Patent GB-771063-A (GB)
Title: Improvements in and relating to the production of amines
Inventor: DENT WALTER THEODORE
Filed: 1954-03-05
Abstract: In a process for the production of amines having the structure <FORM:0771063/IV(b)/1> where R1 and R11 are cycloaliphatic groups or groups having a structure <FORM:0771063/IV(b)/2> where R1 and R11 are alkyl or aralkyl groups, an amine of the structure <FORM:0771063/IV(b)/3> is coupled with a benzene diazonium salt to give an azo compound having a structure <FORM:0771063/IV(b)/4> which is catalytically hydrogenated in the presence of a cycloaliphatic ketone or a ketone having the structure R1.CO.R11, whereby amines having the structures <FORM:0771063/IV(b)/5> and <FORM:0771063/IV(b)/6> are formed simultaneously.  In modifications of the process a substituted benzene diazonium salt, e.g. such as that produced from o-toluidine, and an N-substituted aniline containing alkyl or alkoxy groups situated in ortho or meta positions to the substituted amino group, e.g. N - methyl - o - toluidine, N - methyl - o - or m - anisidine, may be employed.  In a further modification of the process the intermediate amino-azo compound may be converted to the corresponding nitrosamino compound of the formula <FORM:0771063/IV(b)/7> by treatment with sodium nitrite and hydrochloric acid prior to catalytic hydrogenation in the presence of a ketone of the kind defined.  The intermediate amino-azo compound or the nitroso derivative thereof may be freed from traces of chlorine containing organic compounds before hydrogenation by solvent extraction or by treatment in solution with an anion exchange resin. Hydrogenation catalysts specified comprise copper or a metal selected from Group VIII of the Periodic System, e.g. copper chromite, finely divided nickel or platinum or platinum oxide. The hydrogenation is preferably carried out in the liquid phase. Aniline may be added to the reactants before the catalytic hydrogenation.  The products may be used as antioxidants in stabilizing compounds liable to deterioration due to peroxide formation, e.g. petrols, aldehydes, ethers, esters of unsaturated carboxylic acids and unsaturated hydrocarbons or mixtures containing such compounds.  In examples: N,N1-di-sec.-butyl-p-phenylenediamine is obtained by coupling N-sec. butyl-aniline with diazotized aniline in methanol solution, treating the reacted mixture with water and ammonia and extracting with petroleum ether the 4-sec. butyl-aminoazobenzene and hydrogenating the latter with methyl ethyl ketone in the presence of a platinum-on-charcoal catalyst (1); N,N1-di-isopropropyl - p - phenylene - diamine is obtained in a similar process employing N-isopropyl-aniline instead of N-sec. butyl-aniline and acetone instead of methyl ethyl ketone (3); N,N1-di-sec. butyl-p-phenylenediamine is obtained by a process similar to (1) except that the azo compound intermediate is converted to 4-N-(nitroso-sec. butyl)-amino azo benzene by treatment with hydrochloric acid and sodium nitrite before hydrogenation (2).ALSO:Petrols are stabilized with amines having the structure <FORM:0771063/III/1> wherein R1 and R11 are cyclo-aliphatic group or groups having a structure <FORM:0771063/III/2> wherein R1 and R11 are alkyl or aralkyl groups (see Group IV(b))