Patent GB-490922-A (GB)
Title: Improvements in or relating to the manufacture of aliphatic diamines
IPC: C07C209/48
Filed: 1936-11-16
Abstract: Hydrogenating catalysts are produced as follows: (a) sodium metasilicate solution is acidified with nitric acid and nickel nitrate, magnesia alba, and sodium bicarbonate solution are added, the coagulated precipitate being calcined and reduced in reducing gas at 460-475 DEG  C.; (b) sodium bicarbonate solution is added to a suspension of kieselguhr in a solution containing nickel nitrate and sodium silicate, the precipitate being washed, dried, and reduced in hydrogen at 460-475 DEG  C.  These catalysts and other hydrogenating catalysts such as pyrophoric or stabilized nickel catalysts or reduced cobalt or copper or zinc compounds, are used for reducing aliphatic dinitriles to diamines containing 6-10 carbon atoms, at least 4 of which are between the nitrile groups, the hydrogenation being effected in the liquid phase at 25-200 DEG  C. under pressure such as 500-4,000 lb. in the presence of ammonia and, if desired, of a solvent such as an alcohol, ether, or hydrocarbon.  Specifications 282,083, [Class 1 (i)], and 438,793 are referred to.  The Specification as open to inspection under Sect. 91 states that the dinitriles contain from 6 to 10 carbon atoms but is not limited to the treatment of such compounds which have at least 4 carbon atoms between the two nitrile groups.  This subject-matter does not appear in the Specification as accepted.ALSO:Aliphatic diamines are produced by hydrogenating the corresponding dinitrile containing from 6 to 10 carbon atoms in which the nitrile groups are separated by at least 4 carbon atoms, the reduction being effected in the liquid phase at 25-200 DEG  C. under pressure and in the presence of ammonia and a hydrogenating catalyst.  The pressure may be 500-4000 lb. and the quantity of ammonia is preferably at least two molecules for each molecule of dinitrile.  A solvent such as an ether, alcohol or hydrocarbon may be present.  Pyrophoric or stabilized nickel catalysts may be employed in the form of powder or supported on powdered materials such as kieselguhr or pumice.  Other hydrogenating catalysts such as metals or copper or zinc compounds may be used.  In examples, hexamethylene diamine is prepared in the presence of ammonia, from adiponitrile using a nickel catalyst, both with and without the presence of methanol, and also by the use of certain catalysts prepared as follows: (a) sodium metasilicate solution is acidified by nitric acid and nickel nitrate, magnesia alba and sodium bicarbonate solution are added, the coagulated precipitate being calcined and reduced in reducing gas at 460-475 DEG  C.; (b) sodium bicarbonate solution is added to a suspension of kieselguhr in a solution containing nickel nitrate and sodium silicate, the precipitate being washed, dried, and reduced in hydrogen at 460-475 DEG  C.  Other examples describe the production of octamethylene diamine from suberonitrile and of decamethylene diamine from sebaconitrile.  Specifications 282,083, [Class 2 (iii)], and 438,793 are referred to.  The Specification as open to inspection under Sect. 91 states that the dinitriles contain from 6 to 10 carbon atoms but is not limited to the treatment of such dinitriles which have at least 4 carbon atoms between the two nitrile groups.  This subject-matter does not appear in the Specification as accepted.