The Study Of Pilot-Scale Production Of Cyadox And Optimization On Reaction Conditions

1,4-di-N-oxoquinoxaline derivatives were useful chemical substances that were used as animal feed additives. Cyadox is a potential candidate of these drugs. Surprisingly cyadox possessed valuable antimicrobial action both on Gram-positive and Gram-negative microorganisms, and also markedly promoted growth in farm animals. Cyadox has not been unreported substances in our country, and the research about the drug can fill the gaps in this area of our country.Cyadox was synthesized from benzofurazan by three steps including Beirut reaction, Redox reaction and Addition reaction. In the current study, the synthetic method of cyadox was verified by the pilot-scale production that set the base for industrialization and market process. Some proposals about the recovery of solvent reclaim were also put forward. According to the needs of the pilot production, sixteen batches of 2-Methylquinoxaline-di-N-Oxide were produced, and the average yield was 57.1%; five batches of the target product were produced, and the average yield of the last two steps was 77%. The overall yield was 44%. The result of the pilot-scale production was in accordance with that of the laboratorial experiment. Through technological accounting on the basis of the result of the pilot production and the recovery of solvent reclaim, the cost of cyadox was 126.5 thousand Yuan per ton.Many problems were exposed in the process of the quality control. (1) The quality of the product: the product was analysed by high-performance liquid chromatography (HPLC), and the results showed that the purity was no higher than 91%; the content of selenium was as high as 1400ppm after recrystallization. (2) High cost: The problem was caused by the price of the materials and the reagents such as selenium dioxide, dimethylsulfoxide. (3) Three wastes: The recycle of dimethylsulfoxide and selenium weredifficult, which lead to the environment pollution and much more material consumption.In view of the current problems, corresponding improvement methods are described to perfect the route. 2-Methylquinoxaline-di-N-Oxide was obtained at room temperature and benzofurazan and the intermediate of the first step were purified, which made target product's purity reach 98%; In the process of the Redox reaction, activated chemical manganese dioxide was attempted in use to substitute for selenium dioxide, and the reaction cannot occur according to the reaction phenomena; anhydrous ethanol was attempted in use to substitute for dimethyisulfoxide which was ropy and difficult to dry, the result shows the reaction can occur, but the yield was lower.In conclusion, some progress was made, but some problems need further research.