably at 30 mm. Hg or less.  Alcohols and aldehydes so produced may be recycled to the hydrogenator or treated with an aldehyde polymerizing agent and the alcohol remaining distilled off. In this modification esters obtained in the synthesis may be saponified when alkalis are used as polymerizers.  The hydrolysis may be effected with live steam, e.g. at 300-400 DEG  F.  If the alcohols obtained are water soluble they are recovered by conventional methods from the aqueous layer from the hydrolyser.  Aluminia, silica and metals or metal oxides of the eighth group of the Periodic System may be used to convert the acetals instead of acid.  In examples: (1) a U.O.P C7 polymer cut (160-210 DEG  F.) is used as olefinic feed for the first stage in which 1.2 per cent cobalt oleate is present as catalyst reaction being effected at an average temperature of 349 DEG F. and pressure of 3000 pounds per square inch gauge with liquid feed rates of 0.99 v/v/hr., a vol. ratio of H2/CO of 1.14 and H2+CO feed rate of 3000 standard cubic feet per barrel of olefine feed, the hydrogenation stage being effected at an average temperature of 410 DEG  F. and pressure of 2700 pounds per square inch gauge in the presence of nickel and tungsten sulphides with a liquid feed rate of 1.0 v/v/hr. and hydrogen rate of 5000 cubic feet per barrel of feed, the products being distilled to give 24 per cent unreacted hydro-carbons, 61 per cent of alcohols and 15 per cent of bottoms, which latter are autoclaved at 350 DEG  F. with an equal vol. of water for 2 hours and the consequent increase in alcohol and aldehyde content is shown by means of a table of hydroxyl, carbonyl, acid and saponification numbers; in example (2) the bottoms are redistilled to remove C8 alcohols, redistilled at 10 mm. and the fraction boiling between 270-292 DEG  F. is hydrolysed with water alone and 10 per cent HCl at 350 DEG  and 220 DEG  F. respectively, results being tabulated as in (1).