Synthesis Of3,5,6-trichloro-pyridine-2-phenol And Theoretical Study Of The Reaction Mechanism

Chlorpyrifos is a broad-spectrum and low toxicity type insecticide, which is currently the most widely used one of the pesticides.3,5,6-Trichloro pyridine-2-phenol is a key intermediate for synthesis of chlorpyrifos, and thus the synthesis of3,5,6-trichloro pyridine-2-phenol is an important task.This thesis which mainly studies the chlorpyrifos intermediate3,5,6-trichloro pyridine-2-phenol synthesis reaction process. Several main reaction conditions on reaction rate and product yield was investigated. By using nitrobenzene as solvent, trichloro acetyl chloride and acrylonitrile as raw materials in the copper chloride and copper composite catalyst, catalytic synthesis of phenolate was optimized. The optimum reaction conditions were found as follows:When the reactant ratio of CC13COC1to CH2CHCN is1:1.3, addition cyclization reaction was conducted at temperature of135℃for11hours and aromatization reaction was conducted at temperature of55℃for4hours. Under these optimum conditions the highest yield reached71.3%of the domestic high level, and purity of95.3%.The theory research for mechanism of trichloro acetyl chloride and acrylonitrile in the copper chloride catalyst. Generating phenolate is mainly divided into three steps:the addition reaction, cyclization reaction, and aromatization reaction.Among them, the addition reaction is the key step that directly decided the reaction rate and the product yield. The addition reaction of trichloro acetyl chloride with acrylonitrile was chosen as the research focus, and the cuprous chloride composite catalyst under the action of free radical reactions was selected as the research object. By using quantum chemistry calculation method to establish the model and Gauss03to simulate, three possible path was suggested for the trichloro acetyl chloride and copper chloride catalyst in the reaction process, and the most possible reaction pathway was derived. Such theoretical study for the reaction mechanism with quantum chemistry may provide a theoretical basis for further study.