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CN-121974788-A - Purifying method of perfluoro isobutyl methyl ether

CN121974788ACN 121974788 ACN121974788 ACN 121974788ACN-121974788-A

Abstract

The invention provides a method for purifying perfluoro-isobutyl methyl ether, which sequentially comprises the steps of primary metal ion removal, metal oxide colloid interception, deep metal ion removal, dewatering, drying and rectification refining. Through a stepwise collaborative impurity removal strategy, water-soluble salts, colloid particles, heavy metal ions and trace moisture are removed in a targeted manner by adopting modes of water washing, PTFE ultrafiltration membrane filtration, ion exchange resin adsorption, 3A molecular sieve drying, PTFE lining rectification and the like, and finally the electronic grade high-purity product is obtained. The method has the advantages of high purity, tight impurity control, corrosion resistance of equipment, stable and scalable process and the like, and is suitable for large-scale industrialized high-purity preparation of the perfluoro isobutyl methyl ether.

Inventors

  • WU YANTAO
  • Tang Lianbo
  • ZHAO JINGPING
  • WANG CHAOFENG
  • WANG JUAN

Assignees

  • 邵武永和金塘新材料有限公司

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. The purifying method of the perfluoro isobutyl methyl ether is characterized by comprising the following steps in sequence: (1) Primary metal ion removal, namely mixing and stirring the crude product of the perfluoro-isobutyl methyl ether with deionized water, standing for layering, and removing a water phase to obtain an intermediate product A; (2) The metal oxide colloid interception, namely, the intermediate product A obtained in the step (1) is subjected to pressure filtration through a polytetrafluoroethylene ultrafiltration membrane, and filtrate is collected to obtain an intermediate product B; (3) Deeply removing metal ions, namely sequentially passing the intermediate product B obtained in the step (2) through a strong acid cation exchange resin column and a chelating resin column, and collecting effluent liquid to obtain an intermediate product C; (4) Dewatering and drying, namely contacting the intermediate product C obtained in the step (3) with an activated molecular sieve, and separating to obtain an intermediate product D; (5) Rectifying and refining, namely rectifying the intermediate product D obtained in the step (4) in a rectifying tower lined with polytetrafluoroethylene, and collecting the top fraction to obtain the high-purity perfluoro isobutyl methyl ether.
  2. 2. The purification method according to claim 1, wherein in the step (1), the volume ratio of the crude perfluoroisobutyl methyl ether to deionized water is 1:0.8-1:1.2.
  3. 3. The purification method according to claim 1 or 2, wherein in the step (2), the polytetrafluoroethylene ultrafiltration membrane has a molecular weight cut-off of 1000 to 5000 and the pressure filtration is operated at a pressure of 0.2 to 0.5 MPa.
  4. 4. The method according to claim 1, wherein in the step (3), the strongly acidic cation exchange resin is an H+ type styrene-divinylbenzene skeleton sulfonic acid type resin, and the chelate resin is an aminophosphonic acid type resin or an iminodiacetic acid type resin.
  5. 5. The purification method according to claim 1 or 4, wherein in the step (3), the flow rate of the intermediate product B through the resin column is controlled to be 1 to 2 BV/h, wherein BV is the resin bed volume.
  6. 6. The method according to claim 1, wherein in the step (4), the molecular sieve is a 3A molecular sieve, and the activated molecular sieve is activated by roasting at 550 ℃ for 4-6 hours or drying at 200 ℃ and vacuum degree of <10 Pa for 12 hours.
  7. 7. The purification method according to claim 1 or 6, wherein in the step (4), the mass ratio of the intermediate product C to the activated molecular sieve is 10:1 to 20:1.
  8. 8. The purification method according to claim 1, wherein in the step (5), the rectification is normal pressure rectification, and the rectification column is filled with tetrafluoropall ring packing, and the theoretical plate number is not less than 30.
  9. 9. The purification method according to claim 1 or 8, wherein in step (5), the temperature of the top of the rectification column is controlled to be 75-77 ℃ and the reflux ratio is controlled to be 5:1-10:1.
  10. 10. The method according to claim 1, wherein in the step (2), the polytetrafluoroethylene ultrafiltration membrane is pre-soaked with a pure product of perfluoroisobutyl methyl ether before the pressure filtration.

Description

Purifying method of perfluoro isobutyl methyl ether Technical Field The invention relates to the field of fluorine-containing fine chemical industry, in particular to a method for purifying perfluoro-isobutyl methyl ether. Background The perfluoro isobutyl methyl ether (chemical formula (CF 3)2CFCF2OCH3, CAS number: 163702-08-7) is a typical hydrofluoroether fluorine-containing organic compound, has the characteristics of no color and smell, incombustibility, high thermal stability, environmental friendliness (ODP value of 0) and the like, is widely applied to the fields of electronic industry, semiconductor manufacturing, optical precision instrument cooling and the like, and is particularly suitable for electronic grade cooling liquid and cleaning agents. In order to meet the extremely high purity requirements of high-end electronics for cooling media, the impurity content of the perfluoroisobutyl methyl ether product must be tightly controlled, wherein the residual of metal ions (such as K +、Na+、Fe3+、Ni2+, etc.) and moisture is particularly critical. These impurities, even at ppb levels, can cause corrosion, migration, or failure of the chip structure, electrical performance, or solder interface, affecting overall machine stability and life. At present, the industrial synthesis of perfluoro-isobutyl methyl ether generally adopts the reaction of heptafluoro-isobutyryl fluoride and a fluorinating agent (such as KF), and a crude product is obtained through a methylation step. In this process, the following impurities are inevitably introduced: unreacted metal ions and metal salt byproducts, derived from the fluorinating agent or intermediate reactants; Metal oxide colloid particles from equipment corrosion or high temperature reaction byproducts; Moisture impurities may be introduced by reactants, air or post-treatment elements. In view of the above impurities, the existing purification process mainly comprises the steps of water washing, adsorption, membrane separation, resin exchange, rectification and the like, but still has the following prominent problems: 1. Multiple impurities are difficult to be removed simultaneously and effectively in a single process section, for example, the interception of colloid particles is difficult to be considered only by water washing or resin; 2. The traditional rectifying tower material is easy to be corroded by a fluorine-containing system, so that secondary metal impurities enter a product to pollute the purity; 3. The resin selection and the treatment flow in the ion exchange process are improper, which easily causes low efficiency or product loss; 4. the matching performance among the system processes is poor, and the problems of impurity migration, dissolution or adsorption are not solved by the system. Therefore, development of a purification method with stepwise cooperative processing capability and capable of removing three impurities including metal ions, metal oxide colloid and water is urgently needed, and meanwhile, the purification method has the comprehensive properties of good equipment compatibility, mild operation, suitability for industrial scale continuous application and the like, so that the preparation requirement of high-purity electronic grade perfluoro-isobutyl methyl ether is met. Disclosure of Invention Therefore, the invention aims to provide a purification method of perfluoro-isobutyl methyl ether, which is used for efficiently removing metal ions, metal oxide colloid and water impurities in a synthesized crude product, improving the purity of the product, meeting the application requirements of electronic grade, reducing the equipment corrosion risk and being suitable for industrial continuous production. In order to achieve the above purpose, the present invention provides the following technical solutions: in one embodiment of the invention, there is provided a method for purifying perfluoroisobutyl methyl ether comprising the steps of, in order: (1) Primary metal ion removal, namely mixing and stirring the crude product of the perfluoro-isobutyl methyl ether with deionized water, standing for layering, and removing a water phase to obtain an intermediate product A; (2) The metal oxide colloid interception, namely, the intermediate product A obtained in the step (1) is subjected to pressure filtration through a polytetrafluoroethylene ultrafiltration membrane, and filtrate is collected to obtain an intermediate product B; (3) Deeply removing metal ions, namely sequentially passing the intermediate product B obtained in the step (2) through a strong acid cation exchange resin column and a chelating resin column, and collecting effluent liquid to obtain an intermediate product C; (4) Dewatering and drying, namely contacting the intermediate product C obtained in the step (3) with an activated molecular sieve, and separating to obtain an intermediate product D; (5) Rectifying and refining, namely rectifying the intermediate product D obtain