Method for preparing quinclorac through catalytic oxidation

Abstract

The invention provides a method for preparing quinclorac through catalytic oxidation of 7-chloro-8-methylquinoline chloride. A synthetic route of the quincloac is shown in the description. The methodcomprises steps as follows: 7-chloro-8-methylquinoline chloride as a starting material, one or two of water, methanol and acetonitrile as solvents, oxygen, hydrogen peroxide or tert-butyl hydroperoxide as an oxidizing agent and transition metal salt as a catalyst form a compound catalysis system with a catalyst promoter molecular sieve in the description and quaternary ammonium salt, the compoundsynthesis system reacts at the temperature of 35-90 DEG C for 1-12 h, and quinclorac is obtained after conventional separation and has the yield range of 26%-28%. The transition metal salt is taken asthe catalyst, little transition metal salt is used, clean and cheap oxygen and hydrogen dioxide are used to replace high-cost concentrated nitric acid producing severe three wastes, environmental pollution is notably reduced, the production cost is reduced, the reaction condition is relatively mild, and the method is simple and convenient to operate, can be popularized to large-scale industrial production and has great significance in clean production.

Description

technical field

[0001] The present invention relates to a method for preparing aromatic acid, in particular to a method for preparing quinclorac by catalytic oxidation of 7-chloro-8-methylquinoline chloride. Background technique

[0002] Dichloroquinoline acid (Quinclorac), also known as 3,7-dichloro-8-quinoline carboxylic acid, the molecular formula is C 10 h 5 Cl 2 NO 2 , with a molecular weight of 242.1. Quinclorac is an effective selective herbicide for controlling barnyardgrass in paddy fields. It is a hormone-type quinoline carboxylic acid herbicide. The symptoms of weed poisoning are similar to those of auxins. It is mainly used to control barnyard grass and has a long application period. It is effective at the 1-7 leaf stage, and the rice has good safety. In recent years, the excellent herbicidal performance of quinclorac has been favored by the market, and the price of the original drug remains high. Therefore, it has great development value and good prospects ...