| This article describes the importance of fluorine-containing intermediates and common fluorination methodsas well as their characteristics. The recent research status of triethyla-mine trihydrofluoride andα-fluoro β-ketoester compounds such as methyl (ethyl)2-fluoro-3-oxopentanoate was simply summarized in the paper. A synthesis route of methyl (ethyl)2-fluoro-3-oxopentanoate was designed, and a study of the two compounds was car-ried out by experiments using orthogonal design in detail.In this work, methyl (ethyl)3-oxopentanoate was employed as the starting material which reacted with sulfuryl chloride to synthesizeintermediatemethyl (ethyl)2-chloro-3-oxopentanoatewith a crude yield of88.2%or86.1%in mol. separately. Then methyl (ethyl)2-fluoro-3-oxopentanoate was synthesised by halogen-exchange fluorination, with a crude yield of67.3%or74.0%in mol. separately. Triethylamine trihydrofluoride was employed as fluorinating agent in halogen-exchange fluorination, while triethylamine was added as acid-binding agent. Fluoromalonic acid dimethyl ester was synthesised with a crude yield of41.8%in mol., using the same synthesis route. Simple process amplification study was carried out.After enlarging by40times, the molar yield of triethylamine trihy-drofluoride remained basically unchanged, while the molar yield of methyl2-fluoro-3-oxopentanoate reduced by2%.Large amount of solid salts composed of triethylamine hydrochloride and triethylamine hydrofluoride was generated as byproduct in this fluorination process.The treatment of trie-thylamine salts was researched by experiments.In the treatment process, triethylaminewas recovered effectively;in the meanwhilethe fluoride in waterwas removed using a mixture of an alkali and fluoride precipitant.The fluoride content in the treated wastewater was less than20ppm(w/w). The fluorination process reduced cost of production andcomplied with environmental regulatory requirements due to the treatment of the triethylaminesalt. |
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