A highly efficient preparation process of octanoylhydroxamic acid

Abstract

The present application relates to the technical field of fine chemical synthesis, and in particular to an efficient preparation process of octanoyl hydroxamic acid, which comprises the following preparation steps: S1, preparation of ethyl n-octanoate: 90-110 parts by weight of n-octanoic acid and 35-40 parts by weight of ethanol are mixed, and then a solid acid catalyst is added, and the mixture is heated to reflux for reaction for 2.5-3 hours, filtered to obtain a precipitate and a filtrate, and the filtrate is decompressed and distilled to obtain ethyl n-octanoate; S2, preparation of octanoyl hydroxamic acid: 0.4-0.6 parts by weight of sodium acetate and 0.2-0.4 parts by weight of sodium carbonate are added to water, stirred until dissolved, ethanol is added, and after stirring, 24-32 parts by weight of hydroxylamine and ethyl n-octanoate prepared in S1 are added to react to obtain octanoyl hydroxamic acid; the process has the advantage of improving the reusability of the solid acid catalyst.

Description

Technical Field

[0001] The present application relates to the technical field of fine chemical synthesis, and in particular to an efficient preparation process of octanoylhydroxamic acid. Background Art

[0002] Octanoylhydroxamic acid, also known as octanoyl hydroxamic acid, is widely used in the fields of surfactants, cleaning agents, metalworking fluids, etc. In the traditional synthesis process of octanoylhydroxamic acid, octanoic acid and ethanol are usually firstly reacted with sulfuric acid to generate ethyl octanoate; then ethyl octanoate and hydroxylamine are reacted with a catalyst to produce octanoylhydroxamic acid.

[0003] And sulfuric acid is used as a catalyst, and the amount of sulfuric acid required for this step is large, the yield is low, there are many by-products, the energy consumption is high, and a large amount of wastewater will be produced during the reaction, which puts significant pressure on environmental protection. In the existing solution, there is an attempt to replace the liquid acid with a solid acid catalyst for catalysis, which reduces the discharge of wastewater to a certain extent, but due to the small contact surface between the solid acid catalyst and the reactant, its activity performance is not high and the conversion rate is low. In the related art, there is a method of preparing a solid acid catalyst into a hollow sphere to improve its reaction activity and the conversion rate of the reaction, but after repeated use, its structure is prone to collapse, and the reduction of its own catalytic activity makes it perform poorly when reused in the later stage. Summary of the invention

[0004] In order to improve the reusability of solid acid catalysts, the present application provides an efficient preparation process of octanoylhydroxamic acid.

[0005] In the first aspect, the present application provides an efficient preparation process of octanoylhydroxamic acid, which adopts the following technical scheme: An efficient preparation process of octanoylhydroxamic acid comprises the following preparation steps: S1. Preparation of ethyl octanoate: Mix 90-110 parts by weight of n-octanoic acid and 35-40 parts by weight of ethanol, then add a solid acid catalyst, heat and reflux for reaction for 2.5-3 hours, filter to obtain a precipitate and a filtrate, and distill the filtrate under reduced pressure to obtain ethyl n-octanoate; S2. Preparation of octanoylhydroxamic acid: 0.4-0.6 parts by weight of sodium acetate and 0.2-0.4 parts by weight of sodium carbonate are added to water, stirred until dissolved, ethanol is added, and after stirring, 24-32 parts by weight of hydroxylamine and ethyl octanoate prepared from S1 are added, and the mixture is stirred to react for 1.5-2.5 hours, filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to remove ethanol, water is added, the temperature is lowered to (-5)-5°C, the pH of the solution is adjusted to 3, and a white solid is precipitated at the same time, which is filtered to obtain octanoylhydroxamic acid; The preparation steps of the solid acid catalyst are as follows: S1. Using water as solvent, add 0.4-0.6 parts by weight of zirconium oxychloride, 0.05-0.07 parts by weight of titanium sulfate, 0.003-0.007 parts by weight of silver nitrate and 0.005-0.009 parts by weight of cerium ammonium nitrate, stir until dissolved, then add ammonia water dropwise under stirring until the pH reaches 9-11, stop adding dropwise, then age, filter, obtain a solid, wash the solid, and dry; S2. The dried solid is calcined in a muffle furnace, then immersed in a sulfuric acid solution and dried to obtain a solid acid catalyst.

[0006] By adopting the above technical scheme, the solid acid catalyst prepared by adding two metal oxides, silver oxide and cerium dioxide, at the same time can improve the purity and yield of ethyl octanoate, and through experiments, it is found that the solid acid catalyst still has a very high catalytic activity after 100 cycles of catalysis; while the solid acid catalyst only adding silver oxide or cerium dioxide has a large reduction in catalytic activity after 100 cycles of catalysis; it means that by adding silver oxide and cerium dioxide, the crystallization and sintering of zirconium dioxide and titanium dioxide can be greatly slowed down, thereby improving the strength of the solid acid catalyst and the total amount of acid catalytic centers, and can greatly improve the catalytic stability of the solid acid catalyst, shorten the time of the catalytic reaction, and improve the preparation efficiency and the reusability of the solid acid catalyst.

[0007] Preferably, in the preparation of ethyl n-octanoate, the solid acid catalyst is added in an amount of 0.005-0.015 parts by weight.

[0008] By adopting the above technical solution, at this addition amount, the catalytic reaction can be carried out stably and the catalytic efficiency is high.

[0009] Preferably, in the step of preparing the solid acid catalyst, in S1, firstly, 0.1-0.3 parts by weight of polyvinyl pyrrolidone is added to water, stirred until dissolved, and then the zirconium oxychloride, the titanium sulfate, the silver nitrate and the ammonium cerium nitrate are added.

[0010] By adopting the above technical solution, polyvinyl pyrrolidone is added during the preparation of the solid acid catalyst, so that it can adhere to the surface of the particles to prevent the particles from further increasing, thereby further reducing the particle size of the solid acid catalyst, increasing its specific surface area, and improving its catalytic activity.

[0011] Preferably, the model of the polyvinyl pyrrolidone is K30.

[0012] Preferably, in the step of preparing the solid acid catalyst, aqueous ammonia is added dropwise to S1 until the pH value reaches 10.

[0013] By adopting the above technical solution, when the pH is 10, the aging effect is higher and the metal ions can be completely precipitated.

[0014] Preferably, the calcination temperature is 500-600° C. and the calcination time is 2-4 hours.

[0015] By adopting the above technical solution, the acid catalytic center can be better formed by calcining at this temperature.

[0016] Preferably, the mass fraction of the ammonia water is 25%.

[0017] By adopting the above technical solution, the concentration of ammonia water should not be too low, which is not conducive to the aging effect, while too high will easily make the aging speed too fast and the particles of the solid acid catalyst larger.

[0018] Preferably, in the step of preparing the solid acid catalyst, the concentration of the sulfuric acid solution in S2 is 2 mol / L.

[0019] Preferably, the solid acid catalyst is activated after the catalytic reaction and then put into use, and the activation operation is as follows: The precipitate obtained in the preparation step of ethyl n-octanoate is washed with ethanol, then roasted at 500-600° C. for 1.5-3 hours, immersed in a sulfuric acid solution, and dried to obtain an activated solid acid catalyst.

[0020] By adopting the above technical solution, the catalytic activity of the solid acid catalyst can be better restored through activation.

[0021] In summary, the present application includes at least one of the following beneficial technical effects: 1. The solid acid catalyst prepared by adding two metal oxides, silver oxide and cerium dioxide, at the same time in the present application can improve the purity and yield of ethyl octanoate, and through experiments, it is found that after 100 cycles of catalysis, it still has a very high catalytic activity; while the solid acid catalyst only adding silver oxide or cerium dioxide has a higher reduction in catalytic activity after 100 cycles of catalysis; it shows that by adding silver oxide and cerium dioxide, the crystallization and sintering of zirconium dioxide and titanium dioxide can be greatly slowed down, thereby improving the strength of the solid acid catalyst and the total amount of acid catalytic centers, and can greatly improve the catalytic stability of the solid acid catalyst, shorten the time of the catalytic reaction, and improve the preparation efficiency and the reusability of the solid acid catalyst.

[0022] 2. The solid acid catalyst prepared in the present application has excellent catalytic activity. The purity and yield of the obtained ethyl octanoate are both high, with the purity being 99.1% and above, and the highest being 99.5%. At the same time, the yield is also between 91.8% and 96.7%. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with the specific contents.

[0024] raw material The raw materials used in the preparation examples and embodiments of the present application were all purchased from commercial sources and were of analytical purity.

[0025] Preparation Example 1 A solid acid catalyst, the preparation method of which is as follows: S1. Add 0.5 kg of zirconium oxychloride, 0.06 kg of titanium sulfate, 0.005 kg of silver nitrate and 0.007 kg of cerium ammonium nitrate to 15 kg of distilled water, stir until dissolved, then slowly add ammonia water with a mass fraction of 25% under rapid stirring until the pH reaches 10, stop adding, then age for 24 hours, filter to obtain a solid, wash the solid and dry it; S2. The dried solid was calcined in a muffle furnace at 550° C. for 3 h, then immersed in a 2 mol / L sulfuric acid solution for 2 h and dried to obtain a solid acid catalyst.

[0026] Preparation Example 2 A solid acid catalyst is different from Preparation Example 1 in that, in S1, 0.2 kg of polyvinyl pyrrolidone is first added to distilled water, the model of polyvinyl pyrrolidone is K30, and after stirring until dissolved, the subsequent steps are continued to obtain a solid acid catalyst.

[0027] Preparation Example 3 A solid acid catalyst, which is different from Preparation Example 2 in that the calcination temperature in S2 is 500° C., and the remaining steps are the same as Preparation Example 2.

[0028] Preparation Example 4 A solid acid catalyst, which is different from Preparation Example 2 in that the calcination temperature in S2 is 600°C, and the remaining steps are the same as Preparation Example 2.

[0029] Example 1 An efficient preparation process of octanoylhydroxamic acid, the preparation steps are as follows: S1. Preparation of ethyl octanoate: 100.8 g of n-octanoic acid and 36.8 g of ethanol were mixed, and then 0.01 g of a solid acid catalyst was added, and the mixture was heated under reflux for 3 h, and filtered to obtain a precipitate and a filtrate, and the filtrate was distilled under reduced pressure to obtain ethyl n-octanoate; the solid acid catalyst was from Preparation Example 1; S2. Preparation of octanoylhydroxamic acid: Add 0.5 g of sodium acetate and 0.3 g of sodium carbonate to distilled water, stir until dissolved, then add an equal volume of ethanol, stir for 15 min, add 28 g of hydroxylamine and ethyl octanoate prepared from S1, stir and react at 25 °C for 2 h, filter to obtain a filtrate, distill the filtrate under reduced pressure to remove ethanol, then add an equal volume of distilled water, lower the temperature to 0 °C, then add 2 mol / L sulfuric acid dropwise at a rate of 0.4 mL / min until the pH of the solution reaches 3, and a white solid precipitates. Then, after standing for 1 h, filter, wash 3 times with distilled water, and then dry at 70 °C to obtain octanoylhydroxamic acid.

[0030] Example 2 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 1 in that the solid acid catalyst comes from Preparation Example 2, and the remaining steps are the same as those of Example 1.

[0031] Example 3 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 1 in that the solid acid catalyst comes from Preparation Example 3, and the remaining steps are the same as those of Example 1.

[0032] Example 4 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 1 in that the solid acid catalyst comes from Preparation Example 4, and the remaining steps are the same as those of Example 1.

[0033] Example 5 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 2 in that the addition amount of the solid acid catalyst is 0.005g, and the remaining steps are the same as Example 2.

[0034] Example 6 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 2 in that the addition amount of the solid acid catalyst is 0.015g, and the remaining steps are the same as Example 2.

[0035] Example 7 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 2 in that the solid acid catalyst is reused after 100 cycles of catalysis. After the catalytic reaction, the solid acid catalyst is separated from the reaction system by filtration, i.e., the precipitate in S1. The precipitate is activated and then catalyzed. The activation operation is as follows: The precipitate obtained from S1 is washed with ethanol, calcined at 550°C for 2h, immersed in a 2mol / L sulfuric acid solution for 2h, and dried to obtain an activated solid acid catalyst, which is then recycled to S1 as a catalyst for repeated catalysis.

[0036] Comparative Example 1 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 2 in that the preparation method of the solid acid catalyst is as follows: S1. Add 0.5 kg of zirconium oxychloride and 0.072 kg of titanium sulfate to 15 kg of distilled water, stir until dissolved, then slowly add ammonia water with a mass fraction of 25% under rapid stirring until the pH reaches 10, stop adding, then age for 24 hours, filter to obtain a solid, wash the solid, and dry it; S2, calcining the dried solid in a muffle furnace at a temperature of 550° C. for 3 h, then soaking it in a 2 mol / L sulfuric acid solution for 2 h and drying it to obtain a solid acid catalyst; And the catalytic reaction time in step S1 is 5 h.

[0037] Comparative Example 2 An efficient preparation process of octanoylhydroxamic acid, which is different from Comparative Example 1 in that the solid acid catalyst is cyclically catalyzed 100 times, and after each catalytic reaction, the solid acid catalyst is activated according to the activation method in Example 7, and the remaining steps are the same as Comparative Example 1.

[0038] Comparative Example 3 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 2 in that the preparation method of the solid acid catalyst is as follows: S1. Add 0.5 kg of zirconium oxychloride, 0.06 kg of titanium sulfate and 0.012 kg of silver nitrate to 15 kg of distilled water, stir until dissolved, then slowly add ammonia water with a mass fraction of 25% under rapid stirring until the pH reaches 10, stop adding, then age for 24 hours, filter to obtain a solid, wash the solid and dry it; S2, calcining the dried solid in a muffle furnace at a temperature of 550° C. for 3 h, then soaking it in a 2 mol / L sulfuric acid solution for 2 h and drying it to obtain a solid acid catalyst; And the catalytic reaction time in step S1 is 5 h.

[0039] Comparative Example 4 An efficient preparation process of octanoylhydroxamic acid, which is different from Comparative Example 3 in that the solid acid catalyst is cyclically catalyzed 100 times, and after each catalytic reaction, the solid acid catalyst is activated according to the activation method in Example 7, and the remaining steps are the same as Comparative Example 3.

[0040] Comparative Example 5 An efficient preparation process of octanoylhydroxamic acid, which is different from Example 2 in that the preparation method of the solid acid catalyst is as follows: S1. Add 0.5 kg of zirconium oxychloride, 0.06 kg of titanium sulfate and 0.012 kg of cerium ammonium nitrate to 15 kg of distilled water, stir until dissolved, then slowly add ammonia water with a mass fraction of 25% under rapid stirring until the pH reaches 10, stop adding, then age for 24 hours, filter to obtain a solid, wash the solid and dry it; S2, calcining the dried solid in a muffle furnace at a temperature of 550° C. for 3 h, then soaking it in a 2 mol / L sulfuric acid solution for 2 h and drying it to obtain a solid acid catalyst; And the catalytic reaction time in step S1 is 5 h.

[0041] Comparative Example 6 An efficient preparation process of octanoylhydroxamic acid, which is different from Comparative Example 5 in that the solid acid catalyst is cyclically catalyzed 100 times, and after each catalytic reaction, the solid acid catalyst is activated according to the activation method in Example 7, and the remaining steps are the same as Comparative Example 5.

[0042] Performance testing Detection method / test method According to the preparation methods of Examples 1-7 and Comparative Examples 1-6, ethyl octanoate, i.e., the content in S1, was prepared. Then, the prepared ethyl octanoate was tested according to the following method. The test results are shown in Table 1.

[0043] Purity: tested by GC (gas chromatography); Yield = (output / feed amount) × 100%, where the feed amount is calculated based on the amount of the smaller reactant input.

[0044] Table 1 Test results of Examples 1-7 and Comparative Examples 1-6

[0045] It can be seen from Examples 1-7 and Comparative Examples 1-6, as well as the test data in Table 1, that the solid acid catalyst prepared in the present application has excellent catalytic activity, and the purity and yield of the obtained ethyl octanoate are both high, with the purity being 99.1% or above, and the highest being 99.5%, and the yield is also between 91.8% and 96.7%.

[0046] By introducing silver oxide and cerium oxide two kinds of metal oxides in solid acid catalyst, the catalytic stability of solid acid catalyst can be improved, its specific surface area is increased, the content of acidity and acidic center is increased, so as to improve its catalytic activity. It can be seen from the detection data of Example 2, Example 7 and Comparative Examples 1-6 that the solid acid catalyst prepared by adding silver oxide and cerium oxide two kinds of metal oxides simultaneously in the present application can improve the purity and yield of ethyl n-octanoate, and by comparison, it still has very high catalytic activity after 100 cycles of catalysis; and the solid acid catalyst of only adding silver oxide or cerium oxide, after 100 cycles of catalysis, its catalytic activity reduction amplitude is higher; It is explained that by adding silver oxide and cerium oxide, the crystallization and sintering of zirconium dioxide and titanium dioxide can be greatly slowed down, so as to improve the strength of solid acid catalyst and the total amount of acid catalytic center, and the catalytic stability of solid acid catalyst can be greatly improved, the time of catalytic reaction can be shortened, and the preparation efficiency can be improved.

[0047] It can be seen from the test data of Example 1 and Example 2 that by adding polyvinyl pyrrolidone during the preparation of the solid acid catalyst, it can be attached to the surface of the particles to prevent the particles from further increasing, so that the particle size of the solid acid catalyst can be further reduced, its specific surface area can be increased, and its catalytic activity can be improved. Combined with Examples 3-4, the calcination temperature is suitable at 550°C. It is speculated that because the temperature is too high, the ductility of silver and cerium is too high, which is not conducive to the formation of the acid catalytic center or it is easy to cover it. On this basis, combined with Examples 5-6, the addition amount of the solid acid catalyst is 0.01g as the optimal addition amount.

[0048] 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. An efficient preparation process of octanoylhydroxamic acid, characterized in that: It comprises the following preparation steps: S1. Preparation of ethyl octanoate: Mix 90-110 parts by weight of n-octanoic acid and 35-40 parts by weight of ethanol, then add a solid acid catalyst, heat and reflux for reaction for 2.5-3 hours, filter to obtain a precipitate and a filtrate, and distill the filtrate under reduced pressure to obtain ethyl n-octanoate; S2. Preparation of octanoylhydroxamic acid: 0.4-0.6 parts by weight of sodium acetate and 0.2-0.4 parts by weight of sodium carbonate are added to water, stirred until dissolved, ethanol is added, and after stirring, 24-32 parts by weight of hydroxylamine and ethyl octanoate prepared from S1 are added, and the mixture is stirred to react for 1.5-2.5 hours, filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to remove ethanol, water is added, the temperature is lowered to (-5)-5°C, the pH of the solution is adjusted to 3, and a white solid is precipitated at the same time, which is filtered to obtain octanoylhydroxamic acid; The preparation steps of the solid acid catalyst are as follows: S1. Using water as solvent, add 0.4-0.6 parts by weight of zirconium oxychloride, 0.05-0.07 parts by weight of titanium sulfate, 0.003-0.007 parts by weight of silver nitrate and 0.005-0.009 parts by weight of cerium ammonium nitrate, stir until dissolved, then add ammonia water dropwise under stirring until the pH reaches 9-11, stop adding dropwise, then age, filter, obtain a solid, wash the solid, and dry; S2. The dried solid is calcined in a muffle furnace, then immersed in a sulfuric acid solution and dried to obtain a solid acid catalyst.

2. The efficient preparation process of octanoylhydroxamic acid according to claim 1, characterized in that: In the preparation of ethyl n-octanoate, the addition amount of the solid acid catalyst is 0.005-0.015 parts by weight.

3. The efficient preparation process of octanoylhydroxamic acid according to claim 1, characterized in that: In the preparation step of the solid acid catalyst, in S1, 0.1-0.3 parts by weight of polyvinyl pyrrolidone is first added to water, stirred until dissolved, and then the zirconium oxychloride, the titanium sulfate, the silver nitrate and the cerium ammonium nitrate are added.

4. The efficient preparation process of octanoylhydroxamic acid according to claim 3, characterized in that: The model of the polyvinyl pyrrolidone is K30.

5. The efficient preparation process of octanoylhydroxamic acid according to claim 1, characterized in that: In the step of preparing the solid acid catalyst, aqueous ammonia is added dropwise to S1 until the pH value reaches 10.

6. The efficient preparation process of octanoylhydroxamic acid according to claim 1, characterized in that: The calcination temperature is 500-600° C., and the calcination time is 2-4 hours.

7. The efficient preparation process of octanoylhydroxamic acid according to claim 1, characterized in that: The mass fraction of the ammonia water is 25%.

8. The efficient preparation process of octanoylhydroxamic acid according to claim 1, characterized in that: In the step of preparing the solid acid catalyst, the concentration of the sulfuric acid solution in S2 is 2 mol / L.

9. The efficient preparation process of octanoylhydroxamic acid according to claim 1, characterized in that: After the catalytic reaction, the solid acid catalyst is activated before being put into use. The activation operation is as follows: The precipitate obtained in the preparation step of ethyl n-octanoate is washed with ethanol, then roasted at 500-600° C. for 1.5-3 hours, immersed in a sulfuric acid solution, and dried to obtain an activated solid acid catalyst.

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