Study On The Preparation Technology Of 2,3,5,6-Tetraaminopyridine Through Catalytic Hydrogenation

2,3,5,6-tetraaminopyridine (TAP) mainly used for synthesizing a type of functionality heterocyclic polymer fibre PIPD, is an important chemical intermediate product.The good tensile and compressive deformation behaviour,flame-retardant performance,thermal performance,low density,high strength, high modulus of PIPD fibre can widely be used in armor,high strength cable warp,high performance flame-resistant material,high performance fabric and the light advanced composite material.Preparation of 2,3,5,6-tetraaminopyridine via hydrogenation reduction of 2,6-diamino-3,5-dinitropyridine (DADNP) using palladium-ruthenium/carbon as catalyst in methanol medium was studied.The optimum technical conditions determined by orthogonal test, additional test and stability test were as follows:reaction temperature of 55～65℃and pressure of 0.5～2.0 MPa, m(catalyst)/m(DADNP)=6%,molar of raw material:volume of solvent=1mol:2.8L.Under these optimum technical conditions, a yield of about 96.46% and a purity to more than 99.5% were obtained.Thereinto,2,6-diamino-3,5-dinitropyridine was obtained form 2,6-diaminopyridine by acylation and nitrifying reaction, a yield of about 94.13% and a purity to more than 99% were obtained. The structure of the hydrogenation products was respectively characterized by 1HNMR,MS,IR.The structure and performance indexes of the products conformed to the design requirement.