NITRO DERIVATIVES OF ANILINE 565HEXYL MANUFACTURE
Preparation of dinitrodiphenylamine (Ludwigshafen Process)An emulsion of 380 kg of aniline in about 1600 1. of an aqueous solution con-
taining 230kg of sodium carbonate and 1 kg of Nekal (emulsifier) is prepared. After
the emulsion has been heated to 60°C, 800 kg of molten 2,4-chlorodinitrobenzene
is run in. Then the whole is heated to 90°C. The formation of solid dinitrodipheny-
lamine may serve as a control indicating the progress of the reaction.
The solution is cooled to about 50°C, dinitrodiphenylamine is separated by ten-
trifuging, washed with diluted acid (from the nitration process) to remove aniline,
then thoroughly with water, dried at 100°C and pulverized. The product can be
obtained in almost theoretical yield 95-98%.Nitration of di- to tetra-nitrodiphenylamine (after J. Marshall [28])100 parts of dry dinitrodiphenylamine are charged into the nitrator, containing
350-400 parts of a nitrating mixture of the composition:HNO 3 30-45%
H 2 SO 4 40-50%
H 2 O 15-20%a temperature of 70°C being maintained during this procedure. When all the sub-
stance has been run in, the whole is heated to 80-90°C and kept at this temperature
until nitrogen dioxide stops evolving, which takes about 2 hr. Then the nitrator
contents are cooled and the yellowish brown crude product is separated from the
spent acid by filtration.
The approximate composition of the spent acid obtained in a series of runs
averaged :
HNO 3 14%
H 2 SO 4 51%
nitrosylsulphuric acid 7.5%
H 2 O 26%
organic matter 1%Nitration of tetranitrodiphenylatiine to hexyl (after J. Marshall [28]).Immediately after being filtered off, tetranitrodiphenylamine (containing some
acid) is taken in a quantity corresponding to 100 parts of the dry substance and
added to 375 parts of a nitrating mixture:
HNO 3 60%
H 2 SO 4 40%When using a mixture poorer in nitric acid, consisting e.g. of 25% of HNO 3 and
75% of H 2 SO 4 , a very fine crystalline product difficult to filter is obtained..