| 摘要 |
Polybutylene terephthalate is prepared by (a) transesterificating 1,4- butanediol including glycol components of ethylene glycol, 1,3-propanol, 1,6- hexanediol and dimethyl terephthalate with catalysts such as tetraethyl titanate, tetra (2-ethylhexyl) titanate etc., (b) polycondensating the resultant from transesterification, (c) recycling 1,4- butanediol from polycondensation and putting 1,4- butanediol into the transesterification reactor before the initiation of transesterification, (d) separating methanol, tetrahydrofuran and water from 1,4- butanediol by distillation and storing in a reflux tank, (e) transesterificating the mixture of distilled refined 1,4- butanediol and pure 1,4- butanediol, and dimethyl terephthalate, (d) preventing dimethyl terephthalate from the sublimated deposition with totally refluxing methanol, tetrahydrofuran and water after outflowing methanol.
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