Synthesis method of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane

Abstract

The present invention relates to a preparation method of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane, which is characterized by comprising the following steps: S1: adding a solvent to bis-trimethylolpropane in a preparation kettle for dissolution; S2: filling a fixed bed with a strongly acidic catalyst; S3: heating and pressurizing the solution obtained in step S1, passing it through the fixed bed, and then depressurizing and removing it in a loop reactor: removing the solvent to obtain the product; The present invention can improve the yield and continuously produce the diluent, without using expensive raw materials, with low cost and simple process, and can improve the product yield.

Description

Technical Field

[0001] The present invention relates to the technical field of photocurable materials, and particularly to a synthesis method of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane. Background Art

[0002] At present, oxetane monomers used in the market as reactive diluents have advantages such as high bonding strength, low odor, low toxicity, and small shrinkage rate. Moreover, these monomers have strong alkalinity, so they are more likely to undergo cationic polymerization. The production processes of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane in the market mainly adopt a two-step method, that is, first reacting ditrimethylolpropane with dimethyl carbonate, diethyl carbonate, etc. to obtain two lactone rings, and then obtaining 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane through a decarboxylation reaction. The existing processes have disadvantages such as complex operation, low conversion rate, and many by-products in the continuous production process. Therefore, a new preparation method for producing 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane is needed, which has the advantages of simple operation, few by-products, and high yield. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a synthesis method of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane; it can solve the technical problems of low yield, the need to use expensive raw materials, high cost, and complex process existing in the preparation methods of reactive diluents in the prior art.

[0004] To solve the above technical problem, the technical solution of the present invention is as follows: 1. A synthesis method of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane, where 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane is a photocurable reactive diluent; the specific structural formula is:

[0005] ,

[0006] It is characterized in that the specific synthesis method is as follows:

[0007] S1: Dissolve ditrimethylolpropane in a solvent to obtain a corresponding solution;

[0008] S2: Fill a strong acidic cation exchange resin into a fixed bed;

[0009] S3: Heat the ditrimethylolpropane solution obtained in S1 to 120 - 180 °C, and pass it through the fixed bed layer by a pressure pump, and the bed layer pressure is 2 MPa - 3 MPa;

[0010] S4: Enter the loop reactor after passing through the fixed bed. After spraying materials from the nozzle, reduce the pressure to 0.5 - 0.9 MPa, and distill out the water vapor. The liquid-phase material continues to circulate for reaction;

[0011] S5: Take samples at the discharging port at the bottom of the fixed bed for gas chromatography analysis. If the bis-trimethylolpropane is completely converted, stop the reaction and discharge the solution of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane;

[0012] S6: Use a rectification device to carry out desolvation and rectification on the solution of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane obtained in S5 to obtain the product of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane.

[0013] Furthermore, in S1, the mass ratio of the bis-trimethylolpropane to the solvent is 1:50 - 1:25.

[0014] Furthermore, the ratio of the bis(trimethylol)propane to the strongly acidic cation exchange resin is 1:0.05 - 1:0.1.

[0015] Furthermore, in S1, the solvent used is: toluene.

[0016] Furthermore, in S4, the loop reactor is a series reactor of a packed fixed bed reactor and a loop reactor.

[0017] The advantages of the present invention are as follows:

[0018] 1) The present invention greatly improves the yield of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane, and the preparation process is simple, with few by-products. Expensive raw materials are not required during the reaction process, saving costs; it can achieve high-efficiency and continuous preparation of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane. Description of the Drawings

[0019] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0020] Figures 1 to 4 It is the infrared analysis spectrum of a kind of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane of the present invention.

[0021] Figure 5 It is the reactor structure diagram of a kind of 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane of the present invention. Specific Embodiments

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will, in conjunction with the accompanying drawings in the embodiments of the present invention, clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0024] The specific synthesis process related to the present invention is as follows. 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane is made by a method including the following steps: Example 1:

[0025] Put 1 Kg of ditrimethylolpropane and 50 Kg of toluene into the batching kettle and open the steam for heating. When it reaches about 60 °C, dissolve to obtain a toluene solution of ditrimethylolpropane. Then fill 50 g of strongly acidic cation exchange resin catalyst into the fixed-bed reactor; open the steam to raise the temperature of the ditrimethylolpropane toluene solution in the batching kettle to 120 - 180 °C, and pass it through the fixed-bed layer by a pressure pump, and adjust the nitrogen pressure at the top of the tower to maintain the bed pressure at 2 MPa - 3 MPa; after the reaction liquid passes through the fixed-bed, it enters the jet reactor. After spraying the material at the nozzle, the pressure drops to 0.5 - 0.9 MPa. The water vapor and part of the solvent are evaporated through the upper gas outlet and separated in the oil-water separator. Water is discharged from the lower discharge port, and the solvent is recycled. The liquid-phase material continues to circulate and react through the pressure pump. Take a sample at the discharge port at the bottom of the fixed-bed for gas chromatography analysis. If bis(trimethylolpropane) is completely converted, stop the reaction and discharge the 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane solution. Use the distillation device to desolventize and rectify and purify the obtained 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane toluene solution to obtain the 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane product. The yield is 98%, and the purity is 99.2%. Infrared analysis and mass spectra are shown in Appendix Figure 1 , 2. Example 2:

[0026]

[0027] Put 1 Kg of bis(trimethylolpropane) and 50 Kg of toluene into the batching kettle, and turn on the steam for heating. When the temperature reaches about 60 °C, dissolve them to obtain a bis(trimethylolpropane) toluene solution. Then, fill 60 g of strongly acidic cation exchange resin catalyst into the fixed-bed reactor; turn on the steam to heat the bis(trimethylolpropane) toluene solution in the batching kettle to 120 - 180 °C, and pass it through the fixed-bed layer by a pressure pump, and adjust the nitrogen pressure at the top of the tower to maintain the bed pressure at 2 MPa - 3 MPa; after the reaction liquid passes through the fixed-bed, it enters the jet reactor. After spraying the material at the nozzle, the pressure drops to 0.5 - 0.9 MPa. The water vapor and part of the solvent are evaporated through the upper gas outlet and separated in the oil-water separator. Water is discharged from the lower discharge port, and the solvent is refluxed. The liquid-phase material continues to circulate and react through the pressure pump; take a sample from the discharge port at the bottom of the fixed-bed for gas chromatography analysis. If the bis(trimethylolpropane) is completely converted, stop the reaction and discharge the 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane solution. Use the distillation device to remove the solvent from the obtained 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane toluene solution and rectify and purify it to obtain the 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane product, with a yield of 96% and a purity of 99.3%. The infrared analysis and mass spectrum are shown in the appendix Figure 3 , 4.

[0028] In the present invention, by using bis(trimethylolpropane) as the starting material and using a special reactor to obtain 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane, the process is simplified, the reaction conditions are mild, the post-treatment process is simple, the yield is high, the intermediate steps in product synthesis are reduced, the cost is lowered, it is environmentally friendly, and it is suitable for industrial production.

[0029] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for synthesizing 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane, where 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane is a photo-curing active diluent; the specific structural formula is: ， It is characterized in that: The specific synthesis method is as follows: S1: Dissolve ditrimethylolpropane in a solvent to obtain a corresponding solution; S2: Fill a fixed bed with a strongly acidic cation exchange resin; S3: Heat the ditrimethylolpropane solution obtained in S1 to 120 - 180 °C, and pass it through the fixed bed layer by a pressure pump, with the bed layer pressure of 2 MPa - 3 MPa; S4: After passing through the fixed bed, enter a loop reactor. After spraying the material at the nozzle, reduce the pressure to 0.5 - 0.9 MPa, and distill out the water vapor. The liquid-phase material continues to circulate for reaction; S5: Take a sample at the discharge port at the bottom of the fixed bed for gas chromatography analysis. If the ditrimethylolpropane is completely converted, stop the reaction and discharge the 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane solution; S6: Use a distillation device to carry out desolvation and distillation on the 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane solution obtained in S5 to obtain the 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane product.

2. A method for synthesizing 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane according to claim 1; It is characterized in that: In S1, the mass ratio of ditrimethylolpropane to the solvent is 1:50 - 1:

25.

3. A method for synthesizing 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane according to claim 1; It is characterized in that: The ratio of bis(trimethylol)propane to the strongly acidic cation exchange resin is 1:0.05 - 1:0.

1.

4. A method for synthesizing 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane according to claim 1; It is characterized in that: In S1, the solvent used is: toluene.

5. A method for synthesizing 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane according to claim 1; It is characterized in that: The loop reactor in S4 is a series reactor of a packed fixed bed reactor and a loop reactor.

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