Claims
- 1. A process for the purification of oxydiphthalic anhydride prepared by reacting halophthalic anhydride and potassium carbonate in a neat reaction wherein the molar ratio of halophthalic anhydride:potassium carbonate is greater than 2:1; which comprises:
- (1) filtering at a temperature of about 150.degree. to 250.degree. Celsius a solution of the oxydiphthalic anhydride in 1,2,4-trichlorobenzene to remove the solid impurities from the solution,
- (2) cooling the resulting solution to a temperature of below about 30.degree. Celsius to precipitate the oxydiphthalic anhydride, and
- (3) removing the oxydiphthalic anhydride from the solution.
- 2. The process of claim 1 wherein the oxydiphthalic anhydride is removed from the solution in step (3) by filtration.
- 3. The process for the preparation and purification of oxydiphthalic anhydride which comprises:
- (1) reacting a 4-halophthalic anhydride with potassium carbonate, in a neat reaction wherein the molar ratio of 4-halophthalic anhydride:potassium carbonate is greater than 2:1, dissolving the resultant oxydiphthalic anhydride product in 1,2,4-trichlorobenzene, at a temperature of about 150.degree. to 250.degree. Celsius,
- (2) removing solid impurities from the hot solution,
- (3) cooling the resulting solution to precipitate the oxydiphthalic anhydride, and
- (4) removing the precipitated oxydiphthalic anhydride from the solution.
- 4. The process of claim 3 wherein the oxydiphthalic anhydride is removed in step (4) by filtration.
- 5. The process for the purification of the oxydiphthalic anhydride produced by the reaction of a halophthalic anhydride of the formula ##STR8## where Hal is F, Cl, Br or I with potassium carbonate in the presence of a catalytic amount of a catalyst for the reaction in a reaction medium comprising a solvent selected from the group consisting of 1,2,4-trichlorobenzene, 1,2-dichlorobenzene, and 1,3-dichlorobenzene which comprises
- (1) filtering the hot solution of oxydiphthalic anhydride to remove solid impurities,
- (2) cooling the solution of oxydiphthalic anhydride to precipitate the oxydiphthalic anhydride, and
- (3) removing the oxydiphthalic anhydride from the solution.
- 6. The process for the preparation and purification of 4,4'-oxydiphthalic anhydride which comprises:
- (1) reacting a 4-halophthalic anhydride with potassium carbonate, in a liquid reaction medium comprising 1,2,4-trichlorobenzene and wherein the molar ratio of 4-halophthalic anhydride to potassium carbonate is about 2:1 or greater; adding an additional amount of 1,2,4-trichlorobenzene at a temperature of about 150.degree. to 250.degree. Celsius,
- (2) filtering the resulting hot solution of 4,4-oxydiphthalic anhydride in 1,2,4-trichlorobenzene to remove solid impurities therefrom,
- (3) cooling the resulting solution to precipitate the oxydiphthalic anhydride, and
- (4) removing the precipitated oxydiphthalic anhydride from the solution.
- 7. The process of claim 6 wherein the oxydiphthalic anhydride is removed in step (4) by filtration.
- 8. A process for the purification of 4,4'-oxydiphthalic anhydride prepared by the reaction of 4-chlorophthalic anhydride and potassium carbonate in a solvent from the group consisting of 1,2,4-trichlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, and mixtures thereof in a molar ratio of 4-chlorophthalic anhydride:potassium carbonate of greater than 2:1 to form a solution of crude reaction product said purification process consisting essentially of
- (1) removing solid impurities by filtering the solution at a temperature of about 150.degree. C. to 250.degree. C.,
- (2) cooling the solution to below about 30.degree. C. to precipitate oxydiphthalic anhydride,
- (3) removing the precipitated oxydiphthalic anhydride by filtration.
BACKGROUND OF THE INVENTION AND INFORMATION DISCLOSURE STATEMENT
This is a continuation-in-part of application Ser. No. 102,055, filed Sept. 28, 1987, now abandoned.
US Referenced Citations (3)
Continuation in Parts (1)
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Number |
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102055 |
Sep 1987 |
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