Oxygen → Tetrahydrophthalic anhydride

3Me--THPA was produced by the gas phase aeration method. Thus, the air in a 300-ml four-necked flask equipped with a stirrer, thermometer, condenser, a dropping funnel for feeding crude trans-1,3-pentadiene, and an unreactive fraction recovery vessel was replaced with nitrogen and, then, the flask was charged with 98 g of maleic anhydride, 500 ppm of p-tert-butylcatechol by way of radical polymerization inhibitor and 1000 ppm of dilauryl thiodipropionate as auxiliary polymerization inhibitor. The charge was melted at 50° to 55° C. and after the internal atmosphere was replaced with nitrogen gas, nitrogen gas containing 4% of oxygen was passed through the gas phase at a rate of 10 ml/min throughout the reaction period. Under this atmosphere, 374 g of crude trans-1,3-pentadiene of the same composition as that used in Example 1 was continuously added at 50° to 55° C. over a period of 4 hours. During the reaction, major portion of unreactive fractions was distilled off from the reaction system. After completion of addition, the reaction was conducted at 70° C. for 30 minutes. After completion of the reaction, the reaction mixture was distilled at 85° C. under atmospheric pressure and, then, under reduced pressure to remove the volatile fraction. In this manner, 164 g of 3Me--THPA was obtained. The investigation revealed no gels in the product.

1. customThus, the air in a 300-ml four-necked flask equipped with a stirrer
2. customthermometer, condenser, a dropping funnel for feeding
3. customwas passed through the gas phase at a rate of 10 ml/min throughout the reaction period
4. additionwas continuously added at 50° to 55° C. over a period of 4 hours
5. customDuring the reaction, major portion of unreactive fractions
6. distillationwas distilled off from the reaction system
7. additionAfter completion of addition
8. customAfter completion of the reaction
9. distillationthe reaction mixture was distilled at 85° C. under atmospheric pressure
10. customunder reduced pressure to remove the volatile fraction

ORDレコード

ord-4b050eb4c3be4500bf9d93c525f53888

出典データセット

uspto-grants-1993_08

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US05237074