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Method for synthesizing PBT polyester

A technology of polyester and mixture, applied in the field of polyester production, can solve the problems of uneven catalyst feed, precipitation, and poor solubility of titanium series

Active Publication Date: 2019-03-22
CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the preparation process of this method, a certain amount of diol is added to participate in the reaction and serve as a solvent, and the prepared titanium-based catalyst system has poor fluidity, and even forms a gel-like compound after a long period of storage.
In addition, the titanium series system prepared by this method is easy to be opaque, which is caused by the poor solubility of titanium series in diols
However, titanium series have poor solubility in diol, which can easily lead to uneven concentration distribution or precipitation of titanium series, which can easily lead to uneven catalyst feeding during the production process and cause resin performance differences

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Step 1: At room temperature and room pressure, place 13.45g (38.5mmol) of an aqueous solution with a citric acid content of 55% in a flask, slowly add 6.66g (19.6mmol) of TBT dropwise while stirring, and continue at room temperature after the addition is complete Stir at low temperature until the solution is uniform, then add 0.42 g (1.96 mmol) of solid magnesium acetate tetrahydrate, stir at room temperature to dissolve it, and form a turbid liquid without solid particles. Move the turbid liquid into a separatory funnel and let it stand for stratification, and separate the lower liquid to obtain catalyst 1. The titanium content of the obtained catalyst 1 is about 6.2%, and the pH of the catalyst 1 is ≈1;

[0024] Step 2: 35g terephthalic acid and 32.25g1,4-butanediol (ratio of the amount of substance is 1 to 1.7) are placed in the reactor with stirring, condensing and splitting and decompression device, catalyst 1 consumption is 280ppm (the amount of titanium relative ...

Embodiment 2

[0026] Step 1: At room temperature and pressure, put 25.41g (72.7mmol) of 55% citric acid aqueous solution in a flask, slowly add 9.91g (29.1mmol) of TBT dropwise while stirring, and continue at room temperature after the addition is complete Stir at low temperature until the solution is uniform, then add 6.24 g (29.1 mmol) of solid magnesium acetate tetrahydrate, stir at normal temperature to dissolve it, and form a turbid liquid without solid particles, which is moved into a separatory funnel and allowed to stand for layering. The catalyst 2 is obtained by separating the liquid in the lower layer. The titanium content of the obtained catalyst 2 is about 3.9%, and the pH of the catalyst liquid is ≈2.

[0027] Step 2: 35g terephthalic acid, 32.25g 1,4-butanediol (mol ratio is 1 to 1.7) is placed in the reactor that has stirring, condensing split flow and decompression device, and catalyst 2 consumption is 280ppm ( The amount of titanium relative to the amount of terephthalic a...

Embodiment 3

[0029] Step 1: At room temperature and room pressure, dissolve 3.55g of lactic acid (39.4mmol) and citric acid 7.51 (39.1mmol) in 10g of aqueous solution and place in a flask, slowly add TBT 6.66g (19.6g) dropwise while stirring, drop After the addition, continue to stir at room temperature until the solution is uniform, then add 1.64 g (39 mmol) of solid lithium hydroxide monohydrate, stir at room temperature to dissolve it, and form a turbid liquid without solid particles. Transfer the turbid liquid into a separatory funnel, let it stand for stratification, and separate the lower liquid to obtain catalyst 3. The titanium content of the obtained catalyst 3 is about 3.5%, and the pH of the catalyst liquid is ≈1.

[0030] Step 2: 35g terephthalic acid, 32.25g 1,4-butanediol (mol ratio is 1 to 1.7) is placed in the reactor that has stirring, condensing and splitting and pressure reducing device, and catalyst 3 consumption is 280ppm ( The amount of titanium relative to terephthal...

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PUM

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Abstract

The invention belongs to the technical field of polyester production, and particularly discloses a method. The method comprises the following steps: Step 1: preparation of a catalyst: firstly continuously stirring a hydroxycarboxylic acid, dropwise adding titanium alkoxide into the hydroxycarboxylic acid at the same time to carry out stirring reaction, adding an alkali solution, and controlling the pH to be less than or equal to 7, then allowing standing still to layer the solution to obtain lower supernate which is a hydrolysis-resistant titanium-based liquid catalyst, and taking out the lower supernate; Step 2: polyester synthesis: placing terephthalic acid and 1,4-butanediol in a reactor, catalyzing the terephthalic acid and the 1,4-butanediol by using the hydrolysis-resistant titanium-based liquid catalyst prepared in Step 1 for esterification for 60 to 240 min to synthesize a PBT oligomer, lowering the pressure of the PBT oligomer within 30 to 120 min to 1 to 100 Pa, adjusting thetemperature to 240 to 260 DEG C, and performing condensation for 60 to 300 min to synthesize the PBT polyester. The catalyst preparation process used in the method is simple, and no hydrolytic precipitations are produced in the synthesis process; furthermore, the titanium-based liquid catalyst is uniform and high in flowability.

Description

technical field [0001] The invention belongs to the technical field of polyester production, in particular to a method for synthesizing PBT polyester. Background technique [0002] Polybutylene terephthalate (PBT) is a high-strength thermoplastic. Because of its excellent heat resistance, chemical corrosion resistance, and insulation properties, it is widely used in automobile manufacturing, electronic and electrical manufacturing, optical fiber casing, office Machinery, textile and other fields. PBT is synthesized from 1,4-butanediol (BDO) and terephthalic acid (TPA) or dimethyl terephthalate (DMT) through esterification or transesterification. With the solution of TPA purification technology and its cost reduction, the production of PBT by esterification has become the mainstream. [0003] It is reported in the literature that the catalysts used for the synthesis of PBT resins mainly include tin-based catalysts, titanium-based catalysts, silicon-based catalysts, aluminum...

Claims

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Application Information

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IPC IPC(8): C08G63/183C08G63/85
CPCC08G63/183C08G63/85
Inventor 王公应吴淼江王庆印
Owner CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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