Process for preparing glycol terephthalate from terephthalic acid and glycol
A technology of ethylene terephthalate and ethylene terephthalate is applied in the field of preparing ethylene terephthalate from terephthalic acid and ethylene glycol, and can solve the problem of high molar ratio of feeding materials , to achieve the effect of reducing the molar ratio of the feed and the ideal distribution.
Inactive Publication Date: 2008-09-03
CHINA PETROLEUM & CHEM CORP +2
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Problems solved by technology
[0004] The invention provides a method for preparing ethylene terephthalate from terephthalic acid and ethylene glycol, and the reaction is carried out in a new external circulation heating continuous esterification reaction device, which can solve the problems in the prior art The technical problem that the feeding molar ratio of ethylene glycol and terephthalic acid is too high
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[0015] As can be seen from the accompanying drawings, the device used for the esterification reaction includes a reactor 1 and an external circulation tube heater 2, and the inlet and outlet of the heat exchanger are connected to the reactor through pipes 3 and 4, respectively. The reaction kettle has a double-chamber structure with inner and outer chambers, the inner chamber 5 is located at the bottom of the kettle, the space outside the inner chamber in the kettle is the outer chamber 6, and the top of the inner chamber is located at nearly 1 / 2 of the height of the kettle. The pipe connection port 7 connecting the reaction kettle to the inlet of the outer circulation tubular heater is located at the bottom of the inner chamber and communicates with the inner chamber; the pipe connection port 8 connecting the reaction kettle to the outlet of the outer circulation tubular heater is located on the side wall of the lower part of the reaction kettle. The outside room is connected....
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The preparation process of terephthalate of dihydric alcohol is one continuous esterification process at the temperature of 258-290 deg.c and pressure 40-120 KPa and in the material molar ratio between dihydric alcohol and terephthalic acid of 1 to 1.5-1.9. The esterification apparatus includes a reactor and an externally circulating shell and tube heater. The reactor has one double-chamber structure including an inner chamber in the bottom of the reactor and an outer chamber. The connecting pipe between the inlet of the heater and the reactor is led to the inner chamber, the connecting pipe between the outlet of the heater and the reactor is led to the outer chamber, and the liquid material passage connecting the inner chamber and the outer chamber is one annular one with U-shaped cross section. The material feeding port is at the inlet of the heater, the liquid reaction product exit is in the bottom of the reactor and led to the inner chamber, and the gas exit is in the top of the reactor. The present invention has lower material ratio between dihydric alcohol and terephthalic acid.
Description
technical field [0001] The present invention relates to a process for the preparation of ethylene terephthalate from terephthalic acid and ethylene glycol. Background technique [0002] At present, the manufacturing process of polyester is mostly direct esterification method, that is, direct esterification by terephthalic acid (PTA) and ethylene glycol (EG), followed by polycondensation. The existing polyester production is continuous. Although there are many kinds of process routes, they are basically composed of three continuous processes of esterification, precondensation and polycondensation. The esterification process is at the forefront, so it is The most critical part of the entire process route, it will have a great impact on the operability of the subsequent process and the quality of the final product. The esterification reaction has high requirements on the equipment, it must meet a large heating load, and the material must be heated evenly; excess and oligomeriz...
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IPC IPC(8): C07C69/82C07C67/08
Inventor 汪少朋俞明康
Owner CHINA PETROLEUM & CHEM CORP