| 摘要 |
1-(2,3-Dicarboxyphenyl)-3-(3,4-dicarboxyphenyl) -1,1,3,3tetramethyl disiloxane dianhydride of formula (I) is pred. by (A) crystallizing out unwanted 1,3-bis(3,4-dicarboxyphenyl) -1,1,3,3tetramethyl disiloxane dianhydride (II) from ether solvent contg. a 1,3- bis(dicarboxyphenyl) -1,1,3,3-tetramethyl disiloxane dianhydride mixt., and (B) crystallizing out (I) by adding a paraffin solvent to the residual mother liquor after filtering of (II). (I) is useful as a curing agent for epoxy resins.
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