Abstract: This application provides a communication method and a communication apparatus. The method includes: A first core network device obtains a target credential and attribute information of the target credential, and sends the target credential to a terminal device. The first core network device triggers, based on the attribute information of the target credential, the terminal device to perform, by using the target credential, an authentication procedure corresponding to the target credential. According to the communication method provided in this application, the terminal device can learn of a specific authentication procedure that should be performed by using an obtained credential. In other words, according to the method, the terminal device can perform, by using the obtained credential, the authentication procedure corresponding to the credential.

Abstract: Provided is a method for producing a chlorophenoxycarboxylate, comprising the following steps of: a phenoxycarboxylate under actions of a catalyst A and a catalyst B performing a selective chlorination of a chlorinating agent at a 2-position and/or a 4-position to obtain the chlorophenoxycarboxylate; the catalyst A is a Lewis acid; and the catalyst B has the following structure: R1?—S—R2?. The present disclosure redesigns the process route, and finely screens the catalyst and the chlorinating agent, thereby effectively improving the chlorination selectivity while avoiding the loss of the active ingredient, and the content of the obtained chlorophenoxycarboxylate can reach more than 98.5%, and the yield can reach more than 99%.

Abstract: Disclosed is a preparation method of phenoxycarboxylic acid herbicides. The preparation method comprises the following steps. S1: mixing an anhydrous phenol and a basic substance with a chloro-substituted carboxylic acid ester and performing a one-pot condensation reaction in an anhydrous system to obtain a phenoxycarboxylic acid ester. The chloro-substituted carboxylic acid ester is represented by the formula ClR1COOR, in which R1 is a C1-3 alkanediyl or alkylidene group, R is a C1-10 alkyl group or a C3-10 cycloalkyl group; S2: the phenoxycarboxylic acid ester undergoes selective chlorination with a chlorinating agent in the presence of a first catalyst and a second catalyst to obtain a chloro-substituted phenoxycarboxylic acid ester; and S3: the chloro-substituted phenoxycarboxylic acid ester undergoes an acid hydrolysis reaction to obtain a phenoxycarboxylic acid herbicide represented by formula I, in which R3 is H, Cl or CH3.

Abstract: Disclosed is a preparation method of phenoxycarboxylic acid herbicides. The preparation method comprises the following steps. S1: mixing an anhydrous phenol and a basic substance with a chloro-substituted carboxylic acid ester and performing a one-pot condensation reaction in an anhydrous system to obtain a phenoxycarboxylic acid ester. The chloro-substituted carboxylic acid ester is represented by the formula ClR1COOR, in which R1 is a C1-3 alkanediyl or alkylidene group, R is a C1-10 alkyl group or a C3-10 cycloalkyl group; S2: the phenoxycarboxylic acid ester undergoes selective chlorination with a chlorinating agent in the presence of a first catalyst and a second catalyst to obtain a chloro-substituted phenoxycarboxylic acid ester; and S3: the chloro-substituted phenoxycarboxylic acid ester undergoes an acid hydrolysis reaction to obtain a phenoxycarboxylic acid herbicide represented by formula I, in which R3 is H, Cl or CH3.

Abstract: Provided is a method for producing a chlorophenoxycarboxylate, comprising the following steps of: a phenoxycarboxylate under actions of a catalyst A and a catalyst B performing a selective chlorination of a chlorinating agent at a 2-position and/or a 4-position to obtain the chlorophenoxycarboxylate; the catalyst A is a Lewis acid; and the catalyst B has the following structure: R1?—S—R2?. The present disclosure redesigns the process route, and finely screens the catalyst and the chlorinating agent, thereby effectively improving the chlorination selectivity while avoiding the loss of the active ingredient, and the content of the obtained chlorophenoxycarboxylate can reach more than 98.5%, and the yield can reach more than 99%.