A method for producing chlorotrifluoroethylene oligomer and chlorotrifluoroethylene oligomer

Abstract

This invention relates to the field of chemical technology, specifically to a method for preparing trifluorochloroethylene oligomers and the trifluorochloroethylene oligomers themselves. The method includes: polymerizing trifluorochloroethylene monomers in the presence of an initiator using an organic solvent as the reaction medium to obtain the trifluorochloroethylene oligomers; the organic solvent is selected from CF2HCF2OCH2CF2CF2H (HFE458), n-C5F... 12 And HFE458 and n-C5F 12 At least one of the mixed solvents. This invention involves reacting trifluorochloroethylene monomer with an organic solvent (HFE458, n-C5F...) 12 And HFE458 and n-C5F 12 The polymerization reaction of trifluorochloroethylene oligomers (one of the mixed solvents) under the action of an initiator can yield trifluorochloroethylene oligomers with a number average molecular weight between 742 and 9088 and a molecular weight distribution coefficient between 1.48 and 1.98. The operation steps are simple, the reaction effect is good, the molecular weight distribution of the obtained product is narrow, the polydispersity is low, and it has good market prospects.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a method for preparing trifluorochloroethylene oligomers and the trifluorochloroethylene oligomers themselves. Background Technology

[0002] There are many types of trifluorochloroethylene oligomers. Fluorochloro oil is one of them, with a number-average molecular weight between 250 and 10,000. It has high specific gravity, is non-flammable, has high thermal stability, extremely good chemical stability, good lubrication ability, and good insulation and dielectric properties. It can be used as a lubricant for special conditions, a lubricating oil produced from liquid oxygen, and a floatation liquid used in navigation gyroscopes and accelerometers for marine and aviation applications. It is a high-value-added special fluorinated material.

[0003] Currently, the preparation of fluorochloroethylene oil mainly involves two methods: telomerization and pyrolysis. Telomerization refers to the oligomerization reaction that occurs between chlorotrifluoroethylene (CTFE) monomer and the telomerization agent under conditions such as high temperature, irradiation, organic peroxides, and metal catalysts. Pyrolysis uses polychlorotrifluoroethylene (PCTFE) as raw material and pyrolyzes it at a certain temperature to obtain fluorochloroethylene oil with a low degree of polymerization.

[0004] In a U.S. patent (US3054785) concerning a halogenated polymer and its preparation, a method is proposed to prepare low molecular weight PCTFE by polymerizing CTFE monomers in a solution of SOCl2 or PCl3. However, both SOCl2 and PCl3, which are used as reaction solvents, are corrosive.

[0005] In a U.S. patent (US2706715) for a grease composition, a method for preparing a low molecular weight trifluorochloroethylene polymer is disclosed. Benzoyl peroxide, ammonium persulfate, or potassium persulfate are disclosed as initiators, and the reaction temperature is 150-450 degrees Fahrenheit. The disadvantages of this method are that the reaction temperature is high, hydrogen fluoride is generated during the reaction, and the molecular weight distribution of the obtained product is relatively wide.

[0006] In US Patent US2705706, trifluorodichloropropionyl peroxide is used as a promoter to prepare liquid or waxy fluoropolymers at a reaction temperature of 70-200°C and a reaction pressure of 10000-15000 Psi. It has both high reaction temperature and high reaction pressure.

[0007] German invention patent DE934309C discloses a method for preparing fluorine-containing or fluorine- and chlorine-containing polymers. It proposes to polymerize CTFE monomers in solvents such as CCl4, CHCl3, and C2Cl4 in the presence of an initiator at 550 psi and 100-180°C. This method not only involves high reaction temperatures and expensive solvents, but also uses solvents that are carcinogenic. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a method for preparing trifluorochloroethylene oligomers and the trifluorochloroethylene oligomers themselves. By polymerizing CTFE monomers under low temperature and moderate pressure conditions in an environmentally friendly solvent, PCTFE oligomers with a number-average molecular weight of 742-9088 are generated. This solves the technical problems of high reaction temperature, high reaction pressure, and the use of highly toxic organic solvents in the preparation process of low molecular weight PCTFE in the prior art.

[0009] In a first aspect, the present invention provides a method for preparing trifluorochloroethylene oligomers, comprising: polymerizing trifluorochloroethylene monomers in the presence of an initiator using an organic solvent as a reaction medium to obtain the trifluorochloroethylene oligomers;

[0010] The organic solvent is selected from hydrofluoroether CF2HCF2OCH2CF2CF2H(HFE458), n-C5F 12 Or hydrofluoroether HFE458 and n-C5F 12 At least one of the mixed solvents.

[0011] In some embodiments of the present invention, the amount of the organic solvent used is 1-1200 wt% of the total amount of trifluorochloroethylene monomer; further, the amount of the organic solvent used is 80-320 wt% of the total amount of trifluorochloroethylene monomer.

[0012] In some embodiments of the present invention, the initiator is an organic peroxide initiator;

[0013] Preferably, the organic peroxide initiator is one or more of diisopropyl peroxide dicarbonate (IPP), di-tert-butyl peroxide (DTBP), and di(7-hydro-dodecylfluoroheptanoic acid) (DHP).

[0014] In some embodiments of the present invention, the amount of the organic peroxide initiator is 0.5-10 wt% of the total amount of trifluorochloroethylene monomer; further, the amount of the organic peroxide initiator is 1-5 wt% of the total amount of trifluorochloroethylene monomer.

[0015] In some embodiments of the present invention, the polymerization reaction is carried out at a temperature of 10-40°C and a reaction pressure of 1-3 MPa.

[0016] Secondly, the present invention also provides trifluorochloroethylene oligomers prepared by the above method, wherein the number-average molecular weight of the trifluorochloroethylene oligomers is between 742 and 9088, and its molecular weight distribution coefficient is between 1.48 and 1.98.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] This invention provides a method for preparing trifluorochloroethylene oligomers, which involves reacting trifluorochloroethylene monomers with an organic solvent (hydrofluoroether HFE458, n-C5F...). 12 Polymerization of trifluorochloroethylene (trichloroethylene) oligomers (either in a solvent or a mixture thereof) under the action of an initiator yields oligomers with a number-average molecular weight between 742 and 9088 and a molecular weight distribution coefficient between 1.48 and 1.98. The method described in this invention uses inexpensive, non-corrosive, and non-toxic organic solvents as the reaction medium. By controlling the amount of the reaction medium added and selecting appropriate amounts and types of organic peroxides as initiators, polymerization occurs under mild reaction conditions. The operation steps are simple, the reaction effect is good, and the resulting product has a narrow molecular weight distribution and low polydispersity, showing good market prospects. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0020] The present invention will be further described in detail below through embodiments, but the present invention is not limited thereto.

[0021] Example 1

[0022] Add 400g of trifluorochloroethylene monomer and 500ml of n-C5F 12 Solvent and 20g of IPP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 25℃ and a reaction pressure of 2MPa to obtain 219g of trifluorochloroethylene oligomer with a number-average molecular weight of 742. Specific reaction conditions and test results are shown in Table 1.

[0023] Example 2

[0024] Add 500g of trifluorochloroethylene monomer and 500ml of n-C5F 12Solvent and 20g of IPP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 30℃ and a reaction pressure of 2MPa to obtain 275g of trifluorochloroethylene oligomer with a number-average molecular weight of 5639. Specific reaction conditions and test results are shown in Table 1.

[0025] Example 3

[0026] Add 600g of trifluorochloroethylene monomer and 500ml of n-C5F 12 Solvent and 20g of IPP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 35℃ and a reaction pressure of 2MPa to obtain 338g of trifluorochloroethylene oligomer with a number-average molecular weight of 1078. Specific reaction conditions and test results are shown in Table 1.

[0027] Example 4

[0028] 400g of trifluorochloroethylene monomer, 500ml of HFE458 solvent, and 20g of DHP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 10℃ and a reaction pressure of 3MPa to obtain 223g of trifluorochloroethylene oligomer with a number average molecular weight of 2675. Specific reaction conditions and test results are shown in Table 1.

[0029] Example 5

[0030] 500g of trifluorochloroethylene monomer, 500ml of HFE458 solvent, and 25g of DHP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 15℃ and a reaction pressure of 2MPa to obtain 289g of trifluorochloroethylene oligomer with a number average molecular weight of 9088. Specific reaction conditions and test results are shown in Table 1.

[0031] Example 6

[0032] 600g of trifluorochloroethylene monomer, 500ml of HFE458 solvent, and 30g of DHP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 20℃ and a reaction pressure of 1.5MPa to obtain 319g of trifluorochloroethylene oligomer with a number average molecular weight of 6466. Specific reaction conditions and test results are shown in Table 1.

[0033] Example 7

[0034] Add 400g of trifluorochloroethylene monomer and 500ml of n-C5F12 A 1:1 mixture of HFE458 and 20g of DTBP initiator was sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 25℃ and a reaction pressure of 2MPa, yielding 213g of trifluorochloroethylene oligomer with a number average molecular weight of 3578. Specific reaction conditions and test results are shown in Table 1.

[0035] Comparative Example 1

[0036] 400g of trifluorochloroethylene monomer, 500ml of CCl4 solvent, and 20g of IPP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 25℃ and a reaction pressure of 2MPa, yielding 158g of trifluorochloroethylene oligomer with a number-average molecular weight of 626. Specific reaction conditions and test results are shown in Table 1.

[0037] Comparative Example 2

[0038] Add 400g of trifluorochloroethylene monomer and 500ml of n-C5F 12 Solvent and 20g of benzoyl peroxide (BPO) initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 25℃ and a reaction pressure of 2MPa to obtain 146g of trifluorochloroethylene oligomer with a number-average molecular weight of 596. Specific reaction conditions and test results are shown in Table 1.

[0039] Comparative Example 3

[0040] Add 400g of trifluorochloroethylene monomer and 500ml of n-C5F 12 Solvent and 20g of IPP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 50℃ and a reaction pressure of 2MPa to obtain 207g of trifluorochloroethylene oligomer with a number-average molecular weight of 585. Specific reaction conditions and test results are shown in Table 1.

[0041] Comparative Example 4

[0042] Add 400g of trifluorochloroethylene monomer and 500ml of n-C5F 12 Solvent and 20g of IPP initiator were sequentially added to a 1000ml high-pressure reactor. The mixture was stirred uniformly for 20 hours at a reaction temperature of 25℃ and a reaction pressure of 10MPa to obtain 198g of trifluorochloroethylene oligomer with a number-average molecular weight of 603. Specific reaction conditions and test results are shown in Table 1.

[0043] Table 1

[0044]

[0045] Note: Table 1 shows the polymerization conditions of CTFE and the molecular weight and molecular weight distribution coefficient of the products.

[0046] This invention relates to a method for preparing trifluorochloroethylene oligomers using a telomerization process, by selecting hydrofluoroether HFE458 and n-C5F... 12 Or hydrofluoroether HFE458 and n-C5F 12 Using any one of the mixed solvents as the reaction medium, in the presence of IPP, DTBP or DHP, the CTFE monomer undergoes a polymerization reaction. The polymerization reaction temperature is only 10-40℃ and the reaction pressure is only 1-3 MPa. Trifluorochloroethylene oligomers with a number average molecular weight between 742-9088 and a molecular weight distribution coefficient between 1.48-1.98 can be obtained.

[0047] Furthermore, as can be seen from the data in Comparative Examples 1-4 and Example 1 in Table 1, by selecting specific organic solvents and specific organic peroxide initiators, trifluorochloroethylene oligomers can be prepared at lower temperatures and lower reaction pressures. Simultaneously, the reaction medium selected in this invention is not only non-corrosive and non-toxic, but also inexpensive, which helps reduce production costs. Under the action of the initiator, the reaction medium can undergo polymerization under mild reaction conditions, and the resulting polymer has a narrow molecular weight distribution and low polydispersity, showing good market prospects.

[0048] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A method for preparing trifluorochloroethylene oligomers, characterized in that, The trifluorochloroethylene monomer is polymerized in the presence of an initiator using an organic solvent as the reaction medium. The polymerization reaction is carried out at a temperature of 10-40°C and a reaction pressure of 1-3 MPa, thereby obtaining the trifluorochloroethylene oligomer. The organic solvent is selected from hydrofluoroether HFE458 and n-C5F. 12 or at least one of its mixed solvents; the initiator is one or more of diisopropyl peroxide dicarbonate, di-tert-butyl peroxide, and di(7-hydro-dodecylfluoroheptanoic acid) peroxide.

2. The method according to claim 1, characterized in that, The amount of the organic solvent used is 1-1200 wt% of the total amount of trifluorochloroethylene monomer.

3. The method according to claim 2, characterized in that, The amount of the organic solvent used is 80-320 wt% of the total amount of trifluorochloroethylene monomer.

4. The method according to claim 1, characterized in that, The amount of the initiator is 0.5-10 wt% of the total amount of trifluorochloroethylene monomer.

5. The method according to claim 4, characterized in that, The amount of the initiator is 1-5 wt% of the total amount of trifluorochloroethylene monomer.

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