Patent GB-621744-A (GB)
Title: Improvements in and relating to the hydrogenation of cyclic organic compounds
IPC: C07D295/023
Filed: 1946-02-27
Abstract: Monomeric compounds containing an aromatic or unsaturated heterocyclic nucleus and an aliphatic hydrocarbon side chain with at least one olefinic bond are continuously subjected in the vapour phase to the action of hydrogen at elevated temperature in the presence of a copper- or nickel-containing hydrogenating catalyst to produce compounds in which the nucleus is unchanged and at least one double bond in the side chain has been saturated. Vinyl furan, vinyl benzene, vinyl substituted alkyl benzenes containing up to 12 carbon atoms exclusive of the vinyl group, and n-vinyl pyrrole may be hydrogenated to the corresponding ethyl derivatives.  Pressure is generally atmospheric.  Suitable catalysts are copper on zinc oxide, made by precipitating basic carbonates from a mixed nitrate solution, calcining at 400 DEG , pelleting and reducing at 350 DEG  C., and nickel or copper chromite, prepared by ammonia precipitation of a solution of hexavalent chromium and a salt of the other metal, drying, decomposition at up to 300 DEG , pelleting, and reduction at 350 DEG  C.  Foraminate catalysts may be prepared by treating alloys of copper or nickel with other metals, e.g. aluminium, in particulate form, and treating with alkali or acid to dissolve part of the more soluble metal.  Examples of each catalysts are described in Specifications 570,843 and 621,749.  With ordinary copper or nickel catalysts, suitable temperatures are 200-450 DEG  or 70-400 DEG  C. respectively, liquid space velocities being up to 1l. per l. per hr. With foraminate catalysts, lower temperatures are preferred, for example, 70-120 DEG  C. for nickel, with space velocities above 1. Molar ratios of hydrogen to reactant are generally 3-4 : 1.  A diluent gas may be present.  In an example, aqueous zinc nitrate is treated with soda ash to yield a slight precipitate, copper nitrate added, and precipitation completed, the solid being dried, pelleted and reduced below 400 DEG  C. in H2/N2 before being used for hydrogenation of vinyl furan.  Specification 596,880, [Group IV], also is referred to.ALSO:Monomeric compounds containing an aromatic or unsaturated hetrocyclic nucleus and an aliphatic hydrocarbon side-chain with at least one olefinic bond are continuously subjected in the vapour phase to the action of hydrogen at elevated temperature in the presence of a copper- or nickel-containing hydrogenating catalyst to produce compounds in which the nucleus is unchanged and at least one double bond in the side-chain has been saturated. Vinyl furan, vinyl benzene, vinyl substituted alkyl benzenes containing up to 12 carbon atoms exclusive of the vinyl group, and n-vinyl pyrrole, may be hydrogenated to the corresponding ethyl derivatives.  Pressure is generally atmospheric.  Suitable catalysts are copper on zinc oxide, made by precipitating basic carbonates from a mixed nitrate solution, calcining at 400, pelleting and reducing at 350 DEG  C., and nickel or copper chromite, prepared by ammonia precipitation of a solution of hexavalent chromium and a salt of the other metal, drying, decomposition at up to 300, pelleting and reduction at 350 DEG  C.  Foraminate catalysts may be prepared by treating alloys of copper or nickel with other metals, e.g. aluminium, in particulate form, and treating with alkali or acid to dissolve part of the more soluble metal.  Examples of such catalysts are described in Specifications 570,843, [Group III], and 621,749.  With ordinary copper or nickel catalysts, suitable temperatures are 200-450 DEG  or 70-400 DEG  C., respectively, liquid space velocities being up to 1 1. per 1. per hour.  With foraminate catalysts, lower temperatures are preferred, for example 70-120 DEG  C. for nickel, with space velocity above 1.  Molar ratios of hydrogen to reactant are generally 3-4 : 1.  A diluent gas may be present.  In an example: aqueous zinc nitrate is treated with soda ash to yield a slight precipitate, copper nitrate added, and precipitation completed, the solid being dried, pelleted, and reduced below 400 DEG  C. in H2/N2 before being used for hydrogenation of vinyl furan.  Specification 596,880 also is referred to.