Synthesis of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin

Abstract

The present invention relates to the synthesis of hydantoin derivatives, and in particular to the synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin. Comprise the following steps: epichlorohydrin is ring-opened under the catalysis of a weak base and selectively undergoes a substitution reaction with the hydrogen on the nitrogen atom at position 3 of 5,5-dimethylhydantoin, and then a ring-closure reaction occurs under the catalysis of a strong base to generate 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin, with a liquid chromatography purity of 99.4%. The present invention obtains an epoxy resin intermediate with a high nitrogen content, which can effectively improve the flame retardancy, heat resistance and electrochemical properties of epoxy resin, and is expected to promote the industrial application of epoxy resin in the fields of electronics, aerospace, etc.

Description

Technical Field

[0001] The present invention relates to the synthesis of hydantoin derivatives, and in particular to a synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin. Background Art

[0002] 5,5-Dimethylhydantoin is a heterocyclic compound with a certain rigidity. The hydrogen on its nitrogen atom is relatively active. Many valuable derivatives can be prepared through substitution reactions. Its chemical structure is as follows:

[0003]

[0004] Epoxy groups are highly reactive functional groups with a -CH(O)CH- structure. They can react with other compounds through ring-opening and ring-closing reactions to form large cross-linked compounds. They are particularly widely used in epoxy resins. Epoxy resins are a class of polymer materials with excellent properties such as insulation, high strength, and corrosion resistance. They are widely used in industries such as electronics, aerospace, and chemical building materials. However, existing epoxy resins suffer from defects such as high cross-linking density and the presence of hydrophilic hydroxyl groups in their lattice structure, resulting in poor dimensional stability and poor hydrothermal stability. Consequently, epoxy resins with different structures have been developed.

[0005] Thanks to the properties of nitrogen atoms, nitrogen-containing epoxy resins possess excellent flame retardancy, heat resistance, and electrochemical properties. As the nitrogen content increases, the self-extinguishing and arc resistance of the epoxy resins are significantly improved. 5,5-Dimethylhydantoin contains two nitrogen atoms and is an excellent raw material for synthesizing nitrogen-containing epoxy resins. Selectively replacing only the hydrogen on the nitrogen atom at position 3 ensures the nitrogen content of the epoxy resin. 3-(2,3-Epoxypropyl)-5,5-dimethylhydantoin is currently an ideal raw material for synthesizing a class of high-nitrogen epoxy resins. Exploring green processes with simple reaction routes, simple operations, and environmentally friendly processes is essential for industrial development. Summary of the Invention

[0006] The purpose of the present invention is to provide a synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin.

[0007] To achieve the purpose of the invention, the present invention provides the following technical solutions:

[0008] The synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin is characterized in that the steps are:

[0009] 1. Add 1-2 equivalents of epichlorohydrin to a three-necked flask with a stirrer and a condenser at room temperature, add acetone, start stirring, then add 1 equivalent of 5,5-dimethylhydantoin, raise the temperature to 70-90°C, slowly add 20%-30% (ω) of alkaline solution A dropwise, and react for 4-6 hours after the addition is complete;

[0010] 2. After the reaction is completed, water is added to quench the reaction, and the organic phase is dried after extraction and separation. The dried product is dissolved with excess alcohol, stirred thoroughly, and filtered. The filtrate is taken and dried to obtain product A;

[0011] 3. Add 1 equivalent of product A to a three-necked flask with a stirrer and a condenser at room temperature, add acetone, stir and raise the temperature to 60-80°C, slowly add 30%-40% (ω) alkaline solution B dropwise to react, and quench the reaction by adding water when no reactant A is detected by TLC thin-layer chromatography;

[0012] 4. After extraction and separation, the organic phase was spin-dried and dried in an oven at 60°C overnight. It was purified using a 200-300 mesh silica gel column with an eluent of 1 equivalent of dichloromethane: 2 equivalents of petroleum ether to obtain the final product B.

[0013] It is further preferred that the alkaline solution A is one of sodium carbonate solution, potassium carbonate solution and calcium hydroxide solution.

[0014] More preferably, the alcohol is one of isopropyl alcohol, isobutyl alcohol and propylene glycol.

[0015] It is further preferred that the alkaline solution B is one of a sodium hydroxide solution and a potassium hydroxide solution.

[0016] The chemical reaction formula is:

[0017]

[0018] The beneficial effects of the present invention are:

[0019] The invention synthesizes a nitrogen-containing epoxy resin intermediate with high nitrogen content and high liquid chromatography purity (99.4%), has high yield, and is expected to solve the problems of poor flame retardancy and low thermal decomposition temperature of epoxy resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The liquid chromatogram of the sample. DETAILED DESCRIPTION

[0021] Unless otherwise specified, the reagents and instruments used in the following examples are commercially available conventional products.

[0022] In the following embodiments:

[0023] The comprehensive yield calculation method is:

[0024] Comprehensive yield = Product A yield * Product B yield

[0025] Yield of Product A = Amount of Product A / Amount of 5,5-dimethylhydantoin * 100%

[0026] Yield of product B = amount of product B substance / amount of product A substance * 100%

[0027] Example 1

[0028] The synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin comprises the following steps:

[0029] a) Add 0.1 mol of epichlorohydrin to a three-necked flask with a stirrer and a condenser at room temperature, add 80 mL of acetone, start stirring, then add 0.1 mol of 5,5-dimethylhydantoin, raise the temperature to 70°C, and slowly add 30 mL of 20% (ω) sodium carbonate solution dropwise. After the addition is complete, react for 4 hours;

[0030] b) After the reaction is completed, water is added to quench the reaction, and the organic phase is dried after extraction and separation. The dried product is dissolved in excess isopropanol, stirred thoroughly, and filtered. The filtrate is dried to obtain 0.083 mol of product A, with a yield of 83%;

[0031] c) Add 0.1 mol of product A to a three-necked flask equipped with a stirrer and a condenser at room temperature, add 80 mL of acetone, stir, and raise the temperature to 60° C. Slowly add dropwise a 30% (ω) sodium hydroxide solution to react. If no reactant A is detected by TLC thin-layer chromatography, water is added to quench the reaction;

[0032] d) After extraction and separation, the organic phase was spin-dried and dried in an oven at 60°C overnight. Purification was performed using a 200-300 mesh silica gel column with an eluent of 1 equivalent of dichloromethane:2 equivalents of petroleum ether to obtain 0.071 mol of product B with a yield of 71%. Liquid chromatography analysis showed a sample purity of 99.4%.

[0033] In summary, the molar ratio of epichlorohydrin to 5-dimethylhydantoin was 1:1, the overall yield of the reaction was 59%, and the sample purity was 99.4%.

[0034] Example 2

[0035] The synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin is different from that of Example 1 in that the steps are as follows:

[0036] a) Add 0.15 mol of epichlorohydrin to a three-necked flask with a stirrer and a condenser at room temperature, add 80 mL of acetone, start stirring, then add 0.1 mol of 5,5-dimethylhydantoin, raise the temperature to 80°C, and slowly add 30 mL of 25% (ω) sodium carbonate solution dropwise. After the addition is complete, react for 5 hours;

[0037] b) After the reaction is completed, water is added to quench the reaction, and the organic phase is dried after extraction and separation. The dried product is dissolved in excess isopropanol, stirred thoroughly, and filtered. The filtrate is dried to obtain 0.081 mol of product A, with a yield of 81%;

[0038] c) Add 0.1 mol of product A to a three-necked flask equipped with a stirrer and a condenser at room temperature, add 80 mL of acetone, stir, and raise the temperature to 70° C. Slowly add dropwise a 35% (ω) sodium hydroxide solution to react. If no reactant A is detected by TLC thin-layer chromatography, water is added to quench the reaction;

[0039] d) After extraction and separation, the organic phase was spin-dried and dried in an oven at 60° C. overnight. Purification was performed using a 200-300 mesh silica gel column with an eluent of 1 equivalent of dichloromethane:2 equivalents of petroleum ether to obtain 0.073 mol of product B with a yield of 73%. The liquid chromatography results were similar to those in Example 1.

[0040] In summary, the molar ratio of epichlorohydrin to 5-dimethylhydantoin is 1.5:1, and the overall yield of the reaction is 59%.

[0041] Example 3

[0042] The synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin is different from that of Example 1 in that the steps are as follows:

[0043] a) Add 0.2 mol of epichlorohydrin to a three-necked flask with a stirrer and a condenser at room temperature, add 80 mL of acetone, start stirring, then add 0.1 mol of 5,5-dimethylhydantoin, raise the temperature to 90°C, and slowly add 30 mL of 30% (ω) sodium carbonate solution dropwise. After the addition is complete, react for 6 hours;

[0044] b) After the reaction is completed, water is added to quench the reaction, and the organic phase is dried after extraction and separation. The dried product is dissolved in excess isopropanol, stirred thoroughly, and filtered. The filtrate is dried to obtain 0.085 mol of product A, with a yield of 85%;

[0045] c) Add 0.1 mol of product A to a three-necked flask equipped with a stirrer and a condenser at room temperature, add 80 mL of acetone, stir, and raise the temperature to 80° C. Slowly add dropwise a 40% (ω) sodium hydroxide solution to react. If no reactant A is detected by TLC thin-layer chromatography, water is added to quench the reaction;

[0046] d) After extraction and separation, the organic phase was spin-dried and dried in an oven at 60° C. overnight. Purification was performed using a 200-300 mesh silica gel column with an eluent of 1 equivalent of dichloromethane:2 equivalents of petroleum ether to obtain 0.075 mol of product B with a yield of 75%. The liquid chromatography results were similar to those in Example 1.

[0047] In summary, the molar ratio of epichlorohydrin to 5-dimethylhydantoin is 2:1, and the overall yield of the reaction is 64%.

[0048] Example 4

[0049] The synthesis process of 3-3-(2,3-epoxypropyl)-5,5-dimethylhydantoin differs from that in Example 1, in that the alkaline solution A is a potassium carbonate solution. The first step yielded 0.080 mol of product A, with a yield of 80%. The second step yielded 0.074 mol of product B, with a yield of 74%. The overall reaction yield was 59%. Liquid chromatography results were similar to those in Example 1.

[0050] Example 5

[0051] The synthesis process of 3-3-(2,3-epoxypropyl)-5,5-dimethylhydantoin differs from that in Example 1, in that the alkaline solution A is a calcium hydroxide solution. The first step yielded 0.082 mol of product A, with a yield of 82%. The second step yielded 0.071 mol of product B, with a yield of 71%. The overall reaction yield was 58%. Liquid chromatography results were similar to those in Example 1.

[0052] Example 6

[0053] The synthesis process of 3-3-(2,3-epoxypropyl)-5,5-dimethylhydantoin differs from that in Example 1, in that the alcohol used isobutanol. The first step yielded 0.078 mol of product A, with a yield of 78%. The second step yielded 0.074 mol of product B, with a yield of 74%. The overall reaction yield was 58%. Liquid chromatography results were similar to those in Example 1.

[0054] Example 7

[0055] The synthesis process of 3-3-(2,3-epoxypropyl)-5,5-dimethylhydantoin differs from that in Example 1, in that the alcohol used is propylene glycol. The first step yielded 0.082 mol of product A, with a yield of 82%. The second step yielded 0.073 mol of product B, with a yield of 73%. The overall reaction yield was 60%. Liquid chromatography results were similar to those in Example 1.

[0056] Example 8

[0057] The synthesis process of 3-3-(2,3-epoxypropyl)-5,5-dimethylhydantoin differs from that in Example 1, in that the alkaline solution B is a potassium hydroxide solution. The first step yielded 0.084 mol of product A, with a yield of 84%. The second step yielded 0.075 mol of product B, with a yield of 75%. The overall reaction yield was 63%. Liquid chromatography results were similar to those in Example 1.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the present invention. It should be clear to those skilled in the art that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. The synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin is characterized in that: The following steps are involved: Step 1: Add 1-2 equivalents of epichlorohydrin to a three-necked flask with a stirrer and a condenser at room temperature, add acetone, start stirring, then add 1 equivalent of 5,5-dimethylhydantoin, raise the temperature to 70-90°C, and slowly dropwise add 20%-30% by mass of alkaline solution A, wherein the alkaline solution A is one of sodium carbonate solution, potassium carbonate solution, and calcium hydroxide solution. After the addition is complete, react for 4-6 hours; Step 2: After the reaction is completed, water is added to quench the reaction, and the organic phase is dried after extraction and separation. The dried product is dissolved with excess alcohol, stirred thoroughly, and filtered. The filtrate is dried to obtain product A. The structural formula of the product A is:

2. Step 3: Add one equivalent of product A to a three-necked flask equipped with a stirrer and a condenser at room temperature. Add acetone, stir, and heat to 60-80°C. Slowly add a 30%-40% by weight base solution B dropwise to react. If no reactant A is detected by TLC, quench the reaction by adding water. Step 4: After extraction and separation, the organic phase was spin-dried and dried in an oven at 60°C overnight. Purification was performed using a 200-300 mesh silica gel column with an eluent of 1 equivalent of dichloromethane: 2 equivalents of petroleum ether to obtain the final product B.

3. The synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin according to claim 1, characterized in that: The alcohol is one of isopropyl alcohol, isobutyl alcohol and propylene glycol.

4. The synthesis process of 3-(2,3-epoxypropyl)-5,5-dimethylhydantoin according to claim 1, characterized in that: The alkaline solution B is one of sodium hydroxide solution and potassium hydroxide solution.

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