Abstract: 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 single packed extraction column. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

Abstract: 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 in a first extractor for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent in a second extractor for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

Abstract: 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.

Abstract: 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.

Abstract: 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 in a first extractor for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent in a second extractor for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

Abstract: 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 single packed extraction column. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

Abstract: A method of making a polyetherimide includes forming an intermediate polyetherimide with an anhydride-amine stoichiometry of ?2 to ?40 mol % and melt mixing the intermediate polyetherimide with a bis(ether anhydride) for greater than 3 minutes at a temperature 50 to 225° C. greater than the glass transition temperature of a final polyetherimide to produce the final polyetherimide.

Abstract: Polyetherimide compositions of formula (1) are described wherein the polyetherimide compositions comprise a polyetherimide comprising a reacted combination of alkali metal salts comprising an alkali metal salt of a dihydroxy aromatic compound and an alkali metal salt of a monohydroxy aromatic compound with a bis(halophthalimide), wherein the alkali metal salt of the monohydroxy aromatic compound is included in an amount of more than 0 and less than 5 mole percent, based on the total moles of the alkali metal salts, and the polyetherimide has a weight average molecular weight greater than or equal to 43,000 Daltons. The polyetherimide exhibits lower levels of chlorine and chlorine end groups, lower levels of bis(halophthalimide) and bis(phthalimide), and low plate-out during manufacturing.

Abstract: Polyetherimide compositions are described wherein the polyetherimide composition comprises a polyetherimide comprising a reacted combination of alkali metal salts comprising an alkali metal salt of a dihydroxy aromatic compound and an alkali metal salt of a monohydroxy aromatic compound with a bis(halophthalimide), wherein the alkali metal salt of the monohydroxy aromatic compound is included in an amount of greater or equal to 5 mole percent based on the total moles of the alkali metal salts, and the polyetherimide has a weight average molecular weight less than 43,000 Daltons. The polyetherimide exhibits lower levels of chlorine and chlorine end groups, lower levels of bis(halophthalimide) and bis(phthalimide), and low plate-out during manufacturing.

Abstract: Polyetherimide compositions are described wherein the polyetherimide composition comprises a polyetherimide comprising a reacted combination of alkali metal salts comprising an alkali metal salt of a dihydroxy aromatic compound and an alkali metal salt of a monohydroxy aromatic compound with a bis(halophthalimide), wherein the alkali metal salt of the monohydroxy aromatic compound is included in an amount of greater or equal to 5 mole percent based on the total moles of the alkali metal salts, and the polyetherimide has a weight average molecular weight less than 43,000 Daltons. The polyetherimide exhibits lower levels of chlorine and chlorine end groups, lower levels of bis(halophthalimide) and bis(phthalimide), and low plate-out during manufacturing.

Abstract: Polyetherimide compositions of formula (1) are described wherein the polyetherimide compositions comprise a polyetherimide comprising a reacted combination of alkali metal salts comprising an alkali metal salt of a dihydroxy aromatic compound and an alkali metal salt of a monohydroxy aromatic compound with a bis(halophthalimide), wherein the alkali metal salt of the monohydroxy aromatic compound is included in an amount of more than 0 and less than 5 mole percent, based on the total moles of the alkali metal salts, and the polyetherimide has a weight average molecular weight greater than or equal to 43,000 Daltons. The polyetherimide exhibits lower levels of chlorine and chlorine end groups, lower levels of bis(halophthalimide) and bis(phthalimide), and low plate-out during manufacturing.