阅读说明：本技术 一种用于聚合特种三元氟橡胶的全氟醚羧酸的制备工艺 (Preparation process of perfluoroether carboxylic acid for polymerizing special ternary fluororubber ) 是由 景宏伟 吴玉勋 钱厚琴 于 2019-11-15 设计创作，主要内容包括：本发明公开了一种用于聚合特种三元氟橡胶的全氟醚羧酸的制备工艺,它包括如下步骤：将以含氟烯烃进行光化氧化反应聚合得到聚醚酰氟低聚物为原料,分子量在300~1500,然后水解得到聚醚羧酸,最后在微通道反应器内采用氟气直接氟化制得全氟醚羧酸。本发明可以减少目标产物中的其他成分残留和简化常规液相氟化工艺的杂质分离流程,并减少原料降解现象,使全氟产物转化率更高。(The invention discloses a preparation process of perfluoroether carboxylic acid for polymerizing special ternary fluororubber, which comprises the following steps: the method comprises the steps of carrying out photochemical oxidation polymerization on fluorine-containing olefin to obtain polyether acyl fluoride oligomer serving as a raw material, carrying out hydrolysis on the polyether acyl fluoride oligomer to obtain polyether carboxylic acid, and finally carrying out direct fluorination in a microchannel reactor by adopting fluorine gas to obtain the perfluoro ether carboxylic acid. The invention can reduce the residue of other components in the target product, simplify the impurity separation process of the conventional liquid phase fluorination process, reduce the degradation phenomenon of the raw material and ensure that the conversion rate of the perfluorinated product is higher.)

1. A preparation process of perfluoroether carboxylic acid for polymerizing special ternary fluororubber is characterized by comprising the following steps: the method comprises the steps of carrying out photochemical oxidation polymerization on fluorine-containing olefin to obtain polyether acyl fluoride oligomer serving as a raw material, carrying out hydrolysis on the polyether acyl fluoride oligomer to obtain polyether carboxylic acid, and finally carrying out direct fluorination in a microchannel reactor by adopting fluorine gas to obtain the perfluoro ether carboxylic acid.

2. The process of claim 1, wherein the fluoroolefin is one or more selected from the group consisting of vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, pentafluoropropene, hexafluoropropylene, chlorotrifluoroethylene, bromotrifluoroethylene, trifluoropropene, and hexafluoroisobutylene.

3. The process according to claim 1, wherein the volume ratio of water used for hydrolysis to polyetheracylfluoride is 1-10: 1.

4. The process according to claim 1, wherein the stirring speed for hydrolysis is 10-500 rpm.

5. The process according to claim 1, wherein the diameter of the microchannel is 100 to 1000 μm.

6. The process according to claim 1, wherein the fluorine gas has a concentration of 10 to 20% and the balance nitrogen gas.

7. The process for preparing perfluoroether carboxylic acid used in polymerizing special ternary fluororubber according to claim 1, wherein the molar ratio of fluorine gas to polyether carboxylic acid is 1-10: 1.

8. The process according to claim 1, wherein the conversion of perfluoroether carboxylic acid is 80-95%.

9. The process according to claim 1, wherein the perfluoro ether carboxylic acid is 80-99% in technical grade.

Technical Field

The invention relates to a preparation process of perfluoroether carboxylic acid for polymerizing special ternary fluororubber.

Background

The special ternary fluororubber is synthesized by emulsion polymerization of three fluorine-containing monomers (vinylidene fluoride, tetrafluoroethylene, perfluoropropylene, chlorotrifluoroethylene, perfluoroalkyl vinyl ether and the like). The high bond energy and the unique bond length of the C-F bond enable the fluororubber polymerized by the fluorine-containing monomer to have better low-temperature elastic automobile fuel oil resistance and heat resistance, and the typical application is that the fluororubber is applied to O-shaped ring carburetor pump diaphragms and sealing pieces of automobile fuel injectors, in order to be suitable for various production equipment (compression molding transfer molding or injection molding) and die geometric shapes in the processing and molding process, raw rubbers with different Mooney viscosities are required to be selected, the raw rubber with low Mooney viscosity is selected in the injection molding process, and the raw rubber with high Mooney viscosity is selected in the compression molding process. In the process of synthesizing the fluororubber, different auxiliaries are needed to ensure the polymerization reaction to be carried out, so that the fluororubber with stable quality is obtained. Perfluoroether carboxylic acid, as a novel emulsifier, has a significant impact on fluororubber polymerization in place of Perfluorooctanoate (PFOA) which is prohibited in the world.

Disclosure of Invention

The invention provides a preparation process of perfluoroether carboxylic acid for polymerizing special ternary fluororubber, which can reduce other component residues in a target product, simplify the impurity separation process of the conventional liquid phase fluorination process, reduce the degradation phenomenon of raw materials and ensure that the conversion rate of a perfluorinated product is higher.

The invention adopts the following technical scheme: a preparation process of perfluoroether carboxylic acid for polymerizing special ternary fluororubber is characterized by comprising the following steps: the method comprises the steps of carrying out photochemical oxidation polymerization on fluorine-containing olefin to obtain polyether acyl fluoride oligomer serving as a raw material, carrying out hydrolysis on the polyether acyl fluoride oligomer to obtain polyether carboxylic acid, and finally carrying out direct fluorination in a microchannel reactor by adopting fluorine gas to obtain the perfluoro ether carboxylic acid.

The fluorine-containing olefin is one or a combination of more of vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, pentafluoropropylene, hexafluoropropylene, chlorotrifluoroethylene, trifluorobromoethylene, trifluoropropylene and hexafluoroisobutylene. The volume ratio of the water used for hydrolysis to the polyether acyl fluoride is 1-10: 1. The hydrolysis stirring speed is 10-500 rpm. The diameter of the micro channel is 100-1000 mu m. The concentration of the fluorine gas is 10-20%, and the rest is nitrogen gas. The molar ratio of the fluorine gas to the polyether carboxylic acid is 1-10: 1. The conversion rate of the perfluoroether carboxylic acid reaches 80-95%. The content of the industrial-grade perfluoroether carboxylic acid is 80-99%.

The invention has the following beneficial effects: after the technical scheme is adopted, the method takes the polyether acyl fluoride oligomer obtained by polymerization of fluorine-containing olefin through photochemical oxidation reaction as a raw material, the molecular weight is 300-1500, then the polyether acyl fluoride oligomer is hydrolyzed to obtain polyether carboxylic acid, and finally the polyether carboxylic acid is directly fluorinated by fluorine gas in a microchannel reactor to obtain the perfluoroether carboxylic acid; the invention aims to reduce other component residues in a target product, simplify the impurity separation process of the conventional liquid phase fluorination process, reduce the degradation phenomenon of raw materials and ensure that the conversion rate of a perfluorinated product is higher by a fluorination method without using an additional solvent.

Drawings

FIG. 1 is a schematic flow chart of the present invention.

Detailed Description