Research On Synthesis Experiment And Technology Of Sodium 3, 5, 6-trichloropyridin-2-ol

Sodium 3,5,6-trichloropyridin-2-ol is an important chemical material, chelating floating agent of choiceness performance, main intermediate for synthesizing several herbicides, fungicides, and insecticides, for example, the organic phosphorus insecticide O-O-diethyl-O-3,5,6-trichloro-2-pyridyl phosphorothioate.According to the original material, the method for producing trichloropyridinol sodium including pyridine route, acrylic acid way, benzene trichloroacetate and trichloroacetyl chloride way etc. However, trichloroacetyl chloride technology is adopt broadly at home. A great deal of thesis and patents on the synthesis technique of trichloropyridinol sodium which using trichloroacetyl chloride (TCAC) and acrylonitrile (VCN) had been published over the seas. From the literature, the yield of product is mostly 50 percent to 70 percent.Zhejiang xin'an chemical co., Ltd. has a set of lOOOt/a production devices of chlorpyrifos which using TCAC and VCN to synthesize trichloropyridinol sodium at atmospheric pressure. Whereas, the yield of trichloropyridinol sodium which is always under 56 percent. In order to reduce the producing cost and enhance competition of market of chlorpyrifos , it is essential to improve the yield of trichloropyridinol sodium.See from the structure, the'process which to synthesize trichloropyridinol sodium with TCAC and VCN including Addition, Cyclization and Aromatization. Among the three steps, Addition reaction is the crucial step in that it is not only the slowest process but also how much its yield decides stand or fall of content of trichloropyridinol sodium.The thesis mastered the general characteristic and rule, analyzing especially the crucial process that is decisively from the principle of every step at first. In the second, the paper discussed the following factors such as reaction temperature, pressure, times, the kind of catalyst or co-catalyst, and the kind of solvent or co-solvent, and proportion of all kinds of materials and so on, which is how to influence the yield and content of trichloropyridinol sodium. At last, the thesis brought forward optional control parameters of technology;' Innovatively add a process of reducing temperature in the Cyclization. Changing the manner joining of acrylonitrile from join-one-off to titration or batch. The data of production indicate that the yield of trichloropyridinol sodium has proved over nine percent.