Patent GB-874325-A (GB)
Title: Production of ureas
Inventor: APPLEGATH FRED
IPC: C07D235/26
Filed: 1958-03-18
Abstract: Polymeric or cyclic ureas are produced by heating a mixture of carbon monoxide, sulphur and a polyamino compound which contains at least two primary or secondary amino groups or a primary and a secondary amino group and which may contain other substituents inert under the reaction conditions e.g. alkyl, alkenyl, aryl, cycloalkyl, carboxyl, hydroxyl, thiol, cyano, halogen, alkoxy, aryloxy, dialkylamino, organosilyl or polysiloxaryl.  The reaction may take place at between 60 DEG  and 300 DEG C., preferably 60 DEG -160 DEG , preferably at an autogeneously produced pressure between 30 and 1,500 p.s.i. and in the presence of an inert diluent such as ligroin, isopropanol, di-isopropyl ether, ethanol, mineral oil, triethylamine, pyridine, isopropanol-water mixtures, ethylene glycol, b -methoxyethanol, tetrahydrofurfuryl alcohol, dimethylaniline, N, N-diethylethanolamine, formamide, amyl alcohol, benzene or preferably methanol.  When aromatic amines are used an alkaline catalyst, preferably having a KB greater than 1 X 10-10 such as a tert. alkylamine, may be used, e.g. 0,002-0,2 mols per mol of aromatic amine.  The reactants may be used in approximately stoichiometric quantities, the mol. ratio of polyamine to sulphur may range from 0,1 : 1 to 8 : 1.  The nature of the product depends on the polyamine used, in general if the amino groups are separated by less than 6 carbon atoms or are in ortho or similar positions on a ring, cyclic ureas are obtained (see Group IV(b)), if they are separated by six or more carbon atoms or are in meta or para or similar positions on a ring, polymeric ureas are obtained, generally diamines give rise to linear polymers and polyamines to cross-linked polymers.  A list of suitable reactants is given.  In the examples polymeric ureas are obtained using as a reactant m-phenylene diamine, 2, 4, 6-triaminotoluene, 2, 4-diaminophenol hydrochloride, benzidine, o-tolidine, 2, 4-diaminotoluene, o-di-anisidine, bis(3-aminopropyl) ether, p-phenylene diamine and hexa-, octa-, deca- and dodeca-methylene diamine.  The degree of polymerization and softening points of many of the polymers are given.ALSO:Cyclic or polymeric ureas are produced by heating a mixture of carbon monoxide, sulphur and a polyamino compound which contains at least two primary or secondary amino groups or a primary and a secondary amino group and which may contain other substituents inert under the reaction conditions, e.g. alkyl, alkenyl, aryl, cycloalkyl, carboxyl, hydroxyl, thiol, cyano, halogen, alkoxy, aryloxy, dialkylamino, organosilyl or polysiloxanyl.  The reaction may take place at between 60 DEG  and 300 DEG C., preferably 60 DEG  to 160 DEG C., preferably at an autogenously produced pressure between 30 and 1500 p.s.i. and in the presence of an inert diluent such as ligroin, isopropanol, di-isopropyl ether, ethanol, mineral oil, triethylamine, pyridine, isopropanol-water mixtures, ethylene glycol, b -methoxyethanol, tetrahydrofurfuryl alcohol, dimethylaniline, N,N - diethylethanol-amine, formamide, amyl alcohol, benzene or preferably methanol.  When aromatic amines are used an alkaline catalyst, preferably having a KB greater than 1 X 10-10, such as a tert. alkylamine, may be used, for example 0.002 to 0.2 mols. per mol. of aromatic amine. The reactants may be used in approximately stoichiometric quantities, the mol. ratio of polyamine to sulphur may range from 0.1:1 to 8:1.  The nature of the product depends on the polyamine used, in general if the amino groups are separated by less than 6 carbon atoms or are in ortho or similar positions on a ring, cyclic ureas are obtained, if they are separated by 6 or more carbon atoms or are in meta or para or similar positions on a ring, polymeric ureas are obtained (see Group IV(a)).  A list of suitable reactants is given.  In the example in which reaction is carried out in methanol under autogenously produced pressure (1) ethylenediamine gives 2-dihydroimidazolone, (2) 1,2-propylenediamine gives 4-methyldihydro-2-imidazolone, (3) 1,3-diamino-2-propanol gives 5-hydroxy-2-tetrahydropyrimidone, (4) 1,4-diaminobutane gives tetramethylene urea, (5) 1,5-pentamethylene diamine gives pentamethylene urea, (7) triethylene tetramine gives sym. ethylenebis-(2-dihydroimidazolone), (8) diethylene triamine gives N,N1-bis(b -dihydroimidazolonylethyl) urea; (6) o-phenylene diamine in the presence of pyridine and triethylamine gives benzimidazolone.