| 摘要 |
PURPOSE:To improve the purity of 3,4-dicarboxy-1,2,3,4-tetrahydro-1- naphthalenesuccinic acid dianhydride, economically, by converting the anhydride to organic acid using water as the recrystallization solvent and fractionating the product taking advantage of the solubility difference between the objective compound and impurities. CONSTITUTION:3, 4-Dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic acid dian hydride (abbreviated as TDA) is dissolved in water. The impurities floating on water are separated from the aqueous phase e.g. by filtration, preferably under heating. An organic acid of the above succinic acid dianhydride can be obtained by cooling the aqueous phase. The organic acid is separated from the aqueous phase, recovered, dried, and converted to acid anhydride e.g. by heating or dehydration with acetic anhydride, etc. to obtain TDA. TDA is useful especially as a raw material of polymers such as polyimide and the organic acid of TDA is also useful as a raw material for the production of plasticizer, polyimide, etc.
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