Synthesis Of 3,5,6-trichloropyridin-2-ol Sodium

3,5,6-trichloro-2-ol sodium is a important intermediate pesticide of O, O- diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate, Based on the principle of green chemistry to choose the appropriate production plan and reduce the cost,researching its synthesis method has great significance and provide baseline data for industrial production.and has important significance.This paper reviews the various synthetic methods of 3,5,6-trichloro-2-ol sodium.Through theoretical analysis and research, we design synthesis route of3,5,6-trichloro-2-ol sodium.In production process of chloroacetic acid waste mother liquor as raw materials(Main ingredients for a chloroactic acid, dichloroacetic acid,trichloroacetic acid),get mixed qualified chloride by chloride and rectification. Then halogenated also get trichloroacetyl chloride.With trichloroacetyl chloride and acrylonitrile as raw materials, CuCl and Cu as catalyst, obtained intermediate by the addition and cyclization.And get products by realkalization.The results show that:In the acid chloride process of trichloroacetyl chloride preparation,n(acid liquor): n(sulfur) = 1: 0.48,react at 45 ℃ ~70 ℃ for 10~12h,get mixed qualified chloride, the product yield was 80.41%,content of 97.14% by GC;Chloride process m(pyridine): m(4- dimethylaminopyridine) = 1: 0.03,react at 70 ℃ ~110 ℃ for 12 h,get trichloroacetyl chloride,the product yield of 85.5%,content of 99.12% by GC;With trichloroacetyl chloride and acrylonitrile as raw materials, n(trichloroacetyl chloride): n(acrylonitrile)= 1: 1.3, a catalytic amount of CuCl is 2.64% of trichloroacetyl chloride quality,m(CuCl): m(Cu) = 4: 1, with o-dichlorobenzene as a solvent, the solvent amount is 3 times of trichloroacetyl quality,at 140 ℃,reflux below the liquid surface, then cyclized and addition into salt,obtained sodium 3,5,6-trichloro-2-ol,the product yield was 78.6%,content of 98.7% by HPLC;The by-product of 2,3,5,6-tetrachloropyridine reaction after hydrolysis reaction, n(tetrachloropyridine): n(NaOH) = 1: 4, at 140 ℃ for 3h, to give sodium 3,5,6-trichloro-2-ol, yield 84.6%.This synthesis method is a simpleprocess, low price of raw materials, mild reaction conditions, simple post-treatment process route, there is a good prospect.