α-シアノアクリル酸エステルの研究(第1報) : モノクロル酢酸エステルのシアノ化反応

概要

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Reactions to synthesize cyanoacetic acid esters from the corresponding monochloroacetates and various metal cyanides have been studied. The maximum yield of the desired cyanoacetate was 60% and in all cases, cyanosuccinate and cyanotri-carballylate were formed as by-products. The activation energy values for the reaction between potassium cyanide and each one of methyl monochloracetate, ethyl monochlor-acetate, methyl cyanoacetate, and ethyl cyanoacetate were found to be 14.2, 15.5, 17.1, and 18.7 Kcal/mol.The small differences among those values suggest that the byproduct formation is difficult to avoid. In the reaction, the solubility of metal cyanide into the reaction mixture proved to be the rate determining factor. When higher reaction temperature is applied for the reaction between higher alkyl esters of chloracetic acid and potassium cyanide in order to accelerate the reaction, the by-product formation is also accelerated. Thus, for the preparation of higher alkyl esters, ester-interchange reaction is recommended. In this case, approximately 95% yield is attained. The activation energy value for the reaction between ethyl cyanoacetate and 2-ethylhexanol in the presence of sulfuric acid was calculated to be 13.2 Kcal/mol.