Abstract: Crude mixtures of dioxydiphthalic anhydride containing alkali metal salts are purified by treating the crude mixture with an alkanol, such as n-butanol, to form the dioxydiphthalic acid diester; removing the insoluble alkali metal salts by filtration; removing the excess alkanol; and reconverting the dioxydiphthalic acid diester to dioxydiphthalic anhydride.

Abstract: This invention relates to novel fluorinated bis-imides of the formula ##STR1## where X is H or F. The compounds are useful as additives to enhance the properties of high performance polymers such as polyimides.

Abstract: Bis-imides of dioxydiphthalic or oxydiphthalic anhydride, are characterized by the formula ##STR1## where Z is H, alkyl of 1-12 carbon atoms, or ##STR2## A is H, Cl, F, NO.sub.2, OH, CF.sub.3, alkyl, alkoxy, alkylaryl or aryloxy, wherein the alkyl groups are 1-6 carbon atoms and the aryl groups are 6-14 carbon atoms; alkenyl or alkynyl of 2-6 carbon atoms; or benzoyl; and Y is H, Cl, F, NO.sub.2, OH, or CF.sub.3 ; X is halogen; X' is hydrogen or halogen; or X and X' together represent an oxygen atom, forming a second ether linkage.

Abstract: Polyimide copolymers are disclosed having the recurring structure ##STR1## wherein AR is AR.sub.1 or AR.sub.2, wherein AR.sub.1 is ##STR2## and wherein AR.sub.2 is ##STR3## provided that the molar ratio of AR.sub.1 to AR.sub.2 is 3:1 to 1:3, and wherein AR.sub.3 is ##STR4## These polyimides have unexpected properties which are useful in various electronic applications.

Abstract: Oxydiphthalic acid esters of the formula ##STR1## where Z is H or alkyl, and X is halo, X' is H or halo, or X and X' together represent an oxygen atom; are prepared by the esterification reaction of the corresponding halo-oxydiphthalic anhydride or dioxydiphthalic anhydride with an alkanol.

Abstract: Novel halogenated polyimides and co-polyimides comprise recurring imide structural units of the formula ##STR1## where X is F, Cl, Br or I; Y is H, F, Cl, Br or I; and R is a divalent organic radical.

Abstract: Dioxydiphthalic anhydride is prepared by the reaction of dihalophthalic anhydride with an alkali metal compound, such as potassium carbonate. The compound is particularly useful as a monomer in the preparation of polyimides.

Abstract: A co-polyimide based upon a mixture of 4,4'-oxydiphthalic dianhydride (ODPA) and 3,4,3',4'-biphenyltetracarboxylic dianhydride (BPDA) as the dianhydride component and either 4,4'-oxydianiline (ODA) or paraphenylene diamine as the amine component is disclosed. The molar ratio between the ODPA and BPDA ranges from 3:1 to 1:3. The co-polyimide may either be formed as a random copolymer, or as a block copolymer where the blocks are based upon blocks of polymer containing ODPA and blocks of polymer containing BPDA provided that the molar ratios of ODPA and BPDA are in the ratio of 3:1 to 1:3.

Abstract: Oxydiphthalic anhydrides of the formula ##STR1## are prepared by reacting a halophthalic anhydride with potassium carbonate in:(1) a solvent-free reaction medium wherein the molar ratio of halophthalic anhydride:potassium carbonate is greater than 2:1; or(2) a high boiling solvent which improves the mixing of the components, and aids in subsequent purification of the product. The molar ratio of halophthalic anhydride to potassium carbonate is about 1.5:1 or greater.The oxydiphthalic anhydride can be purified by filtering or centrifuging a hot solution of the oxydiphthalic anhydride in a high boiling solvent to remove impurities, followed by cooling the solution to precipitate the oxydiphthalic anhydride, which can be removed from the solution by filtration or centrifuging.

Abstract: Dioxydiphthalic anhydride is prepared by the reaction of dihalophthalic anhydride with an alkali metal compound, such as potassium carbonate. The compound is particularly useful as a monomer in the preparation of polyimides.

Abstract: Novel polyimides and co-polyimides are prepared by the condensation polymerization of an aryl diamine with dioxydiphthalic anhydride or a mixture thereof with oxydiphthalic anhydride. The polyimides and co-polyimides prepared exhibit a low moisture absorption and improved dielectric properties and can be tailored to provide a composition having desirable mechanical properties, specifically, rigidity.

Abstract: A process for the production of 4-bromophthalic anhydride which comprises the reaction of 4-chlorotetrahydrophthalic anhydride with elemental bromine, in the presence of a catalytically effective amount of iron or an iron salt is disclosed.

Abstract: Phenoxy phthalic anhydrides are prepared by the reaction of a fluorophthalic anhydride with a phenol compound in the presence of potassium fluoride and a polar, aprotic solvent.

Abstract: Novel halo-oxydiphthalic anhydrides are of the formula ##STR1## where X is F, Cl, Br, or I; X' is H, F, Cl, Br, or I.

Abstract: Oxydiphthalic anhydrides of the formula ##STR1## are prepared by reacting a halophthalic anhydride with potassium carbonate in:(1) a solvent-free reaction medium wherein the molar ratio of halophthalic anhydride:potassium carbonate is greater than 2:1; or(2) a high boiling solvent which improves the mixing of the components, and aids in subsequent purification of the product. The molar ratio of halophthalic anhydride to potassium carbonate is about 1.5:1 or greater.The oxydiphthalic anhydride can be purified by filtering or centrifuging a hot solution of the oxydiphthalic anhydride in a high boiling solvent to remove impurities, followed by cooling the solution to precipitate the oxydiphthalic anhydride, which can be removed from the solution by filtration or centrifuging.

Abstract: Diether diphthalic anhydrides are prepared by reacting fluorophthalic anhydride with an aromatic dihydroxyl compound in the presence of potassium fluoride and a polar, aprotic solvent.

Abstract: Oxy-diphthalic anhydrides are prepared by reacting a halophthalic anhydride with an hydroxyphthalic anhydride in a polar aprotic solvent and in the presence of an alkali metal compound such as KF, CsF or K.sub.2 CO.sub.3.

Abstract: Phenoxy phthalic anhydrides are prepared by the reaction of a fluorophthalic anhydride with a phenol compound in the presence of potassium fluoride and a polar, aprotic solvent.

Abstract: Oxy-diphthalic anhydrides are prepared by reacting a halophthalic anhydride with water and an alkali metal compound such as KF, CsF or K.sub.2 CO.sub.3 in the presence of a polar, aprotic solvent.

Abstract: Polyamides, flame retarded with a halogenated derivative and blended with a polymer blend resin being at least partially incompatible and having a lower melt viscosity than the polyamide, to improve the arc tracking resistance of the polyamide, are disclosed. The polyamides are particularly useful in the manufacture of flame retarded electrical components.