Preparation method and application of o-tolyl methyl glycidyl ether

Abstract

The invention particularly relates to a preparation method and application of o-tolyl methyl glycidyl ether. The preparation method comprises the following steps: (1) preparing raw materials: o-cresol, methyl epichlorohydrin, a catalyst and alkali liquor; (2) ring-opening reaction: adding o-cresol and methyl epichlorohydrin in proportion, uniformly stirring, adding a catalyst, and maintaining at 50-100 DEG C for a period of time; (3) recovering methyl epichlorohydrin; (4) ring-closure reaction; and (5) after the reaction is finished, standing, cooling, separating an inorganic phase, cutting off salt feet, adding pure water, washing to be neutral, carrying out liquid separation treatment to obtain an organic phase, and removing the solvent in the organic phase to finally obtain the epoxy reactive diluent o-tolyl methyl glycidyl ether. According to the preparation method, the raw materials are low in toxicity and small in volatilization, the production process of the reactive diluent is safer and more environmentally friendly, the raw material conversion rate is high, the conditions are mild, the yield is high, the water resistance and solvent resistance are obviously superior to those of other diluents, and the corrosion resistance is excellent.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and specifically relates to a preparation method and application of o-cresyl methyl glycidyl ether. Background Art

[0002] Epoxy resins are widely used in coatings, construction, composite materials, electronics, aerospace and other fields due to their excellent mechanical properties, chemical resistance, bonding properties and electrical insulation properties. At present, bisphenol A diglycidyl ether prepared by the reaction of bisphenol A and epichlorohydrin accounts for about 90% of the world's epoxy resins and is an important general-purpose epoxy resin. However, industrial products of bisphenol A epoxy resins have high viscosity (above 10,000 mPa·s) and poor fluidity. They cannot be directly applied to downstream fields and have poor processability. Usually, an appropriate amount of diluent needs to be added to reduce the viscosity of the system and improve the processing technology of plastics.

[0003] Epoxy resin diluent is mixed with base resin to reduce the viscosity of the curing system, increase fluidity, improve processing technology, ensure the convenience of resin casting, bonding, sealing, impregnation and other processes, thereby reducing the defects of the curing resin and extending the service life. Diluents can be divided into two types: inactive diluents and active diluents. Among them, inactive diluents cannot participate in the reaction during the curing process because they do not contain active groups. They only play a role in reducing viscosity and exist in a free state in the system. Not only does it reduce the performance of the material, it will also overflow in the form of gas and pollute the environment.

[0004] Reactive diluents refer to low molecular weight epoxy compounds containing epoxy groups, which can not only reduce the viscosity of the curing system, but also participate in the curing reaction of epoxy resins, forming part of the cross-linked network structure, without affecting the performance of epoxy resins, and can even be used to modify epoxy resins to ensure the stability and long-term effectiveness of epoxy resin cured products, which has greater practical value. Therefore, reactive diluents can modify epoxy resins and have greater practical value.

[0005] CN114874417A discloses a method for preparing and using a high boiling point epoxy resin diluent, which is prepared by reacting styrene oxide and its derivatives with alcohols, acids, amines, ethers, and halogen substitutes containing phenolic hydroxyl groups, and purified after the reaction. The diluent is used in epoxy resin to reduce viscosity while also improving the performance and gel properties of the product; however, its preparation process is complicated, the raw materials used are highly irritating to the human body, and the post-processing steps are cumbersome.

[0006] CN116332895A discloses a preparation method of a cyclic carbonate epoxy resin diluent with a simple preparation process and convenient use. The diluent is prepared by reacting a polyfunctional epoxy compound and a catalyst with carbon dioxide gas in a high-pressure reaction kettle. Although this diluent can react with an amine curing agent to generate urethane and hydrogen bonds to provide toughness for the cured resin and enhance the hydrogen bond effect, its cyclic carbonate structure will ring-open during the curing reaction, reducing the thermomechanical properties of the cured resin.

[0007] CN116496236A discloses a preparation method of an epoxy resin active toughening diluent. The diluent is obtained by reacting pentanediol and epoxy haloalkane under the action of a catalyst. Its viscosity is as low as 10 mPa·s, and it has a good toughening effect on the cured product. However, compared with the cyclic structure, the flexible and flexible aliphatic long chain has an adverse effect on the heat resistance of the cured resin.

[0008] The above diluents have disadvantages such as complex synthesis processes, relatively high toxicity of raw materials, and reduction of the heat resistance of the curing system. Summary of the Invention

[0009] To solve the above technical problems, the present invention provides a synthesis method of o-tolylmethyl glycidyl ether with good heat resistance and excellent corrosion resistance. This synthesis method uses the safer and more environmentally friendly raw material methyl epichlorohydrin, whose toxicity and volatility are lower than those of epichlorohydrin, with less air pollution and a safer and more environmentally friendly production process. The method has a simple process, and the catalyst used in the synthesis method has the advantages of reducing the reaction temperature, shortening the reaction time, and improving the selectivity of the ring-opening reaction, with fewer side reactions, resulting in a high epoxy value and low organic chlorine content of the final product.

[0010] To achieve the above object, one aspect of the present invention is to provide a synthesis method of an epoxy active diluent o-tolylmethyl glycidyl ether represented by Formula I

[0011]

[0012] The technical solution adopted by the present invention is as follows:

[0013] A synthesis method of an epoxy active diluent o-tolylmethyl glycidyl ether, comprising the following steps:

[0014] (1) Prepare raw materials: o-cresol, methyl epichlorohydrin, catalyst, alkali solution;

[0015] (2) Ring-opening reaction: Add o-cresol and methyl epichlorohydrin in proportion, stir evenly, add the catalyst, maintain at 50-100 °C, and keep for a period of time;

[0016] Preferably, in step (2), the molar ratio of methyl epichlorohydrin to o-cresol is 2-5:1;

[0017] Preferably, in step (2), the catalyst is one or more of Lewis acid catalysts, boron trifluoride diethyl ether, and quaternary ammonium salts;

[0018] More preferably, the catalyst is boron trifluoride diethyl ether or a mixed catalyst of boron trifluoride diethyl ether and its quaternary ammonium salt; Particularly preferably, the molar ratio of methyl epichlorohydrin to o-cresol is 3-4:1.

[0019] Preferably, the dosage of the catalyst is 0.3%-4% of the total mass of o-cresol;

[0020] Preferably, in step (2), the molar ratio of methyl epichlorohydrin to o-cresol is 2-4:1;

[0021] Preferably, in step (2), the reaction temperature is maintained at 70-85°C for 3 hours.

[0022] (3) Recover methyl epichlorohydrin: Remove and recover methyl epichlorohydrin by vacuum distillation until no distillate is distilled out and end the vacuum distillation.

[0023] Preferably, methyl epichlorohydrin is removed under reduced pressure at 6-21 kPa and 80-130°C.

[0024] (4) Ring-closure reaction: Lower the temperature of the reaction system and add a solvent. While stirring, adjust the temperature to 40-80°C, and dropwise add an alkali solution. After the addition of the alkali solution is completed, continue to keep the temperature for reaction for a period of time;

[0025] Preferably, in step (4), the solvent is at least one of benzene, toluene, and xylene; the alkali solution is a sodium hydroxide solution with a mass concentration of 20%-50%; the molar ratio of sodium hydroxide to o-cresol is 0.8-1.1:1. Particularly preferably, the concentration of the alkali solution is a 30% sodium hydroxide solution, and the molar ratio of sodium hydroxide to o-cresol is 1:1;

[0026] Preferably, in step (4), the alkali solution is dropped at 45-65°C for 1-1.5 hours. After completion, keep the temperature for reaction for 3 hours.

[0027] (5) After the reaction is completed, let it stand and cool, separate the inorganic phase and cut off the salt foot, then add pure water to wash until neutral, and perform liquid separation to obtain the organic phase. Remove the solvent in the organic phase, and finally obtain the epoxy active diluent o-tolyl methyl glycidyl ether.

[0028] In step (5) of the present invention, liquid separation in the laboratory is carried out using a separating funnel. To remove the excess solvent in the organic phase, vacuum pumping is used and a rotary evaporator is employed to recover toluene by vacuum distillation for reuse.

[0029] The preparation process of the present invention is reasonably designed. First, o-cresol and methyl epichlorohydrin react under the action of a catalyst to form a chlorohydrin ether, and then methyl epichlorohydrin is removed to reduce the occurrence of other side reactions during the epoxidation process. Subsequently, a solvent is added to dilute the organic phase, and a phase transfer catalyst and an alkali solution are added to carry out a ring-closure reaction to generate a crude product of the epoxy active diluent. The solvent is removed in a vacuum rotary evaporator, and finally, an epoxy active diluent is obtained. This diluent belongs to a monofunctional active diluent, containing a benzene ring, an ether bond, and an epoxy group, and has certain rigidity, heat resistance, and corrosion resistance. It is used as an epoxy resin diluent to reduce the viscosity of the epoxy system, improve the toughness and heat resistance of the cured resin, and improve the mechanical properties and corrosion resistance of the cured resin. The yield of the synthesis method of the present invention can reach 99%.

[0030] Beneficial Effects

[0031] (1) The present invention provides a method for preparing an epoxy active diluent using methyl epichlorohydrin as a raw material. The raw material has low toxicity and low volatility, and the production process of the active diluent is safer and more environmentally friendly.

[0032] (2) The catalyst used can reduce the reaction temperature, shorten the reaction time, improve the selectivity of the ring-opening reaction, and reduce energy consumption. (3) After the ring-opening reaction is completed, methyl epichlorohydrin is removed under reduced pressure, which can avoid the occurrence of some side reactions and improve the purity and yield of the product.

[0033] (4) The method of the present invention has a high raw material conversion rate, mild conditions, a high yield (99.1%), and a simple process for synthesizing the active diluent o-tolyl methyl glycidyl ether, which is conducive to industrial production.

[0034] (5) The low-viscosity active diluent of the present invention can reduce the viscosity and improve the processing performance while having high heat resistance and mechanical strength, and can meet the application requirements in multiple fields.

[0035] (6) The epoxy active diluent of the present invention is significantly superior to other diluents in terms of water resistance and solvent resistance, has excellent corrosion resistance, and has great application potential in the fields of anticorrosive coatings, ships, and marine industries. Description of the Drawings

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 This is the change in the mass of the samples of o-tolyl methyl glycidyl ether (M-691) and o-tolyl glycidyl ether (691) obtained by the method of the present invention after being immersed in different chemical environments at room temperature for 7 days. Specific Embodiments

[0038] Hereinafter, the present invention will be described in detail. Before the description, it should be understood that the terms used in this specification and the appended claims should not be construed as limited to the general meaning and dictionary meaning, but should be interpreted based on the principle that allows the inventor to appropriately define the terms for the best interpretation, according to the meaning and concept corresponding to the technical aspects of the present invention. Therefore, the description presented here is only a preferred example for illustrative purposes and is not intended to limit the scope of the present invention. Thus, it should be understood that other equivalent ways or improved ways can be obtained without departing from the spirit and scope of the present invention.

[0039] The following examples are merely listed as examples of the embodiments of the present invention and do not constitute any limitation to the present invention. Those skilled in the art can understand that modifications within the scope not deviating from the essence and concept of the present invention fall within the protection scope of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available products.

[0040] Hereinafter, the preferred embodiments of the present disclosure will be described in detail with reference to the drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to the general and dictionary meanings, but should be interpreted based on the principle that allows the inventor to appropriately define the terms for the best interpretation, according to the meaning and concept corresponding to the technical aspects of the present invention. Therefore, the description here is only a preferred example for illustrative purposes and is not intended to limit the scope of the present invention. Thus, it should be understood that other equivalent implementations and modifications can be made without departing from the spirit and scope of the present invention.

[0041] In this document, terms such as "comprising", "including", "having", "containing" or any other similar terms are open-ended transitional phrases that are intended to cover non-exclusive inclusions. For example, a composition or article containing plural elements is not limited to only those elements listed herein, but may also include other elements that are not explicitly listed but are ordinarily inherent in the composition or article. In addition, unless explicitly stated to the contrary, the term "or" means an inclusive "or" rather than an exclusive "or". For example, any of the following situations satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), A and B are both true (or exist). Furthermore, in this document, the interpretations of the terms "comprising", "including", "having", "containing" should be regarded as having specifically disclosed and simultaneously covered closed or semi-closed transitional phrases such as "consisting of" and "substantially consisting of".

[0042] In this document, all features or conditions defined in the form of numerical ranges or percentage ranges are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual values within the range, especially integer values. For example, the description of the range "1 to 8" should be regarded as having specifically disclosed all sub-ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., especially the sub-ranges defined by all integer values, and should be regarded as having specifically disclosed individual values such as 1, 2, 3, 4, 5, 6, 7, 8 within the range. Unless otherwise specified, the foregoing interpretation method applies to all contents of the present invention, regardless of the breadth of the range.

[0043] If a quantity or other numerical or parametric value is expressed as a range, a preferred range or a series of upper and lower limits, it should be understood that all ranges formed by any pair of the upper limit or preferred value of the range and the lower limit or preferred value of the range have been specifically disclosed herein, regardless of whether these ranges are separately disclosed or not. In addition, when a numerical range is mentioned in this document, unless otherwise stated, the range should include its endpoints and all integers and fractions within the range.

[0044] In this document, on the premise that the purpose of the invention can be achieved, a numerical value should be understood to have the precision of the significant digits of that numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0045] In addition, unless otherwise specified, the reagents and solvents disclosed below are all commercially available. Methyl epichlorohydrin was purchased from Hubei Jusheng Technology Co., Ltd., o-cresol was purchased from Tianjin Damao Chemical Reagent Factory, toluene was purchased from Sinopharm Chemical Reagent Co., Ltd., boron trifluoride diethyl ether was self-made, benzyltriethylammonium chloride was purchased from Tianjin Damao Chemical Reagent Factory, sodium hydroxide was purchased from Binzhou Chemical Industry Group Co., Ltd., and general epoxy resin (E51) was purchased from Shanghai Aotun Chemical Technology Co., Ltd.

[0046] The epoxy value of the product was measured using an Eco automatic potentiometric titrator from Metrohm Switzerland, the viscosity was measured using a rotary viscometer NDJ-5S from Shanghai Precision, the glass transition temperature and initial decomposition temperature were measured using a comprehensive thermal analyzer 209F1 from Netzsch Instruments Germany, the tensile strength and flexural strength were measured using a universal tensile machine CMT4024-20 kN from Shenzhen Sansi Materials Testing Co., Ltd., and the impact strength was measured using a CEAST 9050 type cantilever beam impact tester from CEAST Italy.

[0047] Example 1

[0048] A synthesis method of an epoxy active diluent o-tolylmethyl glycidyl ether, which comprises the following steps:

[0049] Add 180 g of o-cresol and 532.1 g of methyl epichlorohydrin to a 1 L four-necked flask, add 0.9 g of benzyltriethylammonium chloride, and keep at 75 °C for 3 hours; under reduced pressure of 6-21 kPa and 80-130 °C, distill off methyl epichlorohydrin until no distillate is distilled out; let stand and cool, add 200 g of toluene, adjust the temperature to 60 °C, dropwise add 222 g of 30% sodium hydroxide solution within 1 hour, keep the temperature for reaction for 3 hours, and end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and perform liquid separation treatment, and distill off toluene from the organic phase under reduced pressure to obtain 293.6 g of o-tolylmethyl glycidyl ether as an epoxy active diluent, with a yield of 99.1%, and the epoxy value was detected to be 0.44 eq / 100 g.

[0050] Example 2

[0051] A synthesis method of an epoxy active diluent o-tolylmethyl glycidyl ether, which comprises the following steps:

[0052] Add 180 g of o-cresol and 532.1 g of methyl epichlorohydrin to a 1-L four-necked flask, add 0.9 g of boron trifluoride diethyl etherate, and keep at 75 °C for 3 hours; carry out vacuum distillation to remove methyl epichlorohydrin at 6 - 21 kPa and 80 - 130 °C until no more distillate is distilled out; let stand and cool, add 200 g of toluene, adjust the temperature to 60 °C, dropwise add 222 g of 30% sodium hydroxide solution within 1 hour, keep the temperature for reaction for 3 hours, and end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and carry out liquid separation treatment, and carry out vacuum distillation on the organic phase to remove toluene to obtain 293.6 g of o-tolylmethyl glycidyl ether as an epoxy active diluent, with a yield of 99.1%, and the epoxy value is detected to be 0.46 eq / 100 g.

[0053] Example 3

[0054] A method for synthesizing o-tolylmethyl glycidyl ether as an epoxy active diluent, which comprises the following steps:

[0055] Add 180 g of o-cresol and 532.1 g of methyl epichlorohydrin to a 1-L four-necked flask, add 0.9 g of SnCl4, and keep at 75 °C for 3 hours; carry out vacuum distillation to remove methyl epichlorohydrin at 6 - 21 kPa and 80 - 130 °C until no more distillate is distilled out; let stand and cool, add 200 g of toluene, adjust the temperature to 60 °C, dropwise add 222 g of 30% sodium hydroxide solution within 1 hour, keep the temperature for reaction for 3 hours, and end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and carry out liquid separation treatment, and carry out vacuum distillation on the organic phase to remove toluene to obtain 293.6 g of o-tolylmethyl glycidyl ether as an epoxy active diluent, with a yield of 99.1%, and the epoxy value is detected to be 0.42 eq / 100 g.

[0056] Example 4

[0057] A method for synthesizing o-tolylmethyl glycidyl ether as an epoxy active diluent, which comprises the following steps:

[0058] Add 180 g of o-cresol and 532.1 g of methyl epichlorohydrin to a 1-L four-necked flask, add 0.6 g of boron trifluoride diethyl etherate and 0.4 g of benzyltriethylammonium chloride, and keep at 75 °C for 3 hours; carry out vacuum distillation to remove methyl epichlorohydrin at 6 - 21 kPa and 80 - 130 °C until no more distillate is distilled out; let stand and cool, add 200 g of toluene, adjust the temperature to 60 °C, dropwise add 222 g of 30% sodium hydroxide solution within 1 hour, keep the temperature for reaction for 3 hours, and end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and carry out liquid separation treatment, and carry out vacuum distillation on the organic phase to remove toluene to obtain 293.6 g of o-tolylmethyl glycidyl ether as an epoxy active diluent, with a yield of 99.1%, and the epoxy value is detected to be 0.54 eq / 100 g.

[0059] Example 5

[0060] A synthesis method of o-tolyl methyl glycidyl ether as an epoxy active diluent, which comprises the following steps:

[0061] Add 180 g of o-cresol and 532.1 g of methyl epichlorohydrin into a 1 L four-necked flask, add 0.6 g of boron trifluoride diethyl ether and 0.4 g of benzyltriethylammonium chloride, and keep at 75 °C for 3 hours; under a reduced pressure of 6 - 21 kPa and a temperature of 80 - 130 °C, distill off methyl epichlorohydrin until no distillate comes out; let it stand and cool, add 200 g of toluene, adjust the temperature to 55 °C, dropwise add 222 g of 30% sodium hydroxide solution within 1.5 hours, keep the reaction at this temperature for 3 hours to end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and then carry out liquid separation treatment, and distill off toluene from the organic phase under reduced pressure to obtain 288 g of o-tolyl methyl glycidyl ether as an epoxy active diluent, with a yield of 97.1%, and the epoxy value is detected to be 0.52 eq / 100 g.

[0062] Example 6

[0063] A synthesis method of o-tolyl methyl glycidyl ether as an epoxy active diluent, which comprises the following steps:

[0064] Add 180 g of o-cresol and 532.1 g of methyl epichlorohydrin into a 1 L four-necked flask, add 0.6 g of boron trifluoride diethyl ether and 0.4 g of benzyltriethylammonium chloride, and keep at 75 °C for 3 hours; under a reduced pressure of 6 - 21 kPa and a temperature of 80 - 130 °C, distill off methyl epichlorohydrin until no distillate comes out; let it stand and cool, add 200 g of toluene, adjust the temperature to 50 °C, dropwise add 222 g of 30% sodium hydroxide solution within 1.5 hours, keep the reaction at this temperature for 3 hours to end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and then carry out liquid separation treatment, and distill off toluene from the organic phase under reduced pressure to obtain 285.4 g of o-tolyl methyl glycidyl ether as an epoxy active diluent, with a yield of 96.2%, and the epoxy value is detected to be 0.51 eq / 100 g.

[0065] Example 7

[0066] A synthesis method of o-tolyl methyl glycidyl ether as an epoxy active diluent, which comprises the following steps:

[0067] Add 180 g of o - cresol and 532.1 g of methyl epichlorohydrin into a 1 L four - necked flask. Then add 0.6 g of boron trifluoride diethyl etherate and 0.4 g of benzyltriethylammonium chloride. Keep the mixture at 75 °C for 3 hours. Distill off methyl epichlorohydrin under reduced pressure at 6 - 21 kPa and 80 - 130 °C until no more distillate comes out. Let it stand and cool, then add 200 g of toluene. Adjust the temperature to 60 °C and dropwise add 177.6 g of 30% sodium hydroxide solution within 1.5 hours. Keep the reaction at this temperature for 3 hours to end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and then perform liquid - liquid separation. Distill off toluene from the organic phase under reduced pressure to obtain 272.9 g of o - tolyl methyl glycidyl ether, an epoxy active diluent, with a yield of 92%. The epoxy value is detected to be 0.49 eq / 100 g.

[0068] Example 8

[0069] A method for synthesizing o - tolyl methyl glycidyl ether, an epoxy active diluent, which comprises the following steps:

[0070] Add 180 g of o - cresol and 532.1 g of methyl epichlorohydrin into a 1 L four - necked flask. Then add 0.6 g of boron trifluoride diethyl etherate and 0.4 g of benzyltriethylammonium chloride. Keep the mixture at 75 °C for 3 hours. Distill off methyl epichlorohydrin under reduced pressure at 6 - 21 kPa and 80 - 130 °C until no more distillate comes out. Let it stand and cool, then add 200 g of toluene. Adjust the temperature to 60 °C and dropwise add 244 g of 30% sodium hydroxide solution within 1.5 hours. Keep the reaction at this temperature for 3 hours to end the reaction. After standing and cooling, separate the inorganic phase, wash with water until neutral and then perform liquid - liquid separation. Distill off toluene from the organic phase under reduced pressure to obtain 289.2 g of o - tolyl methyl glycidyl ether, an epoxy active diluent, with a yield of 97.5%. The epoxy value is detected to be 0.52 eq / 100 g.

[0071] Respectively incorporate the diluent o - tolyl methyl glycidyl ether (M - 691), o - cresol glycidyl ether (691), and the conventional diluent butyl glycidyl ether (501) into the general - purpose epoxy resin (E - 51), and conduct comparative experiments on the relevant properties with pure general - purpose epoxy resin.

[0072] Application Example 1: Prepare an epoxy diluent o - tolyl methyl glycidyl ether obtained in Example 4 and the general - purpose epoxy resin (E - 51) according to a mass ratio of 1:9, and mix with an amine - type curing agent. Use the casting method to conduct high - temperature curing in a mold to obtain a cured resin sample bar.

[0073] Application Comparative Example 1: Prepare o - tolyl glycidyl ether and the general - purpose epoxy resin (E - 51) according to a mass ratio of 1:9, and mix with an amine - type curing agent. Use the casting method to conduct high - temperature curing in a mold to obtain a cured resin sample bar.

[0074] Application Comparative Example 2: Butyl glycidyl ether and general epoxy resin (E-51) were formulated at a mass ratio of 1:9, combined with an amine curing agent, and cured at high temperature in a mold by the casting method to obtain a cured resin spline.

[0075] Application Comparative Example 3: Pure general epoxy resin (E-51) was combined with an amine curing agent, and cured at high temperature in a mold by the casting method to obtain a cured resin spline. The test performances of Application Example 1 and Application Comparative Examples 1, 2, and 3 are shown in Table 1. Among them, the test method for tensile strength is GB_T 1040.2-2022 Determination of Tensile Properties of Plastics; the test method for flexural strength is GB_T9341-2008 Determination of Flexural Properties of Plastics; the test method for impact strength is GB_T 1843-2008 Determination of Izod Impact Strength of Plastics.

[0076] Table 1. Test data of Application Example 1 and Application Comparative Examples 1, 2, and 3

[0077] Application Example 1 Application Comparative Example 1 Application Comparative Example 2 Application Comparative Example 3 Viscosity (mPa.s @ 25°C) 882 880 860 12400 Gel time (min) 155 141 144 105 <![CDATA[Glass transition temperature T g (°C)]]> 191 185 151 196 <![CDATA[Initial decomposition temperature T d5 (°C)]]> 371 368 354 376 Tensile strength (MPa) 73.2 71.4 64.0 69.5 Flexural strength (MPa) 126 123 113 120 <![CDATA[Impact strength (kJ / m 2 )]]> 40 34 31 26.4

[0078] From the data in Table 1, the diluent o-tolylmethyl glycidyl ether (M-691) synthesized in the present invention can significantly reduce the viscosity of the epoxy system and improve its processing performance, and the viscosity of the epoxy system is reduced by 92.9%. Moreover, the gel time of the cured product doped with M-691 is 155 min, which is 10% longer than the gel time of o-tolyl glycidyl ether (691), significantly improving the processing performance of the epoxy system. In addition, M-691 has less influence on the thermal properties of the cured product. The T g and T d5 of Sample 1 only decreased by 2.6% and 1.3%, respectively, and the heat resistance of M-691 is higher than that of 691. M-691 improves the mechanical properties of the cured product, and the toughening effect of M-691 is significantly better than that of the conventional diluent butyl glycidyl ether. The impact strength of the cured product doped with M-691 is increased by 51.5% compared with the pure epoxy system, which is much higher than the toughening effect of 691 (28.8%).

[0079] Application Example 1 and Application Comparative Example 1 were respectively immersed in various solutions, and their chemical solvent resistance was evaluated by the mass change of each cured product. See Figure 1 .

[0080] From Figure 1It can be seen that the synthesized diluent o-tolyl methyl glycidyl ether (M-691) (sample 1) of the present invention is added to the general epoxy resin, so that the weight loss rate of the cured product in pure water, 1 mol / L NaOH solution, 1 mol / L hydrochloric acid, ethanol, toluene, acetone, and 3.5% NaCl solution is lower than that of the epoxy cured product added with o-tolyl glycidyl ether (691) (sample 2), indicating that M-691 is significantly better than 691 in water resistance and chemical solvent resistance. In water, 1M NaOH solution, 1M hydrochloric acid and 3.5% brine, the weight loss rate of the cured product added with M-691 is reduced by 37.5%, 20.6%, 23.1% and 36.0% respectively compared with that of the cured product added with 691. This is because M-691 has one more methyl group in its structure than 691, which makes M-691 more water-resistant and has good corrosion resistance.

[0081] Application Example 2: The epoxy diluent o-tolyl methyl glycidyl ether prepared in Example 4 and the general epoxy resin (E-51) are prepared in a certain mass ratio, and an amine curing agent is added, and the mixture is evenly sprayed onto a tinplate sheet and cured at high temperature to obtain a sample film.

[0082] Application Comparative Example 4: Butyl glycidyl ether and general epoxy resin (E-51) were prepared in a certain mass ratio, matched with an amine curing agent, sprayed evenly on a tinplate sheet, and cured at high temperature to obtain a sample film.

[0083] The corresponding use case 2 and application comparison example 4 were tested, as shown in Table 2 for details.

[0084] Table 2. Test data of application example 2 and comparative application example 4

[0085] Application Example 2 Application Comparative Example 4 Mass ratio of diluent / % 15 15 System viscosity / mPa·s @ 25°C 500 490 Film hardness 4～5H 3H Number of times the film resists MEK wiping / times 145 80 Number of times the film resists THF wiping / times 120 68

[0086] The hand-drawing method is used to test the paint film hardness of epoxy cured products. Chinese pencils are used. The pencil hardness levels from low to high are 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, and 9H.

[0087] The hardness of the cured product of the o-cresyl methyl glycidyl ether added to the general epoxy resin at 15% is better than that of o-cresyl glycidyl ether. In addition, the number of times that o-cresyl methyl glycidyl ether can withstand rubbing with butanone is 1.81 times that of o-cresyl glycidyl ether. It has better solvent resistance and is Figure 1 The conclusions verify each other.

[0088] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for preparing o-cresyl methyl glycidyl ether, as shown in formula I, characterized in that: The following steps are involved: (1) Prepare raw materials: o-cresol, methyl epichlorohydrin, catalyst, and alkali solution; (2) Ring-opening reaction: add o-cresol and methyl epichlorohydrin in proportion, stir evenly, add catalyst, maintain at 50-100°C for a period of time; (3) Recovering methyl epichlorohydrin: removing methyl epichlorohydrin by vacuum distillation and recovering it until no fraction is distilled out and the vacuum distillation is terminated. (4) Ring-closing reaction: lower the temperature of the reaction system and add a solvent. Under stirring, adjust the temperature to 40-80°C, add alkali solution dropwise, and continue to keep the temperature for a period of time after the addition of alkali solution is completed; (5) After the reaction is completed, the mixture is allowed to stand and cool, the inorganic phase is separated and the salt base is removed, and then pure water is added to wash until neutral, and then the organic phase is obtained by liquid separation, and the solvent in the organic phase is removed to finally obtain the epoxy active diluent o-tolyl methyl glycidyl ether.

2. A method for synthesizing o-cresyl methyl glycidyl ether according to claim 1, characterized in that: In step (2), the molar ratio of methyl epichlorohydrin to o-cresol is 2 to 5:1; the amount of the catalyst is 0.3% to 4% of the total mass of o-cresol; particularly preferably, the molar ratio of methyl epichlorohydrin to o-cresol is 3 to 4:

1.

3. A method for synthesizing o-cresyl methyl glycidyl ether according to claim 1, characterized in that: In step (2), the catalyst is one or more of a Lewis acid catalyst, boron trifluoride ethyl ether and a quaternary ammonium salt; preferably, the catalyst is boron trifluoride ethyl ether or a mixed catalyst of boron trifluoride ethyl ether and its quaternary ammonium salt.

4. A method for synthesizing o-cresyl methyl glycidyl ether according to claim 1, characterized in that: In step (2), the reaction temperature is maintained at 70-85°C for 3 hours.

5. A method for synthesizing o-cresyl methyl glycidyl ether according to claim 1, characterized in that: In step (3), methyl epichlorohydrin is removed under reduced pressure at 6 to 21 kPa and 80 to 130°C.

6. A method for synthesizing o-cresyl methyl glycidyl ether according to claim 1, characterized in that: In step (4), the solvent is at least one of benzene, toluene and xylene; the alkali solution is a sodium hydroxide solution with a mass concentration of 20% to 50%; the molar ratio of sodium hydroxide to o-cresol is 0.8 to 1.1:1; preferably, the concentration of the alkali solution is a 30% sodium hydroxide solution, and the molar ratio of sodium hydroxide to o-cresol is 1:

1.

7. A method for synthesizing o-cresyl methyl glycidyl ether according to claim 1, characterized in that: In step (4), alkaline solution is added dropwise at 45-65° C. for 1-1.5 hours. After completion, the reaction is kept warm for 3 hours.

8. A method for synthesizing o-cresyl methyl glycidyl ether according to claim 1, characterized in that: In step (5), the laboratory separation is carried out using a separatory funnel, and the excess solvent in the organic phase is removed by vacuuming and using a rotary evaporator. Toluene is recovered by vacuum distillation and reused.

9. o-Cresyl methyl glycidyl ether obtainable according to any one of claims 1 to 8.

10. Use of o-tolyl methyl glycidyl ether obtained according to any one of claims 1 to 8 in the fields of anti-corrosion coatings, ships and marine industries.

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