| 摘要 |
PURPOSE:The catalytic hydrogenolysis of p-aminoazobenzene is carried out in the presence of a catalyst in aniline as a solvent, as the hydrogen pressure is kept at a specific level to enable high-yield production of the titled compound in a low pressure in no need of expensive high-pressure reaction installation with saved energy. CONSTITUTION:The catalytic hydrogenolysis of p-aminoazobenzene is effected in aniline as a solvent in the presence of a Pd or Ni catalyst, which may be supported on an inert carrier such as carbon, under such conditions as the hydrogen pressure is kept at lower than 10kg/cm<2> (absolute), preferably 2-10kg/cm<2> (absolute), as hydrogen is fed, the concentration of aminoazobenenzene is adjusted to 2-40wt% and the temperature is kept at 40-200 deg.C, preferably 100- 180 deg.C, for 20min-5hr. The catalyst is removed, aniline is distilled off from the reaction mixture and the residue is subjected to fractional distillation or recrystallization to give p-phenylenediamine. USE:A starting material in rubber chemical industry, dye industry and for heat- resistance wholly aromatic polyamides. |
