Preparation method of 2, 2-(1, 3-phenylene) bis (2-oxazoline)

Abstract

The invention discloses a preparation method of 2, 2-(1, 3-phenylene) bis (2-oxazoline), and relates to the field of novel material production, isophthalonitrile and ethanolamine are used as raw materials, in the raw material ratio, the raw material molar ratio of isophthalonitrile to ethanolamine to a catalyst is 1: (2-4): (1.5-2.5): (0.01-0.05), and the reaction temperature is controlled to be 30-60 DEG C; according to the production method, the reaction is more sufficient to obtain the highest yield by properly selecting the ingredient ratio, the proper solvent, the reaction temperature and the catalyst. The 2, 2-(1, 3-phenylene) bis (2-oxazoline) produced by the process has the advantages of simple production process, low production cost and no pollution, the molar yield of the product can reach 87.6%, and the content can reach 99.8%.

Description

Technical Field

[0001] The present invention relates to the technical field of new material production, and particularly relates to a preparation method of 2,2-(1,3-phenylene) bis(2-oxazoline). Background Art

[0002] 2,2-(1,3-phenylene) bis(2-oxazoline) has a wide range of uses. 2,2-(1,3-phenylene) bis(2-oxazoline) is a functional chemical, and its main uses are as follows: it can be used for synthesizing adhesives and polyimide resins; 2) it has the characteristics of good heat resistance, impact resistance and stretching performance, and can be used as a raw material for producing sports equipment; 3) it is a bisoxazoline ligand and can be used to improve the effect of certain catalytic reactions. The product specifications of 2,2-(1,3-phenylene) bis(2-oxazoline) are: appearance: white powder; content: ≥99.0%; melting point: 143-146°C; volatile matter ≤0.5%; ignition residue: ≤0.1%; use: dioxazoline is an important organic reaction intermediate. A compound containing two five-membered heterocycles of carbon, nitrogen, oxygen and carbon-nitrogen double bonds, because its chemical properties are quite active and can undergo ring-opening reactions with carboxyl groups, acid anhydrides, amino groups, epoxy groups, mercapto groups, phenolic hydroxyl groups, isocyanate groups, etc. at a certain temperature, so 2,2-(1,3-phenylene) bis(2-oxazoline) can often be used as a chain extender or crosslinking agent for polymers. The synthesis methods of 2,2-(1,3-phenylene) bis(2-oxazoline) at home and abroad have the following routes, but all have corresponding disadvantages.

[0003] One is the phthalic acid esterification method. The phthalic acid esterification method refers to esterifying phthalic acid with methanol to synthesize dimethyl phthalate, and then reacting with ethanolamine and cyclizing with thionyl chloride to synthesize 2,2-(1,3-phenylene) bis(2-oxazoline). The esterification reaction is a reversible reaction, and it is necessary to control the evaporation of water, which is not conducive to industrial production and the process operation is relatively complex.

[0004] One is the phthalic acid chloride method. The phthalic acid chloride method refers to generating phthalic acid chloride from phthalic acid through thionyl chloride, then reacting with ethanolamine, and then reacting with thionyl chloride to close the ring to obtain 2,2-(1,3-phenylene) bis(2-oxazoline). This method has a high production cost, and thionyl chloride is also a controlled drug, and there are also risks in operation.

[0005] There is also a method of condensing dimethyl cyanide and ethanolamine. Currently, it is a production preparation method of 2,2-(1,3-phenylene) bis(2-oxazoline), and the yield of this synthesis method is relatively low.

[0006] Therefore, the above-mentioned synthesis methods have problems such as poor safety, high production cost and low yield. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems in the related art to a certain extent.

[0008] To this end, the object of the present invention is to provide a preparation method of 2,2-(1,3-phenylene)bis(2-oxazoline), which has the advantages of simple production process, low production cost and no pollution, and the molar yield and content of the product are significantly improved.

[0009] To achieve the above object, the present invention provides a preparation method of 2,2-(1,3-phenylene)bis(2-oxazoline), and the raw materials used are in a molar ratio of: isophthalonitrile, ethanolamine, catalyst of 1:2-4:1.5-2.5:0.01-0.05, and the production steps include: (1) Add the formulated amount of isophthalonitrile into the reaction kettle, and successively add the formulated amount of solvent, ethanolamine, and catalyst, stir and heat for reaction for 3-7 hours. After the reaction is completed, distill off the solvent under reduced pressure, wash with water equal to the volume of the solvent for 2-3 times, and centrifuge to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline); (2) Feed the centrifuged and solidified product 2,2-(1,3-phenylene)bis(2-oxazoline) into a dryer, dry it at a temperature of 60-70 °C for 1.5-2.0 hours, and then feed the dried product into a pulverizer to pulverize it into powder to obtain the finished product.

[0010] Further, the catalyst in step (1) is one or several of zinc chloride, copper chloride, zinc sulfate, copper sulfate, zinc acetate, and copper acetate, and the solvent is one or several of toluene, methanol, ethanol, n-butanol, and xylene.

[0011] Further, the reaction temperature in step (1) is 80-110 °C, and the reaction pressure is 0.1-0.2 MPa.

[0012] Further, the drying temperature in step (2) is 60-70 °C, and the drying time is 1.5-2.0 hours.

[0013] Further, the drying temperature and the corresponding drying time are: when the drying temperature is 60 °C, the corresponding drying time is 2.0 hours; when the drying temperature is 65 °C, the corresponding drying time is 1.75 hours; when the drying temperature is 70 °C, the corresponding drying time is 1.5 hours.

[0014] Further, the isophthalonitrile and ethanolamine in step (1) are of industrial grade, and the content is 99.0%-99.5%.

[0015] Beneficial effects: By providing a method for industrial production of tricyanopyridine, using isophthalonitrile, ethanolamine, and a catalyst (zinc chloride) as raw materials, 2,2-(1,3-phenylene)bis(2-oxazoline) is prepared through the catalytic method of isophthalonitrile. By controlling the reaction temperature, reaction time, ratio of reaction materials, catalyst, etc., the reaction yield is affected. This production method has the characteristics of simple process, high efficiency, low cost, and no pollution. The yield of the product can reach 87.6%, and the product content (purity) can reach 99.8%.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. Detailed implementation manners

[0017] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The following description by reference to the embodiments is exemplary and is intended to explain the present invention, and should not be construed as a limitation of the present invention.

[0018] The preparation method of 2,2-(1,3-phenylene)bis(2-oxazoline) according to the embodiments of the present invention will be described below in conjunction with the embodiments.

[0019] Example 1 Add the formulated amount of isophthalonitrile to the reaction kettle, and then add the formulated amount of solvent, ethanolamine, and catalyst in sequence, stir and heat for 4 hours. After the reaction is completed, the solvent is distilled off under reduced pressure, and an appropriate amount of water is added for washing and centrifugation to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline). When the catalyst is zinc chloride, the highest yield of the product is 81.3%. The main function of the catalyst is to undergo a complexation reaction with the cyano group, which is more conducive to the attack of ethanolamine to occur cyclization reaction. Therefore, the best catalyst is zinc chloride.

[0020]

[0021] Example 2 Add the formulated amount of isophthalonitrile to the reaction kettle, and then add the formulated amount of solvent, ethanolamine, and catalyst in sequence, stir and heat for 4 hours. After the reaction is completed, the solvent is distilled off under reduced pressure, and an appropriate amount of water is added for washing and centrifugation to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline). When the ratio of isophthalonitrile to ethanolamine is 1:3.5, it is the best ratio, and the yield of the product is 85.3%. When the molar ratio is lower than 1:3.5, the intermolecular interaction is low and the effective reaction is less. When the molar ratio is higher than 1:3.5, the intermolecular interaction is strong and side reactions increase simultaneously. Therefore, the best molar ratio of materials is isophthalonitrile to ethanolamine = 1:3.5.

[0022]

[0023] Example 3 Add the formulated amount of isophthalonitrile into the reaction kettle, and successively add the formulated amount of solvent, ethanolamine, and catalyst, then stir and heat for reaction for 4 hours. After the reaction is completed, distill out the solvent under reduced pressure, add an appropriate amount of water for washing, and centrifuge to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline). When the reaction temperature is 90°C, the highest yield of the product is 84.8%. When the temperature is lower than 90°C, the reaction rate decreases. When the reaction temperature is higher than 90°C, the by-products increase and the yield decreases. Therefore, the optimal reaction temperature is 90°C.

[0024]

[0025] Example 4 Add the formulated amount of isophthalonitrile into the reaction kettle, and successively add the formulated amount of solvent, ethanolamine, and catalyst, then stir and heat to 90°C for reaction for 3 - 6 hours. After the reaction is completed, distill out the solvent under reduced pressure, add an appropriate amount of water for washing, and centrifuge to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline). When the reaction temperature is 90°C and the reaction time is 4 hours, the highest yield of the product is 83.8%. When the reaction time is less than 4 hours, the reaction is incomplete. When it is higher than 4 hours, by-products begin to be generated. Therefore, the optimal reaction time is 4 hours.

[0026]

[0027] Example 5 Add the formulated amount of isophthalonitrile into the reaction kettle, and successively add the formulated amount of solvent, ethanolamine, and catalyst, then stir and heat for reaction for 4 hours. After the reaction is completed, distill out the solvent under reduced pressure, add an appropriate amount of water for washing, and centrifuge to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline). When the molar ratio of isophthalonitrile to the catalyst is 1:0.04, the highest yield of the product is 85.3%. When the molar ratio is lower, the reaction rate is slow and the effective reaction is low. When it is higher, the change in yield is not obvious. Therefore, the optimal molar ratio of isophthalonitrile to the catalyst for the reaction is 1:0.04.

[0028]

[0029] Example 6 The optimal reaction conditions of Examples 1-5 were summarized. Isophthalonitrile, ethanolamine, and a catalyst (zinc chloride) were added to the reaction kettle in a molar ratio of 1:3.5:0.04 in sequence, and a solvent was added. The mixture was stirred and heated to 90 °C for reaction for 4 hours. After the reaction, the solvent was distilled off under reduced pressure, and a considerable amount of water was added for washing and centrifugation to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline). The yield of the product was 87.6%, and the purity was 99.8%. The centrifuged and solidified product 2,2-(1,3-phenylene)bis(2-oxazoline) was sent to a dryer and dried at a temperature of 60-70 °C for 1.5-2.0 hours, and then the dried product was sent to a pulverizer and pulverized into powder to obtain the finished product.

[0030] In summary, for the preparation method of 2,2-(1,3-phenylene)bis(2-oxazoline) in the embodiments of the present invention, using isophthalonitrile, ethanolamine, and a catalyst (zinc chloride) as raw materials, 2,2-(1,3-phenylene)bis(2-oxazoline) is prepared by the isophthalonitrile catalytic method. By controlling the reaction temperature, reaction time, ratio of reaction materials, catalyst, etc., the reaction yield is affected to make the reaction more complete to obtain the highest yield. The 2,2-(1,3-phenylene)bis(2-oxazoline) produced according to the above process has the advantages of simple production process, low production cost, and no pollution. The yield of the product can reach 85%, and the content can reach 99.8%.

[0031] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing 2,2-(1,3-phenylene)bis(2-oxazoline), wherein the raw materials used are in a molar ratio of isophthalonitrile, ethanolamine, and catalyst of 1:2-4:1.5-2.5:0.01-0.05, characterized in that: The production steps include: (1) Add isophthalonitrile to a reaction kettle, add a solvent, ethanolamine, and a catalyst in the formula amount in sequence, stir and heat to react for 3 to 7 hours, and after the reaction is completed, distill off the solvent under reduced pressure, add water of an equal volume to the solvent to wash 2 to 3 times, and centrifuge to obtain the product 2,2-(1,3-phenylene)bis(2-oxazoline); (2) The solidified 2,2-(1,3-phenylene)bis(2-oxazoline) after centrifugation is sent to a dryer and dried at a temperature of 60 to 70° C. for 1.5 to 2.0 hours. The dried product is then sent to a pulverizer and pulverized into powder to obtain a finished product.

2. The method for preparing 2,2-(1,3-phenylene)bis(2-oxazoline) according to claim 1, characterized in that: The catalyst in step (1) is one or more of zinc chloride, copper chloride, zinc sulfate, copper sulfate, zinc acetate, and copper acetate; the solvent is one or more of toluene, methanol, ethanol, n-butanol, and xylene.

3. The method for preparing 2,2-(1,3-phenylene)bis(2-oxazoline) according to claim 1, characterized in that: The reaction temperature in step (1) is 80-110° C., and the reaction pressure is 0.1-0.2 MPa.

4. The method for preparing 2,2-(1,3-phenylene)bis(2-oxazoline) according to claim 1, characterized in that: The drying temperature in step (2) is 60-70° C., and the drying time is 1.5-2.0 hours.

5. The method for preparing 2,2-(1,3-phenylene)bis(2-oxazoline) according to claim 4, characterized in that: The drying temperature and the corresponding drying time are: when the drying temperature is 60°C, the corresponding drying time is 2.0 hours; when the drying temperature is 65°C, the corresponding drying time is 1.75 hours; when the drying temperature is 70°C, the corresponding drying time is 1.5 hours.

6. The method for preparing 2,2-(1,3-phenylene)bis(2-oxazoline) according to claim 1, characterized in that: The isophthalonitrile and ethanolamine described in step (1) are of industrial grade, with a content of 99.0% to 99.5%.

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