Aromatic dianhydrides

Claim 2

An aromatic dianhydride compound of the formula ##STR7## wherein Ar is a C 6-10 arylene radical selected from the group consisting of: ##STR8## wherein w in each occurrence is halo, nitro, or a C 1-10 radical selected from alkyl, aryl, alkaryl, aralkyl, haloalkyl, haloaryl, aryloxy and alkoxy; q is an integer from zero to 4; and w' is oxygen, sulfur, alkylene, oxyalkylene, alkylenedioxy or polyoxyalkylene; R', R" individually are hydrogen or alkyl, aryl, aralkyl, or alkaryl radicals containing up to 10 carbon atoms; and both x's are either zeros or ones.

Claim 3

A compound according to claim 1 wherein Ar is a phenylene radical.

Claim 4

A compound according to claim 2 that is 1,4-bis(3-methyltetrahydrofuran-2,5-dion-3-yl)benzene.

Claim 5

A compound according to claim 2 wherein R' and R" are hydrogen.

Claim 6

A compound according to claim 4 that is 1,4-bis(tetrahydrofuran-2,5-dion-3-yl)benzene.

Claim 7

A compound according to claim 4 that is 1,3-bis(tetrahydrofuran-2,5-dion-3-yl)benzene.

Claim 8

A compound according to claim 4 that is 1,4-bis(tetrahydropyran-2,6-dion-3-yl)benzene.

Claim 9

A compound according to claim 4 that is 1,3-bis[4-(tetrahydrofuran-2,5-dion-3-yl)phenoxy]propane.

Claim 10

A process for making an aromatic dianhydride of the formula ##STR9## wherein Ar is a C 6-20 arylene radical selected from the group consisting of: ##STR10## wherein w in each occurrence is halo, nitro, or a C 1-10 radical selected from alkyl, aryl, alkaryl, aralkyl, haloalkyl, haloaryl, aryloxy and alkoxy; q is an integer from zero to 4; and w' is oxygen, sulfur, alkylene, oxyalkylene, alkylenedioxy or polyoxyalkylene; R', R" individually are hydrogen or alkyl, aryl, aralkyl or alkaryl radicals containing up to 10 carbon atoms and x is one, comprising (a) contacting cyanoacetic acid and an aromatic dicarbonyl compound in at least a 4:1 stoichiometric ratio at a temperature from about 80° C. to about 200° C. in pyridine solvent in the presence of a catalytically effective amount of an amine catalyst; (b) refluxing the product so obtained in an excess of a concentrated acid selected from the group consisting of hydrochloric and sulfuric for a time sufficient to produce an aromatic tetra carboxylic acid derivative; and (c) subsequently converting the aromatic tetra carboxylic acid derivative to the corresponding aromatic dianhydride by heating at a temperature of at least about 200° C. under reduced pressure for a sufficient period of time to produce the aromatic dianhydride.

Claim 11

A process for making an aromatic dianhydride of the formula ##STR9## wherein Ar is a C 6-20 arylene radical selected from the group consisting of: ##STR10## wherein w in each occurrence is halo, nitro, or a C 1-10 radical selected from alkyl, aryl, alkaryl, aralkyl, haloalkyl, haloaryl, aryloxy and alkoxy; q is an integer from zero to 4; and w' is oxygen, sulfur, alkylene, oxyalkylene, alkylenedioxy or polyoxyalkylene; R', R" individually are hydrogen or alkyl, aryl, aralkyl or alkaryl radicals containing up to 10 carbon atoms and x is one, comprising (a) contacting cyanoacetic acid and an aromatic dicarbonyl compound in at least a 4:1 stoichiometric ratio at a temperature from about 80° C. to about 200° C. in pyridine solvent in the presence of a catalytically effective amount of an amine catalyst; (b) refluxing the product so obtained in an excess of a concentrated acid selected from the group consisting of hydrochloric and sulfuric for a time sufficient to produce an aromatic tetra carboxylic acid derivative; and (c) subsequently converting the aromatic tetra carboxylic acid derivative to the corresponding aromatic dianhydride by heating at a temperature of at least about 200° C. under reduced pressure for a sufficient period of time to produce the aromatic dianhydride.

Claim 12

The process of claim 9 wherein the aromatic tetra carboxylic acid derivative is converted to the corresponding aromatic dianhydride by contacting with acetic anhydride for a sufficient period of time to produce the dianhydride.

Claim 13

The process of claim 9 or 10 wherein the amine catalyst is piperidine.