Synthesis method of 1, 4-butanediol diglycidyl ether

Abstract

The invention relates to a synthetic method of 1, 4-butanediol diglycidyl ether, 1, 4-butanediol and epichlorohydrin are synthesized in one step under the action of a phase transfer catalyst, in the one-step process, once 1, 4-butanediol and epichlorohydrin are subjected to ring-opening reaction to produce a chlorohydrin ether intermediate, the chlorohydrin ether intermediate is subjected to ring-opening reaction, and the chlorohydrin ether intermediate is subjected to ring-opening reaction to produce the 1, 4-butanediol diglycidyl ether. The intermediate can be subjected to ring-closure production immediately under the action of solid alkali to produce an epoxy group, the obtained 1, 4-butanediol diglycidyl ether is relatively low in easily saponifiable chlorine content, and the target product is relatively high in purity. After the reaction is finished, sodium chloride generated by the reaction and unreacted solid caustic soda can be removed through direct suction filtration to obtain a neutral system, washing is not needed, no waste liquid is generated, operation is easy, and the method is suitable for clean industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a method for synthesizing 1,4-butanediol diglycidyl ether. Background Art

[0002] 1,4-butanediol diglycidyl ether is an organic compound, usually used as a diluent or crosslinking agent for epoxy resins. Due to its structure containing both short-chain aliphatic hydrocarbons and bis-epoxy groups, it is often used in the manufacture of epoxy resins for processing wind turbine blades. However, due to the complex traditional production process, harsh synthesis conditions, unstable product quality and low yield, the 1,4-butanediol diglycidyl ether produced in China at present is difficult to meet the needs of the wind power industry.

[0003] 1,4-butanediol diglycidyl ether is mainly manufactured by a two-step method, that is, using 1,4-butanediol and epichlorohydrin as reactant raw materials, and stannic chloride or boron trifluoride as a catalyst to obtain 1,4-butanediol chlorohydrin ether, and then ring-closing with sodium hydroxide to obtain the product 1,4-butanediol diglycidyl ether. For example, CN113979971A discloses a preparation method of 1,4-butanediol diglycidyl ether. In the etherification reaction stage of 1,4-butanediol and epichlorohydrin, a highly efficient Lewis acid catalyst is used, and then by adding a catalyst in the main reaction, an aqueous alkali solution is added dropwise in segments and dehydrated by negative pressure closed-loop reflux in stages to prepare a 1,4-butanediol diglycidyl ether product. However, this production process is complex and cumbersome to operate, and there is a large amount of waste liquid in the post-treatment reaction; in addition, the catalysts stannic chloride and boron trifluoride have strict requirements for the moisture of raw materials and the reaction kettle; at the same time, the price of stannic chloride and boron trifluoride ether solution is expensive, and the generated reaction wastewater is difficult to treat, which not only increases the production cost, but also causes environmental pollution.

[0004] Easily saponifiable chlorine is an important characteristic index of epoxy diluents. Excessive easily saponifiable chlorine will slow down the curing reaction, and at the same time, the gradually released chloride ions will corrode the cured product and affect its insulation. Therefore, epoxy diluents with low easily saponifiable chlorine are more and more favored. The preparation process of most epoxy diluents uses alcohol as a raw material, and under the action of Lewis acid, it first opens the ring with epichlorohydrin, and then closes the ring with an alkali to obtain. The ring-opening product is a chlorohydrin ether compound. If the ring-closing is incomplete, there will be more ring-opening products remaining in the product, which will lead to a high easily saponifiable chlorine. In order to avoid the polymerization of epoxy groups, the ring-closing generally uses a lower reaction temperature, so the easily saponifiable chlorine of the product is also relatively high.

[0005] CN106995421A discloses a production method of 1,4-butanediol diglycidyl ether with low hydrolyzable chlorine, and the specific steps are as follows: ring-opening reaction, ring-closing reaction, draining brine and washing with water. The upper oil phase is obtained as 1,4-butanediol diglycidyl ether after rectification, and the low-hydrolyzable-chlorine 1,4-butanediol diglycidyl ether finished product is obtained by removing the solvent and dehydrating. In this invention, a method of first low temperature and then high temperature is used for the ring-closing reaction to prepare 1,4-butanediol diglycidyl ether, but the hydrolyzable chlorine is still relatively high.

[0006] Although the existing two-step synthesis method of 1,4-butanediol diglycidyl ether has a high yield, it produces a large amount of wastewater. Therefore, there is an urgent need to develop a green and environmentally friendly preparation method of 1,4-butanediol diglycidyl ether with less wastewater generation, mild conditions, simple operation and suitable for industrial production. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a synthesis method of 1,4-butanediol diglycidyl ether, which has less wastewater generation, mild conditions, simple operation in the production process, and the obtained product has high purity and low easily saponifiable chlorine, and is suitable for industrial production.

[0008] To achieve the purpose of this invention, the following technical solutions are adopted:

[0009] The present invention provides a synthesis method of 1,4-butanediol diglycidyl ether, and the synthesis method includes the following steps:

[0010] Mix 1,4-butanediol, epichlorohydrin and a phase transfer catalyst evenly, then add solid caustic soda in batches and react, controlling the temperature of adding solid caustic soda and the reaction process to be 30 - 40 °C respectively; filter the obtained reaction solution to obtain a filtrate; the obtained filtrate is subjected to vacuum distillation to obtain the 1,4-butanediol diglycidyl ether.

[0011] The synthesis method of 1,4-butanediol diglycidyl ether provided by the present invention synthesizes 1,4-butanediol diglycidyl ether in one step through 1,4-butanediol and epichlorohydrin under the action of a phase transfer catalyst. In this one-step process, once 1,4-butanediol and epichlorohydrin undergo a ring-opening reaction to produce a chlorohydrin ether intermediate, this intermediate will immediately form an epoxy group under the action of solid caustic soda. This makes the easily saponifiable chlorine of the 1,4-butanediol diglycidyl ether obtained by the one-step method very low, and the purity of the target product is relatively high. After the reaction, directly filtering can remove the sodium chloride generated by the reaction and the unreacted solid caustic soda to obtain a neutral system, without the need for washing with water, so there is no waste liquid generation, the operation is simple, and it is suitable for clean industrial production.

[0012] The temperature for controlling the addition of solid base and the reaction process is 30-40°C respectively. For example, it can be 30°C, 32°C, 35°C, 38°C or 40°C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 30-35°C, and more preferably 35°C.

[0013] Preferably, the molar ratio of 1,4-butanediol to epichlorohydrin is 1:(2-10). For example, it can be 1:2, 1:3, 1:5, 1:6 or 1:7, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 1:(3-7), and more preferably 1:6.

[0014] Preferably, the phase transfer catalyst includes any one of tetrabutylammonium bromide, benzyltriethylammonium chloride, 18-crown-6, cetyltrimethylammonium bromide or polyethylene glycol dimethyl ether. Preferably, it is benzyltriethylammonium chloride or 18-crown-6, and more preferably benzyltriethylammonium chloride.

[0015] Preferably, the molar percentage of the phase transfer catalyst is 0.3-2 mol% of 1,4-butanediol. For example, it can be 0.3 mol%, 0.5 mol%, 1 mol%, 1.5 mol% or 2 mol%, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 0.3-1 mol%, and more preferably 0.5 mol%.

[0016] Preferably, the solid base includes any one of sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium methoxide, potassium methoxide, sodium ethoxide or potassium ethoxide. Preferably, it is sodium hydroxide or potassium hydroxide, and more preferably sodium hydroxide.

[0017] Preferably, the molar ratio of the solid base to 1,4-butanediol is (2-5):1. For example, it can be 2:1, 2.5:1, 3:1, 4:1 or 5:1, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is (2-3):1, and more preferably 2.5:1.

[0018] Preferably, the time interval between adjacent batches of adding the solid base is 0.5-1.5 h. For example, it can be 0.5 h, 0.8 h, 1 h, 1.2 h or 1.5 h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 0.5-1 h.

[0019] Preferably, samples are taken every 1 h during the reaction until the reaction is stopped when the content of 1,4-butanediol diglycidyl ether in the system no longer increases.

[0020] Preferably, toluene is added to the reaction solution and mixed evenly before filtration.

[0021] Preferably, the number of suction filtration times is 2 - 3 times, for example, it can be 2 times or 3 times.

[0022] Preferably, the suction filtration is carried out in a Buchner funnel.

[0023] Preferably, the filter cake obtained by suction filtration is washed with toluene, and the obtained washing liquid is combined with the filtrate to make the solution system neutral.

[0024] The step of vacuum distillation can remove epichlorohydrin and toluene.

[0025] As a preferred technical solution of the synthesis method of the present invention, the synthesis method includes the following steps:

[0026] Mix 1,4 - butanediol, epichlorohydrin and a phase transfer catalyst evenly; the molar ratio of 1,4 - butanediol to epichlorohydrin is 1:(2 - 10), and the molar percentage of the phase transfer catalyst is 0.3 - 2 mol% of 1,4 - butanediol; then add solid caustic soda in batches and carry out the reaction. The molar ratio of the solid caustic soda to 1,4 - butanediol is (2 - 5):1; the time interval between adjacent batches is 0.5 - 1.5 h, and the temperatures for adding solid caustic soda and during the reaction are controlled at 30 - 40 °C respectively; in the reaction, samples are taken every 1 h until the content of 1,4 - butanediol diglycidyl ether in the system no longer increases, then stop the reaction; add toluene to the obtained reaction solution and mix evenly, then carry out suction filtration 2 - 3 times to obtain a filtrate and a filter cake, wash the filter cake with toluene, combine the obtained washing liquid with the filtrate to make the solution system neutral, and then obtain the 1,4 - butanediol diglycidyl ether through vacuum distillation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The synthesis method of 1,4 - butanediol diglycidyl ether provided by the present invention synthesizes 1,4 - butanediol diglycidyl ether in one step through 1,4 - butanediol and epichlorohydrin under the action of a phase transfer catalyst. In this one - step process, once the ring - opening reaction between 1,4 - butanediol and epichlorohydrin occurs to produce a chlorohydrin ether intermediate, this intermediate will immediately form a closed - loop to produce an epoxy group under the action of solid caustic soda. This makes the 1,4 - butanediol diglycidyl ether obtained by the one - step method have a lower saponification chlorine content, and the purity of the target product can reach 88%. After the reaction, directly carrying out suction filtration can remove the sodium chloride generated by the reaction and the unreacted solid caustic soda to obtain a neutral system, without the need for water washing, thus no waste liquid is generated. The operation is simple and suitable for clean industrial production. Specific Embodiments

[0029] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0030] Example 1

[0031] This example provides a method for synthesizing 1,4-butanediol diglycidyl ether. The synthesis method includes the following steps:

[0032] Mix 1,4-butanediol, epichlorohydrin, and benzyltriethylammonium chloride evenly; the molar ratio of 1,4-butanediol to epichlorohydrin is 1:6, and the molar percentage of benzyltriethylammonium chloride is 0.5 mol% of 1,4-butanediol; then add sodium hydroxide in batches and react. The molar ratio of sodium hydroxide to 1,4-butanediol is 2.5:1; the time interval between adjacent batches is 0.5 h, control the temperature of adding sodium hydroxide to 30 °C, and the temperature during the reaction process is 35 °C; sample every 1 h during the reaction until the content of 1,4-butanediol diglycidyl ether in the system no longer increases and then stop the reaction; add toluene to the obtained reaction solution and mix evenly, then filter twice with a Buchner funnel to obtain a filtrate and a filter cake, wash the filter cake with toluene, combine the obtained washing solution with the filtrate to make the solution system neutral, and then perform vacuum distillation to obtain the 1,4-butanediol diglycidyl ether.

[0033] The purity of the obtained 1,4-butanediol diglycidyl ether is 88%, the epoxy equivalent is 122 g / mol, the easily saponifiable chlorine is 508 ppm, and the Hazen color number is 15.

[0034] Example 2

[0035] This example provides a method for synthesizing 1,4-butanediol diglycidyl ether. The synthesis method includes the following steps:

[0036] Mix 1,4 - butanediol, epichlorohydrin, and benzyltriethylammonium chloride evenly; the molar ratio of 1,4 - butanediol to epichlorohydrin is 1:3, and the molar percentage of benzyltriethylammonium chloride is 0.3 mol% of 1,4 - butanediol; then add sodium hydroxide in batches and react, the molar ratio of sodium hydroxide to 1,4 - butanediol is 2:1; the time interval between adjacent batches is 0.8 h, control the temperature of adding sodium hydroxide to 32 °C, and the temperature during the reaction process is 32 °C; sample every 1 h during the reaction until the content of 1,4 - butanediol diglycidyl ether in the system no longer increases and then stop the reaction; add toluene to the obtained reaction solution and mix evenly, then filter twice with a Buchner funnel to obtain a filtrate and a filter cake, wash the filter cake with toluene, combine the obtained washing solution with the filtrate to make the solution system neutral, and then perform vacuum distillation to obtain the 1,4 - butanediol diglycidyl ether.

[0037] The purity of the obtained 1,4 - butanediol diglycidyl ether is 85%, the epoxy equivalent is 124 g / mol, the easily saponifiable chlorine is 942 ppm, and the Hazen color number is 20.

[0038] Example 3

[0039] This example provides a method for synthesizing 1,4 - butanediol diglycidyl ether, and the synthesis method includes the following steps:

[0040] Mix 1,4 - butanediol, epichlorohydrin, and 18 - crown - 6 evenly; the molar ratio of 1,4 - butanediol to epichlorohydrin is 1:2, and the molar percentage of 18 - crown - 6 is 1 mol% of 1,4 - butanediol; then add potassium hydroxide in batches and react, the molar ratio of potassium hydroxide to 1,4 - butanediol is 3:1; the time interval between adjacent batches is 1 h, control the temperature of adding potassium hydroxide to 30 °C, and the temperature during the reaction process is 30 °C; sample every 1 h during the reaction until the content of 1,4 - butanediol diglycidyl ether in the system no longer increases and then stop the reaction; add toluene to the obtained reaction solution and mix evenly, then filter three times with a Buchner funnel to obtain a filtrate and a filter cake, wash the filter cake with toluene, combine the obtained washing solution with the filtrate to make the solution system neutral, and then perform vacuum distillation to obtain the 1,4 - butanediol diglycidyl ether.

[0041] The purity of the obtained 1,4 - butanediol diglycidyl ether is 83%, the epoxy equivalent is 126 g / mol, the easily saponifiable chlorine is 1527 ppm, and the Hazen color number is 20.

[0042] Example 4

[0043] This example provides a method for synthesizing 1,4 - butanediol diglycidyl ether, and the synthesis method includes the following steps:

[0044] Mix 1,4 - butanediol, epichlorohydrin, and tetrabutylammonium bromide evenly; the molar ratio of 1,4 - butanediol to epichlorohydrin is 1:10, and the molar percentage of tetrabutylammonium bromide is 2 mol% of 1,4 - butanediol; then add calcium hydroxide in batches and carry out the reaction. The molar ratio of calcium hydroxide to 1,4 - butanediol is 5:1; the time interval between adjacent batches is 1.5 h, control the temperature of adding calcium hydroxide to 30 °C, and the temperature during the reaction process is 40 °C; sample every 1 h during the reaction until the content of 1,4 - butanediol diglycidyl ether in the system no longer increases, then stop the reaction; add toluene to the obtained reaction solution and mix evenly, then filter twice with a Buchner funnel to obtain a filtrate and a filter cake. Wash the filter cake with toluene, combine the obtained washing liquid with the filtrate to make the solution system neutral, and then carry out vacuum distillation to obtain the 1,4 - butanediol diglycidyl ether.

[0045] The purity of the obtained 1,4 - butanediol diglycidyl ether is 81%, the epoxy equivalent is 120 g / mol, the easily saponifiable chlorine is 1123 ppm, and the Hazen color number is 20.

[0046] Example 5

[0047] This example provides a method for synthesizing 1,4 - butanediol diglycidyl ether. The difference from Example 1 is that the molar percentage of benzyltriethylammonium chloride is adjusted to 0.1 mol% of 1,4 - butanediol, and the rest are the same as in Example 1.

[0048] In this example, due to the too low dosage of the phase - transfer catalyst, the reaction rate is slow. The purity of the obtained 1,4 - butanediol diglycidyl ether is 81%, the epoxy equivalent is 123 g / mol, the easily saponifiable chlorine is 1245 ppm, and the Hazen color number is 20.

[0049] Example 6

[0050] This example provides a method for synthesizing 1,4 - butanediol diglycidyl ether. The difference from Example 1 is that the molar percentage of benzyltriethylammonium chloride is adjusted to 2.3 mol% of 1,4 - butanediol, and the rest are the same as in Example 1.

[0051] In this example, due to the too high dosage of the phase - transfer catalyst, the side - reaction rate increases. The purity of the obtained 1,4 - butanediol diglycidyl ether is 80%, the epoxy equivalent is 134 g / mol, the easily saponifiable chlorine is 1056 ppm, and the Hazen color number is 20.

[0052] Example 7

[0053] This example provides a method for synthesizing 1,4-butanediol diglycidyl ether. The difference from Example 1 is that the molar ratio of sodium hydroxide to 1,4-butanediol is adjusted to 1:1, and the rest are the same as in Example 1.

[0054] In this example, due to the too low dosage of solid alkali, the reaction degree is low, the reaction rate is slow, the purity of the obtained 1,4-butanediol diglycidyl ether is 63%, the epoxy equivalent is 148 g / mol, the easily saponifiable chlorine is 3141 ppm, and the Hazen color number is 20.

[0055] Example 8

[0056] This example provides a method for synthesizing 1,4-butanediol diglycidyl ether. The difference from Example 1 is that the molar ratio of sodium hydroxide to 1,4-butanediol is adjusted to 6:1, and the rest are the same as in Example 1.

[0057] In this example, due to the too high dosage of solid alkali, side reactions increase, a large amount of flocculants are produced, and the system becomes very viscous, making stirring difficult. The purity of the obtained 1,4-butanediol diglycidyl ether is 57%, the epoxy equivalent is 152 g / mol, the easily saponifiable chlorine is 4326 ppm, and the Hazen color number is 50.

[0058] Comparative Example 1

[0059] This comparative example provides a method for synthesizing 1,4-butanediol diglycidyl ether. The difference from Example 1 is that an equimolar amount of sodium hydroxide is added at one time for reaction, and the rest are the same as in Example 1.

[0060] In this comparative example, adding sodium hydroxide at one time results in too fast a reaction rate to control the temperature, a large amount of flocculants are produced, the purity of the obtained 1,4-butanediol diglycidyl ether is 49%, the epoxy equivalent is 144 g / mol, the easily saponifiable chlorine is 5213 ppm, and the Hazen color number is 55.

[0061] Comparative Example 2

[0062] This comparative example provides a method for synthesizing 1,4-butanediol diglycidyl ether. Using 1,4-butanediol and epichlorohydrin with a molar ratio of 1:6 as reactant raw materials, boron trifluoride with a molar percentage of 0.5 mol% of 1,4-butanediol as a catalyst, reacting to obtain 1,4-butanediol chloropropanol ether, and then subjecting it to ring closure with sodium hydroxide, controlling the molar ratio of sodium hydroxide to 1,4-butanediol to 2.5:1 to obtain 1,4-butanediol diglycidyl ether.

[0063] In this comparative example, 1,4-butanediol diglycidyl ether was prepared by a two-step method, using boron trifluoride as a catalyst. The purity of the obtained 1,4-butanediol diglycidyl ether was 59%, the epoxy equivalent was 127 g / mol, the easily saponifiable chlorine was 2356 ppm, and the Hazen color number was 15. However, the synthesis method provided in this comparative example has the problems of relatively cumbersome process and the need to treat waste liquid.

[0064] In summary, the synthesis method of 1,4-butanediol diglycidyl ether provided by the present invention synthesizes 1,4-butanediol diglycidyl ether in one step through 1,4-butanediol and epichlorohydrin under the action of a phase transfer catalyst. In this one-step process, once the ring-opening reaction between 1,4-butanediol and epichlorohydrin occurs to produce a chlorohydrin ether intermediate, this intermediate will immediately form a closed loop to produce epoxy groups under the action of solid caustic soda. This makes the easily saponifiable chlorine of the 1,4-butanediol diglycidyl ether obtained by the one-step method relatively low, and the purity of the target product can reach 88%. After the reaction is completed, sodium chloride generated by the reaction and unreacted solid caustic soda can be directly removed by suction filtration to obtain a neutral system, without the need for water washing, thus no waste liquid is generated. The operation is simple and suitable for clean industrial production.

[0065] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for synthesizing 1,4-butanediol diglycidyl ether, characterized in that, The synthesis method comprises the following steps: Mix 1,4-butanediol, epichlorohydrin and a phase transfer catalyst uniformly, then add solid base in batches and carry out the reaction, controlling the temperature of adding the solid base and the reaction process to be 30-40 °C respectively; carry out suction filtration on the obtained reaction solution to obtain a filtrate; subject the obtained filtrate to vacuum distillation to obtain the 1,4-butanediol diglycidyl ether.

2. The synthesis method of 1,4-butanediol diglycidyl ether according to claim 1, wherein The molar ratio of 1,4-butanediol to epichlorohydrin is 1:(2-10), preferably 1:(3-7).

3. The synthesis method of 1,4-butanediol diglycidyl ether according to claim 1 or 2, characterized in that, The phase transfer catalyst includes any one of tetrabutylammonium bromide, benzyltriethylammonium chloride, 18-crown-6, cetyltrimethylammonium bromide or polyethylene glycol dimethyl ether, preferably benzyltriethylammonium chloride or 18-crown-6; Preferably, the molar percentage of the phase transfer catalyst is 0.3-2 mol% of 1,4-butanediol, preferably 0.3-1 mol%.

4. The synthesis method of 1,4-butanediol diglycidyl ether according to any one of claims 1-3, characterized in that, The solid base includes any one of sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium methoxide, potassium methoxide, sodium ethoxide or potassium ethoxide, preferably sodium hydroxide or potassium hydroxide; Preferably, the molar ratio of the solid base to 1,4-butanediol is (2-5):1, preferably (2-3):

1.

5. The synthesis method of 1,4-butanediol diglycidyl ether according to any one of claims 1-4, characterized in that, The time interval between adjacent batches of adding the solid base is 0.5-1.5 h, preferably 0.5-1 h.

6. The synthesis method of 1,4-butanediol diglycidyl ether according to any one of claims 1-5, characterized in that, Control the temperature of adding the solid base and the reaction process to be 30-35 °C respectively.

7. The synthesis method of 1,4-butanediol diglycidyl ether according to any one of claims 1-6, characterized in that, During the reaction, samples are taken every 1 h until the content of 1,4-butanediol diglycidyl ether in the system no longer increases, and then the reaction is stopped.

8. The synthesis method of 1,4-butanediol diglycidyl ether according to any one of claims 1-7, characterized in that, Before the suction filtration, add toluene to the reaction solution and mix uniformly; Preferably, the number of times of suction filtration is 2-3 times.

9. The synthesis method of 1,4-butanediol diglycidyl ether according to any one of claims 1-8, characterized in that, The filter cake obtained by suction filtration is washed with toluene, and the obtained washing liquid is combined with the filtrate to make the solution system neutral.

10. The synthesis method of 1,4-butanediol diglycidyl ether according to claim 1, characterized in that, The synthesis method comprises the following steps: Mix 1,4-butanediol, epichlorohydrin and a phase transfer catalyst uniformly; the molar ratio of 1,4-butanediol to epichlorohydrin is 1:(2-10), and the molar percentage of the phase transfer catalyst is 0.3-2 mol% of 1,4-butanediol; then add solid base in batches and carry out the reaction, the molar ratio of the solid base to 1,4-butanediol is (2-5):1; the time interval between adjacent batches is 0.5-1.5 h, control the temperature of adding the solid base and the reaction process to be 30-40 °C respectively; during the reaction, samples are taken every 1 h until the content of 1,4-butanediol diglycidyl ether in the system no longer increases, and then the reaction is stopped; add toluene to the obtained reaction solution and mix uniformly, then carry out suction filtration 2-3 times to obtain a filtrate and a filter cake, wash the filter cake with toluene, combine the obtained washing liquid with the filtrate to make the solution system neutral, and then carry out vacuum distillation to obtain the 1,4-butanediol diglycidyl ether.