| 摘要 |
The present invention relates to a method of preparing para-phenylenediamine, and more particularly, to a method of preparing para-phenylenediamine including the following steps: a first step for injecting oxygen(O2) into a gas stream, of a process of preparing a nitric acid (HNO3), containing nitrogen dioxide (NO2), nitrogen monoxide (NO), water, and nitric acid impurities to adjust a ratio of the nitrogen monoxide (NO) and the nitrogen dioxide (NO2); a second step for liquefying water and a nitric acid impurity to remove the water and the nitric acid impurity by treating the ratio adjusted gas stream with water; a third step for condensing gas stream, from which water and nitric acid impurities are removed, under a condition of a temperature of 0 to 20°C and of a pressure of 0.9 to 2 bar to prepare nitrogen tetroxide(N2/O4); a fourth step for making the nitrogen tetroxide and mono nitrobenzene to gas phase react in the presence of a zeolite catalyst to prepare 1,4-dinitrobenzene; and a fifth step for hydrogenation of the prepared 1,4-dinitrobenzene to prepare para-phenylenediamine, thus having less content of ortho or meta-dinitrobenzene to have high purity and high yield of para-phenylenediamine. |
