Toluene → N-Phenyl-p-phenylenediamine

Participants

Reaction Steps

In this example the sodium salt of p-nitrosodiphenylamine was hydrogenated in a continuous manner over a fixed bed of catalyst. Diphenylamine (338 g, 2 mols) was converted to the sodium salt of p-nitrosodiphenylamine as in Example 2. A solution of approximately equal weights of toluene and 1-butanol was added to dilute the solution of the sodium salt to a concentration of about 13.5 wt. %, and enough water was added to dissolve all the inorganic salts present in the aqueous phase. The two phases were separated and simultaneously pumped into a tube reactor over a 0.4 wt. % palladium on charcoal catalyst at 125° C., 1000 psig hydrogen pressure at 1 liquid hourly space velocity based on total liquid. Thin layer chromatography indicated 100% conversion of p-nitrosodiphenylamine. Distillation of the residue after separation of the aqueous phase and removal of the organic solvents gave 95% p-aminodiphenylamine exclusive of losses from column hold-up.

Provenance & Evidence