Patent GB-792575-A (GB)
Title: Production of nitriles
IPC: B01J23/86
Filed: 1955-06-08
Abstract: Organic nitriles are produced by reacting in the vapour phase and at elevated temperature a primary alcohol and ammonia in the presence of a catalyst comprising activated alumina impregnated with copper, chromium oxide and an alkaline earth metal hydroxide or carbonate, or lithium hydroxide or carbonate, the hydroxide or carbonate being present in an amount less than 10 per cent by weight of the total catalyst.  The concentration of copper in the catalyst may range from 3-15 per cent by weight, calculated as copper oxide, and the amount of chromium oxide may range from 0.25 to 2 per cent by weight of the total catalyst.  The effective concentrations of alkaline earth metals and lithium in per cent by weight are: calcium carbonate 1.8 to 7.5, barium hydroxide 1.0 to 5, strontium hydroxide 1.0 to 6.0 and lithium hydroxide 2.0 to 6.0.  The process may be effected at 250 DEG to 350 DEG  C., the preferred range being 275 DEG  to 325 DEG  C. The reactants may be charged to the reactor as liquids or gases, and are vaporized within a preheating zone before contact with the catalyst.  It is preferred to employ hydrogen as a diluent for the reactants to assist in controlling the rate of flow of reactants and to maintain the catalyst in an active condition.  Suitable primary alcohols for use in the process are ethanol, n-propanol, n-butanol, isobutanol, 2-ethylhexanol, n-hexanol, 2-butyloctanol, 2-ethylbutanol, 2- or 4-methylcyclohexanemethanol, isoamyl alcohol, lauryl alcohol, benzyl alcohol, and homologues of benzyl alcohol. The apparatus used in the examples comprises two concentric tubes welded together at the ends, the outer tube being wound with a heating element and the annular space between the tubes being partially filled with a commercial heating fluid.  The products are collected in a series of condensers and refined by distillation. The catalyst is located in the lower half of the tube after a preheating and vaporizing space which is packed with an inert ceramically-bonded porous alumina.  Examples are given in which ethanol is converted to acetonitrile using hydrogen as a diluent and using a catalyst of the above-described type under varying conditions with calcium carbonate, barium hydroxide, strontium hydroxide or lithium hydroxide as the promoter.ALSO:A catalyst, suitable for use in producing organic nitriles by reaction of a primary alcohol and ammonia in vapour phase, comprises activated alumina impregnated with copper, chromium oxide and an alkaline earth metal hydroxide or carbonate, or lithium hydroxide or carbonate, the hydroxide or carbonate being present in an amount less than 10 per cent by weight of the total catalyst.  The concentration of copper may range from 3-15 per cent by weight, calculated as copper oxide; the chromium may range from 0.25 to 2 per cent by weight of the total catalyst. Effective concentrations of alkaline earth metals and lithium, in per cent by weight are: calcium carbonate 1.8 to 7.5; barium hydroxide 1 to 5; strontium hydroxide 1 to 6; lithium hydroxide 2 to 6.  The catalyst may be prepared by covering activated alumina with a solution of a water-soluble compound of an alkaline earth, metal or lithium and evaporating the solution, then immersing the treated alumina in an aqueous solution of copper and chromium salts, again evaporating off the water, roasting the treated particles to convert the deposited copper and chromium salts to oxides and finally reducing with gaseous hydrogen to leave the copper present mainly as the free metal.  It is preferred to deposit calcium as an organic salt which is converted by the roasting to carbonate.  Barium, strontium and lithium are preferably deposited as the hydroxides.  The catalyst may also be formed simultaneous deposition of alkaline earth metals or lithium and the copper and chromium from aqueous solution on to the activated alumina, followed by evaporation of the water, roasting at 400 DEG C. and finally reduction with gaseous hydrogen.  In an example activated alumina is covered with an aqueous solution of calcium acetate, the water is evaporated off, the treated alumina is then immersed in a solution containing copper nitrate-trihydrate and chromium nitrate-nonahydrate and the water is again evaporated off, the treated alumina is then roasted at 400 DEG  C. until the evolution of nitric fumes ceases, and the resulting catalyst is reduced in a stream of hydrogen at 290 DEG  C. before use.