Study On Process Of 1, 3, 5-Benzenetriol

As an important organic intermedium, 1,3,5-benzenetriol is widely used inpharmaceutics, dying and the related fields. In this paper, 1,3,5-benzenetriol wasprepared through three steps using 2,4,6-trinitrotoluene as raw material.2,4,6-trinitrotoluene was first oxidized to 2,4,6-trinitrobenzoic acid, then2,4,6-trinitrobenzoic acid was reduced to 1,3,5-triaminobenzene, at last1,3,5-triaminobenzene was hydrolyzed to 1,3,5-benzenetriol.It has special significance to choose 2,4,6-trinitrotoluene as raw material.2,4,6-trinitrotoluene has been forbidden to use in the field of military project because ofthe environment factors. But in our country, the preparation technology of2,4,6-trinitrotoluene is very mature and its annual output reaches ten thousandstons .Transforming 2,4,6-trinitrotoluene to 1,3,5-benzenetriol can make good use of theproduce route of 2,4,6-trinitrotoluene and find a new outlet for 2,4,6-trinitrotoluene.2,4,6-trinitrotoluene was oxidized separately by Na2Cr2O7/H2SO4, KClO3/HNO3 andKClO4/H2SO4/H3PO4. The processes of oxidation using the latter two oxidizers weremainly argued.2,4,6-trinitrotoluene was successfully oxidized to 2,4,6-trinitrobenzoic acid byKClO₃/HNO₃(68%). The process was optimized by orthogonal experiment .When thereaction proceeded at 75⁸0℃ for 1.5h, molar ratio of 2,4,6-trinitrotoluene to KClO₃ toHNO3 was 1:3:13, the yield of 2,4,6-trinitrobenzoic acid reached 90%.2,4,6-trinitrobenzoic acid was also obtained by oxidizing 2,4,6-trinitrotoluene usingthe oxidizer of KClO₄/H₂SO₄(98%)/H₃PO₄(98%). The effects of several factors on thereaction were discussed and an optimized synthetic condition was obtained. When themolar ratio of 2,4,6-trinitrotoluene to KClO₄ to H₂SO₄ to H₃PO₄ was 1:4:12:3, the yieldof 2,4,6-trinitrobenzoic acid reached 94% after acting at 70℃ for 1 hour.2,4,6-trinitrobenzoic acid was reduced separately by iron-powder and catalytichydrogenation.The process for making 1,3,5-triaminobenzene was studied by reducing2,4,6-trinitrobenzoic acid with iron-powder as reduced agent in the presence ofhydrochloric acid (36%), which consisted in adding successive small quantities of themixture of 2,4,6-trinitrobenzoic acid and iron-powder to hydrochloric acid containing asmall quantity of iron chloride. The process and the followed hydrolyzed condition wereoptimized by orthogonal experiment. When the reaction at 75℃ , molar ratio of2,4,6-trinitrobenzoic acid to iron-powder was 1:15, the pH of hydrolyzed solvent was1.0¹.5, the yield of 1,3,5-benzenetriol reached 70% after hydrolyzing the reducedproduction(1,3,5-triaminobenzene) for 24 hours in the N2 atmosphere. The order ofeffects of these factors on the yield was as follows: reduced temperature>the pH of thehydrolyzed solvent>molar ratio> hydrolyzed time.When using acetone-water as solvent, Raney Ni as catalyst, 2,4,6-trinitrobenzoic acidwas reduced by catalytic hydrogenation after reacting 2.5h at 60⁶5℃ under thepressure of 0.5×106Pa. Although 1,3,5-benzenetriol was obtained by hydrolyzing thereduced production(1,3,5-triaminobenzene )in the N2 atmosphere with pH1¹.5 for20²4h, the yield of 1,3,5-benzenetriol was low. The process of catalytic hydrogenationneeds to be further studied.