Method of producing high-purity monochloroacetic acid
AssigneePcc Mcaa Sp. Z O. O.
InventorBartosz Bankowski
Life of this patent
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Abstract
A method has been disclosed of obtaining high purity, colourless monochloroacetic acid encompassing the chlorination of acetic acid with chlorine in the presence of a catalyst, followed by the recovery of the catalyst through vacuum distillation and purification of the obtained liquid raw product by its hydrodehalogenation by hydrogen in the presence of a palladium catalyst and then vacuum distillation.
Claims12
A method of obtaining, colourless monochloroacetic acid comprising chlorination of acetic acid with chlorine in the presence of a catalyst, followed by recovery of the catalyst through vacuum distillation and purification of a remaining liquid raw product by hydrodehalogenation in the presence of a further catalyst containing metal from group X of the periodic table of elements and then vacuum distillation, wherein
- a. prior to said hydrodehalogenation, conducting a hydrolysis of the liquid raw product in order to hydrolyze anhydrides and acid chlorides present in the liquid raw product obtained after the recovery of the catalyst, at a temperature of between 50° C. to 160° C. with an overall retention time of between 30 minutes and 12 hours, whereby the hydrolysis is conducted with an excess of water, with respect to the content of acid chlorides and anhydrides, such that the concentration of water in the hydrolysed liquid raw product is between 0.05 and 5% by weight, and then
- b. the excess water from the hydrolysed liquid raw product is removed by a reaction with acid chlorides so that the concentration of water in the reaction mixture entering the hydrodehalogenation process is less than 0.01% by weight.
Dependencies are inferred from the claim text.