Alpha, omega-diiodo perfluoroalkane derivative, alpha, omega-diiodo ethyl perfluoroalkane derivative, and preparation method and application of alpha, omega-diiodo perfluoroalkane derivative

Abstract

The invention discloses an alpha, omega-diiodo perfluoroalkane derivative, an alpha, omega-diiodo ethyl perfluoroalkane derivative as well as a preparation method and application of the alpha, omega-diiodo perfluoroalkane derivative and the alpha, omega-diiodo ethyl perfluoroalkane derivative. According to the method, alpha, omega-diiodo perfluoroalkane is taken as a raw material, and the alpha, omega-diiodo perfluoroalkane and ethylene are subjected to free radical addition reaction under the action of an initiator and a solvent to prepare the alpha, omega-diiodo ethyl perfluoroalkane. The alpha, omega-diiodoethyl perfluoroalkane and alkali are subjected to a one-molecule and / or two-molecule hydrogen iodide hydride elimination reaction, and alpha, omega-iodoethyl vinyl perfluoroalkane and / or alpha, omega-divinyl perfluoroalkane are / is generated. The method is simple and convenient to operate, the raw material utilization rate and the target product yield are high, the preparation cost is effectively reduced, and the industrial production requirement is met. The alpha, omega-diiodo perfluoroalkane derivative or alpha, omega-diiodo ethyl perfluoroalkane derivative prepared by the method disclosed by the invention can be used as a vulcanization point monomer for preparing peroxide vulcanized fluororubber, and compared with common rubber, the rubber has more excellent compression deformation performance, strength and medium resistance and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the field of organic fluorine chemistry, and specifically relates to α,ω-diiodoperfluoroalkane derivatives, α,ω-diiodethylperfluoroalkane derivatives, and preparation methods and applications thereof. Background Art

[0002] α,ω-diiodoperfluoroalkanes refer to a series of straight-chain perfluoroalkane homologues containing two iodine atoms at both ends of the molecular chain. Since the CI bond in α,ω-diiodoperfluoroalkanes is very easy to break, free radical addition reactions, telomerization reactions and polymerization reactions can occur, so α,ω-diiodoperfluoroalkanes are widely used in the synthesis of long-chain, branched perfluoro or polyfluoro compounds and are very important intermediates.

[0003] α,ω-diiodoperfluoroalkane can react with ethylene in the presence of a catalyst to generate α,ω-diiodoethylperfluoroalkane. The diadduct is a very important intermediate. It can convert the iodine at both ends into other functional groups through functional group conversion to synthesize various fluorine-containing polymer monomers. For example, it can react with sodium azide to generate fluorine-containing diamines, which can be used to synthesize fluorine-containing polyimide esters, fluorine-containing polyamide esters, etc.; further oxidation of the above diamines can obtain diisocyanate fluoride, which can be used to synthesize fluorine-containing polyisocyanates; it can also be converted into fluorine-containing diols, fluorine-containing diacids and other adducts, and these products can be used to obtain fluorine-containing polyamide esters, fluorine-containing polyesters, fluorine-containing polyimide esters, etc.; the diadduct can also eliminate HI to synthesize fluorine-containing olefins with double bonds at both ends, and the olefins react with silane to obtain fluorosilicone resins.

[0004] The addition reaction of α,ω-diiodoperfluoroalkanes with ethylene free radicals can be divided into thermal initiation, photoinitiation, free radical initiator initiation, etc. For example, patents US3016407, GB1114782, WO9744300, and literature Bull.Acad.Sci.USSR, Div.Chem.Sci.1964:P359 use α,ω-diiodoperfluoroalkane and ethylene as raw materials, and heat at 180-350°C to obtain the mono-addition product and di-addition product of α,ω-diiodoperfluoroalkane and ethylene, and the highest yield of ethylene di-addition product can reach 90%; literature Journal of Fluorine Chemistry 1997(86):113-114 reported a method for preparing diiodoperfluoroethane ethylene diaddition product by irradiating 1,2-diiodoethane and ethylene under mercury catalysis for 13 days, and the yield is 35%; patents EP0247614, EP0383141, and literature J.Fluorine Chem.1995(73):151 use CuI or Fe(CO) 9or12As a free radical initiator, α,ω-diiodoethyl perfluoroalkane was prepared by solvent method, and the yield of the target product can reach up to 90%; the literature Macromolecules 2010(43):4489 used di-4-tert-butylcyclohexyl peroxydicarbonate as an initiator and IC6F 12 I reacts with ethylene at 50°C for 8 hours, and the yield of ethylene diaddition product can reach more than 80%; the document J.Org.Chem.1982(47):2251 uses di-tert-butyl peroxide as an initiator, adds ethylene, IC4F8I and initiator together into an autoclave, heats to 130°C and reacts for 22 hours, and the product is extracted, washed and dried to obtain ICH2CH2C4F8CH2CH2I, with a yield of 82%. The thermal initiation method has a high reaction temperature and pressure, and the product is mainly ethylene monoaddition product, and the yield of ethylene diaddition product is low; the photoinitiation method has a low reaction temperature, but a long reaction time and a low yield, and is not suitable for industrialization; the free radical initiator initiation method has a relatively mild reaction condition, a short addition reaction time, high selectivity and yield, and is more suitable for development as an industrialization route, but the current existing process route has a maximum yield of only about 90%, resulting in a relatively complicated product purification process, and the process needs to be further improved.

[0005] The iodine in α,ω-diiodoethyl perfluoroalkane is easy to undergo elimination reaction under alkaline conditions, thereby obtaining α,ω-iodoethyl vinyl perfluoroalkane and α,ω-divinyl perfluoroalkane. For example, in patent US3016407, IC2H4C2F4C2H4I and tributylamine are added to the reaction distillation tower, the tower bottom temperature is 200℃, and CH2=CHC2F4CH=CH2 is obtained at the top of the tower, and the reaction yield is 75%; in patent US5204441, KOH is used in ethylene glycol solvent to eliminate IC2H4C4F8C2H4I at 140℃, and the yield of CH2=CHC4F8CH=CH2 is 73%. If the raw material is IC2H4C6F 12 C2H4I, the yield of diene can be increased to 82%; Literature J. Fluorine Chem. 1995 (73): 151 Dissolve IC2H4C4F8C2H4I in ethanol, slowly add it to the ethanol solution of KOH, then heat it to 60℃ for 4 hours, dilute the product with water, extract, crystallize and dry it to obtain the target product, the yield is 72%. Using organic amines as bases, because it can complex up to three hydrogen iodides, it is difficult to control the amount of base to obtain α,ω-iodoethyl vinyl perfluoroalkane and α,ω-divinyl perfluoroalkane at the same time; using inorganic bases as bases, the product yield is 70-85%, the post-processing process is relatively complicated and the raw material utilization rate is not high, it is not suitable as an industrial production route, and the process needs further improvement. Summary of the invention

[0006] The purpose of the present invention is to provide α,ω-diiodoperfluoroalkane derivatives, α,ω-diiodoethylperfluoroalkane derivatives and preparation methods and applications thereof in view of the deficiencies of the prior art. The preparation method of the present invention is simple and easy to operate, and the method has high product yield and high raw material utilization. The α,ω-diiodoperfluoroalkane derivatives and α,ω-diiodoethylperfluoroalkane derivatives prepared by the method of the present invention can be used as vulcanization point monomers to prepare high fluorine content, low compression deformation peroxide vulcanized fluororubber.

[0007] The first aspect of the present invention provides a method for preparing an α,ω-diiodoperfluoroalkane derivative, wherein the α,ω-diiodoperfluoroalkane derivative is an α,ω-diiodethylperfluoroalkane, and the preparation method thereof is as follows: a free radical addition reaction is carried out between the α,ω-diiodoperfluoroalkane and ethylene in the presence of a solvent A and an initiator to obtain the α,ω-diiodethylperfluoroalkane.

[0008] Preferably, the structural formula of the α,ω-diiodoperfluoroalkane is I(C2F4) n I, wherein n is an integer from 1 to 5. Raw material I (C2F4) n The number of I chains is too long (n>5), making it difficult to separate and obtain the corresponding high-purity raw materials.

[0009] Preferably, the α,ω-diiodoperfluoroalkane is 1,6-diiodo-3,3,4,4-tetrafluorohexane, 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane, 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane, 1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane or 1,14-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12-eicosylfluorotetradecane.

[0010] Preferably, the solvent A is a polar solvent, which is conducive to free radical addition reaction, including one or more of dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, acetone, pyridine or methanol.

[0011] Preferably, the initiator is at least one of dibenzoyl peroxide, tert-butyl perbenzoate, tert-butyl hydroperoxide, diisopropyl peroxide, azodicarbonamide, diisopropyl azodicarboxylate, azobisisobutyronitrile, azobisisovaleronitrile or azobisisoheptanenitrile. Compared with other free radical initiators, azo radicals have a more stable free radical generation rate and milder reaction conditions.

[0012] Preferably, the mass ratio of the α,ω-diiodoperfluoroalkane to the solvent A and the initiator is 1:0.2-2.0:0.0005-0.05.

[0013] Preferably, the feed molar ratio of ethylene to α,ω-diiodoperfluoroalkane is 2.0 to 3.0: 1. When ethylene and α,ω-diiodoperfluoroalkane react to generate α,ω-diiodoethylperfluoroalkane, the theoretical molar ratio of ethylene reaction is 2.0 equivalents. When it is slightly larger than the theoretical equivalent, the conversion rate of the raw materials is guaranteed. When the input is too large, the reaction selectivity is affected.

[0014] Preferably, the temperature of the free radical addition reaction is 60-150°C, preferably 80-120°C.

[0015] Preferably, the pressure of the free radical addition reaction is 0.2 to 1.5 MPa, preferably 0.5 to 1.0 MPa.

[0016] The method of the present invention is used to prepare α,ω-diiodoethylperfluoroalkane, so that the conversion rate of raw materials can be close to 100%, the selectivity of α,ω-diiodoethylperfluoroalkane is greater than 95%, and the purity of the prepared α,ω-diiodoethylperfluoroalkane is above 99%, and the yield is above 92%.

[0017] The second aspect of the present invention provides α,ω-diiodoethylperfluoroalkane prepared by the above preparation method, wherein the α,ω-diiodoethylperfluoroalkane derivative is α,ω-diiodoethylperfluoroalkane.

[0018] The third aspect of the present invention provides a method for preparing an α,ω-diiodoethyl perfluoroalkane derivative, wherein the α,ω-diiodoethyl perfluoroalkane derivative is an α,ω-iodoethyl vinyl perfluoroalkane and / or an α,ω-divinyl perfluoroalkane, and the preparation method is as follows: subjecting the above-mentioned α,ω-diiodoethyl perfluoroalkane to a one molecule of hydrogen iodide and / or two molecules of hydrogen iodide elimination reaction under the action of solvent B and a base, respectively, to obtain the α,ω-iodoethyl vinyl perfluoroalkane and / or the α,ω-divinyl perfluoroalkane.

[0019] Preferably, the solvent B is a polar solvent, including at least one of methanol, water, dimethyl sulfoxide or ethylene glycol.

[0020] Preferably, the base is an aqueous solution or a solvent B solution of one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, lithium hydroxide, lithium carbonate, cesium carbonate, and cesium hydroxide.

[0021] Preferably, the ratio of the α,ω-iodoethylvinylperfluoroalkane to the α,ω-divinylperfluoroalkane can be controlled by the molar ratio of the α,ω-diiodoethylperfluoroalkane to the base. Preferably, the molar ratio of the α,ω-diiodoethylperfluoroalkane to the base is controlled at 1:0.8 to 2.5.

[0022] As the molar ratio of the alkali feed increases, the raw material conversion rate gradually increases, and α,ω-iodoethylvinyl perfluoroalkane with unilateral iodine elimination is preferentially generated, while a small amount of α,ω-divinyl perfluoroalkane with bilateral iodine elimination is generated. As the amount of alkali feed further increases, the raw material concentration in the reaction system decreases, and the concentration of α,ω-iodoethylvinyl perfluoroalkane, the product of unilateral iodine elimination, increases. The alkali tends to react with the α,ω-iodoethylvinyl perfluoroalkane with a higher concentration to generate α,ω-divinyl perfluoroalkane. When preparing α,ω-divinyl perfluoroalkane, the theoretical molar ratio of the alkali feed is 2.0. When the alkali feed molar ratio is slightly greater than 2.0, the raw material conversion can be completely achieved, and the product obtained is basically α,ω-divinyl perfluoroalkane. When the alkali feed molar ratio is less than 0.8, the raw material conversion rate is low, resulting in low production efficiency and large raw material loss during post-processing.

[0023] Preferably, the temperature of the hydrogen iodide elimination reaction is 20 to 120°C, preferably 40 to 80°C.

[0024] The method of the present invention can realize the co-production preparation of α,ω-divinylperfluoroalkane and α,ω-iodoethylvinylperfluoroalkane, and the product ratio of α,ω-divinylperfluoroalkane and α,ω-iodoethylvinylperfluoroalkane can be controlled by adjusting the feeding molar ratio of the alkali, so that the utilization rate of the raw materials is greater than 98%, and the total selectivity of α,ω-iodoethylvinylperfluoroalkane and α,ω-diiodoethylperfluoroalkane can be as high as 99%.

[0025] The fourth aspect of the present invention provides an α,ω-diiodoethyl perfluoroalkane derivative prepared by the above preparation method, wherein the α,ω-diiodoethyl perfluoroalkane derivative is α,ω-iodoethyl vinyl perfluoroalkane and / or α,ω-divinyl perfluoroalkane.

[0026] The fifth aspect of the present invention provides the use of the above-mentioned α,ω-diiodoperfluoroalkane derivatives or α,ω-diiodoethylperfluoroalkane derivatives as vulcanization site monomers in the preparation of peroxide-cured fluororubber. The peroxide-cured fluororubber prepared by using the α,ω-divinylperfluoroalkane, α,ω-iodoethylvinylperfluoroalkane, and α,ω-diiodoethylperfluoroalkane prepared by the present invention has better compression deformation performance, strength and medium resistance than ordinary rubber.

[0027] Preferably, the preparation process of the peroxide-cured fluororubber is as follows:

[0028] (1) adding deionized water to a reactor and then evacuating the reactor, then adding a dispersant and a vulcanization point monomer to the reactor, heating the reactor to 85 to 100° C., and introducing an initial mixed monomer until the pressure in the reactor is 1.8 to 3.5 MPa, and then adding an initiator to initiate a polymerization reaction;

[0029] (2) After the polymerization reaction is carried out, the pressure in the reactor is maintained constant by adding additional mixed monomers. When the amount of the additional mixed monomers introduced is 5-20% of the total mass of the mixed monomers, the vulcanization point monomers are continuously added at a constant flow rate, and the flow rate of the vulcanization point monomers is 0.1-1% of the feed flow rate of the additional mixed monomers;

[0030] (3) When the solid content of the emulsion in the reactor reaches 25-33 wt %, the addition of the vulcanization point monomer is stopped to terminate the polymerization reaction, and the obtained emulsion is coagulated and dried to obtain the peroxide-cured fluororubber;

[0031] Wherein, the initial mixed monomer and the additional mixed monomer are a mixture of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene;

[0032] The vulcanization point monomer is the above-mentioned α,ω-diiodoperfluoroalkane derivative or a mixture of α,ω-diiodoethylperfluoroalkane derivative and difluoroiodoethylene.

[0033] Preferably, in step (1), the reactor is evacuated to a vacuum level of ≤20 ppm.

[0034] Preferably, in step (1), the dispersant is selected from trimer dispersants, including perfluoro-2,5-dimethyl-3,6-dioxanonanoate; preferably its ammonium salt, sodium salt or potassium salt.

[0035] Preferably, in the vulcanization site monomer, the mass ratio of α,ω-diiodoperfluoroalkane derivative or α,ω-diiodethylperfluoroalkane derivative to difluoroiodoethylene is 0.1 to 3:1.

[0036] Preferably, in step (1), the mass ratio of the deionized water to the dispersant and the vulcanization site monomer is 100:0.001-1:0.1-3.

[0037] Preferably, in step (1), the initiator is ammonium persulfate or potassium persulfate, and the mass ratio of the initiator to deionized water is 0.001 to 5:100.

[0038] Preferably, in step (1), in the initial mixed monomers, the molar ratio of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is 20-55:12-35:20-65; in step (2), in the additional mixed monomers, the molar ratio of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is 35-55:15-35:20-35. The reason for controlling the molar ratio is mainly to control the fluorine content and molecular composition, and to control the composition of the monomers in the polymer according to the monomer reactivity ratio.

[0039] The fifth aspect of the present invention provides a peroxide-cured fluororubber prepared by the above preparation method. The peroxide-cured fluororubber prepared by the present invention has excellent compression deformation performance, strength and medium resistance.

[0040] Preferably, the peroxide-cured fluororubber has a fluorine content of more than 70%, a compression deformation of less than 16%, a tensile strength of more than 21 MPa, an elongation at break of more than 150%, and a medium resistance of ≤5%.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] (1) The present invention controls the types of initiator and solvent A and the feed ratio, so that the conversion rate of α,ω-diiodoperfluoroalkane raw materials is close to 100%, the selectivity of α,ω-diiodoethylperfluoroalkane is greater than 95%, and the α,ω-diiodoethylperfluoroalkane with a purity of ≥99% can be obtained by cooling and crystallizing the reaction solution. The synthesis yield is ≥92%, the preparation yield is high, and the process is simple.

[0043] (2) The present invention adopts an inorganic base as a base to achieve the co-production of α,ω-divinylperfluoroalkane and α,ω-iodoethylvinylperfluoroalkane, and the product ratio of α,ω-divinylperfluoroalkane and α,ω-iodoethylvinylperfluoroalkane can be controlled by adjusting the molar ratio of the base. The unreacted raw materials can be recycled, and the raw material utilization rate is greater than 98%, which effectively reduces the raw material cost of the preparation process and can meet the requirements of industrial production.

[0044] (3) The α,ω-diiodoperfluoroalkane derivatives and α,ω-diiodethylperfluoroalkane derivatives of the present invention are suitable for the preparation of peroxide-cured fluororubber. The rubber prepared by using them has better compression deformation performance, strength and medium resistance than ordinary rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a process flow chart of the present invention.

[0046] Figure 2This is the mass spectrum of the derivative 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane prepared using 1,6-diiodoperfluorohexane as raw material.

[0047] Figure 3 This is the mass spectrum of the preparation of 10-iodine-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluoro-1-decene from 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane.

[0048] Figure 4 This is the mass spectrum of the preparation of 1,6-divinylperfluorohexane from 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with the embodiments, but the present invention is not limited to the following embodiments.

[0050] The process flow chart of the present invention is as follows Figure 1 shown.

[0051] Example 1

[0052] Preparation of 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane: In a 2L autoclave, add 800g of acetone, 8g of dibenzoyl peroxide, and 800g of 1,6-diiodoperfluorohexane. After nitrogen replacement, start stirring, heat to 80°C, and then continuously introduce ethylene. The internal temperature is controlled at 80°C to 100°C. The pressure in the reactor is maintained at 0.5 to 0.8MPa until the pressure in the reactor does not drop. The cumulative mass of ethylene introduced is 89g. The temperature is lowered and ethylene is replaced with nitrogen. Sampling and analysis show that the raw material conversion rate is 100% and the product selectivity is 96.8%. The material was discharged into a 2L glass reaction bottle and cooled and crystallized under stirring to precipitate a white solid. After filtration, washing and drying, 831 g of 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane with a purity of 99.3% was obtained (its mass spectrum is shown in FIG. Figure 2 The recrystallization solvent is distilled and recovered to obtain acetone with a purity of 99.9%, which can be used as a solvent for the reaction.

[0053] Preparation of 10-iodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecylfluoro-1-decene and 1,6-divinylperfluorohexane: In a 5L continuous reaction device, add 2kg of methanol to a 5L continuous reaction kettle, start stirring, raise the temperature to 50°C, add a methanol solution of 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecylfluorodecane prepared at a mass ratio of 1:1 through a pump at a rate of 2kg / hour, and at the same time add 48% potassium hydroxide water at a rate of 288g / hour. The molar ratio of 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane to potassium hydroxide was 1:1.5. The reaction solution in the reactor was collected through overflow. The reaction was continued for 24 hours. Sampling and analysis showed that the ratio of 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane to 10-iodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluoro-1-decene to 1,6-divinylperfluorohexane in the reaction solution was 7%:41%:52%.

[0054] The reaction solution was purified by distillation to obtain the recovered solvents methanol, water, 10-iodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluoro-1-decene (whose mass spectrum is shown in Figure 3 As shown), 1,6-divinylperfluorohexane (whose mass spectrum is as shown Figure 4 As shown), then a certain amount of potassium iodide precipitated from high-purity water was added to the bottom liquid of the kettle. After separation, methanol was added to the fluorine phase to prepare a solution as a raw material for reaction. Material balance was performed, and the utilization rate of the raw material 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane was 99.1%.

[0055] Example 2

[0056] Preparation of 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane: In a 2L continuous reaction device, 800g of N,N-dimethylformamide was added as a solvent base, and stirring was started after nitrogen replacement. The temperature was raised to 65°C, and a mixed solution of N,N-dimethylformamide, 1,4-diiodoperfluorobutane and azobisisobutyronitrile (the mass ratio of N,N-dimethylformamide, 1,4-diiodoperfluorobutane and azobisisobutyronitrile in the mixed solution was 1:1:0.002) was added at a rate of 800g / h through a feed pump. At the same time, ethylene was continuously introduced at a flow rate of 50-60g / h. The internal temperature was controlled at 70°C-80°C, and the pressure in the reactor was maintained at 0.4-0.6MPa. The reaction solution in the reactor was collected through overflow, and the reaction was continued for 24 hours. Sampling and analysis showed that the raw material conversion rate was 99.8% and the product selectivity was 95.9%. The reaction solution was added to a 20L glass reactor and cooled and crystallized under stirring to precipitate a white solid, which was filtered, washed and dried to obtain 861g of 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane with a purity of 99.4% and a yield of 95.8%. The recrystallization solvent was distilled and recovered to obtain N,N-dimethylformamide with a purity of 99.9%, which could be used as a solvent for the reaction.

[0057] Preparation of 8-iodo-3,3,4,4,5,5,6,6-octafluoro-1-octene and 1,4-divinylperfluorobutane In a 5L continuous reaction device, 2kg of ethylene glycol was added to the 5L continuous reactor, stirring was started, the temperature was raised to 60°C, and a 1:1 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane ethylene glycol solution was added at a rate of 2kg / hour through a pump, and 10% hydrogen was added at a rate of 784g / hour. The ethylene glycol solution of sodium hydroxide, the molar ratio of 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane: sodium hydroxide is 1:1, the reaction liquid in the reactor is collected through overflow, the reaction is continued for 24 hours, and sampling and analysis are performed. The ratio of 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane: 8-iodo-3,3,4,4,5,5,6,6-octafluoro-1-octene: 1,4-divinylperfluorobutane in the reaction liquid is 29%:51%:20%.

[0058] The reaction liquid was extracted and purified by distillation to obtain water, 1,4-divinylperfluorobutane, 8-iodo-3,3,4,4,5,5,6,6-octafluoro-1-octene, and the recovered solvent ethylene glycol. Then, a certain amount of sodium iodide dissolved in high-purity water was added to the bottom liquid of the kettle. After separation, ethylene glycol was added to the fluorine phase to prepare a solution as a raw material for reaction. Material balance was performed, and the utilization rate of the raw material 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane was 98.2%.

[0059] Example 3

[0060] 1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane was prepared in a 2L autoclave, 800g of dimethyl sulfoxide, 8g of tert-butyl perbenzoate and 800g of 1,8-diiodoperfluorooctane were added, stirring was started after nitrogen replacement, the temperature was raised to 105°C, the internal temperature was controlled at 105°C-120°C, the pressure in the reactor was maintained at 0.6-0.9MPa, until the pressure in the reactor did not drop, the cumulative mass of ethylene introduced was 78g, the temperature was lowered and ethylene was replaced with nitrogen, sampling and analysis showed that the raw material conversion rate was 99.9% and the product selectivity was 97.1%. The material was discharged into a 2L glass reaction bottle and cooled and crystallized under stirring to precipitate a white solid, which was filtered, washed and dried to obtain 815 g of 1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane with a purity of 99.1% and a yield of 93.8%. The recrystallization solvent was distilled and recovered to obtain dimethyl sulfoxide with a purity of 99.9%, which could be used as a solvent for the reaction.

[0061] Preparation of 12-iodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluoro-1-dodecene and 1,8-divinylperfluorooctane In a 20L glass reactor, add 8kg of ethanol and 8kg of 1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane, start stirring, raise the temperature to 60°C, and add 3424g of 50% potassium carbonate aqueous solution (1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane: potassium carbonate feed molar ratio is 1:1.1), the addition time is 1.5 hours, after the addition is completed, the reaction is kept warm for 1 hour, and sampling is analyzed. The ratio of 1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane: 12-iodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluoro-1-dodecene: 1,8-divinylperfluorooctane in the reaction solution is 1%:3%:96%.

[0062] The reaction liquid was extracted and purified by distillation to obtain ethanol-water mixed liquid, 1,8-divinylperfluorooctane, and 12-iodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluoro-1-dodecene, and then a certain amount of potassium iodide was added to the bottom liquid of the kettle. After separation, ethanol was added to the fluorine phase to prepare a solution as a raw material for reaction. Material balance was performed, and the utilization rate of the raw material 1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane was 99.5%.

[0063] Example 4

[0064] A method for preparing high-fluorine content and low-compression deformation peroxide-cured fluororubber, the operating steps of which are:

[0065] a. In a high-pressure reactor, 30 kg of deoxygenated deionized water was added, the reactor was evacuated, and then 0.025 kg of dispersant and 0.01 kg of 1,6-divinylperfluorohexane and 0.01 kg of diiodoperfluorobutane were added and stirred evenly. The reactor was heated to 90 ° C, and a mixed monomer 1 (initial mixed monomer) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene was introduced to make the pressure in the reactor 2.0 MPa, and then 0.01 kg of initiator was added to initiate the polymerization reaction;

[0066] b. After the polymerization reaction is carried out, the pressure in the reactor is maintained constant by adding a mixed monomer 2 of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene (addition of mixed monomers). When the total amount of the mixed monomers begins to be added to 5%, 0.03 kg of the vulcanization point monomer 1,6-divinylperfluorohexane and 0.03 kg of the vulcanization point monomer diiodoperfluorobutane are continuously added at a constant flow rate;

[0067] c. When the solid content of the emulsion in the reactor reaches 25wt%, the addition of the vulcanization point monomer is stopped, the polymerization reaction is terminated, the unreacted monomer is recovered, and the emulsion is placed in a coagulation barrel. After coagulation and drying, peroxide-cured fluororubber is obtained.

[0068] In the step a, the reactor is evacuated until the oxygen content is ≤20 ppm.

[0069] The dispersant in step a is perfluoro-2,5-dimethyl-3,6-dioxanononanoic acid ammonium.

[0070] In the step a, the molar ratio of the mixed monomer 1 (initial mixed monomer) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is 25:15:60.

[0071] The initiator in step a is ammonium persulfate.

[0072] In the step b, the molar ratio of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene mixed monomer 2 (additional mixed monomer) is 45:32.5:32.5.

[0073] Example 5

[0074] A method for preparing high-fluorine content and low-compression deformation peroxide-cured fluororubber, the operating steps of which are:

[0075] a. In a high pressure reactor, 30 kg of deoxygenated deionized water was added, the reactor was evacuated, and then 0.025 kg of dispersant and 0.01 kg of 10-iodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecylfluoro-1-decene and 0.01 kg of difluoroethylene iodide were added, stirred evenly, the reactor was heated to 90 ° C, and a mixed monomer 1 (initial mixed monomer) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene was introduced to make the pressure in the reactor 2.0 MPa, and then 0.01 kg of initiator was added to initiate the polymerization reaction;

[0076] b. After the polymerization reaction, the pressure in the reactor is maintained constant by adding a mixed monomer 2 (mixed monomer addition) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene. When the total amount of the mixed monomer begins to be added at 5%, 0.03 kg 10-iodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecylfluoro-1-decene and 0.03 kg difluoroethylene iodide are continuously added at a constant flow rate;

[0077] c. When the solid content of the emulsion in the reactor reaches 25wt%, the addition of the vulcanization point monomer is stopped, the polymerization reaction is terminated, the unreacted monomer is recovered, and the emulsion is placed in a coagulation barrel. After coagulation and drying, peroxide-cured fluororubber is obtained.

[0078] In the step a, the reactor is evacuated until the oxygen content is ≤20 ppm.

[0079] The dispersant in step a is perfluoro-2,5-dimethyl-3,6-dioxanononanoic acid ammonium.

[0080] In the step a, the molar ratio of the mixed monomer 1 (initial mixed monomer) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is 25:15:60.

[0081] In the step a, the initiator is selected from ammonium persulfate.

[0082] In the step b, the molar ratio of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene mixed monomer 2 (additional mixed monomer) is 45:32.5:32.5.

[0083] Example 6

[0084] A method for preparing high-fluorine content and low-compression deformation peroxide-cured fluororubber, the operating steps of which are:

[0085] a. In a high pressure reactor, 30 kg of deoxygenated deionized water was added, the reactor was evacuated, and then 0.025 kg of dispersant and 0.01 kg of 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane were added, stirred evenly, the reactor was heated to 100 ° C, and a mixed monomer 1 (initial mixed monomer) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene was introduced to make the pressure in the reactor 2.0 MPa, and then 0.01 kg of initiator was added to initiate the polymerization reaction;

[0086] b. After the polymerization reaction, the pressure in the reactor is maintained constant by adding a mixed monomer 2 (mixed monomer addition) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene. When the total amount of the mixed monomer begins to be added at 5%, 0.03 kg of 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane and 0.03 kg of difluoroethylene iodide are continuously added at a constant flow rate;

[0087] c. When the solid content of the emulsion in the reactor reaches 25wt%, the addition of the vulcanization point monomer is stopped, the polymerization reaction is terminated, the unreacted monomer is recovered, and the emulsion is placed in a coagulation barrel. After coagulation and drying, peroxide-cured fluororubber is obtained.

[0088] In the step a, the reactor is evacuated until the oxygen content is ≤20 ppm.

[0089] The dispersant in step a is perfluoro-2,5-dimethyl-3,6-dioxanononanoic acid ammonium.

[0090] In the step a, the molar ratio of the mixed monomer 1 (initial mixed monomer) of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is 25:15:60.

[0091] In the step a, the initiator is selected from ammonium persulfate.

[0092] In the step b, the molar ratio of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene mixed monomer 2 (additional mixed monomer) is 45:32.5:32.5.

[0093] The properties of the obtained vulcanized fluororubber were tested, and the test method was as follows:

[0094] 1. Determination of fluorine content

[0095] Weigh an appropriate amount of vulcanized fluororubber sample, crush it and mix it evenly. Use the oxygen bomb combustion method (oxygen bomb combustion coulometer), the specific steps are as follows:

[0096] 1) Place the rubber sample in an oxygen bomb and burn it in a high-pressure oxygen environment.

[0097] 2) The combustion products are absorbed by the absorption liquid.

[0098] 2. Compression deformation measurement

[0099] Prepare rubber specimens of standard size, usually cylindrical (29 mm in diameter, 12.5 mm in height), and conduct the test at 200°C.

[0100] 1) Place the sample in a compression device and keep it at a compression rate of 25% for 70 hours.

[0101] 2) After the test, remove the sample from the compression device and return it to room temperature for 30 minutes.

[0102] 3) Measure the height after recovery.

[0103] 3. Tensile strength determination

[0104] Prepare standard dumbbell-shaped rubber specimens, the dimensions of which conform to GB / T 528-2009 (ISO 37:2005) standard. Tests were performed at room temperature.

[0105] 1) Use a universal material testing machine to perform a tensile test at a constant tensile speed (such as 500 mm / min).

[0106] 2) Record the maximum tensile force of the sample.

[0107] 4. Determination of elongation at break

[0108] The dumbbell-shaped rubber specimen is the same as that for tensile strength determination. The test is carried out at room temperature.

[0109] 1) Using a universal material testing machine, continue stretching until the specimen breaks.

[0110] 2) Record the elongation at break of the specimen.

[0111] 5. Determination of medium resistance

[0112] The test was carried out in accordance with the provisions of GB / T 1690. The test time was 24 hours, the test temperature was 200°C, and the test oil was 3# standard oil.

[0113] The results of the above performance tests are shown in Table 1 below:

[0114] Table 1 Properties of peroxide-cured fluororubber prepared in Examples 4-6

[0115]

[0116] From the test results of Examples 4 to 6, it can be seen that the use of α,ω-divinylperfluoroalkane, α,ω-iodoethylvinylperfluoroalkane, and α,ω-diiodovinylperfluoroalkane to prepare peroxide-cured fluororubber has better compression deformation, strength, and medium resistance than ordinary fluororubber.

[0117] Although the present invention has been described in detail above by means of general description, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements may be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing an α,ω-diiodoperfluoroalkane derivative, characterized in that: The α,ω-diiodoperfluoroalkane derivative is α,ω-diiodineethylperfluoroalkane, and the preparation method of the α,ω-diiodineethylperfluoroalkane is as follows: α,ω-diiodineperfluoroalkane undergoes a free radical addition reaction with ethylene under the action of solvent A and an initiator to obtain the α,ω-diiodineethylperfluoroalkane.

2. The preparation method according to claim 1, characterized in that: The structural formula of the α,ω-diiodoperfluoroalkane is I(C2F4) n I, wherein n is an integer from 1 to 5.

3. The preparation method according to claim 1 or 2, characterized in that: The α,ω-diiodoperfluoroalkane is 1,6-diiodo-3,3,4,4-tetrafluorohexane, 1,10-diiodo-3,3,4,4,5,5,6,6,7,7,8,8-dodecafluorodecane, 1,8-diiodo-3,3,4,4,5,5,6,6-octafluorooctane, 1,12-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexafluorododecane or 1,14-diiodo-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12-eicosicofluorotetradecane.

4. The preparation method according to claim 1, characterized in that: The solvent A is a polar solvent, including at least one of dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, acetone, pyridine or methanol; And / or, the initiator is at least one of dibenzoyl peroxide, tert-butyl perbenzoate, tert-butyl hydroperoxide, diisopropyl peroxide, azodicarbonamide, diisopropyl azodicarboxylate, azobisisobutyronitrile, azobisisovaleronitrile or azobisisoheptanenitrile.

5. The preparation method according to claim 1, characterized in that: The feed mass ratio of the α,ω-diiodoperfluoroalkane to the solvent A and the initiator is 1:0.2-2.0:0.0005-0.05; the feed molar ratio of ethylene to the α,ω-diiodoperfluoroalkane is 2.0-3.0:1; the temperature of the free radical addition reaction is 60-150°C, and the pressure is 0.2-1.5MPa.

6. An α,ω-diiodoperfluoroalkane derivative prepared by the preparation method according to any one of claims 1 to 5.

7. A method for preparing an α,ω-diiodoethyl perfluoroalkane derivative, characterized in that: The α,ω-diiodoethyl perfluoroalkane derivative is α,ω-iodoethyl vinyl perfluoroalkane and / or α,ω-divinyl perfluoroalkane, and the preparation method is as follows: the α,ω-diiodoethyl perfluoroalkane described in claim 6 is subjected to a hydrogen iodide elimination reaction with one molecule and / or two molecules of hydrogen iodide under the action of solvent B and a base to obtain the α,ω-iodoethyl vinyl perfluoroalkane and / or α,ω-divinyl perfluoroalkane.

8. The preparation method according to claim 7, characterized in that: The solvent B is a polar solvent, including at least one of methanol, water, dimethyl sulfoxide or ethylene glycol; And / or, the base is an aqueous solution or a solvent B solution of one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, lithium hydroxide, lithium carbonate, cesium carbonate, and cesium hydroxide.

9. The preparation method according to claim 7, characterized in that: The molar ratio of the α,ω-diiodoethyl perfluoroalkane to the base is controlled at 1:0.8-2.5; and the reaction temperature of the hydrogen iodide elimination reaction is 20-120°C. 10 . The α,ω-diiodoethyl perfluoroalkane derivative prepared by the preparation method according to claim 7 .

11. Use of the α,ω-diiodoperfluoroalkane derivative according to claim 6 or the α,ω-diiodineethylperfluoroalkane derivative according to claim 10 as a vulcanization site monomer in the preparation of peroxide-cured fluororubber.

12. A method for preparing peroxide-cured fluororubber, characterized in that: The following steps are involved: (1) adding deionized water to a reactor and then evacuating the reactor, then adding a dispersant and a vulcanization point monomer to the reactor, heating the reactor to 85 to 100° C., and introducing an initial mixed monomer until the pressure in the reactor is 1.8 to 3.5 MPa, and then adding an initiator to initiate a polymerization reaction; (2) After the polymerization reaction is carried out, the pressure in the reactor is maintained constant by adding additional mixed monomers. When the amount of the additional mixed monomers introduced is 5-20% of the total mass of the mixed monomers, the vulcanization point monomers are continuously added at a constant flow rate, and the feed flow rate of the vulcanization point monomers is 0.1-1% of the feed flow rate of the additional mixed monomers; (3) When the solid content of the emulsion in the reactor reaches 25-33 wt %, the addition of the vulcanization point monomer is stopped to terminate the polymerization reaction, and the obtained emulsion is coagulated and dried to obtain the peroxide-cured fluororubber; Wherein, the initial mixed monomer and the additional mixed monomer are a mixture of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene; The vulcanization site monomer is the α,ω-diiodoperfluoroalkane derivative described in claim 6 or a mixture of the α,ω-diiodineethylperfluoroalkane derivative and difluoroiodoethylene described in claim 10.

13. The preparation method according to claim 12, characterized in that: In the vulcanization point monomer, the mass ratio of α,ω-diiodoperfluoroalkane derivative or α,ω-diiodoethylperfluoroalkane derivative to difluoroethylene iodide is 0.1-3:1; in the initial mixed monomer, the molar ratio of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is 20-55:12-35:20-65; in the additional mixed monomer, the molar ratio of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is 35-55:15-35:20-35.

14. Peroxide-cured fluororubber prepared by the preparation method according to claim 12 or 13.

15. The peroxide-cured fluororubber according to claim 14, characterized in that: The fluorine content of the peroxide-cured fluororubber is above 70%, the compression deformation is below 16%, the tensile strength is above 21 MPa, and the medium resistance is ≤5%.

Images