Patent GB-734247-A (GB)
Title: A process for producing alpha, beta-olefinic alcohols
IPC: B01J23/00
Filed: 1953-07-24
Abstract: Alpha, beta-olefinic alcohols are obtained by reducing alpha, beta-olefinic carbonylic compounds with hydrogen in the vapour phase by reacting hydrogen and the carbonylic compound in a molar ratio of at least 7 : 1 at 210-280 DEG  C. under a pressure of between 20 and 50 kilograms per square centimetre and in the presence of a catalyst comprising cadmium and one or more heavy metals of Groups I, II, VI and VIII of the Periodic Classification, the weight ratio of the total cadmium to the total of said heavy metal or metals present in said catalyst lying within the range 3 : 97 to 4 : 6.  The molar ratio of hydrogen to the carbonylic compound which may be an aldehyde or ketone is preferably between 10 : 1 and 15 : 1 and the reaction mixture may contain one or more inert gaseous diluents such as nitrogen or carbon dioxide.  Also small amounts of one or more of the various products formed during the reaction may be present in the gas stream fed to the reactor.  The cadmium present in the catalyst may be in the form of the free metal or as cadmium oxide and preferably at least 90 per cent of the cadmium present should be in the metallic form.  Specified heavy metals are iron, copper, silver, zinc, titanium, chromium, nickel, molybdenum, tungsten, cobalt, and manganese and these metals can also be employed either in the form of the free metal or in the form of an oxide, but preferably at least 90 per cent of the heavy metal is in the metallic form.  Metallic cadmium may be present as an alloy with one or more of the heavy metals.  Preferred catalysts are combinations of metallic copper and/or silver with metallic cadmium and/or cadmium oxide.  If desired, the catalyst may be supported on an inert carrier such as silica, alumina, pumice, or a diatomaceous earth material, such as kieselguhr.  The catalyst is preferably prepared by co-precipitating a mixture of cadmium hydroxide and the heavy metal hydroxide (see Group III).  The precipitate is then dried but it is preferably heated in air and then reduced to the metallic state with hydrogen prior to use. The co-precipitation is advantageously effected in the presence of a porous material, e.g. a siliceous material in finely-divided form, especially diatomaceous earth in amounts ranging from 10 to 75 per cent of the total weight of the catalyst.  The catalyst can be in the form of a fixed bed or in the fluidized state in which the catalyst is in finely-divided form and is maintained in the fluidized condition by the upward passage of the gaseous reactants.  The process may be carried out as an intermittent operation but is preferably carried out in a continuous manner, e.g. by bringing together the gaseous components and passing the mixture at the desired pressure through the heated catalyst which may be contained in an elongated tube or in a series of tubes. Examples describe the reduction of acrolein to allyl alcohol under various reaction conditions using catalysts comprising various proportions of copper and cadmium obtained by co-precipitation of the hydroxides in the presence or absence of varying proportions of siliceous material, the precipitate being washed with water, dried, heated in air, and reduced with hydrogen before use. Examples are also given for the reduction of acrolein using a catalyst comprising silver and cadmium prepared by co-precipitation as above in the presence of siliceous material and for the reduction of methyl isopropyl ketone, methacrolein and crotonaldehyde respectively to the corresponding unsaturated alcohols using a catalyst prepared as above and comprising copper, cadmium and inert siliceous material. Specification 398,982 is referred to.ALSO:A catalyst used in the production of alpha, beta-olefinic alcohols by reducing alpha, beta-olefinic carbonylic compounds with hydrogen in the vapour phase (see Group IV (b)) comprises cadmium and one or more heavy metals of Groups I, II, VI and VIII of the Periodic Classification, the weight ratio of the total cadmium to the total of said heavy metal or metals present in said catalyst lying within the range 3 : 97 to 4 : 6.  The cadmium may be present as the free metal or in the form of cadmium oxide. Preferably at least 90 per cent of the cadmium is present in the metallic form.  Specified heavy metals are iron, copper, silver, zinc, titanium, chromium, nickel, molybdenum, tungsten, cobalt and manganese.  These metals can be used either in the form of the free metal or in the form of an oxide, but preferably at least 90 per cent of the metal should be in the metallic form.  Metallic cadmium may be present as an alloy with one or more of the heavy metals.  Preferred catalysts are combinations of metallic copper and/or silver with metallic cadmium and/or cadmium oxide.  If desired, the catalyst can be supported on an inert carrier such as silica, alumina, pumice or a diatomaceous earth material, such as kieselguhr.  The catalyst is preferably obtained by co-precipitating a mixture of cadmium hydroxide and a hydroxide of the heavy metal.  The precipitate is then dried but preferably it is heated in air and then reduced to the metallic state prior to use.  It is advantageous to effect the coprecipitation in the presence of a porous material, e.g. a siliceous material in finely-divided form.  The preferred porous material is diatomaceous earth which is added in amounts of 10 to 75 per cent of the total weight of the catalyst.  Alternatively the catalyst may be prepared by impregnating a supporting material with a solution of a cadmium salt and a salt of the heavy metal, e.g. of copper or nickel, and then heating the impregnated material in air to convert the salts to the oxides which are then preferably reduced with hydrogen.  In examples, catalysts are prepared by adding an aqueous sodium hydroxide solution to an aqueous solution of the respective nitrates in which a sliceous filter-air is suspended.  The slurry formed is stirred, filtered and washed with water until the product is neutral.  The filter cake is then dried at 100 DEG  C., heated in air at 400 DEG  C. for about 4 hours and then ground and pelleted, the pellets being finally reduced in a stream of hydrogen at about 300 DEG  C. for 3 hours. Another catalyst is prepared in a similar way but without the addition of the siliceous material. Specification 398,982 is referred to.