Synthesis
A solution of 4-amino-benzenethiol (1.00 Kg, 7.99 mol) was dissolved in toluene (2 liters) under nitrogen and slowly added with mechanical stirring to a reactor containing 4-1-chloro-4-nitrobenzene (1.32 Kg; 8.38 mol), toluene (2 liters), 30% sodium hydroxide (1.17 Kg; 8.78 mol), and tetrabutylammonium hydrogensulfate (68 g; 0.2 mol). mixture in a reactor. The reaction temperature was maintained at about 85C during addition; the mixture was then maintained at the same temperature for about 2 hours. Toluene was added to the mixture and then the phases were separated at about 85C. The organic phase was then flushed with dilute sulfuric acid. The organic phase was then flushed with dilute sulfuric acid and the organic phase was concentrated under vacuum to about 4 liters and cooled. It was then separated by filtration at 60C under vacuum, rinsed and the crystalline product was dried. 1.87 Kg of pure 4-amino-4'-nitrodiphenyl sulfide was obtained (95% yield; 99% purity).
