METHOD OF PRODUCING CARBOXYLIC ACID ANHYDRIDE Russian patent published in 2020 - IPC C07C51/56 C07C53/12 

FIELD: woodworking industry.

SUBSTANCE: invention relates to an improved method of producing a carboxylic acid anhydride-containing fraction by reacting a fraction containing a carboxylic acid with ketene, wherein at least one of the following conditions is met: I. at least a portion of the fraction containing a carboxylic acid is a fraction, containing carboxylic acid and terpene and/or impurities of terpene derivatives and/or II. at least a portion of the ketene is obtained from a fraction containing a carboxylic acid, where the carboxylic acid-containing fraction further contains terpene and/or impurities of terpene derivatives, in which a fraction containing a carboxylic acid and terpene and impurities of terpene derivatives, method comprises adding to a method of producing an anhydride of carboxylic acid with intermediate treatment of a fraction containing a carboxylic acid and terpene and impurities of terpene derivatives which includes a) treating a fraction containing a carboxylic acid and terpene and impurities of terpene derivatives, a metal salt in the presence of water, b) treating at least a portion of the fraction, obtained at step a), for removing metal salt and optionally c) treating at least a portion of the fraction obtained at step b) using at least one of operations selected from a group of operations, consisting of distillation, distillation or membrane separation, for extraction of at least purified carboxylic acid fraction. Invention also relates to a method of producing acetylated wood and a method of acylating polysaccharides.

EFFECT: improved method of producing a fraction containing carboxylic acid anhydride.

12 cl, 1 ex