Dialkene fluorine-containing vulcanization point monomer as well as synthesis method and application thereof

Abstract

The invention belongs to the technical field of fluorine chemical industry, and particularly relates to a diolefin fluorine-containing vulcanization point monomer and a synthesis method and application thereof, the diolefin fluorine-containing vulcanization point monomer has a structural general formula as shown in formula (I): # imgabs0 #, in the formula, n is a positive integer; the synthesis method comprises the following steps: step 1, in a solvent, mixing perfluorodiiodoalkane with a free radical initiator, then introducing ethylene, and carrying out an addition reaction to obtain an intermediate product; and 2, mixing the intermediate product obtained in the step 1 with an inorganic base, and carrying out an elimination reaction to obtain the diene fluorine-containing vulcanization point monomer. Compared with the prior art, the invention solves the problems of complexity and low efficiency of the synthesis method of the diolefin fluorine-containing vulcanization point monomer in the prior art, and realizes rapid and convenient synthesis of the diolefin fluorine-containing vulcanization point monomer.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorine chemical industry, and specifically relates to a diene fluorine-containing sulfide point monomer and a synthesis method and application thereof. Background Art

[0002] Cure site monomers play a key role in the rubber and elastomer industry. These low molecular weight compounds contain vulcanizable functional groups and are mainly used in the production of vulcanized rubber and elastomers. They enhance the mechanical strength, elasticity and heat resistance of the product by building a cross-linked network. In addition, cure site monomers can also improve the chemical resistance of the product, enable the product to be customized according to specific applications, improve processing performance for ease of production, and play a decisive role in the final use and environmental impact of rubber products. Fluorinated cure site monomers can form an inert network structure that is heat-resistant, antioxidant, and fluid-resistant through vulcanization reactions during the polymerization process. These properties make fluoroelastomers have excellent performance in harsh environments such as high temperature and chemical corrosion, and are suitable for chemical, aviation, automotive and other fields.

[0003] However, they also face challenges such as high cost, potential adverse impacts on the environment, health and safety risks, difficulty in processing, stability issues, difficulty in recycling, strong supply chain dependence, and possible patent and intellectual property restrictions, which may limit their widespread application and require industry and research institutions to adopt innovative strategies to overcome these obstacles in the development and use of these materials.

[0004] For example, CN1053200C discloses a peroxide-curable fluorine-containing elastomer containing iodine and / or bromine atoms in a macromolecular chain having a monomer structure and / or at the chain end, comprising a) 1,1-difluoroethylene, b) tetraethylene, c) hexafluoropropylene or perfluoromethyl vinyl ether and d) a diene of the general formula CH2=CH-Z-CH=CH2, wherein Z is -(CF2)6- or -CH2OCH2-CF2O-(CF2CF2O) m -(CF2O) n -CF2CH2OCH2-. However, the synthesis method of this scheme is complex, difficult and costly, and still needs further improvement.

[0005] The synthesis methods of diene fluorinated sulfurization point monomers disclosed in current domestic and foreign patents are complex and inefficient, and it is necessary to propose a more suitable synthesis method of diene fluorinated sulfurization point monomers for industrial and large-scale production. Summary of the invention

[0006] The purpose of the present invention is to provide a diene fluorinated sulfurization point monomer and its synthesis method and application in order to solve at least one of the above problems, so as to solve the problem that the synthesis method of diene fluorinated sulfurization point monomer in the prior art is complicated and inefficient. This scheme realizes the rapid and convenient synthesis of diene fluorinated sulfurization point monomer.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] The first aspect of the present invention discloses a method for synthesizing a diene fluorinated sulfide point monomer, comprising the following steps:

[0009] Step 1: In a solvent, a perfluorodiiodoalkane is mixed with a free radical initiator, and then ethylene is introduced to undergo an addition reaction to obtain an intermediate product;

[0010] Step 2: mixing the intermediate product obtained in step 1 with an inorganic base to undergo an elimination reaction to obtain the diene fluorinated sulfurization point monomer;

[0011] The perfluorodiiodoalkane has a general structural formula as shown in formula (II):

[0012]

[0013] The intermediate product has the general structural formula of formula (III):

[0014]

[0015] Wherein, n is a positive integer.

[0016] Preferably, the solvent includes dichloromethane, acetonitrile, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and dioxane.

[0017] Preferably, the perfluorodiiodide alkanes include at least 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane and 1,10-diiodoperfluorodecane.

[0018] Preferably, the free radical initiator includes dibenzoyl peroxide (BPO), dicumyl peroxide (DCP), peroxydicarbonate, dialkyl peroxydicarbonate, tert-butyl perbenzoate (TBPB) and tert-butylperbenzoate.

[0019] Preferably, the inorganic base is sodium carbonate, potassium carbonate, potassium hydroxide or sodium hydroxide.

[0020] Preferably, in the addition reaction, the molar ratio of ethylene to perfluorodiiodine is 1.5-3:1, the molar amount of the free radical initiator is 5-20 mol% of the perfluorodiiodine, the reaction temperature is 20-50° C., and the reaction pressure is 0.1-1.2 MPa.

[0021] Preferably, in the elimination reaction, the molar ratio of the inorganic base to the intermediate product is 1 to 3:1, and the reaction temperature is 30 to 90°C.

[0022] More preferably, in the elimination reaction, the molar ratio of the inorganic base to the intermediate product is 2:1.

[0023] The second aspect of the present invention discloses a diene fluorine-containing vulcanization site monomer having a general structural formula as shown in formula (I):

[0024]

[0025] Where n is a positive integer;

[0026] The diene fluorine-containing sulfurization point monomer is obtained by any of the above-mentioned synthesis methods.

[0027] The third aspect of the present invention discloses the application of the above-mentioned diene fluorine-containing vulcanization point monomer in the chemical, aviation and automobile fields.

[0028] Preferably, the diene fluorinated cure site monomers are used to produce vulcanized rubber and elastomers.

[0029] The working principle of the present invention is:

[0030]

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention is applicable to various perfluorodiiodoalkanes with iodine end groups, and can prepare diene fluorinated sulfurization point monomers through experimental steps;

[0033] 2. The experimental route of the present invention is short, the operation is simple and easy to control, and it is suitable for the production of kilogram-level vulcanization point monomers. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 For the product in Example 8 19 F NMR (CDCl3, 376.51 MHz) spectrum. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] The present invention will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the present invention belong to the scope of protection of the present invention.

[0037] Unless otherwise indicated in specific circumstances, the numerical ranges listed in the present invention include the upper and lower limits, and all integers and fractions within the range, and are not limited to the specific values ​​listed when defining the range.

[0038] In the following description, unless otherwise specified, the reagents used are conventional commercially available products, and the methods used are well known in the art.

[0039] A method for preparing a diene fluorinated sulfide point monomer

[0040] The specific preparation route is as follows:

[0041]

[0042] Wherein, n can be any positive integer value in the range of 1, 2, 3 and a larger range.

[0043] For example, when n=2, the raw material is 1,6-diiodoperfluorohexane; when n=3, the raw material is 1,8-diiodoperfluorooctane; and so on.

[0044] The above-mentioned preparation route of the present invention can be used to prepare perfluorinated sulfur-containing monomers with olefin as terminal groups. According to the molecular chain length of the reaction raw materials, the reaction temperature needs to be adjusted to obtain diene fluorinated sulfur-containing monomers with different n values. The preparation route of the present invention is short, the operation is simple and easy to control, and it is suitable for the production of kilogram-level sulfur-containing monomers.

[0045] In some embodiments (taking 1,4-diiodooctafluorobutane to synthesize 3,3,4,4,5,5,6,6-octafluoro-1,7-octadiene as an example), the specific steps are as follows:

[0046] Step 1: In a reaction solvent, 1,4-diiodooctafluorobutane reacts with ethylene under the action of a free radical initiator; the reaction product is separated and purified: the reaction is quenched with an aqueous sodium thiosulfate solution, the organic layer and the water layer are separated, and the organic layer is collected and distilled under reduced pressure to obtain a 3,3,4,4,5,5,6,6-octafluoro-1,8-diiodooctane compound.

[0047] The reaction temperature is 20-50°C; too high a reaction temperature will increase the formation of by-products, and too low a reaction temperature will reduce the reaction rate; for example, the reaction temperature can be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, etc., as well as all ranges and sub-ranges between the above values.

[0048] The reaction pressure is 0.1-1.2 MPa. Too high or too low a reaction pressure will affect the extent of the addition reaction, thereby affecting the amount of compounds with different n values ​​produced. For example, the pressure can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.2 MPa, and all ranges and sub-ranges between the above values.

[0049] The amount of ethylene used in the reaction is 1.5 to 3 equivalents of 1,4-diiodooctafluorobutane, which can be understood here as a molar ratio of 1,4-diiodooctafluorobutane to ethylene of 1:(1.5 to 3). For example, the amount of ethylene used can be 1.5 equivalents, 1.8 equivalents, 2 equivalents, 2.2 equivalents, 2.4 equivalents, 2.6 equivalents, 2.8 equivalents, 3 equivalents, etc. of 1,4-diiodooctafluorobutane, as well as all ranges and sub-ranges between the above values.

[0050] The free radical initiator is one of dibenzoyl peroxide (BPO), diisopropylbenzene peroxide (DCP), peroxydicarbonate, dialkyl peroxydicarbonate, tert-butyl peroxybenzoate (TBPB), and tert-butyl peroxybenzoate (Tert-Butylperbenzoate); calculated by mole percentage, the amount of the free radical initiator is 2 mol%, 4 mol%, 6 mol%, 8 mol%, 10 mol%, 12 mol%, 14 mol%, etc. (calculated as perfluorodiiodoalkane), as well as all ranges and sub-ranges between the above values.

[0051] The reaction solvent is one of dichloromethane, tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, acetonitrile and diethylene glycol dimethyl ether.

[0052] In the above embodiments, any of the above ranges may be combined with any other ranges.

[0053] Step 2: Using the product 3,3,4,4,5,5,6,6-octafluoro-1,8-diiodooctane prepared in step 1 as a raw material, 3,3,4,4,5,5,6,6-octafluoro-1,8-diiodooctane undergoes an elimination reaction in the presence of an inorganic base to obtain a diene fluorinated sulfurization point monomer 3,3,4,4,5,5,6,6-octafluoro-1,7-octadiene.

[0054] In step 2, the inorganic base is one of sodium carbonate, potassium carbonate, potassium hydroxide and sodium hydroxide.

[0055] The ratio of 3,3,4,4,5,5,6,6-octafluoro-1,8-diiodooctane to the inorganic base is 1:(1-3). For example, the ratio of 3,3,4,4,5,5,6,6-octafluoro-1,8-diiodooctane to the inorganic base can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc., as well as all ranges and sub-ranges between the above values.

[0056] The reaction temperature is 30 to 90° C., for example, the reaction temperature can be 30, 40, 50, 60, 70, 80, 90° C., and all ranges and subranges between the above values.

[0057] In the above embodiments, any of the above ranges may be combined with any other ranges.

[0058] Example 1

[0059] Step 1, synthesis of diiodide-terminated fluorinated alkanes:

[0060] 48.4g (0.2mol) of dibenzoyl peroxide powder was placed in a 3L reactor, and 1100mL of tetrahydrofuran solvent and 907.6g (2mol) of 1,4-diiodooctafluorobutane (n=1) were added. Nitrogen was passed and vacuumed for three cycles; then ethylene was passed and vacuumed once. Then ethylene was introduced, stirring was started, and the reaction temperature was maintained at 30-35°C and the reaction pressure was 0.5MPa. The reaction was stopped when 112g (4mol) of ethylene was consumed. The reaction system was transferred to a separatory funnel, and the reaction was quenched with a 0.2mol / L sodium thiosulfate aqueous solution. After adding dichloromethane to separate the layers, the organic phase was collected, and the solvent was evaporated under reduced pressure to obtain the product 3,3,4,4,5,5,6,6-octafluoro-1,8-diiodooctane. The obtained product was washed with n-hexane to remove impurities remaining on the product. After drying, the product 3,3,4,4,5,5,6,6-octafluoro-1,8-diiodooctane with a purity higher than 99% was obtained, the yield was 80%, and the product GC purity was 99.1%.

[0061] When the diiodoperfluoroalkane n=2 (1,6-diiodoperfluorohexane is used as the reaction raw material), the other steps remain unchanged, the yield is 74%, and the product GC purity is 98.4%.

[0062] When the diiodoperfluoroalkane n=3 (1,8-diiodoperfluorooctane is used as the reaction raw material), the other steps remain unchanged, the yield is 75%, and the product GC purity is 98.1%;

[0063] The results are summarized in Table 1.

[0064] Table 1 Example 1 Results Integration Table

[0065] n 1 2 3 Yield (%) 80 74 75 purity(%) 99.1 98.4 98.1

[0066] Example 2

[0067] Adjustments were made on the basis of Example 1, except that the reaction temperature was adjusted to 35-40° C., and diiodoperfluoroalkane addition products with different n values ​​were also obtained. The results are summarized in Table 2.

[0068] Table 2 Example 2 Results Integration Table

[0069] n 1 2 3 Yield (%) 78 77 80 purity(%) 99.2 98.1 98.3

[0070] Example 3

[0071] Adjustments were made on the basis of Example 1, except that the reaction pressure was adjusted to 1.0 MPa, and diiodoperfluoroalkane addition products with different n values ​​were also obtained. The results are summarized in Table 3.

[0072] Table 3 Example 3 Results Integration Table

[0073] n 1 2 3 Yield (%) 84 81 80 purity(%) 98.5 99.1 98.4

[0074] Example 4

[0075] Adjustments were made based on Example 1, except that the reaction solvent was replaced with acetonitrile, and diiodoperfluoroalkane addition products with different n values ​​were also obtained. The results are summarized in Table 4.

[0076] Table 4 Example 4 Results Integration Table

[0077] n 1 2 3 Yield (%) 77 84 80 purity(%) 99.5 98.9 98.3

[0078] Example 5

[0079] Adjustments were made based on Example 1, except that the reaction free radical initiator was replaced with tert-butyl perbenzoate, and diiodoperfluoroalkane addition products with different n values ​​were also obtained. The results are summarized in Table 5.

[0080] Table 5 Example 5 Results Integration Table

[0081] n 1 2 3 Yield (%) 87 81 80 purity(%) 99.5 98.9 99.0

[0082] Example 6

[0083] Adjustments were made based on Example 1, except that the free radical initiator was replaced with diisopropylbenzene peroxide, and diiodoperfluoroalkane addition products with different n values ​​were also obtained. The results are summarized in Table 6.

[0084] Table 6 Example 6 Results Integration Table

[0085] n 1 2 3 Yield (%) 89 84 83 purity(%) 99.0 98.8 99.6

[0086] Example 7

[0087] Adjustments were made based on Example 1, except that the amount of the free radical initiator was changed to 5 mol %, and diiodoperfluoroalkane addition products with different n values ​​were also obtained. The results are summarized in Table 7.

[0088] Table 7 Example 7 Results Integration Table

[0089] n 1 2 3 Yield (%) 85 81 83 purity(%) 98.6 98.9 98.1

[0090] Comparing Tables 1 to 7, we can see that:

[0091] (1) Reaction temperature, pressure, solvent, free radical initiator type and dosage and other conditions have a significant effect on the yield and purity of fluorinated sulfur point monomers.

[0092] (2) Appropriate high pressure and suitable solvent can improve the yield, while the selection and dosage of initiator can optimize the purity of the product.

[0093] (3) For compounds with different carbon chain lengths, the reaction conditions need to be adjusted accordingly to improve the yield. For example, as can be seen from Example 2, when the chain length is longer, a higher temperature can improve the reaction yield.

[0094] Example 8

[0095] Step 2, synthesis of 3,3,4,4,5,5,6,6-octafluoro-1,7-octadiene:

[0096] The product of Example 1 with n=1 was selected as the raw material, placed in a reaction bottle, and slowly added with sodium hydroxide aqueous solution at 50°C for one hour. Water was added to quench and extracted with dichloromethane, and the organic phase was collected. The product was obtained by distillation with a yield of 60% and a GC purity of ≥99%. 19 F NMR (CDCl3, 376.51MHz) spectrum is shown in Figure 1 As shown, it can be seen from the spectrum that the product mainly has two groups of peaks, corresponding to the signals of two types of fluorine atoms, Fa and Fb.

[0097] Example 9

[0098] Adjustments were made based on Example 8, except that the inorganic base was replaced by potassium hydroxide. The same diene fluorinated sulfide point monomer was obtained with a yield of 65% and a product GC purity of ≥99%.

[0099] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for synthesizing a diene fluorinated sulfide monomer, characterized in that: The steps include: Step 1: In a solvent, a perfluorodiiodoalkane is mixed with a free radical initiator, and then ethylene is introduced to undergo an addition reaction to obtain an intermediate product; Step 2: mixing the intermediate product obtained in step 1 with an inorganic base to undergo an elimination reaction to obtain the diene fluorinated sulfurization point monomer; The perfluorodiiodoalkane has a general structural formula as shown in formula (II): The intermediate product has the general structural formula of formula (III): Wherein, n is a positive integer.

2. The method for synthesizing a diene fluorinated sulfide monomer according to claim 1, characterized in that: The solvent includes dichloromethane, acetonitrile, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and dioxane.

3. The method for synthesizing a diene fluorinated sulfide monomer according to claim 1, characterized in that: The perfluorodiiodide alkanes include 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane and 1,10-diiodoperfluorodecane.

4. The method for synthesizing a diene fluorinated sulfide monomer according to claim 1, characterized in that: The free radical initiator includes dibenzoyl peroxide, dicumyl peroxide, peroxydicarbonate, peroxydialkyl dicarbonate, tert-butyl peroxybenzoate and tert-amyl peroxybenzoate.

5. The method for synthesizing a diene fluorinated sulfide monomer according to claim 1, characterized in that: The inorganic base is sodium carbonate, potassium carbonate, potassium hydroxide or sodium hydroxide.

6. The method for synthesizing a diene fluorinated sulfide monomer according to claim 1, characterized in that: In the addition reaction, the molar ratio of ethylene to perfluorodiiodine is 1.5-3:1, the molar amount of the free radical initiator is 5-20 mol% of the perfluorodiiodine, the reaction temperature is 20-50°C, and the reaction pressure is 0.1-1.2 MPa.

7. The method for synthesizing a diene fluorinated sulfide monomer according to claim 1, characterized in that: In the elimination reaction, the molar ratio of the inorganic base to the intermediate product is 1-3:1, and the reaction temperature is 30-90°C.

8. A diene fluorinated sulfide monomer, characterized in that: It has the general structural formula shown in formula (I): Where n is a positive integer; The diene fluorinated sulfide point monomer is obtained by the synthesis method as described in any one of claims 1-7.

9. Use of the diene fluorinated sulfide monomer as claimed in claim 8 in the chemical, aviation and automobile fields.

10. The use according to claim 9, characterized in that: The diene fluorinated vulcanization site monomer is used to produce vulcanized rubber and elastomer.

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