GB984510A - New polyethers - Google Patents

Abstract

Compounds having polyether chains terminated by primary amine groups are prepared by the reduction of the corresponding nitriles <FORM:0984510/C2/1> where R1 and R2 are hydrocarbon or halohydrocarbon groups, or one may be hydrogen, R3 and R4 are hydrogen, or one may be a methyl group, a and m are greater than 1, and X is the residue of a compound XHa having a hydrogen atoms reactive towards cyclic oxides. The reduction may be effected by any conventional nitrile-reducing agent, such as sodium amalgam/ethanol, but catalytic hydrogenation is preferred, platinum, nickel or, in particular, cobalt catalysts being suitable. The hydrogenation may be effected in the liquid phase at 20-200 atmospheres and 70-150 DEG C., with or without diluents, such as methanol, ethanol, or dioxan, in the presence of excess ammonia. Instead of ammonia excess acetic anhydride may be used, in the presence of sodium acetate (optional), in which case the amine is recovered by hydrolysis, and pressures and temperatures as low as 50 p.s.i. and 50 DEG C. may be sufficient. The examples describe the hydrogenation of a b -cyanoethyl polyoxypropylene of molecular weight about 1000, in the presence of Raney nickel in acetic anhydride sodium acetate, and the recovery of the product by treatment with sulphuric acid, then sodium hydroxide, before distilling, and the hydrogenation of the same nitrile, and of a cyanoethylated oxypropylated trimethyl propane, in the presence of cobalt on kieselguhr in ammonia/methanol. Specification 984,372 is referred to.ALSO:Compounds having polyether chains terminated by primary amine groups are prepared by the reduction of the corresponding nitriles X[-(-CHR1-CHR2-O-)-mCHR3-CHR4 -CN]n where R1 and R2 are hydrocarbon or halohydrocarbon, or one may be hydrogen, R3 and R4 are hydrogen, or one may be a methyl group, a and m are greater than 1, and X is the polyvalent residue of a compound XHa having a hydrogen atoms reactive towards cyclic oxides. The preparation of such compounds is described in Specification 984,372. The reduction may be effected by any conventional nitrile-reducing agent, such as sodium amalgam ethanol, but catalytic hydrogenation is preferred, suitable catalysts being platinum and nickel, and, particularly, cobalt catalysts. The hydrogenation may be effected in the liquid phase at 20-200 atmospheres and 70-150 DEG C., with or without diluents, e.g. methanol, ethanol, or dioxan, in the presence of excess ammonia, or excess acetic anhydride, with or without sodium acetate. When acetic anhydride is used, the amine is recovered by hydrolysis, and pressures and temperatures as low as 50 p.s.i. and 50 DEG C. may be sufficient. The examples describe the hydrogenation of a b -cyanoethyl polyoxypropylene of molecular weight about 1000 in the presence of Raney nickel, in acetic anhydride/sodium acetate, and in the presence of cobalt on kieselguhr in ammonia/methanol, and the reduction of a cyanoethylated oxypropylated trimethylol propane in the latter manner, and the isolation of the products.