The Green Synthesis Of Nicotinic Acid And Study Of Catalysts

Nicotinic acid is widely used in Chemical industry , it was firstly synthesized by the oxidation of nicotine. But in industry it is always derived from alkylpyridine , such as 3-picoline, 2-methyl-5-ethylpyridine and quinoline .The synthesis methods are known as: liquid-phase direct oxidation using HNO3 and H2SO4, ammoxidation and oxidation of quinoline. Disadvantages of above processes include pollution, low productivity, complexity of process steps and high expense on equipments. With the rapid development of pharmaceutical and chemical industry, the demand for nicotinic acid increases quickly. But the existed methods haven't satisfied the market needs. Defined by the backward technology, of country and the increasing pressure on environmental protection, it is urgent to develop new, environment compatible synthesis means with low capital investment. So, we experimented on this subject and had achieved some positive results.The thesis consists two parts: Synthesis of Nicotinic acid through gas-phase oxidation of 3-picoline ; Synthesis of Nicotinic acid through liquid-phase oxidation of 3-picoline.For the gas-phase oxidation of 3-picoline , the main contents are: Comparing the performance of catalysts with different TiO2 crystal form, anatase is better; Designing and preparing different V2O5/TiO2 catalyst, and selecting a better one by the yield of nicotinic acid and through characterization. By comparing and analyzing a large amount of experimental results, we concluded a better reaction condition as follows:(l) anatase TiO2 is the best carrier for the catalyst.(2)when the V2O5-containing TiCVsupported catalyst with Cr2O3 as promoter has a 25:74:l(wt) composition, it has better performance.(3)the oxidation is carried out at a reaction temperature of 330 , velocity of 3-picoline was 0.05h-1and the mole ratio of air/water/3-picoline is 100/120/1. Results showed that the process employed gavehigher yield, better product quality and less pollution. The highest yield of nicotinic acid (>90%) was obtained.For the liquid-phase oxidation of 3-picoline, we tested the activity of different catalysts. Furthermore, the effect of reaction conditions on yield was studied. We concluded that the NHPI (N-hydroxyphthalimide) -Co-Mn catalyst system is better than Co-Mn-Br. Acetic acid was the best as solvent.The better reaction conditions are as follows, the amount of catalyst used: NHPI (9mol%X Co(OAc)2 (0.5mol%), Mn(OAc)2 (O.lmol%) ;the volume ratio of AcOH to 3-picoline was 35:1 ;the initial pressure was 1.6~1.7MPa and reaction was carried out at 170 for 4 h. The highest yield of nicotinic acid (83.2%) was obtained.