阅读说明：本技术 一种六氟丙烯齐聚物的合成方法 (Synthesis method of hexafluoropropylene oligomer ) 是由 李建辉 李伟鹏 张立忠 沈泽钦 王士涛 张俊 孙毅飞 于 2021-11-04 设计创作，主要内容包括：一种六氟丙烯齐聚物的合成方法,在极性非质子溶剂中,以碱金属盐为主催化剂,烯丙基类季铵盐的聚合物为辅助催化剂,在反应温度60～120℃,反应压力0.3～1MPa下通入六氟丙烯气体使其发生齐聚反应；所述极性非质子溶剂、主催化剂与辅助催化剂的质量比为100:3～10:1～5。本发明方法的组合催化剂活性好,价格低廉,反应收率高,三聚体全氟壬烯选择性高。(A method for synthesizing hexafluoropropylene oligomer comprises the steps of introducing hexafluoropropylene gas into a polar aprotic solvent at the reaction temperature of 60-120 ℃ and the reaction pressure of 0.3-1 MPa by taking alkali metal salt as a main catalyst and taking a polymer of allyl quaternary ammonium salt as an auxiliary catalyst to perform oligomerization reaction; the mass ratio of the polar aprotic solvent to the main catalyst to the auxiliary catalyst is 100: 3-10: 1-5. The combined catalyst of the method has the advantages of good activity, low price, high reaction yield and high selectivity of tripolymer perfluorononene.)

1. A method for synthesizing hexafluoropropylene oligomer is characterized in that: in a polar aprotic solvent, introducing hexafluoropropylene gas into the polar aprotic solvent at the reaction temperature of 60-120 ℃ and the reaction pressure of 0.3-1 MPa by taking alkali metal salt as a main catalyst and taking a polymer of allyl quaternary ammonium salt as an auxiliary catalyst to perform oligomerization reaction; the mass ratio of the polar aprotic solvent to the main catalyst to the auxiliary catalyst is 100: 3-10: 1-5.

2. The process for the synthesis of hexafluoropropylene oligomer as claimed in claim 1, wherein: the polar aprotic solvent is at least one selected from ethers, alkyl nitriles, alkyl sulfoxides, and alkylamides.

3. The process for the synthesis of hexafluoropropylene oligomer as claimed in claim 2, wherein: the polar aprotic solvent comprises at least one of acetonitrile, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, ethylene glycol dimethyl ether, sulfolane, tetrahydrofuran, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, and diethylene glycol dibutyl ether.

4. The process for the synthesis of hexafluoropropylene oligomer as claimed in claim 1, wherein: the alkali metal salt is at least one selected from NaF, KF, CsF, NaSCN, NaOCN, NaCN, KSCN, KOCN, KCN, CsSCN, CsOCN and CsCN.

5. The process for the synthesis of hexafluoropropylene oligomer as claimed in claim 1, wherein: the polymer of the allyl quaternary ammonium salt comprises at least one of polydimethyldiallylammonium chloride and polydimethyldiallylammonium bromide.

6. The process for the synthesis of hexafluoropropylene oligomer as claimed in claim 1, wherein: the mass ratio of the polar aprotic solvent to the main catalyst to the auxiliary catalyst is 100: 4-6: 2-3.

7. The process for the synthesis of hexafluoropropylene oligomer as claimed in claim 1, wherein: the reaction temperature is 100 ℃, and the reaction pressure is 0.5 MPa.

8. The process for the synthesis of hexafluoropropylene oligomer as claimed in claim 1, wherein: the hexafluoropropylene oligomer contains one or two of perfluorohexene and perfluorononene.

Technical Field

The invention relates to the field of catalysis, in particular to a method for synthesizing hexafluoropropylene oligomer.

Background

The hexafluoropropylene oligomer has good thermodynamic stability and chemical stability, can be used as an excellent solvent for dissolving fluorine-containing compounds, can also react with other reagents to introduce fluorine-containing hydrophobic and oleophobic groups, and is an important intermediate for preparing various fluorine-containing surfactants. The hexafluoropropylene oligomer is prepared through oligomerization of hexafluoropropylene, and its synthesis process is mainly around activation of hexafluoropropylene double bond and regulation of product selectivity.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a method for synthesizing hexafluoropropylene oligomers, wherein the combined catalyst has the advantages of good activity, low cost, high reaction yield and high selectivity of tripolymer perfluorononene.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for synthesizing hexafluoropropylene oligomer comprises the steps of introducing hexafluoropropylene gas into a polar aprotic solvent at the reaction temperature of 60-120 ℃ and the reaction pressure of 0.3-1 MPa by taking alkali metal salt as a main catalyst and taking a polymer of allyl quaternary ammonium salt as an auxiliary catalyst to perform oligomerization reaction; the mass ratio of the polar aprotic solvent to the main catalyst to the auxiliary catalyst is 100: 3-10: 1-5.

The polar aprotic solvent is selected from at least one of ethers, alkyl nitriles, alkyl sulfoxides, and alkylamides, for example, at least one of acetonitrile, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, ethylene glycol dimethyl ether, sulfolane, tetrahydrofuran, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, and diethylene glycol dibutyl ether.

The alkali metal salt includes, but is not limited to, at least one of NaF, KF, CsF, NaSCN, NaOCN, NaCN, KSCN, KOCN, KCN, CsSCN, CsOCN, CsCN.

The polymer of the allyl quaternary ammonium salt includes but is not limited to at least one of polydimethyldiallylammonium chloride and polydimethyldiallylammonium bromide.

Preferably, the mass ratio of the polar aprotic solvent to the main catalyst to the auxiliary catalyst is 100: 4-6: 2-3.

Preferably, the reaction temperature is 100 ℃ and the reaction pressure is 0.5 MPa.

The hexafluoropropylene oligomer contains one or two of perfluorohexene and perfluorononene.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

the invention relates to a method for synthesizing hexafluoropropylene oligomer, in particular to a method for synthesizing tripolymer perfluorononene with good activity of a combined catalyst, low cost, high reaction yield and high selectivity. The invention adopts the polymer of the allyl quaternary ammonium salt as the cocatalyst, can obviously promote the oligomerization reaction of hexafluoropropylene catalyzed by the alkali metal salt main catalyst, and can obviously improve the selectivity of tripolymer perfluorononene.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention clearer and more obvious, the present invention is further described in detail below with reference to the following embodiments.

Example 1

100mL of N, N-dimethylformamide is measured and put into an autoclave, 5g of KF and 2.5g of poly-dimethyldiallylammonium chloride are added, a vacuumizing device is connected after a kettle cover is sealed, air in the kettle is removed, nitrogen is introduced, vacuumizing is carried out again, and the air exchange operation is repeated for three times. After the air exchange operation is finished, the autoclave is heated to 100 ℃ to be activated for 1h, then a stirrer is opened, hexafluoropropylene gas is introduced at the temperature, the pressure is maintained at 0.5MPa, and the rotating speed is 800 r/min. After 30min, the air inlet valve is closed, and the mass of the charged gas is 167 g. And (3) stopping stirring after the reaction is carried out for 1h at 100 ℃, cooling to normal temperature, opening a kettle cover, transferring the product into a separating funnel, standing and separating 156.9g of a lower-layer light yellow transparent product, wherein the yield is 93.9%. After washing and drying, the product is separated by distillation and analyzed by gas chromatography, wherein the mass content of perfluorohexene is 1.3%, the mass content of perfluorononene is 98%, and the mass content of other byproducts is about 0.7%.

Example 2

100mL of N, N-dimethylformamide is measured and put into an autoclave, 5g of CsF and 2.5g of poly-dimethyldiallylammonium chloride are added, a vacuumizing device is connected after a kettle cover is sealed, air in the kettle is removed, nitrogen is introduced, vacuumizing is carried out again, and the air exchange operation is repeated for three times. After the air exchange operation is finished, the autoclave is heated to 100 ℃ to be activated for 1h, then a stirrer is opened, hexafluoropropylene gas is introduced at the temperature, the pressure is maintained at 0.5MPa, and the rotating speed is 800 r/min. And (3) after 30min, closing an air inlet valve, introducing 189g of gas, stopping stirring after reacting for 1h at 100 ℃, cooling to normal temperature, opening a kettle cover, transferring a product into a separating funnel, standing and separating 181g of a lower-layer light yellow transparent product, wherein the yield is 95.7%. After washing and drying, the product is separated by distillation and analyzed by gas chromatography, wherein the mass content of perfluorohexene is 0.7%, the mass content of perfluorononene is 97%, and the mass content of other byproducts is about 2.3%.

Example 3

100mL of N, N-dimethylformamide is measured and put into an autoclave, 5g of KF and 1.67g of poly-dimethyldiallylammonium chloride are added, a vacuumizing device is connected after a kettle cover is sealed, air in the kettle is removed, nitrogen is introduced, vacuumizing is carried out again, and the air exchange operation is repeated for three times. After the air exchange operation is finished, the autoclave is heated to 100 ℃ to be activated for 1h, then a stirrer is opened, hexafluoropropylene gas is introduced at the temperature, the pressure is maintained at 0.5MPa, and the rotating speed is 800 r/min. After 30min, the air inlet valve is closed, and the mass of the charged gas is 132 g. And (3) stopping stirring after the reaction is carried out for 1h at 100 ℃, cooling to normal temperature, opening a kettle cover, transferring the product into a separating funnel, standing and separating out 120.2g of a lower-layer light yellow transparent product, wherein the yield is 91%. After washing and drying, the product is separated by distillation and analyzed by gas chromatography, wherein the mass content of perfluorohexene is 3.1%, the mass content of perfluorononene is 95.8%, and the mass content of other byproducts is about 1.1%.

Example 4

100mL of dimethyl sulfoxide is measured and put into an autoclave, 5g of KF and 2.5g of poly-dimethyldiallylammonium chloride are added, a vacuum extractor is connected after a kettle cover is sealed, air in the kettle is removed, nitrogen is introduced, vacuum is extracted again, and the air exchange operation is repeated for three times. After the air exchange operation is finished, the autoclave is heated to 100 ℃ to be activated for 1h, then a stirrer is opened, hexafluoropropylene gas is introduced at the temperature, the pressure is maintained at 0.5MPa, and the rotating speed is 800 r/min. After 30min, the air inlet valve is closed, and the mass of the charged gas is 167 g. And (3) stopping stirring after the reaction is carried out for 1h at 100 ℃, cooling to normal temperature, opening a kettle cover, transferring the product into a separating funnel, standing and separating 150.3g of a lower-layer light yellow transparent product, wherein the yield is 90%. After washing and drying, the product is separated by distillation and analyzed by gas chromatography, wherein the mass content of perfluorohexene is 1.5%, the mass content of perfluorononene is 95.1%, and the mass content of other byproducts is about 3.4%.

Example 5

100mL of dimethyl sulfoxide is measured and put into an autoclave, 5g of CsF and 2.5g of poly-dimethyl diallyl ammonium chloride are added, a vacuumizing device is connected after a kettle cover is sealed, air in the kettle is removed, nitrogen is introduced, vacuumizing is carried out again, and the air exchange operation is repeated for three times. After the air exchange operation is finished, the autoclave is heated to 100 ℃ to be activated for 1h, then a stirrer is opened, hexafluoropropylene gas is introduced at the temperature, the pressure is maintained at 0.5MPa, and the rotating speed is 800 r/min. And (3) after 30min, closing an air inlet valve, filling gas with the mass of 161g, stopping stirring after reacting for 1h at 100 ℃, cooling to normal temperature, opening a kettle cover, transferring a product into a separating funnel, standing and separating 154.5g of a lower-layer light yellow transparent product, namely the yield is 95.9%. After washing and drying, the product is separated by distillation and analyzed by gas chromatography, wherein the mass content of perfluorohexene is 1.3%, the mass content of perfluorononene is 94%, and the mass content of other byproducts is about 4.7%.

Example 6

100mL of acetonitrile is measured and put into an autoclave, 5g of KF and 2.5g of poly dimethyl diallyl ammonium chloride are added, after a kettle cover is sealed, the autoclave is connected with a vacuumizing device, air in the kettle is removed, nitrogen is introduced, vacuumizing is carried out again, and the air exchange operation is repeated for three times. After the air exchange operation is finished, the autoclave is heated to 60 ℃ to be activated for 1h, then a stirrer is opened, hexafluoropropylene gas is introduced at the temperature, the pressure is maintained at 0.5MPa, and the rotating speed is 800 r/min. After 30min, the air inlet valve is closed, and the mass of the charged gas is 131 g. And (3) stopping stirring after the reaction is carried out for 1h at the temperature of 100 ℃, cooling to normal temperature, opening a kettle cover, transferring the product into a separating funnel, standing and separating out 125.6g of a colorless and transparent product at the lower layer, wherein the yield is 95.9%. After washing and drying, the product is separated by distillation and analyzed by gas chromatography, wherein the mass content of perfluorohexene is 97.1%, the mass content of perfluorononene is 1.2%, and the mass content of other byproducts is about 1.7%.

Comparative example 1

100mL of dimethyl sulfoxide is measured and put into an autoclave, 5g of CsF and 2.5g of 60% dimethyldiallylammonium chloride are added, a cover of the autoclave is sealed, a vacuumizing device is connected to remove air in the autoclave, nitrogen is introduced, vacuumizing is carried out again, and the air exchange operation is repeated for three times. After the air exchange operation is finished, the autoclave is heated to 100 ℃ to be activated for 1h, then a stirrer is opened, hexafluoropropylene gas is introduced at the temperature, the pressure is maintained at 0.5MPa, and the rotating speed is 800 r/min. And (3) closing the air inlet valve after 30min, filling 6g of gas, stopping stirring after reacting for 1h at 100 ℃, cooling to normal temperature, opening the kettle cover, transferring the product to a separating funnel, and failing to obtain an oligomerization product.

In conclusion, the alkali metal salt and the micromolecular allyl quaternary ammonium salt are used in a combined mode, and the hexafluoropropylene polymerization is not catalyzed, but the hexafluoropropylene oligomerization reaction can be obviously promoted and the selectivity of the hexafluoropropylene tripolymer can be obviously improved by using the alkali metal salt and the polymer of the allyl quaternary ammonium salt in a combined mode. The poly (diallyldimethylammonium chloride) is prepared by special cyclic polymerization (radial cyclization), and has high charge density and flexible chain segments, and the intramolecular electrostatic repulsive force between the chain segments ensures that a polymer chain adopts a more extended conformation, thereby improving the phase transfer efficiency of the catalyst. Resulting in both having significant catalytic properties when used as catalyst promoters.