A preparation process of environmentally friendly pyridone ethanolamine salt

Abstract

The present application discloses a process for preparing an environmentally friendly pyridone ethanolamine salt, comprising the following preparation steps: reacting isononanoyl chloride and 3,3-dimethacrylate methyl under the catalysis of a solid acid catalyst to obtain 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester; the preparation method of the solid acid catalyst is as follows: S1, using water as a solvent, adding 14-16 parts by weight of zirconium oxychloride, 1-3 parts by weight of titanium sulfate, 0.1-0.5 parts by weight of chloroplatinic acid and 0.05-0.4 parts by weight of cerium chloride, adjusting the pH to 10-11, aging, and obtaining a precipitate; S2, calcining the precipitate obtained in S1 at 500-600° C. in an air atmosphere to obtain a solid acid catalyst; the solid acid catalyst has the advantages of easy catalyst recovery and strong reusability.

Description

Technical Field

[0001] The present application relates to the technical field of synthesis of pyridone ethanolamine salt, and in particular to a preparation process of an environmentally friendly pyridone ethanolamine salt. Background Art

[0002] Pyridone ethanolamine salt, chemically named 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridinolamine salt, is an effective anti-dandruff and antipruritic agent. Its antipruritic effect is better than other similar additives. It can not only mix well with other added ingredients in shampoo, but also is non-toxic and non-irritating, preservative and bactericidal, with high safety performance. It is widely used in shampoo and hair care products, bath gel and detergents.

[0003] In the related art, the synthesis method of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridineethanolamine salt is to first subject the raw materials 3,3-dimethylacrylate and isononanoyl chloride to Friedel-Crafts acylation reaction, obtain the intermediate, and then subject it to ring closure reaction, hydroxyoximation reaction and salt formation reaction to obtain the target product. In the Friedel-Crafts acylation reaction, aluminum chloride is generally used as a catalyst. Although aluminum chloride has high catalytic activity, is cheap and easy to obtain, it is not easy to recycle and reuse, and post-processing is difficult. In related studies, there are also catalysts prepared by loading, etc. Although the recovery step is simplified, the catalytic effect of the catalyst is significantly reduced after being reused dozens of times, resulting in a significant reduction in the reaction yield. Summary of the invention

[0004] In order to make the catalyst easy to recover and highly reusable, the present application provides a preparation process of an environmentally friendly pyridone ethanolamine salt.

[0005] In the first aspect, the present application provides a preparation process of an environmentally friendly pyridone ethanolamine salt, which adopts the following technical scheme:

[0006] A preparation process of an environmentally friendly pyridone ethanolamine salt comprises the following preparation steps:

[0007] S1, reacting isononanoyl chloride and 3,3-dimethacrylate methyl under the catalysis of a solid acid catalyst to obtain 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester;

[0008] S2, subjecting the 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester obtained in S1 to a ring-closing reaction to obtain 4-methyl-6-2-pyrone;

[0009] S3, mixing the 4-methyl-6-2-pyrone obtained in S2 with hydroxylamine hydrochloride to carry out hydroxylation reaction to obtain 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone;

[0010] S4, subjecting the 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone prepared in S3 to a salt-forming reaction with ethanolamine to obtain pyridone ethanolamine salt;

[0011] The preparation method of the solid acid catalyst is as follows:

[0012] S1. Using water as solvent, add 14-16 parts by weight of zirconium oxychloride, 1-3 parts by weight of titanium sulfate, 0.1-0.5 parts by weight of chloroplatinic acid and 0.05-0.4 parts by weight of cerium chloride, adjust the pH to 10-11, age, and obtain a precipitate;

[0013] S2. calcining the precipitate obtained in S1 in the preparation method of the solid acid catalyst in an air atmosphere at 500-600° C. to obtain a solid acid catalyst.

[0014] By adopting the above technical scheme, a multiphase solid acid catalyst is prepared, which can be easily recovered with excellent catalytic selectivity, and the solid acid catalyst can be separated by filtration; and adding platinum and cerium to the solid acid catalyst can improve the catalytic activity, and when the activity of the solid acid catalyst decreases with the recycling use, it can be calcined in an air atmosphere, and platinum can catalyze the reaction to generate hydrogen, thereby promoting the recovery and rearrangement of the acidic sites, and the addition of metallic cerium can promote the recovery of the isomerization activity of the solid acid catalyst, so that the solid acid catalyst can be reused again.

[0015] Preferably, in the method for preparing the solid acid catalyst, in S2, the precipitate obtained in S1 is firstly immersed in a 0.4-0.8 mol / L sulfuric acid solution, and then calcined in an air atmosphere at 500-600° C. to obtain the solid acid catalyst.

[0016] By adopting the above technical solution, the acidity of the solid acid catalyst can be enhanced by soaking in sulfuric acid, so that the solid acid catalyst has stronger catalytic activity and catalytic selectivity.

[0017] Preferably, the calcination temperature is 600°C.

[0018] By adopting the above technical solution, when the calcination temperature is high, zirconium dioxide can fully form the tetragonal crystal necessary for solid acid, which is beneficial to the distribution of titanium dioxide on its surface, making the catalytic activity of the solid acid catalyst better.

[0019] Preferably, in the method for preparing the solid acid catalyst, 4-7 parts by weight of polyvinyl pyrrolidone is further added to the solvent of S1.

[0020] By adopting the above technical solution and adding polyvinyl pyrrolidone, when the solid acid catalyst is aged, the polyvinyl pyrrolidone can be adsorbed on the surface of its particles to prevent its crystals from further growing. Therefore, its particle size can be controlled and the specific surface area of ​​the solid acid catalyst of the same mass can be increased, so that it can have more catalytic active centers, and therefore, its catalytic effect is better.

[0021] Preferably, the amount of zirconium oxychloride added is 15 parts by weight, the amount of titanium sulfate added is 1.5 parts by weight, the amount of chloroplatinic acid added is 0.3 parts by weight, and the amount of cerium chloride added is 0.2 parts by weight.

[0022] By adopting the above technical solution and optimizing the addition amount of each raw material, the catalytic performance of the solid acid catalyst can be further improved.

[0023] Preferably, the solid acid catalyst is washed with dichloromethane after the catalytic reaction and then dried under vacuum at 80-100°C.

[0024] By adopting the above technical solution, impurities attached to the catalyst can be cleaned through washing and vacuum drying, thereby exposing its catalytic active sites, and the catalytic performance is better when reused.

[0025] Preferably, the solid acid catalyst is calcined again in an air atmosphere after being recycled for several times.

[0026] By adopting the above technical solution, air oxidation plays a very important role in the oxidation of the acidic catalytic centers on the catalyst surface and the sulfur species on its surface and the rearrangement of the active centers, so that the solid acid catalyst can restore its isomerization activity.

[0027] Preferably, the temperature of the second calcination in air atmosphere is 450-550°C.

[0028] By adopting the above technical solution, at this temperature, the isomerization activity of the solid acid catalyst is better restored.

[0029] In summary, the present application includes at least one of the following beneficial technical effects:

[0030] 1. By preparing a multiphase solid acid catalyst, it can be easily recovered with excellent catalytic selectivity, and the solid acid catalyst can be separated by filtration; and adding platinum and cerium to the solid acid catalyst can improve the catalytic activity, and when the activity of the solid acid catalyst decreases with the recycling use, it can be calcined in an air atmosphere, and platinum can catalyze the reaction to generate hydrogen, thereby promoting the recovery and rearrangement of the acidic sites, and the addition of metallic cerium can promote the recovery of the isomerization activity of the solid acid catalyst, so that the solid acid catalyst can be reused again.

[0031] 2. The catalyst prepared in the present application is used in the preparation process of environmentally friendly pyridinone ethanolamine salt, and the yield of the target intermediate product is 86.3% or above, and the highest can reach 94.6%; and after 100 cycles of use, the yield can still reach 77.5%, indicating that the catalyst prepared in the present application has excellent catalytic selectivity and reusability; and after 100 cycles of catalysis, the solid acid catalyst can be completely restored to its catalytic activity by calcination in an air atmosphere, greatly extending the service life of the solid acid catalyst. DETAILED DESCRIPTION

[0032] The present application is further described in detail below in conjunction with the specific contents.

[0033] raw material

[0034] The raw materials used in the preparation examples and embodiments of the present application can all be purchased from the market, among which the model of polyvinyl pyrrolidone is K30; the remaining raw materials are of analytical grade.

[0035] Preparation Example 1

[0036] A solid acid catalyst, the preparation method of which is as follows:

[0037] S1. Add 15 g of zirconium oxychloride, 1.5 g of titanium sulfate, 0.3 g of chloroplatinic acid and 0.2 g of cerium chloride to 200 g of distilled water, stir until completely dissolved, then add ammonia water dropwise while stirring until the pH of the system reaches 10, stop adding dropwise, then age for 24 hours, filter to obtain a precipitate, wash the precipitate with water, and dry it at 100 ° C;

[0038] S2. The dried solid of S1 was calcined at 600° C. for 2 h in an air atmosphere to obtain a solid acid catalyst.

[0039] Preparation Example 2

[0040] A solid acid catalyst, which is different from Preparation Example 1 in that the content of S2 is as follows: the dried solid of S1 is soaked in a 0.6 mol / L sulfuric acid solution for 12 hours, then filtered, and the filtered solid is calcined in an air atmosphere at 600°C for 2 hours to obtain a solid acid catalyst.

[0041] Preparation Example 3

[0042] A solid acid catalyst, which is different from Preparation Example 2 in that 5 g of polyvinyl pyrrolidone is also added to the distilled water in S1, and the remaining steps are the same as Preparation Example 1.

[0043] Preparation Example 4

[0044] A solid acid catalyst, which is different from Preparation Example 1 in that the calcination temperature in S1 is 500° C., and the remaining steps are the same as Preparation Example 1.

[0045] Preparation Example 5

[0046] A solid acid catalyst, which is different from Preparation Example 3 in that the amount of chloroplatinic acid added in S1 is 0.1 g, and the remaining steps are the same as Preparation Example 3.

[0047] Preparation Example 6

[0048] A solid acid catalyst, which is different from Preparation Example 3 in that the amount of chloroplatinic acid added in S1 is 0.5 g, and the remaining steps are the same as Preparation Example 3.

[0049] Preparation Example 7

[0050] A solid acid catalyst, which is different from Preparation Example 3 in that the amount of cerium chloride added in S1 is 0.05 g, and the remaining steps are the same as Preparation Example 3.

[0051] Preparation Example 8

[0052] A solid acid catalyst, which is different from Preparation Example 3 in that the amount of cerium chloride added in S1 is 0.4 g, and the remaining steps are the same as Preparation Example 3. Example Example 1

[0053] A preparation process of an environmentally friendly pyridone ethanolamine salt, the preparation method is as follows:

[0054] S1. Add 10 g of the solid acid catalyst prepared in Preparation Example 1 to 150 mL of dichloromethane, control the temperature of the system below 5 ° C, then drop 12 g of isononanoyl chloride, control the temperature of the system at 27 ° C, then drop 12 g of 3,3-dimethylacrylate, heat and reflux for 8 h, cool the system to 25 ° C, filter to obtain a precipitate and a reaction solution, add 50 mL of dichloromethane to the obtained reaction solution; take 4 mol / L hydrochloric acid, dilute it to 100 mL with an ice-water mixture, then add it to the reaction solution, stir and stand to separate, take the lower layer, then wash with water, dry, and remove the solvent by rotary evaporation to obtain a brown oily liquid, i.e., 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester;

[0055] The filtered precipitate was washed with dichloromethane and then dried under vacuum at 90° C. to obtain an activated solid acid catalyst, which can be further used for the catalytic reaction in this step;

[0056] S2, add 6g of sodium hydroxide to 50mL of distilled water to obtain a sodium hydroxide solution; add 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester obtained in S1 to 50mL of anhydrous methanol, then add the obtained sodium hydroxide solution, reflux for 8h, then dropwise add dilute hydrochloric acid for neutralization, then add 50mL of dichloromethane for extraction, repeat the extraction twice, wash with deionized water, then dry over anhydrous sodium sulfate, filter, and remove the solvent by reduced pressure distillation to obtain 4-methyl-6-2-pyrone;

[0057] S3, add 4-methyl-6-2-pyrone obtained in S2 to a mixture of 50 mL of dichloromethane and 50 mL of methanol, add 11 g of hydroxylamine hydrochloride and stir evenly, heat to 40°C, heat under reflux for 10 h, then cool to 25°C, add 100 mL of saturated saline to extract, take the organic phase, extract the aqueous phase with 50 mL of ethyl acetate, repeat three times, combine the organic phases, wash with 50 mL of deionized water, dry over anhydrous sodium sulfate, and remove the solvent by distillation under reduced pressure to obtain 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone;

[0058] S4. Add 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone obtained in S3 to 120 mL of ethyl acetate, add 3 g of ethanolamine and mix well, raise the temperature to 40°C, and when crystals precipitate, lower the temperature to 0°C. When the number of crystals stops increasing, wash three times with 50 mL of ethyl acetate at 0°C, and dry to obtain pyridone ethanolamine salt.

[0059] Embodiment 2-8

[0060] The preparation process of an environmentally friendly pyridone ethanolamine salt in Example 2-8 is different from that in Example 1 in that the solid acid catalyst in S1 is sequentially from Preparation Examples 2-8, and the remaining steps are the same as those in Example 1. Example 9

[0061] A process for preparing an environmentally friendly pyridone ethanolamine salt is different from that in Example 3 in that the solid acid catalyst used in S1 is a solid acid catalyst that has been repeatedly catalyzed 100 times, and after each catalysis, it is activated. Example 10

[0062] A preparation process of an environmentally friendly pyridone ethanolamine salt is different from that of Example 9 in that the solid acid catalyst used in S1 is first activated after repeated catalysis 100 times, and then passed through an air environment and high-temperature calcination treatment. The specific operation is as follows:

[0063] The solid acid catalyst was washed with dichloromethane and then vacuum dried at 90°C to obtain an activated solid acid catalyst; the activated solid acid catalyst was then calcined at 500°C for 2h in an air atmosphere to obtain a high-temperature calcined solid acid catalyst. Comparative Example

[0064] Comparative Example 1

[0065] A preparation process of an environmentally friendly pyridone ethanolamine salt, which is different from Example 3 in that, during the preparation of the solid acid catalyst, cerium chloride is replaced by an equimolar amount of chloroplatinic acid, and the remaining steps are the same as those in Example 3.

[0066] Comparative Example 2

[0067] A preparation process of an environmentally friendly pyridone ethanolamine salt, which is different from Example 10 in that, during the preparation of the solid acid catalyst, cerium chloride is replaced by an equimolar amount of chloroplatinic acid, and the remaining steps are the same as those of Example 10.

[0068] Comparative Example 3

[0069] A preparation process of an environmentally friendly pyridone ethanolamine salt, which is different from Example 10 in that the calcination environment of the solid acid catalyst is nitrogen, and the remaining steps are the same as Example 10.

[0070] Environmentally friendly pyridone ethanolamine salts were prepared according to the preparation methods in Examples 1-10 and Comparative Examples 1-3, and then the yields of the target intermediate products were calculated, and the recorded results are shown in Table 1.

[0071] Yield: After the preparation process S1 is completed, the yield of 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester is calculated based on the mass of the raw material isononanoyl chloride, and this is used to indirectly reflect the activity and reusability of the solid acid catalyst.

[0072] Table 1 Experimental results of Examples 1-10 and Comparative Examples 1-3

[0073]

[0074] It can be seen from the test data of Examples 1-10 and Comparative Examples 1-3 that the catalyst prepared in the present application is applied to the preparation process of environmentally friendly pyridone ethanolamine salt, and the yield of the obtained target intermediate product is 86.3% or more, and the highest can reach 94.6%; and after being recycled 100 times, the yield can still reach 77.5%, indicating that the catalyst prepared in the present application has excellent catalytic selectivity and reusability; and after 100 catalytic reactions, the solid acid catalyst can be completely restored to its catalytic activity by calcination in an air atmosphere, thereby greatly extending the service life of the solid acid catalyst.

[0075] It can be seen from the test data of Examples 1-2 that after the solid acid catalyst is impregnated with sulfuric acid, it is more acidic, has stronger catalytic activity and catalytic selectivity, and the same experimental conditions give a higher product yield; in conjunction with Example 3, polyvinyl pyrrolidone is added, and when the solid acid catalyst is aged, polyvinyl pyrrolidone can be adsorbed on its particle surface to prevent its crystal from further growing, so that its particle size can be controlled, and the specific surface area of ​​the solid acid catalyst under the same mass is increased, so that more catalytic active centers can be provided, and therefore, its catalytic effect is better. In conjunction with Example 4, the calcination temperature is 500°C, that is, after reducing by 100°C, the catalytic activity of its solid acid catalyst is significantly reduced; this is because when the calcination temperature is low, zirconium dioxide cannot fully form the tetragonal crystal necessary for solid acid, and is also not conducive to the dispersion of titanium dioxide on its surface, so that the acidity of the solid acid catalyst is low and the catalytic activity is reduced.

[0076] It can be seen from the test data of Example 3 and Examples 5-8 that the addition amount of chloroplatinic acid and cerium chloride has a certain influence on the catalytic selectivity, and the preferred addition amount is Preparation Example 3.

[0077] It can be seen from the test data of Examples 9-10 and Comparative Examples 1-2 that the catalytic effect of the solid acid catalyst prepared in Preparation Example 3 is greatly reduced after 100 cycles of catalysis; the catalytic activity can be almost completely restored by calcining in air. When preparing the solid acid catalyst, cerium chloride is not added. Although its catalytic effect is better, the degree of recovery of the catalytic activity after calcination is low, which is not conducive to the service life of the solid acid catalyst. Combining the test data of Example 10 and Comparative Examples 1-3, it can be seen that when the calcination environment of the solid acid catalyst is nitrogen, its catalytic activity is almost not restored. It shows that the solid acid catalyst after high-temperature activation or calcination of nitrogen completely loses its isomerization activity and its catalytic ability is greatly reduced; and air oxidation plays a very important role in the oxidation of the acidic catalytic center on the catalyst surface and the sulfur species on its surface and the rearrangement of the active center. The ductility of metallic cerium is better, and its addition helps to restore its isomerization activity and maintain the reusability of the solid acid catalyst.

[0078] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A process for preparing an environmentally friendly pyridone ethanolamine salt, characterized in that: It comprises the following preparation steps: S1, reacting isononanoyl chloride and 3,3-dimethacrylate methyl under the catalysis of a solid acid catalyst to obtain 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester; S2, subjecting the 3,7,9,9-tetramethyl-2-decene-5-keto acid methyl ester obtained in S1 to a ring-closing reaction to obtain 4-methyl-6-2-pyrone; S3, mixing the 4-methyl-6-2-pyrone obtained in S2 with hydroxylamine hydrochloride to carry out hydroxylation reaction to obtain 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone; S4, subjecting the 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone prepared in S3 to a salt-forming reaction with ethanolamine to obtain pyridone ethanolamine salt; The preparation method of the solid acid catalyst is as follows: S1. Using water as solvent, add 14-16 parts by weight of zirconium oxychloride, 1-3 parts by weight of titanium sulfate, 0.1-0.5 parts by weight of chloroplatinic acid and 0.05-0.4 parts by weight of cerium chloride, adjust the pH to 10-11, age, and obtain a precipitate; S2. calcining the precipitate obtained in S1 in the preparation method of the solid acid catalyst in an air atmosphere at 500-600° C. to obtain a solid acid catalyst.

2. The process for preparing an environmentally friendly pyridone ethanolamine salt according to claim 1, characterized in that: In the preparation method of the solid acid catalyst, in S2, the precipitate obtained in S1 is firstly soaked in a 0.4-0.8 mol / L sulfuric acid solution, and then calcined in an air atmosphere at 500-600° C. to obtain a solid acid catalyst.

3. The preparation process of an environmentally friendly pyridone ethanolamine salt according to claim 2, characterized in that: The calcination temperature is 600°C.

4. The process for preparing an environmentally friendly pyridone ethanolamine salt according to claim 2, characterized in that: In the preparation method of the solid acid catalyst, 4-7 parts by weight of polyvinyl pyrrolidone is also added to the solvent of S1.

5. The process for preparing an environmentally friendly pyridone ethanolamine salt according to claim 2, characterized in that: The added amount of the zirconium oxychloride is 15 parts by weight, the added amount of the titanium sulfate is 1.5 parts by weight, the added amount of the chloroplatinic acid is 0.3 parts by weight, and the added amount of the cerium chloride is 0.2 parts by weight.

6. The process for preparing an environmentally friendly pyridone ethanolamine salt according to claim 1, characterized in that: The solid acid catalyst is washed with dichloromethane after the catalytic reaction and then dried under vacuum at 80-100°C.

7. The process for preparing an environmentally friendly pyridone ethanolamine salt according to claim 1, characterized in that: After being recycled for several times, the solid acid catalyst is calcined again in an air atmosphere.

8. The process for preparing an environmentally friendly pyridone ethanolamine salt according to claim 7, characterized in that: The temperature of the second calcination in air atmosphere is 450-550°C.

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