| 摘要 |
PROBLEM TO BE SOLVED: To efficiently obtain a carbonic diester useful as a terminal blocking agent in producing a polycarbonate resin, by distillation/purification of a crude product of a carbonic diester in the presence of a specific inorganic acidic compound or an organic sulfonic acid compound so as to inhibit any disproportionation reaction. SOLUTION: This carbonic diester is obtained by distillation/purification of a crude product of a carbonic diester of the formula (R<1> is methyl or ethyl; R<2> is a 1-24C alkyl, a 6-20C aryl, etc.) (e.g. 2-methyloxycarbonylphenyl-phenyl carbonate) in the presence of at least one acidic compound selected from inorganic acidic compounds (inorganic acids, solid acids, pref. phosphoric acid, diphosphorus pentoxide, talc or ZMS-5) and organic sulfonic acid compounds [e.g. compounds of the formula A<1> -(Y<1> -SO3 X<1> )m (A<1> is a substituent or m-valent hydrocarbon group; Y is a single bond or oxygen; X<1> is a secondary or tertiary monovalent hydrocarbon group, one equivalent of metal cation, ammonium cation or phosphonium cation; (m) is 1-4)]. |
