Method for preparing N-(4-ethyoxylcarbonylphenyl)-N'-methyl-N'-phenyl carbonamidine

Abstract

The invention discloses a method for preparing N-(4-ethyoxylcarbonylphenyl)-N'-methyl-N'-phenyl carbonamidine. The method comprises the following steps of: (1) adding N-methylaniline, ethyl p-aminobenzoate and triethyl orthoformate into a reaction device, stirring and heating up to 80-90 DEG C; (2) adding propionic acid or glacial acetic acid used as a catalyst into the reaction device, meanwhile, evaporating out generated alcohol, and reacting for 1-3 hours at a temperature of 80-90 DEG C; (3) heating up to 100-110 DEG C, meanwhile, reducing the pressure to 1-20mmHg, continuously reacting until no alcohol is evaporated out; and (4) after the reaction ends, reducing the pressure and distilling to obtain the N-(4-ethyoxylcarbonylphenyl)-N'-methyl-N'-phenyl carbonamidine. The method has the advantages of simple process, moderate condition and high productivity and is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the field of fine chemicals, and in particular relates to a preparation method of N-(4-ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine. Background technique [0002] N-(4-ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine (CAS No.: 57834-33-0) is a highly efficient diarylformamidine light stabilizer . [0003] At present, there are mainly two preparation methods: [0004] Chinese patent document CN101481330A (application number 200910029006.0) discloses one of the preparation methods, that is, the intermediate O- Ethyl-(4-ethoxyformylphenyl)oxime; then the intermediate is condensed with N-methylaniline to obtain N-(4-ethoxycarbonylphenyl)-N'-methyl- N'-phenylformamidine. The disadvantage of this method is that two-step condensation reactions are required, and the reaction intermediates must be separated and purified, resulting in cumbersome process routes and low yields, which are not suitable for large-scale product...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that two-step condensation reactions are required, and the reaction intermediates must be separated and purified, resulting in cumbersome process routes and low yields, which are not suitable for large-scale production

The deficiency of this method is: raw material N-phenyl-N-methylformamide is difficult to obtain, and has used strong corrosive reagent phosphorus oxychloride, so equipment corrosion resistance requirement is high, and this method total yield is lower, production High cost, not conducive to industrial mass production

[0006] In addition, the document "Guangdong Chemical Industry" (2007, Issue 1, Volume 34, Pages 28-34) discloses a method of producing p-aminobenzoic acid ethyl ester, orthoformic acid in ethyl acetate solvent and under the catalysis of glacial acetic acid. Trimethyl ester and N-methylaniline reaction prepare the method for N-(4-ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine, the deficiency of this method is: condensation reaction needs in In the ethyl acetate solvent, the post-treatment process also needs to use a large amount of dichloromethane and other solvents for extraction. In addition, this method also introduces a large amount of lye for acid-base neutralization. The lye may cause hydrolysis of the product or other side reactions. Occurrence, resulting in yield and product purity reduction; Therefore, this method reaction operation and aftertreatment are loaded down with trivial details, and production cost is higher, and product purity is lower, and industrialization value is little

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