| 摘要 |
Long-chain ketene dimers are prepared in a process in which in the absence of an organic solvent, carboxylic acid chloride is fed, with intensive mixing, into a recipient of triethyl amine at a rate of not more than 3 moles/hour per mole of present triethyl amine, and the mixing rate, feed rate, and heat exchange are so attuned to each other that the viscosity of the mixture always is less than 250 mPa.s, measured at 60.degree.C (rate of shear higher than 100 1/sec). The process is characterized in that the molar ratio of the total amount of carboxylic acid chloride fed in to the recipient amount of amine is 1 : 1,025 to 1 : 2, and, after the conversion, the reaction mixture containing the ketene dimer is treated with diluted aqueous hydrochloric acid or an aqueous solution of triethyl amine hydrochloride and hydrochloric acid, and the ketene dimer is separated. The ketenes prepared in accordance with the present invention are highly suitable for use in paper sizing.
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