Patent GB-620314-A (GB)
Title: Improvements in or relating to aniline condensation products and process of preparing same
IPC: C07D215/06
Filed: 1946-08-19
Abstract: Aniline condensation products are prepared by condensing aniline successively, in any desired order, with a hydrocarbon having a double bond connecting two carbon atoms, neither of which is in an aromatic nucleus, one of said carbon atoms being attached to a carbon atom in an aromatic nucleus, and with an aliphatic mono-ketone the condensations being performed by heating the reactants in the presence of an acidic condensation catalyst. Hydrocarbons instanced are alpha-substituted styrenes, e.g. o-, m- or p-methyl- or -ethyl-styrene, nuclear-substituted alpha-substituted styrenes, e.g. a  - p - dimethyl - styrene, poly - (nuclear-alkyl)-styrenes, vinyl-biphenyl, vinyl-naphthalene, vinyl-diphenyl-ethane, indene and dihydronaphthalene.  Ketones instanced are acetone, methyl-ethyl-ketone, diethyl-ketone, ethyl-hexyl-ketone, mesityl-oxide and phorone.  Catalysts instanced are hydrochloric, hydriodic, phosphoric and sulphuric acids, sodium bisulphate, zinc, aluminium and stannic chloride, boron trifluoride, iodine and amine hydrochlorides.  In the preferred method aniline is reacted with the hydrocarbon and the product with the ketone, but aniline may be reacted first with the ketone and then with the hydrocarbon. Temperatures employed range from 100-300 DEG  C. and pressure may be necessary.  In examples, aniline is reacted with (1) styrene in the presence of aniline hydrochloride to give a product, probably o-(a -phenyl-ethyl)-aniline, which is reacted with acetone in the presence of hydrochloric acid to give a product of unknown constitution; (2) a -methyl-styrene in the presence of aniline hydrochloride to give p - amino - 2,2 - diphenyl - propane which with acetone and hydrochloric acid yields 2,2,4-trimethyl-6-(a -phenyl-isopropyl)-1,2-dihydroquinoline; (3) a -p-dimethyl-styrene and hydrochloric acid to yield p-amino-p1-methyl-2,2-diphenyl-propane which with acetone and hydrochloric acid gives a product which is believed to be 2,2,4-trimethyl-6-(a -p-tolyl-isopropyl)-1,2-dihydroquinoline; (4) indene and hydrochloric acid to give an unidentified product which is condensed with acetone and hydrochloric acid, in (5) 2,2,4-trimethyl-1,2-dihydroquinoline, a condensation product of acetone and aniline is reacted with a -methyl-styrene in the presence of boron trifluoride to give 2,2,4-trimethyl-6- and -1-(a -phenyl-isopropyl)-1,2-dihydroquinoline, aluminium chloride may be used as catalyst in the above examples and its use results in a faster reaction and higher yields of required product and in (6) aluminium chloride is substituted for the aniline hydrochloride used in (2).  The products are antioxidants.ALSO:Antioxidants for rubber and latex are obtained by condensing aniline successively, in any desired order, with a hydrocarbon having a double bond connecting two carbon atoms neither of which is present in an aromatic nucleus and with an said carbon atoms attached to a carbon atom present in an aromatic nucleus and with an aliphatic mono-ketone, the condensation being performed by heating the reactants in the presence of an acidic condensation catalyst.  For details of preparation see Group IV (b).  They may be added to rubber on a roll mill or in an internal mixer or applied to the surface thereof in their pure form or dissolved in a solvent and can be used in the presence of other compounding ingredients such as pigments, fillers, dyes, accelerators and other antioxidants; they can be dispersed in rubber latex. Preferably they are used in amounts from 0.1 - 5.0 per cent based on the weight of rubber.  Stress-strain and flexing figures are given of a rubber composition after vulcanisation and before and after ageing in which the composition has no antioxidants, has two separate standard antioxidants and two separate antioxidants prepared as above from aniline  -methyl styrene and acetone and aniline,  -p-dimethyl styrene and acetone.