The Study On Synthesis And Kinetics Of MTP

MTP is an important microbial immunity adjuvant, which can not only enhance the immunity of body fluid and cells, but also heighten the protected ability of bacterin, sub-units virus, and helminth seedling. However, according to some published literature, the synthesis of MTP by hydrogenolysis debenzylation of PMTP has many disadvantages. On one hand, it needs a very long reaction time (three-days), on the other hand, the yield and purity of the product are quit low. Therefore, it is desired to improve the synthesis process of MTP.In this paper, the synthesis of MTP from PNAM through three steps was studied. The synthesis conditions of MTP were improved, then the kineties of hydrogenolysis of PMTP was studied.First, the synthesis of NAM by hydrogenolysis debenzylation of PNAM was investigated. Based on the investigations concerning the influence of the reaction condition, such as pressure, temperature, reaction time, the type of solvent and the amount of the catalyst, the favorable reaction conditions were found: solvent=80% acetic acid, w[Pd(OH)₂]: w (PNAM)=3%, P_H2 =0.1MPa, t=310min, T=45℃. Under these conditions, the yield of NAM is 92.70% with a purity of 97.53%.Based on the experimental data, a kinetic equation of the PNAM hydrogenolysis was obtained using integrated method. The reaction was the first-order with respect to PNAM under the experimental conditions. The apparent activation energy (E_a) of the reaction was 76.496kJ·mol^-1 and the pre-exponential factor (A) was 4.868×10¹⁰ min^-1. Structure of NAM was verified by IR, ¹H NMR, ¹³C NMR, LC-MS, and elemental analysis.Second, PMTP was synthesized from PNAM according to literature. The yield is 90.80% with a purity of 97.69%. This product was used as the starting material for the synthesis of MTP via hydrogenolysis. The effects of various factors, such as temperature, reaction time and the amount of catalyst in the synthesis of MTP were investigated. The optimized technical conditions were: solvent=80% acetic acid, w[Pd(OH)₂]: w (PMTP)=5%, t=220min, P_H2=0.1MPa, T=45℃. With these conditions, the yield of MTP is 90.05% with a purity of 99.23%. Based on the experimental results, a kinetic equation for the hydrogenolysis of PMTP was obtained. The reaction was the first-order with respect to PMTP. The apparent activation energy (E_a) of the reaction was 84.678 kJ·mol^-1 and pre-exponential factor (A) was 1.394×10¹² min^-1. Structure of MTP was verified by IR, ¹H NMR, ¹³C NMR, LC-MS, and elemental analysis.