The present invention concerns a process for manufacturing a fraction comprising carboxylic acid anhydride by reaction of a fraction comprising carboxylic acid with a ketene, and the use of the fraction comprising carboxylic acid anhydride in a process for acylation of polysaccharides.

The present invention concerns a process for manufacturing a fraction comprising carboxylic acid anhydride by reaction of a fraction comprising carboxylic acid with a ketene, and the use of the fraction comprising carboxylic acid anhydride in a process for acylation of polysaccharides.

The invention relates to a method for producing a (meth)acrylic anhydride A-C(O)O(O)C-A, comprising the following steps: a) a step of reacting an anhydride BC(O)O(O)CB with an acid A-COOH, resulting in the formation of mixed anhydride A-C(O)O(O)CB and acid BCOOH; and b) a step of reacting the mixed anhydride with A-COOH, resulting in the (meth)acrylic anhydride. According to the invention, reaction steps (a) and (b) are carried out in the presence of hydrated triflic acid, and the anhydride A-C(O)O(O)C-A is isolated from the reaction medium produced in step (b) as follows: e1) heavy compounds having a volatility less than or equal to that of the anhydride A-C(O)O(O)C-A are separated from the reaction medium, said compounds including the anhydride and the hydrated triflic acid; e2) the anhydride is separated from the heavy compounds by difference in volatility.

The invention relates to a method for producing a (meth)acrylic anhydride A-C(O)O(O)C-A, comprising the following steps: a) a step of reacting an anhydride BC(O)O(O)CB with an acid A-COOH, resulting in the formation of mixed anhydride A-C(O)O(O)CB and acid BCOOH; and b) a step of reacting the mixed anhydride with A-COOH, resulting in the (meth)acrylic anhydride. According to the invention, reaction steps (a) and (b) are carried out in the presence of hydrated triflic acid, and the anhydride A-C(O)O(O)C-A is isolated from the reaction medium produced in step (b) as follows: e1) heavy compounds having a volatility less than or equal to that of the anhydride A-C(O)O(O)C-A are separated from the reaction medium, said compounds including the anhydride and the hydrated triflic acid; e2) the anhydride is separated from the heavy compounds by difference in volatility.

The invention relates to a method for producing a (meth)acrylic anhydride A-C(O)O(O)C-A, comprising the following steps: a) a step of reacting an anhydride BC(O)O(O)CB with an acid A-COOH, resulting in the formation of mixed anhydride A-C(O)O(O)CB and acid BCOOH; and b) a step of reacting the mixed anhydride with A-COOH, resulting in the (meth)acrylic anhydride. According to the invention, reaction steps (a) and (b) are carried out in the presence of hydrated triflic acid, and the anhydride A-C(O)O(O)C-A is isolated from the reaction medium produced in step (b) as follows: e1) heavy compounds having a volatility less than or equal to that of the anhydride A-C(O)O(O)C-A are separated from the reaction medium, said compounds including the anhydride and the hydrated triflic acid; e2) the anhydride is separated from the heavy compounds by difference in volatility.

The present invention provides a method for producing acrylic acid comprising thermally decomposing a poly(3-hydroxypropionate) in the presence of a predetermined transition metal oxide to produce acrylic acid.

The invention relates to a method for separating a mixture containing at least one carboxylic acid vinyl ester of general formula RC(O)OCHCH.sub.2 and at least one carboxylic acid of general formula RCOOH, wherein R in either case can be an aliphatic group having 12 to 22 C atoms or a cycloaliphatic group having 12 to 22 C atoms, or an aromatic group having 12 to 22 C atoms, and R can be identical or different, characterized in that the carboxylic acid is converted to its anhydride RC(O)OC(O)R and the carboxylic acid vinyl ester is subsequently separated.

The invention relates to a method for separating a mixture containing at least one carboxylic acid vinyl ester of general formula RC(O)OCHCH.sub.2 and at least one carboxylic acid of general formula RCOOH, wherein R in either case can be an aliphatic group having 12 to 22 C atoms or a cycloaliphatic group having 12 to 22 C atoms, or an aromatic group having 12 to 22 C atoms, and R can be identical or different, characterized in that the carboxylic acid is converted to its anhydride RC(O)OC(O)R and the carboxylic acid vinyl ester is subsequently separated.

The invention relates to a method for separating a mixture containing at least one carboxylic acid vinyl ester of general formula RC(O)OCHCH.sub.2 and at least one carboxylic acid of general formula RCOOH, wherein R in either case can be an aliphatic group having 12 to 22 C atoms or a cycloaliphatic group having 12 to 22 C atoms, or an aromatic group having 12 to 22 C atoms, and R can be identical or different, characterized in that the carboxylic acid is converted to its anhydride RC(O)OC(O)R and the carboxylic acid vinyl ester is subsequently separated.

Provided is a method for preparing levulinic acid using a solid acid catalyst in the presence of an ethylene glycol-based compound. The levulinic acid according to the present invention can be prepared by using a linear or cyclic ethylene glycol-based compound as a solvent and preparing the levulinic acid from fructose in the presence of the solid acid catalyst at a reaction temperature of 100 to 200 C., thereby reducing the dependency on petroleum in response to greenhouse gas emission regulations. Also, a high yield of levulinic acid can be obtained from fructose, and the solvent and the catalyst can be efficiently separated, collected, and reused after the reaction has completed.