Preparation for low molecular weight hydroxy-terminated polybutadiene

A hydroxyl polybutadiene, low molecular weight technology, applied in the field of chemical synthesis, can solve the problems of many preparation steps, low yield, incomplete hydrolysis of protective groups, etc., and achieve good mechanical properties and high activity

Inactive Publication Date: 2008-10-01
SINOPEC LANZHOU GASOLINEEUM CHEM IND CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, this kind of protective group initiator still has the disadvantages of many preparation steps and low yi

Method used

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  • Preparation for low molecular weight hydroxy-terminated polybutadiene
  • Preparation for low molecular weight hydroxy-terminated polybutadiene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Preparation of initiator tert-butyldimethylsiloxane n-propyllithium

[0023] In a 250ml three-necked flask, add 38g (0.4mol) 3-chloro-1-propanol, 60g (0.4mol) tert-butyldimethylsilyl chloride, 100ml N, N-dimethylformamide and 38g ( 0.44mol) of imidazole, reacted at 5°C for 30 minutes, and stirred at room temperature for 6 hours under nitrogen protection. Add 350ml of n-hexane, then wash with 5% aqueous sodium bicarbonate solution three times, and separate the n-hexane layer. After drying with calcium hydride, the solvent was evaporated by rotary evaporation, and a colorless liquid was obtained by chromatographic column separation with a yield of 93%.

[0024] Under Ar atmosphere, add 8g (1.01mol) of lithium and 50ml of cyclohexane into the reaction flask into a 250ml three-necked flask equipped with a condenser, a constant pressure dropping funnel, and magnetic stirring, and then add 22.3g (0.107mol) of t 50 ml of a cyclohexane solution of butyl-(3-chloropropoxy)d...

Embodiment 2

[0028] (1) Preparation of tert-butyldimethylsiloxane n-propyllithium

[0029] With embodiment 1.

[0030] (2) Preparation of hydroxyl-terminated polybutadiene

[0031] Under the protection of high-purity argon, take 3.5ml of n-propyllithium tert-butyldimethylsilyl ether and add it to a 250ml reaction bottle containing 6g of butadiene and 50ml of cyclohexane, polymerize at 25°C for 5h, and then use Inject 3ml of propylene oxide into the syringe and continue the reaction at 50°C for 1 hour. After the reaction is completed, stop the reaction with 2ml of ethanol. The glue is precipitated and separated in ethanol. Dissolve the lower glue in 40ml of tetrahydrofuran, and add 0.5g of ammonium fluoride to remove the protecting group. Then, settle and separate with ethanol, and dry at 50°C and -0.1MPa for 8 hours to obtain a hydroxyl-terminated polybutadiene telechelic polymer. GPC measured Mn=5100, Mw / Mn=1.07, and the average functionality was 2.0 by HNMR analysis.

Embodiment 3

[0033] (1) Preparation of triethylsilyl ether n-propyllithium initiator

[0034] In a 250ml three-necked flask, 38g (0.4mol) of 3-chloro-1-propanol, 61g (0.4mol) of triethylchlorosilane, and 80ml of tetrahydrofuran were sequentially added. Then the N, N-dimethylformamide (30ml) solution containing 38g (0.44mol) imidazole was added dropwise to the reaction system within 30min at 5°C. 2 Stir at room temperature under protection for 6 hours. 350ml of cyclohexane was added, and then washed three times with 5% aqueous sodium bicarbonate solution, and the cyclohexane layer was separated. After drying with calcium hydride, the solvent was evaporated by rotary evaporation, and a colorless liquid was obtained by column separation with a yield of 90%.

[0035] Under Ar atmosphere, add 8g (1.01mol) lithium, 100ml cyclohexane and 22.3g (0.107mol) triethyl-(3- Chloropropoxy)-silane was added into the reaction flask, the temperature was raised to 60°C, and stirred for 2h. The crude prod...

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Abstract

The invention provides a method for preparing hydroxyl-terminated polybutadiene of low molecular weight. The method adopts butadiene as a monomer, lithium alkylide of aliphatic series which contains silane protecting hydroxyl as an evocating agent, an organic non-polar compound as a solvent, an epoxy compound as an end capping reagent and fluoride as a detaching reagent for protecting groups. Anion polymer technology is adopted and polymerization is carried out at a temperature of 20 to 80 DEG C in the environment of inert gases; a prepolymer obtained goes through acid hydrolysis and a series of hydroxyl-terminated polybutadiene fluid rubber with narrow molecular distribution and controllable molecular weight is obtained. In the process of preparing hydroxyl-terminated polybutadiene polymer of the invention, the polymer does not encounter with a fake gel phenomenon during the process of end capping and detaching protecting group and the polymerization process is easy for control; the micro-structure of molecular chains is adjustable and controllable. The obtained hydroxyl-terminated polybutadiene has a molecular weight distributing index less than or equal to 1.2; the average functionality is close to 2; the cured products of hydroxyl-terminated polybutadiene have extremely good mechanical property and can be applied to the fields of rocket technology, optical fiber communication technology, etc.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and relates to a preparation method of polybutadiene, in particular to a preparation method of anion of low-molecular-weight hydroxyl-terminated polybutadiene. Background technique [0002] Hydroxyl-terminated polybutadiene low-molecular-weight polymers are telechelic polymers and are the main products in liquid rubber. Hydroxyl-terminated polybutadiene low-molecular-weight polymer not only has the function of adhesion, but also has the function of rocket fuel. As a component of rocket solid propellant, it is used in the field of aerospace technology. [0003] The synthesis methods of hydroxyl-terminated polybutadiene mainly include free radical polymerization and anionic polymerization. The hydroxyl-terminated polybutadiene synthesized by free radical polymerization is not easy to control the microstructure of its molecular chain, and its molecular weight distribution is relatively w...

Claims

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Application Information

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IPC IPC(8): C08F136/06C08F4/58C08F8/00
Inventor 陈继明齐永新鲁在君易建军于晶潘广勤张耀亨柏海见胡少坤黄英
Owner SINOPEC LANZHOU GASOLINEEUM CHEM IND CORP
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