Patent GB-589342-A (GB)
Title: An improved process for the production of aromatic amines
IPC: C07C209/36
Filed: 1944-03-16
Abstract: <PICT:0589342/III/1> Aryl amines of the benzene series are obtained by introducing a mixture of aryl nitro hydrocarbons, (which may include polynitro compounds) hydrogen and large quantities of a liquid diluent into a reaction zone at a plurality of points in the presence of a hydrogenation catalyst at an elevated temperature, removing the reaction products from said reaction zone separating the liquid diluent from the reaction products and preferably recycling the diluent to the reaction zone to act as a cooling medium. Advantageously, the liquid diluent is a hydrocarbon and is present in an amount varying between 20 and 90 per cent. by volume of the total liquid feed mixture.  Specified diluents are: a light hydrocarbon oil boiling within the motor fuel range, i.e., between 100 and 400 DEG F., e.g., xylene and the liquid products obtained by the hydrogenation of dis-isobutylene or by the alkylation of olefins with isoparaffins or by the hydrogenation of carbon monoxide, or a heavy hydrocarbon diluent boiling above 400 DEG F., e.g., lubricating oil, gas oil, white oil or kerosene.  In an example the nitro compounds such as nitro xylene isomers, containing about 10 per cent. of the di nitro derivatives, are mixed with hydrogen and fed to a pre-heater at a temperature of 300 to 400 DEG F. and thence to a plurality of catalyst chambers heated at 350 to 600 DEG F. under a pressure of 500 to 5,000 lbs. square inch diagrammatically represented as 13a, 13b, 13c, and 13d containing a hydrogenation catalyst such as 5 to 80 per cent. by weight of molybdenum sulphide deposited on charcoal; tungsten sulphide; a mixture of 1 part nickel and 2 parts of tungsten sulphide; molybdenum oxide and/or zinc oxide with magnesium oxide; and molybdenum sulphide, nickel or nickel sulphide supported on alumina, silica, porcelain, or charcoal; copper oxide on alumina. The diluent is introduced through line (25) and (26) or through line 27 with or without hydrogen from line 40 and thence to a plurality of points such as 29a, 29b, 29c.  The xylidene products are passed through heat exchanger (8) condensed in cooler (18) and separated from unreacted gases in separator (20) the unreacted gases being recycled to the system.  The diluent is separated from the amines by distillation and returned to the reactor through line (25).ALSO:<PICT:0589342/IV/1> Aryl amines of the benzene series are obtained by introducing a mixture of aryl nitro hydrocarbons (which may include polynitro compounds) hydrogen and large quantities of a liquid diluent into a reaction zone at a plurality of points in the presence of a hydrogenation catalyst at an elevated temperature, removing the reaction products from said reaction zone, separating the liquid diluent from the reaction products and preferably recycling the diluent to the reaction zone to act as a cooling medium. Advantageously, the liquid diluent is a hydrocarbon and is present in an amount varying between 20 and 90 per cent by volume of the total liquid feed mixture.  Specified diluents are: a light hydrocarbon oil boiling within the motor fuel range, i.e. between 100 DEG  and 400 DEG  F., e.g. xylene and the liquid products obtained by the hydrogenation of di-isobutylene or by the alkylation of olefins with isoparaffins or by the hydrogenation of carbon monoxide, or a heavy hydrocarbon diluent boiling above 400 DEG  F., e.g. lubricating oil, gas oil, white oil or kerosene.  In an example, the nitro compounds such as nitro xylene isomers, containing about 10 per cent of the di-nitro derivatives, are mixed with hydrogen and fed to a pre-heater at a temperature of 300 DEG  to 400 DEG  F. and thence to a plurality of catalyst chambers heated at 350 DEG  to 600 DEG  F. under a pressure of 500 to 5000 lbs. sq. in. diagrammatically represented as 13a, 13b, 13c and 13d containing a hydrogenation catalyst such as 5 to 80 per cent by weight of molybdenum sulphide deposited on charcoal; tungsten sulphide; a mixture of 1 part nickel and 2 parts of tungsten sulphide; molybdenum oxide and/or zinc oxide with magnesium oxide; and molybdenum sulphide, nickel or nickel sulphide supported on alumina, silica, porcelain, or charcoal; copper oxide on alumina. The diluent is introduced through lines 25 and 26 or through line 27 with or without hydrogen from line 40 and thence to a plurality of points such as 29a, 29b, 29c.  The xylidene products are passed through heat exchanger 8 condensed in cooler 18 and separated from unreacted gases in separator 20, the unreacted gases being recycled to the system.  The diluent is separated from the amines by distillation and returned to the reactor through line 25.