Method for detecting ethyl 2-chloroacetoacetate in ethyl 4-chloroacetoacetate

Abstract

The invention discloses a method for detecting ethyl 2-chloroacetoacetate in ethyl 4-chloroacetoacetate. The method is easy to operate, and an analysis result is accurate. A gas chromatograph with an FID (flame ionization detector) is used for implementing analysis. The method comprises the following steps: (1) selecting gas chromatography conditions, wherein a chromatographic column is SE-5,430 m*0.25 mm*0.25 Mum; the temperature of a column box is that the start temperature of 90 plus or minus 5 DEG C, the heating speed is 30 plus or minus 5 DEG C / min, and the end temperature is 160 plus or minus 5 DEG C; the temperature of a detection chamber is 200 plus or minus 5 DEG C; the temperature of a gasification chamber is 180 plus or minus 5 DEG C; the carrier gas is nitrogen; the fuel gas is hydrogen; the combustion-assistant gas is compressed air or oxygen; (2) firstly switching on the gas chromatograph, adjusting pressure and flow of all types of gas, and setting temperatures of all the parts; (3) heating to rise the temperature and ignition, and repeatedly wetting and washing a sample to be detected for at least three times after a base line is stable; (4) analyzing the injected sample, and recording a chromatogram; (5) obtaining the ethyl 2-chloroacetoacetate content of the sample to be detected by an area normalization method.

Description

technical field [0001] The invention relates to the technical field of chemical analysis, in particular to a detection method for ethyl 2-chloroacetoacetate in ethyl 4-chloroacetoacetate. Background technique [0002] Ethyl 4-chloroacetoacetate is a colorless or light yellow transparent liquid with a content of more than 98%. As a halogenated β-diketone compound, it can be widely used in medicine, pesticides, pigments, food and feed additives, etc. in the synthesis of compounds. At present, with the continuous expansion of the production scale of cephalosporin products, amlodipine, oxiracetam, L-carnitine and other products, the continuous development of various downstream products of ethyl 4-chloroacetoacetate, ethyl 4-chloroacetoacetate The demand for esters is growing rapidly. [0003] At present, a kind of synthetic route of ethyl 4-chloroacetoacetate is as follows: [0004] CH 2 COCH 2 CO+Cl 2 =ClCH 2 COCH 2 COCl [0005] ClCH 2 COCH 2 COCl+CH 3 CH 2 OH=ClC...

AI Technical Summary

Problems solved by technology

[0009] In the above reaction process, it is often accompanied by the generation of ethyl 2-chloroacetoacetate (CH 3 COCLCH 2 COOCH 2 CH 3 ), because ethyl 2-chloroacetoacetate is an isomer of ethyl 4-chloroacetoacetate, its physical and chemical properties are very close, it is difficult to carry out qualitative and quantitative analysis of ethyl 2-chloroacetoacetate by general analytical methods Analysis, so far there is no report on its analysis method