阅读说明：本技术 一种制备端2-呋喃甲酸酯基聚丁二烯的方法 (Method for preparing 2-furanformate-terminated polybutadiene ) 是由 杨帆致 刘宁宁 夏敏 罗运军 于 2020-12-16 设计创作，主要内容包括：本发明提供一种制备端2-呋喃甲酸酯基聚丁二烯的方法,包括以下步骤：在反应器中加入端羟基聚丁二烯、4-二甲氨基吡啶和有机溶剂,室温搅拌充分混匀；混合物冷却到0℃,缓慢加入2-呋喃甲酰氯,随后搅拌反应,反应温度为0℃～室温、反应时间为1h～48h；混合物洗涤、干燥、浓缩有机相、柱层析分离纯化得到产物端2-呋喃甲酸酯基聚丁二烯。本发明中使用4-二甲氨基吡啶作为缚酸剂的同时,能够有效提高酯化反应效率,2-呋喃甲酰氯反应活性高,且成本低廉,避免了二环己基碳二亚胺的使用。本发明中的反应操作及后处理简便安全,在放大制备过程中产率稳定,具有很大的工业应用潜力。(The invention provides a method for preparing 2-furanformate-terminated polybutadiene, which comprises the following steps: adding hydroxyl polybutadiene, 4-dimethylaminopyridine and an organic solvent into a reactor, and stirring at room temperature to be fully and uniformly mixed; cooling the mixture to 0 ℃, slowly adding 2-furoyl chloride, and then stirring for reaction at the reaction temperature of 0-room temperature for 1-48 h; washing the mixture, drying, concentrating an organic phase, and separating and purifying by column chromatography to obtain the product 2-furancarboxylic acid ester polybutadiene. The method disclosed by the invention has the advantages that 4-dimethylaminopyridine is used as an acid-binding agent, the esterification reaction efficiency can be effectively improved, the 2-furoyl chloride has high reaction activity and low cost, and the use of dicyclohexylcarbodiimide is avoided. The reaction operation and the post-treatment in the invention are simple, convenient and safe, the yield is stable in the amplification preparation process, and the method has great industrial application potential.)

1. A method for preparing 2-furancarboxylate-terminated polybutadiene is characterized by comprising the following steps:

(1) adding hydroxyl polybutadiene, 4-dimethylaminopyridine and an organic solvent into a reactor, and stirring at room temperature to be fully and uniformly mixed;

(2) cooling the mixture in the step (1) to 0 ℃, slowly adding 2-furoyl chloride, and then stirring for reaction at the reaction temperature of 0-room temperature for 1-48 h;

(3) and (3) washing the mixture obtained in the step (2), drying, concentrating an organic phase, and performing column chromatography separation and purification to obtain the product 2-furancarboxylic acid ester-terminated polybutadiene.

2. The method for preparing 2-furancarboxylate-terminated polybutadiene according to claim 1, wherein the hydroxyl-terminated polybutadiene has a number-average molecular weight of 1800-4600 and a hydroxyl value of 0.47-1.50.

3. The method of claim 2, wherein the hydroxyl-terminated polybutadiene has a number average molecular weight of 2700-3300 and a hydroxyl value of 0.71-0.80.

4. The method of claim 1, wherein the molar ratio of the hydroxyl-terminated polybutadiene to the 4-dimethylaminopyridine is 1: 0.75-1: 1.5, and the molar ratio of the hydroxyl-terminated polybutadiene to the 2-furoyl chloride is 1: 0.6-1: 1.

5. The method for preparing 2-furancarboxylate-terminated polybutadiene according to any one of claims 1 to 4, wherein the organic solvent is one or more of dry aromatic hydrocarbon, alkane or ether solvents.

6. The method of claim 5, wherein the organic solvent is one or more selected from benzene, toluene, xylene, chlorobenzene, dichloromethane, chloroform, 1, 2-dichloroethane, diethyl ether, tetrahydrofuran, methyl tert-butyl ether, and ethylene glycol dimethyl ether.

Technical Field

The invention relates to a method for preparing 2-furanformate-terminated polybutadiene, belonging to the technical field of novel materials.

Background

Hydroxyl-terminated polybutadiene (HTPB), namely butylate, is widely applied to the fields of adhesives, coatings, rubber materials, insulating materials, sealing materials, defense science and technology and the like due to the advantages of low viscosity, good process performance, high solid filling amount, relatively complete curing reaction, good storage performance and reduced cost. With the continuous improvement of the requirement on the stability of the material, the development of a novel self-repairing material system based on a hydroxyl-terminated polybutadiene skeleton structure is a feasible solution.

The research of intrinsic self-repairing materials based on covalent reversible reaction has attracted much attention in recent years, and Diels-Alder (Diels-Alder) reversible cycloaddition reaction is one of the hot spots. Diels-Alder reactive groups are introduced into the molecular structure of the material, and the material damage is repaired through heating and cooling circulation. Furan and maleimide are an economically efficient combination of Diels-Alder reactive groups. Xiamon, Roche et al use terminal 2-furanurethane Polybutadiene (FTPB) with N, N' -m-phenylene bismaleimide (PDMI) to form Self-healing adhesives and apply to solid propellants (Performance and Kinetics Study of Self-healing Hydroxyl-Terminated Polybutadiene Binders Based on the Diels-Alder Reaction, Polymers, 2017-5-30, 9 (6): 200).

In the report, hydroxyl-terminated polybutadiene and 2-furancarboxylic acid are used as raw materials, and the 2-furancarboxylic acid ester-based polybutadiene is obtained by esterification under the action of a dehydrating agent Dicyclohexylcarbodiimide (DCC). After the reaction is finished, the excessive dicyclohexylcarbodiimide and the byproduct Dicyclohexylurea (DCU) are difficult to separate from the system. In addition, dicyclohexylcarbodiimide has significant contact toxicity and can cause allergic reactions such as rash.

Disclosure of Invention

The invention aims to provide a method for preparing 2-furanformate-terminated polybutadiene with high efficiency, mildness and convenience.

A method for preparing 2-furancarboxylate-terminated polybutadiene, comprising the following steps:

(1) adding hydroxyl polybutadiene, 4-dimethylaminopyridine and an organic solvent into a reactor, and stirring at room temperature to be fully and uniformly mixed;

(2) cooling the mixture in the step (1) to 0 ℃, slowly adding 2-furoyl chloride, and then stirring for reaction at the reaction temperature of 0-room temperature for 1-48 h;

(3) and (3) washing the mixture obtained in the step (2), drying, concentrating an organic phase, and performing column chromatography separation and purification to obtain the product 2-furancarboxylic acid ester-terminated polybutadiene.

The reaction formula is as follows:

the hydroxyl-terminated polybutadiene has a number average molecular weight of 1800-4600 and a hydroxyl value of 0.47-1.50, preferably a number average molecular weight of 2700-3300 and a hydroxyl value of 0.71-0.80.

The molar ratio of the hydroxyl-terminated polybutadiene to the 4-dimethylaminopyridine is 1: 0.75-1: 1.5; the molar ratio of the hydroxyl-terminated polybutadiene to the 2-furoyl chloride is 1: 0.6-1: 1.

The reaction time of the step (2) is preferably 5 hours.

The organic solvent is one or more of dried aromatic hydrocarbon, alkane or ether solvents. Preferably one or more of a dry aromatic, alkane or ether solvent, more preferably one or more of benzene, toluene, xylene, chlorobenzene, dichloromethane, chloroform, 1, 2-dichloroethane, diethyl ether, tetrahydrofuran, methyl tert-butyl ether, ethylene glycol dimethyl ether, most preferably dichloromethane.

The detergent for the organic phase in the present invention is water or an aqueous solution of an inorganic salt, preferably a saturated aqueous solution of ammonium chloride.

Compared with the prior art, the invention has the following beneficial results:

1. hydroxyl-terminated polybutadiene causes the system to be viscous, which is not favorable for the esterification reaction. 4-dimethylamino pyridine has obvious catalytic action on esterification reaction of alcohols with large steric hindrance and low activity. The esterification reaction efficiency can be effectively improved while the 4-dimethylamino pyridine is used as an acid-binding agent.

2. The 2-furoyl chloride used in the invention has high reaction activity and low cost, and avoids the use of dicyclohexyl carbodiimide.

3. The reaction operation and the post-treatment in the invention are simple, convenient and safe, the yield is stable in the amplification preparation process, and the method has great industrial application potential.

Drawings

FIG. 1 shows the product of the present invention¹H nuclear magnetic spectrum;

FIG. 2 shows the product of the present invention¹³C nuclear magnetic spectrum;

FIG. 3 is an IR spectrum of a product obtained in an example of the present invention.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.

Example 1

10g of hydroxyl-terminated polybutadiene and 1.19g (1.3 eq) of 4-dimethylaminopyridine were dissolved in 40mL of dry dichloromethane. Stirring for 10min at normal temperature to completely dissolve 4-dimethylaminopyridine and hydroxyl-terminated polybutadiene, slowly adding 0.88mL (1.2 equivalent) of 2-furoyl chloride in an ice bath, removing the ice bath, and stirring at room temperature for reaction for 5 h. Washing the reaction system for 2-3 times by using a saturated ammonium chloride solution, removing most of the solvent of an organic phase under reduced pressure, loading the sample by a dry method, and separating by column chromatography to obtain 4.2g of light yellow transparent viscous liquid end 2-furancarboxylic acid ester polybutadiene with the yield of 39%.

1.9 to 2.2ppm in FIG. 1 correspond to hydrogen atoms in methylene groups attached to olefins in the polybutadiene chain; 4.9-5.0 ppm, 5.3-5.5 ppm respectively correspond to two types of hydrogen atoms of olefin molecules on the main chain; 7.6ppm, 7.1 and 6.5ppm correspond to the three types of hydrogen atoms of the furan ring, respectively.

In FIG. 2, 158ppm corresponds to the carbon atom of the ester group, 146ppm, 144ppm, 111ppm, 117ppm corresponds to the carbon atom of the furan ring, 27ppm, 32ppm, 43ppm corresponds to the carbon atom of the methylene group and the methine group bonded to the olefin in the polybutadiene chain, 114ppm, 129ppm, 130ppm, 142ppm corresponds to the carbon atom of the olefin molecule in the main chain.

C ═ O bond in fig. 3: 1719.75cm^-1(ii) a Furan ring skeleton: 1292.05, 1178.62 and 1117.46cm^-1(ii) a Furan ring C-H bond: 761.40cm^-1。

The products in the following examples are identical to the product of example 1.

Example 2

10g of hydroxyl-terminated polybutadiene and 1.37g (1.5 eq) of 4-dimethylaminopyridine were dissolved in 40mL of dry dichloromethane. Stirring for 10min at normal temperature to completely dissolve 4-dimethylaminopyridine and hydroxyl-terminated polybutadiene, slowly adding 0.89ml (1.2 equivalent) of 2-furoyl chloride in an ice bath, removing the ice bath, and stirring at room temperature for reaction for 5 h. Washing the reaction system for 2-3 times by using a saturated ammonium chloride solution, removing most of the solvent of an organic phase under reduced pressure, loading the sample by a dry method, and separating by column chromatography to obtain 7.6g of light yellow transparent viscous liquid end 2-furanformate polybutadiene with the yield of 71%.

Example 3

10g of hydroxyl-terminated polybutadiene and 1.83g (2.0 equivalents) of 4-dimethylaminopyridine were dissolved in 40mL of dry dichloromethane. Stirring for 10min at normal temperature to completely dissolve 4-dimethylaminopyridine and hydroxyl-terminated polybutadiene, slowly adding 1.11mL (1.5 equivalent) of 2-furoyl chloride in an ice bath, removing the ice bath, and stirring at room temperature for reaction for 5 h. Washing the reaction system for 2-3 times by using a saturated ammonium chloride solution, removing most of the solvent of an organic phase under reduced pressure, loading the sample by a dry method, and performing column chromatography separation to obtain 6.2g of light yellow transparent viscous liquid end 2-furancarboxylic acid ester polybutadiene with the yield of 58%.

Example 4

10g of hydroxyl-terminated polybutadiene and 2.75g (3.0 equivalents) of 4-dimethylaminopyridine were dissolved in 40mL of dry dichloromethane. Stirring for 10min at normal temperature to completely dissolve 4-dimethylaminopyridine and hydroxyl-terminated polybutadiene, slowly adding 1.48mL (2.0 equivalent) of 2-furoyl chloride in an ice bath, removing the ice bath, and stirring at room temperature for reaction for 5 h. Washing the reaction system for 2-3 times by using a saturated ammonium chloride solution, removing most of the solvent of an organic phase under reduced pressure, loading the sample by a dry method, and separating by column chromatography to obtain 7.7g of light yellow transparent viscous liquid end 2-furanformate polybutadiene with the yield of 72%.

Example 5

30g of hydroxyl-terminated polybutadiene and 4.12g (1.2 eq) of 4-dimethylaminopyridine were dissolved in 120mL of dry dichloromethane. Stirring for 10min at normal temperature to completely dissolve 4-dimethylaminopyridine and hydroxyl-terminated polybutadiene, slowly adding 2.66mL (1.5 equivalent) of 2-furoyl chloride in an ice bath, removing the ice bath, and stirring at room temperature for reaction for 5 h. Washing the reaction system for 2-3 times by using a saturated ammonium chloride solution, removing most of the solvent of an organic phase under reduced pressure, loading the sample by a dry method, and separating by column chromatography to obtain 20.3g of light yellow transparent viscous liquid end 2-furancarboxylic acid ester polybutadiene with the yield of 63%.

Example 6

100g of hydroxyl-terminated polybutadiene and 13.74g (1.2 eq) of 4-dimethylaminopyridine were dissolved in 375mL of dry dichloromethane. Stirring for 10min at normal temperature to completely dissolve 4-dimethylaminopyridine and hydroxyl-terminated polybutadiene, slowly adding 8.87mL (1.5 equivalent) of 2-furoyl chloride in an ice bath, removing the ice bath, and stirring at room temperature for reaction for 5 h. Washing the reaction system for 2-3 times by using a saturated ammonium chloride solution, removing most of the solvent of an organic phase under reduced pressure, loading the sample by a dry method, and performing column chromatography separation to obtain 67.3g of light yellow transparent viscous liquid end 2-furancarboxylic acid ester polybutadiene with the yield of 63%.

Example 7

180g of hydroxyl-terminated polybutadiene, 24.8g (1.2 eq) of 4-dimethylaminopyridine are dissolved in 500mL of dry dichloromethane. Stirring for 10min at normal temperature to completely dissolve 4-dimethylaminopyridine and hydroxyl-terminated polybutadiene, adding 15.97mL (1.5 equivalent) of 2-furoyl chloride in an ice bath, removing the ice bath, and stirring at room temperature for reaction for 5 h. Washing the reaction system for 2-3 times by using a saturated ammonium chloride solution, removing most of the solvent of an organic phase under reduced pressure, loading the sample by a dry method, and separating by column chromatography to obtain 117.8g of light yellow transparent viscous liquid end 2-furancarboxylic acid ester polybutadiene with the yield of 61%.