Study On The Synthesis Of 2, 6-Dichlorobenzoxaxole As An Important Intermediate Of Pesticides

2,6-dichlorobenzoxazole is a very important intermediate in organic chemistry.It is widely used in the formation of pesticide,medicine and especially dense aryloxyphenoxypropionate（APP）herbicides.For example,the synthesis fenoxaprop-P-ethyl herbicide and metamifop herbicide.Based on the evaluation of the bibliographer and the analysis of the principle of reactions,we studied the two routes in the synthesis of 2,6-dichlorobenzoxazole:Route 1:Benzoxazotone was firstly synthesized by using o-aminophenol and urea or BTC as the raw materials, 6-chloro-2-benzoxazole was synthesized between Benzoxazotone and Sulfuryl chloride with FeCl₃ as catalyst,then the 6-chloro-2-benzoxazole was chloridized with Phosphorus pentachloride to obtain 2,6-dichlorobenzoxazol.The total yield was 43.5%.Route 2:p-Chloroaniline was coverted to N-（4-chlorophenyl）acetamide by heating with acetic anhydride,then O-hydroxylation obtained 2-acetamido-5-chlorophenyl acetate.2-Amino-5-chlorophenol was prepared from 2-acetamido-5-chlorophenyl.Then the 2-Amino-5-chloro-phenol reacts with carbon disulfide,and finally 2,6-dichlorobenzoxazol was obtained after chloridized by various chloride reagent.The total yield was 56.6%.Compare the advantages and disadvantages of the two route,the second rout was selected as the better one for preparation of 2,6-dichl-orobenzoxazol, and the technology conditions were tested by Orthogona-lized experiment.The dissertation a theoretical basis and feasible process parameters for the industrialization of 2,6-dichloro-benzoxazole.