| 摘要 |
Tetrahydrophthalic anhydride for the preparation of polyesters is conveniently prepared in a stable, liquid form for transportation and storage by adding molten anhydride to a 100 DEG to 120 DEG C., C2 to C9 glycol at rate to maintain this temperature range without raising the temperature of the mixture in increments of more than 5 DEG F., reacting the mixture for a sufficient time to reduce the acid number of the mixture to a number in the range below the theoretical acid number for the half ester of the glycol and anhydride and 165; thereafter cooling the mixture to 155 DEG C., adding glycol as necessary to provide a mole ratio of glycol to anhydride in the range of 1.2 to 2:1 and cooling the mixture to a temperature in the range of 40 DEG to 70 DEG C.
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