A glycolic acid salt that can be a raw material (intermediate product) for producing glycolic acid is more efficiently produced by a simple process. A method for producing a glycolic acid salt includes step (1) of reacting at least one compound selected from the group consisting of glycolonitrile and glycolamide with water in the presence of a metal oxide containing 50% by mass or more of at least one element selected from the group consisting of a rare earth element, a group 4 element of the periodic table, and a group 12 element of the periodic table, and a base to obtain a glycolic acid salt.

A glycolic acid salt that can be a raw material (intermediate product) for producing glycolic acid is more efficiently produced by a simple process. A method for producing a glycolic acid salt includes step (1) of reacting at least one compound selected from the group consisting of glycolonitrile and glycolamide with water in the presence of a metal oxide containing 50% by mass or more of at least one element selected from the group consisting of a rare earth element, a group 4 element of the periodic table, and a group 12 element of the periodic table, and a base to obtain a glycolic acid salt.

The present invention relates to an improved process for the preparation of [[2(S)-[[4(R)-(3-hydroxyphenyl)-3(R),4-dimethyl-1-piperidinyl]methyl]-1-oxo-3-phenylpropyl]amino]acetic acid dihydrate, represented by the following structural formula (I).

The present invention relates to an improved process for the preparation of [[2(S)-[[4(R)-(3-hydroxyphenyl)-3(R),4-dimethyl-1-piperidinyl]methyl]-1-oxo-3-phenylpropyl]amino]acetic acid dihydrate, represented by the following structural formula (I).

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent using a sieve tray extraction column. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent using a sieve tray extraction column. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

Described herein are methods of preparing compounds derived from triglycerides or condensation polymers such as polyesters and/or polyamides. The methods may include subjecting triglyceride or condensation polymer containing matter to mechanical processing in the presence of a nucleophile.

There is described a method of reducing polymer tar build-up in the production of methyl methacrylate and/or methacrylic acid by the acetone cyanohydrin process. In the method a stabiliser is contacted with the amide stage reaction medium. The stabiliser includes a hydrocarbon moiety capable of donating a labile hydrogen atom to a methacrylamide derivative capable of reaction with said labile hydrogen atom under the conditions in the said medium. The method herein is especially useful for the continuous production of methyl methacrylate and/or methacrylic acid.

There is described a method of reducing polymer tar build-up in the production of methyl methacrylate and/or methacrylic acid by the acetone cyanohydrin process. In the method a stabiliser is contacted with the amide stage reaction medium. The stabiliser includes a hydrocarbon moiety capable of donating a labile hydrogen atom to a methacrylamide derivative capable of reaction with said labile hydrogen atom under the conditions in the said medium. The method herein is especially useful for the continuous production of methyl methacrylate and/or methacrylic acid.

There is described a method of reducing polymer tar build-up in the production of methyl methacrylate and/or methacrylic acid by the acetone cyanohydrin process. In the method a stabiliser is contacted with the amide stage reaction medium. The stabiliser includes a hydrocarbon moiety capable of donating a labile hydrogen atom to a methacrylamide derivative capable of reaction with said labile hydrogen atom under the conditions in the said medium. The method herein is especially useful for the continuous production of methyl methacrylate and/or methacrylic acid.