Study On New Synthetic Process Of Pendimethalin And Sulcotrione

The function and development of pesticide were reviewed in this paper, and then the history and present situation of pesticide intermediate of pyridine were summarized. Then the detailed summary of 2-chloronicotinic acid which were included about its physical and chemical property, application and its synthetic routes.Based on references, the synthetic routes of 2-chloronicotinic were picked out and optimized. Route 1 we choose 3-cyanopyridine N-oxide as raw material and bis(trichloromethyl)carbonate as chloride regent for the chlorination reaction, and then hydrolyzed to give the title product 2-chloronictinic acid in stong alkaline solution. The factors which on the synthesis of the key intermediate 2-chloro-3-cyanopyridine were focused on and optimized with some experiments, and the best yield was 86%. Big reduction of environment pollution by use bis(trichloromethyl)carbonate as chloride reagent instead of POCl3. A new synthetic process of 2-chloronicotinic acid, that is route 2: N-methyl aniline as the staring material to produce 2-chloronicotinic acid for 5 steps: Firstly, N-methyl-formyl aniline was synthesized through the formylation with formic acid. And then reacted with bis(trichloromethyl)carbonate and vinyl ether to give the product N-methyl phenyl amino acrolein . Next to carry out the Knoevenagel reaction with ethyl cyanoacetate to abtain 1-cyano-4-(N-methyl-phenylamino)-1- ethoxycarbonyl 1,3-butadiene, and then methyl 2-chloronicotinate was obtained by closed-cycle reaction with HCl. Finally, the title produt was got by hydrolyzing. Each step of the reaction factors were discussed and optimized, the total yield was above 58.3%, and purity was greater than 99.5%. The second step in this line to prepare N-methyl phenyl amino acrolein by the use of bis (trichloromethyl) carbonate instead of POCl3, so as to reduce toxicity, environmental pollution and waste acid, which consistented with green chemical requirements. N-methyl aniline as raw material instead of dimethylamine in cycle reaction to avoid the difficult recovery of the gas that caused the air pollution.The optimum synthetic routes of 2-chloronicotinic acid were choosed suitable for industrial production.