阅读说明：本技术 一种含氟单体2,2,4,5-四(三氟甲基)-1,3-二氧杂环戊烯的制备方法 (Preparation method of fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole ) 是由 吴雀群 马小燕 邹伟 颜杰 杨虎 李颜利 郑汶江 李伟 于 2021-09-14 设计创作，主要内容包括：本发明公开了一种含氟单体2,2,4,5-四(三氟甲基)-1,3-二氧杂环戊烯的制备方法,采用酒石酸二乙酯作为生产路线的起始原料,通过溴代、消除、加成、水解、氟化、取代和加成等系列反应,制备得到含氟单体2,2,4,5-四(三氟甲基)-1,3-二氧杂环戊烯。本发明选用的原料和反应试剂廉价易得,对环境污染小,路线简洁、收率高；每步反应操作简单,容易控制,非常适用于工业化生产应用。(The invention discloses a preparation method of fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole, wherein diethyl tartrate is used as a starting raw material of a production route, and the fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole is prepared through bromination, elimination, addition, hydrolysis, fluorination, substitution, addition and other series of reactions. The raw materials and the reaction reagents selected by the invention are cheap and easily available, the environmental pollution is small, the route is simple, and the yield is high; the reaction in each step is simple to operate, easy to control and very suitable for industrial production and application.)

1. A preparation method of 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole containing fluorine monomer is characterized by comprising the following steps:

step 1: carrying out bromination reaction on hydroxyl of the diethyl D- (-) -tartrate under the action of a glacial acetic acid solution containing hydrogen bromide to obtain (2S,3S) -diethyl 2-bromo-3-hydroxysuccinate;

step 2: diethyl (2S,3S) -2-bromo-3-hydroxysuccinate is subjected to elimination reaction under the action of carbonate to obtain diethyl (2S,3S) -oxirane-2, 3-diacetate;

and step 3: carrying out addition reaction on ether bonds of (2S,3S) -ethylene oxide-2, 3-diethyl diacetate and a hexafluoroacetone trihydrate under the catalysis of tetrabutylammonium bromide to obtain (4S, 5R) -ethyl-5- ((ethyl peroxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetate;

and 4, step 4: the ester group of (4S, 5R) -ethyl 5- ((ethyl peroxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetate is hydrolyzed to obtain (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid;

and 5: carrying out fluorination reaction on (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid and fluoride to obtain 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane;

step 6: reacting 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane with chlorine to obtain 4, 5-dichloro-2, 2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane;

and 7: reacting 4, 5-dichloro-2, 2,4, 5-tetrakis (trifluoromethyl) -1, 3-dioxolane with a mixture of zinc and zinc chloride to give 2,2,4, 5-tetrakis (trifluoromethyl) -1, 3-dioxole.

2. The method for preparing the fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole according to claim 1, wherein the reaction in the step 1 is carried out at normal temperature for 7h to 8h, and the molar ratio of the diethyl D- (-) -tartrate to the hydrogen bromide is 1: (11-13).

3. The preparation method of the fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole according to claim 1, wherein acetone is used as a solvent in the step 2, carbonate is potassium carbonate, and the reaction is carried out for 3h to 5h under the condition of an ice salt bath or an ice water bath, wherein the molar ratio of diethyl (2S,3S) -2-bromo-3-hydroxysuccinate to potassium carbonate is 1 (6-7).

4. The method for preparing 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole as claimed in claim 1, wherein the reaction in step 3 is carried out at 120-130 ℃ for 23-25 h, and the molar ratio of diethyl (2S,3S) -oxirane-2, 3-diacetate to hexafluoroacetone trihydrate is 1 (1-2).

5. The method for preparing a fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole according to claim 1, wherein in the step 4, methanol aqueous solution is used as a solvent, sodium hydroxide is used as a hydrolysis reagent, the reaction system is heated to 75-90 ℃, and the reflux reaction is carried out for 0.5-1.5 h, wherein the molar ratio of (4S, 5R) -ethyl 5- ((ethylperoxy) methyl) -2, 2-di (trifluoromethyl) -1, 3-dioxolane-4-acetate to sodium hydroxide is 1 (2-3).

6. The method for preparing a fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole according to claim 1, wherein the fluoride in the step 5 is bis (2-methoxyethyl) aminosulfur trifluoride, and the mixture is heated to 80 ℃ to 90 ℃ to react for 48 to 50 hours, wherein the molar ratio of (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid (compound 5) to the fluoride is 1 (2 to 4).

7. The method for preparing 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole as claimed in claim 1, wherein the reaction in step 6 is carried out at 120-130 ℃, and chlorine gas is introduced until 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole is completely reacted.

8. The method for preparing the fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole according to claim 1, wherein in the step 7, N-methylpyrrolidone is used as a solvent, and the reaction is carried out at 80-100 ℃ for 10-14 h, wherein the molar ratio of the 4, 5-dichloro-2, 2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole to zinc is 1 (0.008-0.015).

Technical Field

The invention relates to the technical field of organic matter synthesis, in particular to a preparation method of a fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxacyclopentene.

Background

DuPont, U.S. A, has proposed an amorphous fluoropolymer, the emergence of which is considered to be a major leap forward in the polymer process. The new polymer has higher transmittance, thermal and electrical properties than those of the existing various Teflon products, can meet various special requirements of high-tech applications, can be used for offset printing, lenses, optical fiber cores, cladding materials and pole covers of semiconductors and printed circuit boards, and can also be used for passivation layers of optical devices and dielectric materials for medical, military and aerospace industries and external packaging materials for various integrated circuits. Amorphous perfluoropolymers have a wide range of applications in particular applications such as ultra-thin films or integrated circuits. However, at present, the core preparation technology of the amorphous perfluoropolymer is not mastered at home, and the preparation technology of the special copolymerization monomer corresponding to the amorphous perfluoropolymer is relatively lagged behind, so that the economic cost for producing the monomer is correspondingly improved due to the factors of more monomer synthesis steps, low yield, high process difficulty and the like.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method of a fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole, so as to solve the problems of multiple monomer synthesis steps, low yield and high process difficulty in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole containing fluorine monomer comprises the following steps:

step 1: carrying out bromination reaction on hydroxyl of the diethyl D- (-) -tartrate under the action of a glacial acetic acid solution containing hydrogen bromide to obtain (2S,3S) -diethyl 2-bromo-3-hydroxysuccinate;

step 2: diethyl (2S,3S) -2-bromo-3-hydroxysuccinate is subjected to elimination reaction under the action of carbonate to obtain diethyl (2S,3S) -oxirane-2, 3-diacetate;

and step 3: carrying out addition reaction on ether bonds of (2S,3S) -ethylene oxide-2, 3-diethyl diacetate and a hexafluoropropylene trihydrate under the catalysis of tetrabutylammonium bromide to obtain (4S, 5R) -ethyl-5- ((ethyl peroxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetate;

and 4, step 4: the ester group of (4S, 5R) -ethyl 5- ((ethyl peroxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetate is hydrolyzed to obtain (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid;

and 5: carrying out fluorination reaction on (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid and fluoride to obtain 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane;

step 6: reacting 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane with chlorine to obtain 4, 5-dichloro-2, 2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane;

and 7: reacting 4, 5-dichloro-2, 2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane with a mixture of zinc and zinc chloride to obtain 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole.

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

1. the diethyl tartrate is used as the initial raw material of the production route, wherein the adopted raw material compounds are cheap and easily obtained, the whole reaction route is simple and clear, the reaction conditions are mild, the reaction operation of each step is simple, the reaction process of each intermediate is easy to control, the environmental pollution is small, the yield is high, and the method is very suitable for industrial production and application.

2. The fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole prepared by the invention can be polymerized with tetrafluoroethylene, and the polymer has excellent chemical, thermal and electrical properties, high transparency, good solubility and better mechanical properties; the films prepared from the polymers possess excellent optical clarity, have the lowest refractive index of all known organic materials, are particularly suitable for certain special optical applications, exhibit extremely high UV transparency, near IR wavelength visibility, and have the lowest dielectric constant of known polymers, have better solubility in fluorosolvents and lower viscosity, are suitable for solution processing techniques, and can also be used as gas separation membranes; the monomer and a perfluoro vinyl ether monomer with a sulfonyl fluoride group at the tail end are subjected to free radical copolymerization to obtain a perfluoro sulfonic acid polymer with a dioxa ring structure on the main chain, and the perfluoro sulfonic acid polymer is used for a solid electrode material in a polymer fuel cell, has good gas permeability and a good softening point, and can be better adapted to the high-temperature use environment of the solid polymer fuel cell.

Detailed Description

The present invention will be further described with reference to the following examples.

Preparation method of fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole

Step 1: carrying out bromination reaction on hydroxyl of the D- (-) -diethyl tartrate (1) under the action of a glacial acetic acid solution containing hydrogen bromide to obtain (2S,3S) -diethyl 2-bromo-3-hydroxysuccinate (2); in the step 1, the reaction is carried out for 7-8 h at normal temperature, and the molar ratio of the D- (-) -diethyl tartrate to the hydrogen bromide is 1: (11-13), the reaction equation is as follows:

step 2: the (2S,3S) -2-bromine-3-hydroxysuccinic acid diethyl ester (2) is subjected to elimination reaction under the action of carbonate to obtain (2S,3S) -ethylene oxide-2, 3-diacetic acid diethyl ester (3); in the step 2, acetone is used as a solvent, carbonate is potassium carbonate, the reaction is carried out for 3 to 5 hours in the presence of an ice salt bath or an ice water bath, and the molar ratio of (2S,3S) -2-bromo-3-hydroxysuccinic acid diethyl ester to the potassium carbonate is 1: (6-7), the reaction equation is as follows:

and step 3: carrying out addition reaction on ether bonds of (2S,3S) -ethylene oxide-2, 3-diethyl diacetate (3) and a hexafluoroacetone trihydrate under the catalysis of tetrabutylammonium bromide to obtain (4S, 5R) -ethyl-5- ((ethyl peroxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetate (4); in the step 3, the reaction is carried out for 23 to 25 hours at the temperature of between 120 and 130 ℃, the molar ratio of (2S,3S) -ethylene oxide-2, 3-diethyl diacetate to hexafluoroacetone trihydrate is 1: (1 to 2), the reaction formula is as follows:

and 4, step 4: the ester group of (4S, 5R) -ethyl 5- ((ethyl peroxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetic acid ester (4) is hydrolyzed to obtain (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid (5); in the step 4, a methanol water solution is used as a solvent, sodium hydroxide is used as a hydrolysis reagent, a reaction system is heated to 75-90 ℃, and reflux reaction is carried out for 0.5-1.5 h, wherein the molar ratio of (4S, 5R) -ethyl 5- ((ethyl peroxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetic ester to sodium hydroxide is 1: (2-3), the reaction equation is as follows:

and 5: carrying out a fluorination reaction on (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid (5) and fluoride to obtain 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane (6); in the step 5, the fluoride is bis (2-methoxyethyl) aminosulfur trifluoride, the bis (2-methoxyethyl) aminosulfur trifluoride and the bis (2-methoxyethyl) aminosulfur trifluoride are mixed and heated to 80-90 ℃ to react for 48-50 h, wherein the molar ratio of (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid (compound 5) to the fluoride is 1: (2-4), the reaction equation is as follows:

step 6: reacting 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane (6) with chlorine to obtain 4, 5-dichloro-2, 2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane (7); the reaction in the step 6 is carried out at the temperature of 120-130 ℃, chlorine gas is introduced until the 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane is completely reacted, and the reaction equation is as follows:

and 7: reaction of 4, 5-dichloro-2, 2,4, 5-tetrakis (trifluoromethyl) -1, 3-dioxolane (7) with a mixture of zinc and zinc chloride affords 2,2,4, 5-tetrakis (trifluoromethyl) -1, 3-dioxole (8). In the step 7, N-methyl pyrrolidone is used as a solvent, the reaction is carried out for 10 to 14 hours at the temperature of between 80 and 100 ℃, the molar ratio of 4, 5-dichloro-2, 2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane to zinc is 1: (0.008-0.015) according to the following reaction equation:

after the existing synthesis process of the fluorine-containing monomer is deeply researched, the synthesis route of the fluorine-containing monomer is newly planned, so that the whole reaction route is simpler and clearer, D- (-) -diethyl tartrate is used as an initial raw material, bromine is used for replacing one hydroxyl on a carbon chain through a bromination reaction, an intermediate is gradually formed into ester of a five-membered ring through an elimination reaction and an addition reaction, the ester group is hydrolyzed to obtain acid, the carboxyl is converted into trifluoromethyl after the reaction with fluoride, and finally the fluorine-containing monomer 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole is obtained through the addition reaction. The raw materials and various reaction reagents adopted by the invention are cheap and easily available, the production cost of the fluorine-containing monomer is fundamentally reduced, the reaction conditions of various intermediates are mild, the operation is simple, the reaction process is easy to control, the product yield is high, the environmental pollution is low, and the method is very suitable for application of industrial production.

Second, preparation of examples

Example 1:

the first step is as follows: preparation of diethyl (2S,3S) -2-bromo-3-hydroxysuccinate (Compound 2)

Diethyl D- (-) -tartrate (Compound 1) (6.1857g,30mmol) was added to 0Glacial acetic acid solution containing hydrogen bromide (mass fraction of hydrogen bromide is 33%, 18.51mL) is added dropwise at the temperature of lower part, and stirring is continued for 15min after the dropwise addition is finished. The reaction was stirred at room temperature for 7.5h, 100mL of water was added, the aqueous phase was extracted with diethyl ether (4X 75mL), the organic phases were combined, washed with saturated brine (50mL), water (2X 50mL), anhydrous Na₂SO₄The organic phase was freed of water and the ethyl acetate was distilled off under reduced pressure to give a crude product. The crude product was added dropwise to anhydrous ethanol (150mL) and a glacial acetic acid solution (4mL) containing 33% hydrogen bromide was refluxed for 12.5h to terminate the reaction.

5.4223g of crude (2S,3S) -2-bromo-3-hydroxysuccinic acid diethyl ester with 75% content, 33% hydrogen bromide with 2% content in glacial acetic acid solution and 23% content of other components were collected, and the yield was 70%.

The second step is that: preparation of (2S,3S) -ethylene oxide-2, 3-diacetic acid diethyl ester (Compound 3)

Compound 2(268.9mg,1mmol) was dissolved in anhydrous acetone (10mL), potassium carbonate (848.7mg, 6.15mmol) was added slowly at 0 deg.C, and the reaction was terminated by stirring in an ice-water bath for 3 h.

230mg of crude (2S,3S) -ethylene oxide-2, 3-diacetic acid diethyl ester with the content of 98 percent, potassium carbonate with the content of 0.5 percent, acetone with the content of 1 percent and other contents with the content of 0.5 percent are collected, and the yield reaches 92 percent.

The third step: preparation of (4S, 5R) -ethyl-5- ((ethylperoxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetic acid ester (Compound 4)

Compound 3(125.5mg,0.67mmol), tetrabutylammonium bromide (4.5mg, 0.0014mmol), and hexafluoroacetone trihydrate (151.8mg,0.69mmol) were placed in a 50mL polytetrafluoroethylene-lined autoclave and reacted at 125 ℃ for 23 hours, whereupon the reaction was completed.

90mg of crude (4S, 5R) -ethyl-5- ((ethylperoxy) methyl) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4-acetate was collected at 75%, tetrabutylammonium bromide at 0.1%, the other at 39.9%, and the yield reached 72%.

The fourth step: preparation of (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid (Compound 5)

Compound 4(34.7mg,0.098mmol) was dissolved in methanol: to a mixed solution of water (v: v ═ 1:1,40mL), a solution of NaOH solid (8.1mg,0.2009mmol) dissolved in deionized water (6mL) was added dropwise thereto, and the mixture was refluxed at 80 ℃ for 1 h. The aqueous phase was adjusted to pH 2 with 2mol/L hydrochloric acid, extracted with ethyl acetate (3 × 40mL), and the organic phases were combined. Adding water (50mL), dropwise adding a saturated sodium carbonate aqueous solution to adjust the pH value of the water phase to 8-9, standing for layering, and taking the water phase. The aqueous phase was adjusted to pH 2 with 2mol/L hydrochloric acid, extracted with ethyl acetate (3 × 40mL), and the organic phases were combined.

30mg of crude (4S, 5S) -2, 2-bis (trifluoromethyl) -1, 3-dioxolane-4, 5-diacetic acid is collected, the content of the crude (4S, 5S) -2, 2-bis (trifluoromethyl) -4, 5-diacetic acid is 82 percent, the content of methanol is 10 percent, the content of sodium hydroxide is 0.5 percent, the content of hydrochloric acid is 0.5 percent, the content of other components is 7 percent, and the yield reaches 76 percent.

The fifth step: preparation of 2,2,4, 5-tetrakis (trifluoromethyl) -1, 3-dioxolane (Compound 6)

Compound 5(101mg,0.339mmol) and bis (2-methoxyethyl) aminosulfur trifluoride (165mg,0.746mmol) were placed in a 25mL polytetrafluoroethylene-lined autoclave and reacted at 85 ℃ for 48 hours, and the reaction was completed.

89mg of crude 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane was collected with a content of 78%, a content of 5% bis (2-methoxyethyl) aminosulfur trifluoride and a further content of 17%, and the yield was 71%.

And a sixth step: preparation of 4, 5-dichloro-2, 2,4, 5-tetrakis (trifluoromethyl) -1, 3-dioxolane (Compound 7)

Chlorine gas was introduced into dried compound 6(82mg, 0.24mmol), and irradiated with a fluorescent lamp at 120 ℃ to 130 ℃ until the compound 6 was completely reacted.

100mg of crude 4, 5-dichloro-2, 2,4, 5-tetra (trifluoromethyl) -1, 3-dioxolane was collected with a chlorine content of 99% and a yield of 100%.

The seventh step: preparation of 2,2,4, 5-tetrakis (trifluoromethyl) -1, 3-dioxole (Compound 8)

Compound 7(68mg,0.21mmol) is dissolved in N-methylpyrrolidone (1mL) and Zn: ZnCl is added₂(m: m ═ 1:1, 0.14mg), and the reaction was stirred at 90 ℃ for 12 hours.

63mg of crude 2,2,4, 5-tetra (trifluoromethyl) -1, 3-dioxole was collected in a yield of 90%, N-methylpyrrolidone in a content of 2% and the other in a content of 8%.

The same preparation method as in example 1 was used to prepare the raw materials shown in table 1, thereby obtaining examples 2 to 6.

TABLE 1

In the embodiments 1-6 prepared by the method, the product content is over 90 percent, the product purity is high, and the method can be directly used for synthesizing the fluorine-containing polymer. In the preparation process, the yield of each intermediate is high, the obtained intermediate has high purity and almost no by-product, the reaction process in each step is easy to control, and the method is very suitable for industrial production.

Third, product verification

Taking example 1 as an example, ESI-MS and GC/MS were used to examine the intermediate compounds during the reaction, and the results are shown in the following table.

TABLE 2

Item	Compound 2	Compound 3	Compound 4	Compound 5	Compound 6	Compound 7
							ESI-MS(g/mol)	269.09	188.18	356.22	298.09	346.07	344.05
GC/MS(％)	97	96	96	97	98	98

As can be seen from Table 2, the desired intermediate compound can be prepared during the preparation process, and the purity of the intermediate compound is high, which is beneficial for the next reaction and can ensure that the fluorine-containing monomer is finally obtained.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the technical solutions, and those skilled in the art should understand that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all the modifications and equivalent substitutions should be covered by the claims of the present invention.