[C:1]1(=[O:7])[O:6][C:4](=[O:5])[CH:3]=[CH:2]1.[OH-:8].[NH4+:9].[OH-].[Na+]>O>[C:1]([O-:6])(=[O:7])/[CH:2]=[CH:3]\[C:4]([O-:8])=[O:5].[NH4+:9].[NH4+:9]Following the examples of U.S. Pat. No. 4,839,461, a solution of 1.96 g (0.02 mole) maleic anhydride was dissolved in 1 ml water at 50°-60° C. and stirred for 30 minutes while allowing the mixture to cool to 25° C. To this colorless solution at 2° C. was added 2.4 g of 30% aqueous solution of ammonium hydroxide (0.022 mol NH3) to give a colorless solution. This solution was boiled to dryness over a period of 30 minutes at approximately 100°-120° C. and 10-20 Torr, to give a white crystalline solid. The solid was tumbled under nitrogen at 100 Torr, at 135°-140° C. for 8 hours to give a water insoluble, pinkish-tan brittle glasslike solid weighing 2.7 g. This solid was dissolved in 6.6 g of an aqueous solution containing 0.8 g of sodium hydroxide to form a clear orange solution, pH 7.0, containing 25% solids.
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