| 摘要 |
PURPOSE: To effectively prevent a raw material feed pipe or a circulating pipe from being clogged in carrying out the esterifylng reaction of terephthalic acid with ethylene glycol according to a batch method and producing bis(β- hydroxyethyl)terephthalate and/or its oligomer (BHET). CONSTITUTION: Ethylene glycol is passed through the interior of a slurry takeout pipe 4 from a circulating line 3 after completing the feed of a slurry to an esterifying reactional vessel 1. A return line 3b of the circulating line 3 in which the flow of the slurry is stopped due to the feed of the slurry to the reactional vessel 1 is blown with an inert gas and the circulation of the slurry is then restarted. The interior of the pipe is washed with ethylene glycol or an inert gas thereby to prevent the pipe from being clogged by the precipitation of solid substances. As the result, the batch reaction can repetitively be carried out to improve the production efficiency of the BHET.
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