Synthesis And Optimization Of Triclopyr

Triclopyr, the chemical name 3,5,6-trichloro-2-pyridyloxy-acetic acid, is a kind of high efficiency, low toxicity and strong absorption conductibility of the herbicide. Triclopyr can be used for weeding out of infused before afforestation, laying out young pine trees and seeding forestation.As studied references completely, this paper focus on the technology of preparing Triclopyr with Sodium Salt Of Trichloro Pyridinol and Methyl Chloroacetate as raw material, while using N,N-Dimethylformamid(DMF) or Acetonitrile as the reaction medium. It’s dried after the product produced completely, and hydrolyzed in the aqueous Sodium Hydroxide, then acidized with Hydrochloric acid. Besides, the reaction condition is optimized.Through the establishment of water weight measuring and method of assaying of the Sodium Salt Of Trichloro Pyridinol, the purity of raw material is 85.23% and the moisture content is 2.49%, while, the method of assaying of the intermediate and Triclopyr are also established.It is studied the producing of intermediate of Triclopyr in the paper, using DMF as organic solvent. As the reaction condition is optimized, such as the mole ratio of material, the temperature, the weight of DMF, and so on, better results are achieved, which 46.6g(0.18 mol) Sodium Salt Of Trichloro Pyridinol(NaTCP) is added in the reaction vessel and the mole ratio of NaTCP and Methyl Chloroacetate is 2.22:1, the intermediate is produced 6.5 hours in 65℃after 110g DMF is added in the vessel. Under these conditions, the conversion of NaTCP is 99.18%, and the yield of intermediate [(3,5,6-trichloro-2-pyridinyl)oxy] acetate methyl is 96.40% as well as the purity of it is 98.84%.The Acetonitrile is also used in the reaction as solvent to produce intermediate of Triclopyr [(3,5,6-trichloro-2-pyridinyl)oxy] acetate methyl and the reaction condition is optimized too. The amazing condition is also obtained, which 13.06g(0.05 mol) Sodium Salt Of Trichloro Pyridinol is added in the vessel and the mole ratio of NaTCP and Methyl Chloroacetate is 1.1:1, the intermediate is synthetized 27 hours in 82℃after 50g Acetonitrile is added,15g Acetonitrile is recycled by atmospheric distillation. Under these conditions, the conversion of NaTCP is get to 99.53%, and the yield of intermediate is achieved to 94.53% while the purity of it is 92.31%. With the advantages of mild reaction conditions, low prices and reused of recycling Acetonitrile, it’s a process of simple, economical and environmental. In this paper, it is also studied the producing of Triclopyr with [(3,5,6-trichloro-2-pyridinyl)oxy] acetate methyl and water in aqueous Sodium Hydroxide by hydrolysis reaction, then Triclopyr is synthetized after the acidification by Hydrochloric acid. As the reaction conditions are optimized, such as the weight ratio of material, the concentration of aqueous Sodium Hydroxide, the temperature of hydrolysis, and so on, the better results are gained, which 5g [(3,5,6-trichloro-2-pyridinyl)oxy] acetate methyl is added in the reaction vessel and the weight of [(3,5,6-trichloro-2-pyridinyl)oxy] acetate methyl and water is 30:1, while hydrolyzed 4 hours in 75℃in 10% of aqueous Sodium Hydroxide, then acidized 1 hour with Hydrochloric acid. Under these conditions, the yield of Triclopyr is reached 98.42%, and the purity of the product is 99.13%.