Diepoxy functional group vinyl ether reactive diluent as well as application and preparation method thereof

Abstract

The invention discloses a diepoxy functional group vinyl ether reactive diluent as well as application and a preparation method thereof. The preparation method comprises the following steps: reacting diethylene glycol / ethylene glycol / 1, 4-butanediol with acetylene to generate a divinyl ether intermediate, and carrying out two-stage reaction of hydrogen peroxide epoxidation and peracetic acid synergistic epoxidation. HO is activated under the assistance of electrochemistry to generate * OOH free radicals, and a cobalt phthalocyanine molecular catalyst is combined, so that the high-efficiency epoxidation conversion rate of vinyl ether is realized. Through a rectifying tower multi-stage separation process and a catalyst recycling technology, the product purity is greater than 99%, and the process waste liquid recovery rate is greater than 90%. The technology is particularly suitable for a large-molecular-weight epoxy resin system, and has remarkable application value in the fields of heavy anti-corrosion coatings, electronic encapsulating materials and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of active diluent, in particular to a double epoxy functional vinyl ether active diluent, application and preparation method thereof. BACKGROUND

[0002] Solvent-free heavy-duty anticorrosive coating is a high-performance environmentally friendly coating containing no or only a trace amount of volatile organic solvents (VOC). Its solid content is usually ≥ 95%. This kind of coating forms a dense coating through chemical reaction (such as crosslinking of epoxy resin and curing agent), and has the following core characteristics: 1, long-term corrosion protection: the service life can reach more than 10 years in harsh environments such as acid, alkali, salt and oil; 2, thick film: the single-layer coating thickness can reach 200-300 microns, far exceeding the 100 microns of traditional coatings; 3, environmental protection: the VOC emission is extremely low or even zero, meeting international environmental protection standards (such as EU RoHS).

[0003] Reactive diluent, commonly known as monomer or functional monomer or reactive solvent, is an organic small molecule containing a polymerizable functional group, which can not only dissolve or disperse film-forming substances, but also participate in film-forming reactions during the coating film-forming process, forming a class of compounds that remain in the coating film as non-volatile components; it is used in high solid and solvent-free coating systems. Among the various components of light-cured coatings, reactive diluent is an important component. It not only dissolves and dilutes oligomers, adjusts the viscosity of the system, but also participates in the light-curing process, affecting the light-curing rate of the coating and various properties of the dry film such as wear resistance, hardness, flexibility, etc. Therefore, selecting the appropriate reactive diluent is particularly important in the formulation design of light-cured coatings.

[0004] The purpose of the present application is to provide a double epoxy functional vinyl ether active diluent, which can be applied in solvent-free heavy-duty anticorrosive coating to significantly reduce the viscosity of the solvent-free heavy-duty anticorrosive coating and reduce the heat distortion temperature of the solvent-free heavy-duty anticorrosive coating. SUMMARY

[0005] In order to solve the problems of the prior art, the purpose of the present application is to provide a double epoxy functional vinyl ether active diluent, application and preparation method thereof, which can be applied in solvent-free heavy-duty anticorrosive coating to significantly reduce the viscosity of the solvent-free heavy-duty anticorrosive coating and reduce the heat distortion temperature of the solvent-free heavy-duty anticorrosive coating.

[0006] To achieve the above purpose, the technical solution adopted by the present application is as follows: The present application provides a double epoxy-terminated diglycidyl ether, which has the following molecular formula: ; or ; or .

[0007] The application also provides a use of the above-mentioned double epoxy-terminated diglycidyl ether, which is used as an active diluent of an epoxy resin and applied in a solvent-free coating.

[0008] The application also provides a preparation method of the double epoxy-terminated diglycidyl ether, which comprises the following steps: Step 1: preparing a divinyl ether by reacting diethylene glycol, ethylene glycol or 1,4-butanediol with acetylene; Step 2: preparing a double epoxy-terminated diglycidyl ether by reacting the divinyl ether obtained in Step 1 with an epoxidation reagent.

[0009] Further, Step 1: preparing a diethylene glycol divinyl ether by reacting diethylene glycol with acetylene; Step 1 comprises the following steps: Step 1a: mixing and dissolving a pre-prepared mixed solution of diethylene glycol, a catalyst, a polymerization inhibitor and a stabilizer in proportion, and then filtering the solution, and then pumping the solution into a reaction kettle through a liquid inlet pump; Step 1b: replacing the air in the reaction kettle with nitrogen, vacuumizing the reaction kettle, introducing acetylene into the reaction kettle, maintaining the pressure in the reaction kettle ≤0.3 MPa, and preheating the reaction kettle to 150°C; gradually increasing the temperature of the reaction kettle to 150-170°C, and simultaneously uniformly introducing acetylene, controlling the liquid inlet speed to make the reaction, and continuing to keep the temperature after the acetylene feeding is completed for at least 1 h to make the reaction sufficient; Step 1c: cooling the reaction kettle, and discharging the reaction mixture when the temperature is reduced to about 40°C; Step 1d: performing vacuum rectification on the reaction mixture obtained in Step 1c, gradually increasing the temperature and collecting different fractions to obtain diethylene glycol monovinyl ether and diethylene glycol divinyl ether, respectively.

[0010] Further, Step 1d comprises the following steps: Step 1d1: adding the reaction mixture obtained in Step 1c into a first rectification tower; Step 1d2: vacuumizing the first rectification tower, and gradually increasing the initial temperature of the first rectification tower to 112-118°C; Step 1d3: adding the gas phase components first rectified out of the first rectification tower into a second rectification tower, condensing the gas phase components rectified out of the first rectification tower through a condenser and collecting the components into a first monoether receiving tank, and collecting the remaining liquid phase components of the first rectification tower into a flash tank; Step 1d4, vacuumize the secondary rectification tower, and gradually increase the initial temperature of the secondary rectification tower from 107-113℃ to 112-118℃; Step 1d5, condense the gaseous components first rectified from the secondary rectification tower through a condenser and collect them into a diether receiving tank, and condense the gaseous components rectified later from the secondary rectification tower through a condenser and collect them into a second monoether receiving tank.

[0011] Further, step 1 further comprises: Step 1e, recycle the remaining liquid in the rectification tank of the secondary rectification tower, and mix and dissolve it with the pre-prepared mixed solution of the catalyst, the polymerization inhibitor and the stabilizer in step 1b in a proportion, and reuse it. Step 1f, recycle the flash liquid in the flash tank, and mix and dissolve it with the pre-prepared mixed solution of the catalyst, the polymerization inhibitor and the stabilizer in step 1b in a proportion, and reuse it.

[0012] Further, step 1 further comprises the following steps: Step 1i, sample the rectification fraction of the primary rectification tower, perform gas phase test to analyze the composition of the fraction, and then adjust the reflux ratio of the secondary rectification tower and the first monoether receiving tank; sample the rectification fraction of the secondary rectification tower, perform gas phase test to analyze the composition of the fraction, and then adjust the reflux ratio of the diether receiving tank and the second monoether receiving tank.

[0013] Further, step 2 comprises: Step 2a, hydrogen peroxide epoxidation: Mix diethylene glycol divinyl ether, 30-50% concentration H2O2 and cobalt phthalocyanine molecular catalyst, activate hydrogen peroxide by electrochemistry, generate peroxyl radical *OOH, and stir for 6-12 hours.

[0014] Further, step 2 further comprises: Step 2b, peroxiacetic acid epoxidation: Add acetic acid and 1% mass fraction of sulfuric acid to the reaction product of step 2a, control the temperature at 50-60℃, continue to add H2O2 at a uniform speed to maintain the concentration stable, and fully react for 3-5 hours.

[0015] Further, step 2 further comprises: Step 2c, remove the cobalt phthalocyanine molecular catalyst from the reaction liquid by filtration, dilute it with water, separate the epoxide by extraction or distillation, purify it by silica gel column chromatography, and obtain the finished product of di-glycidyl ether capped with double epoxy groups.

[0016] Compared with the prior art, the application has the beneficial effects that: The present application discloses a kind of epoxy-functional vinyl ether reactive diluents, uses and preparation method thereof, which can be applied in solvent-free heavy-duty coatings to significantly reduce the viscosity of solvent-free heavy-duty coatings and reduce the heat distortion temperature of solvent-free heavy-duty coatings. DETAILED DESCRIPTION

[0017] In order to make the personnel in the art better understand the present application, the technical solutions in the specific embodiments of the present application are described clearly and completely below.

[0018] The present application provides a kind of epoxy-terminated diglycidyl ether, with the following molecular formula: ; Or ; Or .

[0019] The present application also provides a kind of epoxy-terminated diglycidyl ether as described above, which is used as an active diluent for epoxy resin and applied in solvent-free coatings.

[0020] According to the curing mechanism, active diluents can be divided into two categories: free radical type and cationic type. From the chemical structure, the active diluents for free radical photopolymerization are monomers with C=C unsaturated double bonds, such as acryloyloxy, methacryloyloxy, vinyl, and allyl, and their photopolymerization activity is in the order of acryloyloxy > methacryloyloxy > vinyl > allyl. Therefore, in general, the active diluents for free radical photopolymerization are mainly acrylate monomers. The active diluents for cationic photopolymerization are monomers with vinyl ether "CH2=CH-O-" or epoxy groups. Epoxy-based active diluents belong to cationic active diluents, and their curing reaction mechanism is cationic polymerization.

[0021] Active diluents can be divided into monofunctional active diluents such as 2-hydroxyethyl methacrylate (HEMA), bifunctional active diluents such as 2-hydroxyethyl methacrylate (HEMA), and multifunctional active diluents according to the number of reactive groups contained in each molecule. The number of functional groups in each molecule is called functionality, so the functionality of monofunctional and bifunctional active diluents is 1 and 2, respectively, and the functionality of multifunctional active diluents is 3, 4, or more. The more functional groups that can participate in photopolymerization reactions in active diluents, the higher the functionality, the higher the photopolymerization activity, and the faster the photopolymerization rate. This is because the use of monomers containing more functional groups not only increases the reaction activity, but also imparts crosslinking to the cured film. Linear polymers can only be obtained after the polymerization of monofunctional monomers, while high crosslinking network structures can be obtained from multifunctional monomers.

[0022] The above-mentioned diglycidyl ethers with epoxy groups at the end have the following main beneficial properties: 1. High-efficiency viscosity reduction and process optimization Significantly reduces viscosity: The long molecular chain of the diepoxy reactive diluent contains diepoxy groups, which can effectively reduce the initial viscosity of the epoxy resin system. At room temperature, the viscosity is so low that it is miscible, making it suitable for efficient application of solvent-free heavy-duty anti-corrosion coatings.

[0023] Thick coating capability: High film thickness (e.g., over 200 micrometers) can be achieved with a single coat, reducing the number of coats and improving construction efficiency.

[0024] 2. Enhance the overall performance of cured materials Flexibility and impact resistance: long chain structure (such as...) It imparts excellent flexibility and impact resistance to the cured product, making it suitable for applications requiring dynamic fatigue resistance, such as transformer potting and automotive electrophoretic coatings.

[0025] Enhanced chemical resistance: The participation of diepoxy groups in cross-linking forms a dense network, enhancing resistance to acids, alkalis, and solvents. For example, The modified epoxy resin can withstand more than 60 hours in 33% hydrochloric acid.

[0026] Thermal stability optimization: Compared to monoepoxy diluents, diepoxy structures can reduce the loss of heat distortion temperature (HDT), and some modified varieties (such as...) It can withstand temperatures up to 126–129℃.

[0027] 3. Environmental and safety advantages Zero / low VOC emissions: The dual-epoxy reactive diluent fully participates in the curing reaction, with no solvent evaporation, and complies with environmental standards such as RoHS. It is suitable for confined spaces (such as ship cabins) and food contact scenarios (such as the inner wall of drinking water tanks).

[0028] Reduced health risks: No volatile irritating odor, reducing the risk of respiratory and skin exposure for construction workers.

[0029] 4. Multifunctional application adaptability Wide range of applications: including solvent-free coatings, electronic potting compounds (such as capacitor encapsulation), composite materials (such as resin matrix for wind turbine blades), and adhesives (such as automotive structural adhesives).

[0030] Compatibility with curing systems: The diepoxy diluent exhibits good reactivity with amine and acid anhydride curing agents, and the dosage is flexible (usually 5%-25%), allowing the formulation to be adjusted according to performance requirements.

[0031] 5. Economic viability and technological development trends Long-term cost advantage: Although the initial raw material cost is higher, the comprehensive cost performance is significantly improved by reducing the number of coating times, prolonging the service life of equipment (such as pipeline anticorrosion coating service life over 10 years).

[0032] Technical upgrading direction: combined with graphene modification (such as adding 0.5% graphene microsheet) or polyurea hybridization, further improve the high temperature resistance (>200℃) and wear resistance, and promote its application in high-end fields such as aerospace and nuclear power.

[0033] The application also provides a preparation method of a double epoxy group terminated diglycidyl ether, characterized in that the preparation method comprises: Step 1, preparing a divinyl ether by reacting diethylene glycol, ethylene glycol or 1,4-butanediol with acetylene; Step 2, preparing a double epoxy group terminated diglycidyl ether by performing an epoxy reaction on the divinyl ether obtained in step 1 and an epoxidizing agent.

[0034] Specifically, in step 1, diethylene glycol divinyl ether is prepared by reacting diethylene glycol with acetylene:

[0035] In step 2, a double epoxy group terminated diglycidyl ether is prepared by performing an epoxy reaction on the diethylene glycol divinyl ether obtained in step 1 and an epoxidizing agent: .

[0036] The double epoxy group terminated diglycidyl ether is used as an active diluent of an epoxy resin in a solvent-free heavy-duty anticorrosion coating. The active diluent of the epoxy resin is used in combination with the epoxy resin, which can reduce the viscosity of the curing system, increase the flowability, prolong the service life and facilitate large-area construction; improve the operability without affecting the basic properties of the cured product.

[0037] More specifically, in one embodiment, the diethylene glycol divinyl ether in step 1 is prepared by the following method: Step 1a, dissolving the pre-prepared mixed solution of diethylene glycol, catalyst, polymerization inhibitor and stabilizer in proportion after mixing, passing through a filter, and pumping into a reaction kettle by a liquid inlet pump; Step 1b, replacing the air in the reaction kettle by nitrogen, vacuumizing the reaction kettle, introducing acetylene into the reaction kettle, keeping the pressure in the reaction kettle ≤0.3 MPa, preheating the reaction kettle to 150℃, gradually increasing the temperature of the reaction kettle to 150~170℃, and simultaneously uniformly introducing acetylene at a constant speed, controlling the liquid inlet speed to make it react, and continuing to keep warm for at least 1h after the acetylene feeding is completed, so that the reaction is sufficient; The reaction equation is as follows: .

[0038] The reaction generates diethylene glycol monovinyl ether, which continues to react with acetylene to generate diethylene glycol divinyl ether.

[0039] Specifically, the weight components of diethylene glycol, acetylene, and the pre-prepared mixed solution are as follows: diethylene glycol 250-270 parts, acetylene 25-35 parts, and the pre-prepared mixed solution 8-9 parts; preferably: diethylene glycol 255-265 parts, acetylene 27-32 parts, and the pre-prepared mixed solution 8.3-8.7 parts.

[0040] Specifically, in the pre-prepared mixed solution: the catalyst is potassium hydroxide or the like, diethylene glycol reacts with potassium hydroxide to generate potassium diethylene glycol, potassium diethylene glycol reacts with acetylene to generate the potassium salt of diethylene glycol divinyl ether, and then reacts with diethylene glycol to generate diethylene glycol divinyl ether and potassium diethylene glycol salt, and the two steps are repeated until the reaction is completed. The polymerization inhibitor is hydroquinone or methoxyhydroquinone or the like, which is used to prevent spontaneous polymerization during storage or mixing, to maintain the stability of the solution by capturing free radicals or interfering with chain reactions, to avoid the generation of by-products such as polyethylene glycol and polyethylene glycol vinyl ether. The stabilizer is triphenyl phosphate or phosphite compounds or the like, which is used to inhibit decomposition at high temperatures to maintain the thermal stability of the system.

[0041] More specifically, when the catalyst is potassium hydroxide, the polymerization inhibitor is hydroquinone, and the stabilizer is triphenyl phosphate, the weight components of the catalyst, the polymerization inhibitor, and the stabilizer are as follows: 7 parts of catalyst, 0.35 parts of polymerization inhibitor, and 1.2 parts of stabilizer.

[0042] Step 1c, the reaction kettle is cooled, and when the temperature is reduced to about 40℃, the reaction mixture is discharged.

[0043] In step 1c, the obtained reaction mixture includes diethylene glycol monovinyl ether, diethylene glycol divinyl ether, and diethylene glycol. Therefore, the purpose of step 1d is how to separate diethylene glycol monovinyl ether, diethylene glycol divinyl ether, and diethylene glycol.

[0044] Step 1d, the reaction liquid obtained in step 1b is subjected to vacuum rectification, and different fractions are collected by gradually increasing the temperature: Step 1d1, the reaction liquid obtained in step 1b is added to the first-stage rectification column; Step 1d2, the first-stage rectification column is vacuumed, the initial temperature of the first-stage rectification column is 107-113℃, and gradually increased to 112-118℃; Step 1d3, the gaseous components first rectified out of the primary rectification tower are added to the secondary rectification tower (containing 80% or more diethylene glycol divinyl ether and 20% or more diethylene glycol monovinyl ether), the gaseous components rectified out of the primary rectification tower (containing 98% or more diethylene glycol monovinyl ether) are condensed by a condenser and collected into the first monoether receiving tank, and the remaining liquid components in the primary rectification tower are collected into the flash tank (containing 20% or more diethylene glycol monovinyl ether in the flash tank); Step 1d4, the secondary rectification tower is vacuumed, and the initial temperature of the secondary rectification tower is 107-113℃, which is gradually increased to 112-118℃. Step 1d5, the gaseous components first rectified out of the secondary rectification tower are condensed by a condenser and collected into the diether receiving tank, and the gaseous components rectified out of the secondary rectification tower are condensed by a condenser and collected into the second monoether receiving tank.

[0045] The rectification tower is prior art: the rectification tower includes a rectification tower kettle, a rectification section and a stripping section. The rectification section is above the feed plate, responsible for concentrating light components; the stripping section is below the feed plate, responsible for concentrating heavy components, and the stripping section includes a reboiler. The main function of the rectification tower kettle is to provide an ascending vapor stream, which is heated by the reboiler to partially vaporize the liquid.

[0046] The boiling point of diethylene glycol is 245℃, the boiling point of diethylene glycol monovinyl ether is 208℃, and the boiling point of diethylene glycol divinyl ether is 198-199℃. The boiling points of diethylene glycol monovinyl ether and diethylene glycol divinyl ether are similar, so the separation of diethylene glycol monovinyl ether and diethylene glycol divinyl ether is difficult. In the present application, vacuum rectification is used to make the boiling point difference between diethylene glycol monovinyl ether and diethylene glycol divinyl ether larger, thereby facilitating the separation of diethylene glycol monovinyl ether and diethylene glycol divinyl ether.

[0047] In addition, the present application improves the purity of diethylene glycol monovinyl ether and diethylene glycol divinyl ether through the two-stage rectification method of the primary rectification tower and the secondary rectification tower.

[0048] Among them, the product diethylene glycol monovinyl ether can be used for the preparation of polycarboxylic acid water reducing agent. With monovinyl ether as the initiator and alkylene oxide as the polymerization monomer, a polyether monomer with a certain molecular weight and a terminal vinyl double bond is synthesized by anionic ring-opening polymerization, and with the development of polycarboxylic acid water reducing agent, it is gradually favored by downstream water reducing agent manufacturers. The carboxylic acid water reducing agent synthesized by water phase free radical polymerization of the polyether monomer, acrylic acid, acrylic ester and other monomers has the characteristics of good anti-mud effect and low dosage sensitivity, and has certain application in the fields of commercial mixing, pipe pile and UHPC (Ultra-High Performance Concrete; super high performance concrete).

[0049] Since the flash liquid in the flash tank contains about 20% diethylene glycol monovinyl ether, the remaining liquid in the second rectification column contains about 2% diethylene glycol monovinyl ether, and the yield of diethylene glycol monovinyl ether is low. In order to improve the yield of diethylene glycol monovinyl ether, the following method is adopted: Step 1e, the remaining liquid in the second rectification column (containing about 2% diethylene glycol monovinyl ether and about 98% diethylene glycol) is mixed and dissolved with the pre-prepared mixed solution of catalyst, polymerization inhibitor and stabilizer in step 1b in proportion, and is reused.

[0050] Step 1f, the flash liquid in the flash tank (containing about 20% diethylene glycol monovinyl ether and about 80% diethylene glycol) is mixed and dissolved with the pre-prepared mixed solution of catalyst, polymerization inhibitor and stabilizer in step 1b in proportion, and is reused.

[0051] In order to determine the time when the gaseous components first rectified out of the first rectification column are added to the second rectification column, the time when the gaseous components rectified out of the first rectification column are condensed by the condenser and collected into the first monoether receiving tank, and in order to determine the time when the gaseous components first rectified out of the second rectification column are condensed by the condenser and collected into the diether receiving tank, the time when the gaseous components rectified out of the second rectification column are condensed by the condenser and collected into the second monoether receiving tank, step 1 further includes the following steps: Step 1i, sampling the rectification fraction of the first rectification column, performing gas phase test to analyze the fraction composition, and then adjusting the reflux ratio of the second rectification column and the first monoether receiving tank; sampling the rectification fraction of the second rectification column, performing gas phase test to analyze the fraction composition, and then adjusting the reflux ratio of the diether receiving tank and the second monoether receiving tank.

[0052] Gas phase test conditions: injector 250℃, detector 250℃, column oven 150℃, diethylene glycol divinyl ether peak time 1.83min, diethylene glycol monovinyl ether peak time 3.3min, diethylene glycol peak time 7.8min.

[0053] In addition, as shown in Table 1, the reaction liquid obtained in step 1b is also subjected to gas phase test and water content test (a total of 4 times, corresponding to 4 times of epoxidation reaction), to obtain the ratio of diethylene glycol monovinyl ether and diethylene glycol divinyl ether in the reaction liquid.

[0054] Table 1 Gas phase test and water content test data of reaction liquid

[0055] From the data in Table 1, the prepared reaction liquid diethylene glycol monovinyl ether content is basically between 41%~47%, diethylene glycol divinyl ether content is basically between 5%~8%.

[0056] In this application, the reaction kettle feeding mode is as follows: Open the jacketed liquid storage tank and the reaction kettle top jacketed liquid pipeline valve, pump the jacketed liquid into the reaction kettle, calculate the required amount of raw material alcohol according to the jacketed liquid quality, the raw material alcohol supplement is 10500-jacketed liquid quality, after the jacketed liquid and raw material alcohol feeding is completed, close the raw material alcohol feeding pump and raw material alcohol feeding pipeline valve, close the reaction kettle venting pipeline valve; Open the reaction kettle vacuum pipeline valve, draw the pressure in the reaction kettle to-0.1MPa, close the vacuum pipeline valve; open the nitrogen pipeline valve of the polymerization kettle, pressurize the reaction kettle to 0.0~0.03MPa. Repeat the above vacuum and nitrogen replacement operation 3 times, and then draw the reaction kettle to-0.1MPa again, and the nitrogen replacement is completed; Start the reaction kettle external circulation pump, open the heat conducting oil heating pipeline valve of the reaction kettle body, open the steam heating valve of the reaction kettle heat exchanger, raise the temperature in the reaction kettle to 150℃, close the steam heating valve of the reaction kettle heat exchanger, use heat conducting oil to keep the temperature in the reaction kettle at 155±5℃, and at the same time open the steam heating valve of the reaction kettle heat exchanger for heating when the heat conducting oil heating capacity is not enough. Open the acetylene feeding pipeline valve at the top of the reaction kettle, control the acetylene feeding rate at 120±20Kg / h by adjusting the valve opening, and the total feeding amount is 1200±10Kg. Close the acetylene feeding pipeline valve after feeding is completed; continue to maintain the reaction temperature at 155±5℃, and the holding time is 1.0h.

[0057] Open the pump after sampling pipeline valve of the reaction kettle external circulation pump slightly, take 50~100g of sample, and perform gas chromatography test, the main product content is ≥38%, which meets the reaction degree requirement; if the main product content is <38%, continue to introduce appropriate amount of acetylene into the reaction kettle, repeat the holding reaction temperature and time, then empty the residual liquid in the pump after sampling pipeline, and take 50~100g of sample again, Perform gas chromatography test until the main product content is ≥38%, and the acetylene feeding is completed.

[0058] After the holding reaction is completed, perform pressure reduction and devolatilization operation on the reaction kettle, open the vacuum pipeline valve, gradually adjust the vacuum pipeline valve opening, and control the pressure and time in the reaction kettle as shown in Table 2.

[0059] Table 2 Pressure and time in the reaction kettle Pressure 0 ~ -0.03 MPa 0 ~ -0.05 MPa 0 ~ -0.07 MPa 0.07 ~ -0.1 MPa Time / minute 20 20 10 10 After the end of the step of decompression and devolatilization, the nitrogen pipeline valve of the reaction kettle is opened, the bottom valve of the reaction kettle and the pipeline valve between the kettle and the rectification tower are opened, and the material in the reaction kettle is pressed into the kettle of the rectification tower for rectification operation or the pipeline valve between the reaction kettle and the reaction liquid storage tank is opened, and the material in the reaction kettle is pressed into the reaction liquid storage tank.

[0060] More specifically, in one embodiment, the di-epoxy terminated diglycidyl ether in Step 2 is prepared by the following method: Step 2a, hydrogen peroxide (H2O2) epoxidation: Mix diethylene glycol divinyl ether, H2O2 (30-50% concentration) and catalyst, stir for 6-12 hours.

[0061] Wherein, the catalyst is a cobalt phthalocyanine molecular catalyst, and hydrogen peroxide is activated by electrochemical assistance to generate peroxyl radical *OOH, realizing cis-epoxidation of the olefinic double bond of divinyl ether under mild conditions.

[0062] The cobalt phthalocyanine molecule has an 18-π electron conjugated macrocyclic structure, and the central cobalt atom can regulate its electronic state through axial coordination or carrier loading (such as carbon nanotubes and two-dimensional conductive materials). Under electrochemical assistance, H2O2 is activated by heterolysis on the surface of CoPc to generate highly active peroxyl radical *OOH. The epoxy functional groups on the surface of the carrier reduce the electron density of cobalt through dipole interaction, promote the transition of Co²⁺ to Co³⁺ oxidation state, and enhance the adsorption capacity of H2O2.

[0063] H2O2 activation path: H2O2+Co2+→Co3+–OOH−+OH−. Subsequently, the ·OOH radical participates in the double bond epoxidation through single electron transfer.

[0064] In the double bond epoxidation of divinyl ether (structure: CH2=CH-O-CH2-CH2-O-CH=CH2), the stereoselective attack of the ·OOH radical is the key: Radical initiation: Under electrochemical conditions, H2O2 generates ·OOH on the surface of CoPc, and its oxygen atom preferentially attacks from the same side of the double bond (cis), forming a cyclic transition state. Epoxide formation: The two carbon atoms of the double bond are combined with the oxygen of ·OOH, respectively, to form a cis-epoxy structure (lower ring strain, thermodynamically favorable). Catalyst regeneration: Co³⁺ is reduced by electrochemistry (such as applying a negative potential) to Co²⁺, completing the catalytic cycle.

[0065] Applying a moderate potential (such as 0.3-0.8 V vs. RHE) can accelerate the activation of H2O2, while inhibiting side reactions (such as the decomposition of H2O2 into H2O or O2).

[0066] Cobalt phthalocyanine molecular catalysts are compounded with carbon nanotubes to increase the specific surface area of the catalyst. In addition, carbon nanotubes can improve the dispersibility of CoPc and the efficiency of electron transfer, and enhance the generation rate of ·OOH.

[0067] In step 2a, the addition of a neutral or weakly acidic medium (such as 0.1 M K2SO4) to the mixture is conducive to the stability and free radical activity of H2O2.

[0068] The above method has the following advantages: high selectivity: the electron-deficient state of cobalt phthalocyanine can inhibit the over-oxidation of double bonds (such as ring opening or isomerization), and the selectivity of cis-epoxidation can reach more than 90%. Mild conditions: reaction at room temperature to 40°C, avoiding the high temperature and high pressure requirements of traditional epoxidation. Cycle stability: carrier-loaded CoPc (such as CoPc-S-COF) maintains activity in 20 hours of continuous operation, with a H2O2 conversion rate decay of <10%.

[0069] Due to the weak oxidizing ability of H2O2, it is necessary to prolong the reaction time or increase the temperature, so the yield of di-glycidyl ether capped with di-epoxy groups is low by hydrogen peroxide (H2O2) epoxidation alone. Therefore, further, step 2 also includes: Step 2b, peracetic acid (CH3COOOH) epoxidation: In the reaction product of step 2a, acetic acid and 1% mass fraction of sulfuric acid are added, the temperature is controlled at 50-60°C, H2O2 is continuously added at a uniform speed to maintain a stable concentration, and the reaction is fully reacted for 3-5 hours.

[0070] Acetic acid and hydrogen peroxide (H2O2) generate peracetic acid in situ under the catalysis of sulfuric acid, and peracetic acid preferentially attacks the sites with high electron cloud density of double bonds to generate di-epoxy products.

[0071] The temperature is controlled at 50-60°C to avoid the risk of explosion caused by high temperature (>60°C), and low temperature is used to reduce side reactions such as ring opening of epoxides.

[0072] Peracetic acid is an electrophilic peroxy acid, which undergoes cis-addition with double bonds through a double-ring transition state to generate epoxides. Due to the electron-donating effect of ether oxygen on the double bond of diethylene glycol divinyl ether, the electron cloud density is high and the reactivity is strong, and both ethylene glycol groups can be epoxidized, thereby increasing the yield of di-glycidyl ether capped with di-epoxy groups. In addition, since the H2O2 by-product is only water by first epoxidation with hydrogen peroxide (H2O2), the use of acetic acid is reduced, which is conducive to environmental protection.

[0073] In addition, the cobalt phthalocyanine molecular catalyst in step 2a is generally recovered and reused by acid washing and calcination, i.e. 5% dilute hydrochloric acid soaking and calcination at 300°C, which can restore 85% of the initial activity. By step 2b, the acid washing step of the cobalt phthalocyanine molecular catalyst can be omitted, which is conducive to environmental protection.

[0074] Further, step 2 also includes: Step 2c, the reaction solution is filtered to remove the catalyst, diluted with water, and the epoxide is separated by extraction or distillation, and purified by silica gel column chromatography to obtain the di-epoxy-terminated diglycidyl ether product.

[0075] It should be noted that the terms "first", "second", and similar terms used in the specification and claims of the present application do not necessarily mean any order, number or importance, but are only used to distinguish different components. Similarly, the terms "one" or "a" or similar terms do not mean a quantity limitation, but mean the presence of at least one. "Multiple" or "several" means at least two. Unless otherwise specified, the terms "before", "after", "left", "right", "down" and / or "up" and the like are intended to facilitate the description and are not limited to a position or spatial orientation. The terms "include" or "contain" and the like mean that the elements or objects appearing before "include" or "contain" cover the elements or objects listed after "include" or "contain" and their equivalents, and do not exclude other elements or objects. The terms "connected" or "connected" and the like are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0076] The singular forms "a", "said" and "the" used in the specification and claims of the present application are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein means and includes any or all possible combinations of one or more associated listed items.

[0077] It should be understood that for those skilled in the art, modifications or changes can be made according to the above description, and all such modifications and changes shall fall within the scope of the claims appended to the present application.

Claims

1. Bis-epoxy-terminated diglycidyl ether, characterized in that, The bis-epoxy-terminated diglycidyl ether has the following molecular formula: ； or ; or .

2. Use of the bis-epoxy terminated diglycidyl ether according to claim 1, characterized in that The bis-epoxy-terminated diglycidyl ether is used as an active diluent of epoxy resin in solvent-free coatings.

3. Process for the preparation of bis-epoxide terminated diglycidyl ether, characterized in that, The preparation method comprises: Step 1, preparing a divinyl ether by reacting diethylene glycol, ethylene glycol or 1,4-butanediol with acetylene; Step 2, preparing a bis-epoxy-terminated diglycidyl ether by reacting the divinyl ether obtained in step 1 with an epoxidation reagent.

4. The preparation method of the bis-epoxy-terminated diglycidyl ether according to claim 3, wherein, Step 1, preparing a diethylene glycol divinyl ether by reacting diethylene glycol with acetylene; Step 1 comprises: Step 1a, mixing and dissolving the pre-prepared mixed solution of diethylene glycol and the catalyst, polymerization inhibitor and stabilizer in proportion, and then passing through a filter and being pumped into a reaction kettle by a liquid inlet pump; Step 1b, replacing the air in the reaction kettle by nitrogen, vacuumizing the reaction kettle, introducing acetylene into the reaction kettle, keeping the pressure in the reaction kettle less than or equal to 0.3 MPa, and preheating the reaction kettle to 150 DEG C; gradually increasing the temperature of the reaction kettle to 150-170 DEG C, and simultaneously uniformly introducing acetylene, controlling the liquid inlet speed to make the reaction, and continuing the heat preservation reaction for at least 1 h after the acetylene feeding is completed, so as to make the reaction sufficient; Step 1c, cooling the reaction kettle, and discharging the reaction mixture when the temperature is reduced to about 40 DEG C; Step 1d, performing vacuum rectification on the reaction mixture obtained in step 1c, gradually increasing the temperature and collecting different fractions to obtain diethylene glycol monovinyl ether and diethylene glycol divinyl ether, respectively.

5. The method of claim 4, wherein the bis-epoxy terminated diglycidyl ether is prepared by the reaction of a diol with a diacid chloride in the presence of a base. Step 1d comprises: Step 1d1, adding the reaction mixture obtained in step 1c into a primary rectification tower; Step 1d2, vacuumizing the primary rectification tower, and gradually increasing the initial temperature of the primary rectification tower to 112-118 DEG C; Step 1d3, adding the gas phase components first rectified out of the primary rectification tower into a secondary rectification tower, condensing the gas phase components rectified out of the primary rectification tower by a condenser and collecting them into a second monovinyl ether receiving tank, and collecting the remaining liquid phase components of the primary rectification tower into a flash tank; Step 1d4, vacuumizing the secondary rectification tower, and gradually increasing the initial temperature of the secondary rectification tower to 112-118 DEG C; Step 1d5, condensing the gas phase components first rectified out of the secondary rectification tower by a condenser and collecting them into a bis-ether receiving tank, and condensing the gas phase components rectified out of the secondary rectification tower by a condenser and collecting them into a second monovinyl ether receiving tank.

6. The method of claim 5, wherein the di-epoxy terminated diglycidyl ether is prepared by the reaction of a di-epoxide with a di-phenol in the presence of a base. Step 1 further comprises: Step 1e, recycling the remaining liquid in the kettle of the secondary rectification tower, mixing and dissolving the pre-prepared mixed solution of the catalyst, polymerization inhibitor and stabilizer in step 1b in proportion, and reusing; Step 1f, recycling the flash liquid in the flash tank, mixing and dissolving the pre-prepared mixed solution of the catalyst, polymerization inhibitor and stabilizer in step 1b in proportion, and reusing.

7. The method of claim 5, wherein the di-epoxy terminated diglycidyl ether is prepared by the reaction of a di-epoxide with a di-phenol in the presence of a base. Step 1 further comprises the following steps: Step 1i, sampling the distillation fraction of the primary rectification tower, performing gas phase test analysis of the fraction composition, then adjusting the reflux ratio of the secondary rectification tower and the first monoether receiving tank; sampling the distillation fraction of the secondary rectification tower, performing gas phase test analysis of the fraction composition, then adjusting the reflux ratio of the diether receiving tank and the second monoether receiving tank.

8. The method of claim 3, wherein the di-epoxy terminated diglycidyl ether is prepared by the reaction of a di-epoxide with a di-phenol in the presence of a base. The step 2 includes: Step 2a, hydrogen peroxide epoxidation: Mix diethylene glycol divinyl ether, 30-50% concentration H2O2 and cobalt phthalocyanine molecular catalyst, activate hydrogen peroxide by electrochemistry to generate peroxyl radical *OOH, stir for 6-12 hours.

9. The method for preparing the diglycidyl ether with a diepoxy group terminus according to claim 8, characterized in that, Step 2 also includes: Step 2b, peroxyl acetic acid epoxidation: Add acetic acid and 1% mass fraction of sulfuric acid to the reaction product of step 2a, control the temperature at 50-60℃, continue to add H2O2 at a uniform speed to maintain the concentration stable, and fully react for 3-5 hours.

10. The method of claim 9, wherein the bis-epoxy terminated diglycidyl ether is prepared by the reaction of a diol with a diacid chloride in the presence of a base. Step 2 also includes: Step 2c, the reaction solution is filtered to remove the cobalt phthalocyanine molecular catalyst, diluted with water, and then separated by extraction or distillation, and the product of the di-glycidyl ether capped with epoxy groups is obtained by silica gel column chromatography purification.

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