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Purification method for preparing PECH through cationic polymerization

A cationic polymerization and purification method technology, which is applied in the chemical industry, can solve the problems of low yield of main products, high energy consumption, and influence on product production, and achieve the effects of reducing production costs, narrow molecular weight distribution, and improving product purity

Pending Publication Date: 2022-04-08
天元(杭州)新材料科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To prepare PECH with a narrow distribution, on the one hand, the polymerization reaction conditions can be controlled, such as terminating the polymerization reaction before reaching the polymerization equilibrium; on the other hand, low molecular weight oligomers can be removed through post-treatment. The commonly used method is solvent extraction and vacuum distillation. The vacuum distillation method consumes a lot of energy and is difficult to remove cyclic crown ethers and oligomers. However, there are few reports on the separation of by-products produced during the PECH synthesis process at home and abroad. The relevant literature introduces Organic solvent extraction of crown ether by-products is not completely separated, and even a large amount of the main product is dissolved in the separation liquid, resulting in a low yield of the main product, which affects the production of the product, and also increases the environmental protection pressure of the enterprise

Method used

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  • Purification method for preparing PECH through cationic polymerization
  • Purification method for preparing PECH through cationic polymerization
  • Purification method for preparing PECH through cationic polymerization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] a) Washing: put the crude product and 10% methanol aqueous solution into a single-necked flask with magnetic stirring according to the mass ratio of 1:1, after stirring for 30 minutes, put the lower layer after standing for stratification, and wash according to this method 4 times, the first crude product was obtained after the solvent was removed by rotary evaporation;

[0028] b) Extraction: Add petroleum ether and the first crude product into a single-necked flask at a mass ratio of 10:5, raise the temperature in the bottle to 64°C under magnetic stirring, and cool down to 45°C after reflux for 1 hour, and let stand to separate. , the upper layer is the by-product cyclic crown ether, and the lower layer is the second crude product. According to this method, extract 3 to 4 times;

[0029] c) drying and filtering: add 5% desiccant anhydrous magnesium sulfate in mass ratio to the second crude product, fully mix, and filter through filter paper after drying to obtain the...

Embodiment 2

[0032] a) Washing: put the crude product and 10% methanol aqueous solution into a single-necked flask with magnetic stirring according to the mass ratio of 1:1, after stirring for 30 minutes, put the lower layer after standing for stratification, and wash according to this method 4 times, the first crude product was obtained after the solvent was removed by rotary evaporation;

[0033] b) Extraction: Add petroleum ether and the first crude product into a single-necked flask at a mass ratio of 30:5. Under the condition of magnetic stirring, the temperature in the bottle is raised to 65°C, and after reflux for 0.5h, the temperature is lowered to 50°C, and the After the first layer, take the second crude product of the lower layer, and extract 3 to 4 times according to this method;

[0034] c) Drying: add 5% desiccant anhydrous magnesium sulfate to the second crude product, mix well, and filter through filter paper after drying to obtain the third crude product;

[0035] d) Solv...

Embodiment 3

[0037] a) Washing: put the crude product and methanol aqueous solution with a mass concentration of 10% into a single-necked flask with magnetic stirring according to the mass ratio of 1:2, after stirring for 30 minutes, put the lower layer after standing for stratification, and wash according to this method 4 times, the first crude product was obtained after the solvent was removed by rotary evaporation;

[0038] b) Extraction: Add petroleum ether and the first crude product into a single-necked flask at a mass ratio of 30:10. Under the condition of magnetic stirring, the temperature in the bottle is raised to 68°C, and after reflux for 0.8h, the temperature is lowered to 35°C, and the After the first layer, take the second crude product of the lower layer, and extract 3 to 4 times according to this method;

[0039] c) Drying: add 5% desiccant anhydrous magnesium sulfate to the second crude product, mix well, and filter through filter paper after drying to obtain the third cr...

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Abstract

The invention discloses a purification method for preparing PECH by cationic polymerization, which comprises the following steps: a) mixing a crude product and a methanol aqueous solution, stirring, standing for layering, taking a lower oil phase, and removing a solvent to obtain a first crude product; b) adding petroleum ether into the first crude product, stirring, heating to T1 DEG C, refluxing for a preset time, cooling to T2 DEG C, and standing for layering to obtain an upper layer which is a by-product cyclic crown ether and a small molecule oligomer and a lower layer which is a second crude product; c) drying the second crude product, and filtering after drying to obtain a third crude product; and d) removing the solvent in the third crude product system by utilizing rotary evaporation equipment to obtain the main product PECH. The main and by-products are thoroughly separated, the product PECH with high purity and narrow molecular weight distribution can be obtained, and the separation process is safe and controllable.

Description

technical field [0001] The application relates to the field of chemical technology, in particular to a purification method for preparing PECH by cationic polymerization. Background technique [0002] Hydroxyl-terminated polyepichlorohydrin (PECH) is an important raw material for polyazidoglycidyl ether (GAP), a solid propellant binder component. During the preparation of PECH by cationic ring-opening polymerization, due to the complex reaction and many side reactions , in addition to generating zero-functionality cyclic crown ethers, it is often accompanied by some small molecule oligomers. The existence of these cyclic crown ethers and small molecular oligomers will seriously affect the number-average relative molecular weight of polyethers and their distribution, average functionality and other indicators, and deteriorate the quality of polyethers. The polyurethane prepared with this polyether, when the temperature rises, the low molecular weight oligomer will slowly vola...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G65/30
Inventor 齐永新王建生胡盼李冰吕德斌史哲董长春
Owner 天元(杭州)新材料科技有限公司