Method for preparing azelaic acid by combining ozone with hydrogen peroxide

Abstract

The invention discloses a method for preparing azelaic acid through combination of ozone and hydrogen peroxide, and relates to the technical field of organic compounds, and the method comprises the following steps: S100, taking nonanoic acid or a mixture of the nonanoic acid and water as a solvent, taking unsaturated fatty acid and derivatives thereof as raw materials, adding the unsaturated fatty acid and the derivatives thereof into the solvent, and mixing; s200, ozone is adopted as an oxidizing agent, a normal-temperature and normal-pressure reaction is carried out, and an ozone compound is prepared; and S300, by taking low-concentration hydrogen peroxide as an oxidizing agent, heating and cracking the ozone compound prepared in the step S200 under the action of a catalyst to prepare azelaic acid. The nonanoic acid or the water / nonanoic acid mixed solvent is adopted, the technological operation is simple and safe, no pollution is caused to the product and the environment, and the reaction system is homogeneous and good in heat dissipation. Meanwhile, the nonanoic acid is generated in the reaction, the solvent dosage is small, no extra solvent type is introduced, the energy consumption and flow of the subsequent separation process are reduced, the nonanoic acid can be recycled, the reaction yield is high, and the emission of three wastes is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of organic compounds, and in particular to a method for preparing azelaic acid by combining ozone with hydrogen peroxide. Background Art

[0002] Azelaic acid is an organic compound with the molecular formula C 9 H 16 O 4 The appearance is white to slightly yellow monoclinic prism, needle-shaped crystal or powder. Azelaic acid has a wide range of uses, mainly used for: synthesizing polyester resins, as an additive for industrial lubricants, as an additive for beverages and foods, synthesizing some drugs and pharmaceutical intermediates, synthesizing softeners and flame retardants, and fuel additives, etc. In addition, azelaic acid has strong antibacterial and bactericidal properties, and is often used in clinical treatment of acne, seborrheic dermatitis, superficial fungal infections and pigmentation, etc. The development prospects of azelaic acid are very broad.

[0003] Chinese patent CN1927806A records that oleic acid is used as raw material, phosphotungstic acid is used as catalyst, quaternary ammonium salt is used as phase transfer catalyst, 30% hydrogen peroxide is added dropwise while passing ozone, reacting at 60-70°C for a period of time and then reacting at 95-105°C to obtain azelaic acid. The above method has many shortcomings, such as: using high-concentration hydrogen peroxide and needing to be matched with a wide variety of catalysts, and high cost; when ozone oxidation cracking alone is easy to increase the temperature sharply, there is a risk of material impact, and it pollutes the environment; when the solvent is not selected well, there is a situation of oil-water stratification (such as water as the solvent), stirring is difficult, and it is difficult to effectively mix, resulting in low reaction efficiency and other problems. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing azelaic acid by combining ozone with hydrogen peroxide, which solves one or more of the above problems.

[0005] In one aspect, the present invention provides a method for preparing azelaic acid by combining ozone with hydrogen peroxide, the method comprising the following steps:

[0006] S100. Using nonanoic acid or a mixture of nonanoic acid and water as a solvent, unsaturated fatty acids and their derivatives as raw materials, and adding unsaturated fatty acids and their derivatives to the solvent for mixing;

[0007] S200. Using ozone as an oxidant in a solvent, reacting at room temperature and pressure to obtain an ozone compound;

[0008] S300. Add a certain amount of catalyst to the above reaction system, use low concentration hydrogen peroxide as an oxidant, and heat and crack the ozone compound obtained in step S200 under the action of the catalyst to obtain azelaic acid.

[0009] Preferably, the step S400 is further included: filtering and recovering the catalyst from the azelaic acid prepared in S300, performing thermal stratification, extracting the oil layer with hot water, combining the water layers, cooling them, filtering them, and refining them to obtain a finished product.

[0010] Preferably, the unsaturated fatty acid and its derivatives are oleic acid, linoleic acid or a mixture of oleic acid and linoleic acid, wherein the mass ratio of oleic acid to linoleic acid in the mixture of oleic acid and linoleic acid is (1-7):1 (w / w). More preferably, the mass ratio of oleic acid to linoleic acid is 3:1 (w / w).

[0011] Preferably, the mass ratio of nonanoic acid to water in the mixture of nonanoic acid and water is 1:(1-4). More preferably, nonanoic acid:water=1:2 (w / w). The amount of solvent used is 0.3-2.0 times (w / w) of the raw material.

[0012] Preferably, the concentration of hydrogen peroxide is 20-30% (w / w). More preferably, the concentration of hydrogen peroxide is 25-30% (w / w).

[0013] Preferably, the amount of hydrogen peroxide used in the step is 1.0-2.0 times the mass of the unsaturated fatty acids and their derivatives. More preferably, the amount of hydrogen peroxide used is 1.4-1.8 times the mass of the unsaturated fatty acids and their derivatives.

[0014] Preferably, the catalyst is a transition metal oxide. The transition metal oxide is one or more of iron oxide, ferrous oxide, molybdenum oxide, and copper oxide. More preferably, the transition metal oxide is iron oxide or molybdenum oxide.

[0015] Preferably, the reaction temperature of the cracking in step S300 is 80-100° C. More preferably, the reaction temperature is 90-95° C.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The present application avoids the danger of material impact caused by rapid temperature rise when ozone is used alone, and adopts the method of hydrogen peroxide cracking. After the dropwise addition is completed, the reaction is kept warm until the end, and the process temperature is controllable.

[0018] 2) This application avoids the unsafe factors caused by continuous ventilation. Since the cracking reaction is generally carried out under high temperature conditions, high-temperature ventilation can easily take away the heat and solvent of the system, and a large amount of heat energy must be continuously provided and the lost solvent must be replenished. The method of hydrogen peroxide cracking used in this application can effectively simplify the operation, reduce energy consumption, and improve the safety of the operation.

[0019] 3) The present application avoids the use of highly corrosive and potentially explosive high-concentration (about 50%) hydrogen peroxide, thereby improving the safety of the operation.

[0020] 4) The present application avoids the problems caused by low utilization rate of hydrogen peroxide, large dosage, long-term ventilation, etc. when ozone and hydrogen peroxide are used simultaneously. Different oxidants are used according to the requirements of each step of the reaction, which has the advantages of high reaction selectivity, high product yield, and no pollution to the product.

[0021] 5) To avoid the problems of large amount of catalyst used in the existing process and the need for combined use of multiple catalysts, the catalyst used in the present invention is of a single type, cheap and easy to obtain. Since it is insoluble in water, it can be filtered and collected after the reaction is completed, without pollution to the product and the environment.

[0022] 6) In the present application, nonanoic acid or a water / nonanoic acid mixed solvent is used, the process is simple, the reaction system is homogeneous, the reaction is uniform, and the heat dissipation is good. At the same time, since nonanoic acid is produced by the reaction itself, the amount of solvent used is small and no additional solvent types are introduced, which reduces the energy consumption and process of the subsequent separation process. Nonanoic acid can be recycled and reused, reducing the emission of three wastes, the reaction yield is increased to more than 75%, and the product content is greater than 99.0%, meeting the relevant quality standard requirements. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0025] Example 1

[0026] In this embodiment, the mass ratio of oleic acid: linoleic acid = 3:1, the solvent is a mixture of nonanoic acid and water, the mass ratio of nonanoic acid: water = 1:2, the catalyst is molybdenum oxide, the concentration of hydrogen peroxide is 30%, and the cracking temperature is 90-95°C.

[0027] 50g of oleic acid mixture (oleic acid 63% + linoleic acid 21%, total content 84%) and 24g of nonanoic acid / water (nonanoic acid: water = 1:2) were added to a reaction flask, and ozone was introduced at room temperature with stirring for a period of time until the bromine did not fade to obtain an ozone compound, and then 0.1g of molybdenum trioxide was added, and 70g of 30% hydrogen peroxide was added dropwise at about 40°C. During this period, the system temperature gradually increased to 90-95°C. After the addition was completed, the reaction was kept warm for 5-6 hours until the reaction was complete. The system was hot filtered and the water layer was separated. The organic layer was extracted with 500ml of boiling water in batches, the water layers were combined, and the crude product was cooled and crystallized at 0-5°C. After hot water purification, 22.2g of the product was obtained with a yield of 79.3% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the nonanedioic acid product content was 99.52%.

[0028] Example 2

[0029] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and the scheme is the same as that of Example 1, except that the mass ratio of oleic acid to linoleic acid is 1:1.

[0030] 50g of oleic acid mixture (oleic acid 44% + linoleic acid 43%, total content 87%) and 24g of nonanoic acid / water (nonanoic acid: water = 1:2) were added to a reaction flask, and ozone was introduced at room temperature with stirring for a period of time until the bromine did not fade to obtain an ozone compound, and then 0.1g of molybdenum trioxide was added, and 70g of 30% hydrogen peroxide was added dropwise at about 40°C. During this period, the system temperature gradually increased to 90-95°C. After the addition was completed, the reaction was kept warm for 5-6 hours until the reaction was complete. The system was hot filtered and the water layer was separated. The organic layer was extracted with 500ml of boiling water in batches, the water layers were combined, and the crude product was cooled and crystallized at 0-5°C. After hot water purification, 23.3g of the product was obtained with a yield of 80.4% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the nonanedioic acid product content was 99.53%.

[0031] Example 3

[0032] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and its scheme is the same as that of Example 1, except that the mass ratio of oleic acid to linoleic acid is 7:1.

[0033] 50g of oleic acid mixture (oleic acid 71% + linoleic acid 12%, total content 83%) and 24g of nonanoic acid / water (nonanoic acid: water = 1:2) were added to a reaction flask, and ozone was introduced at room temperature with stirring for a period of time until the bromine did not fade to obtain an ozone compound, and then 0.1g of molybdenum trioxide was added, and 70g of 30% hydrogen peroxide was added dropwise at about 40°C. During this period, the system temperature gradually increased to 90-95°C. After the addition was completed, the reaction was kept warm for 5-6 hours until the reaction was complete. The system was hot filtered and the water layer was separated. The organic layer was extracted with 500ml of boiling water in batches, the water layers were combined, and the crude product was cooled at 0-5°C for crystallization. After hot water purification, 21.4g of the product was obtained with a yield of 77.4% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the nonanedioic acid product content was 99.48%.

[0034] Example 4

[0035] The present invention provides a safe and environmentally friendly method for producing azelaic acid, the scheme of which is the same as that of Example 1, except that the solvent is a mixture of nonanoic acid and water, and the mass ratio of nonanoic acid to water is 1:4. 21.5 g of product is obtained, the yield is 76.8% (the yield is calculated based on the actual content of oleic acid + linoleic acid), and the content of azelaic acid product is 99.42%.

[0036] Example 5

[0037] The present invention provides a safe and environmentally friendly method for producing azelaic acid, the scheme of which is the same as that of Example 1, except that the solvent is a mixture of nonanoic acid and water, and the mass ratio of nonanoic acid to water is 1:1. 22.8 g of product is obtained, the yield is 78.7% (the yield is calculated based on the actual content of oleic acid + linoleic acid), and the content of azelaic acid product is 99.55%.

[0038] Example 6

[0039] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and its scheme is the same as that of Example 1, except that the amount of hydrogen peroxide used is 1.8 times the mass of the oleic acid mixture.

[0040] 22.3 g of product was obtained with a yield of 79.7% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the product content of azelaic acid was 99.58%.

[0041] Comparative Example 1

[0042] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and the scheme is the same as that of Example 1, except that the mass ratio of oleic acid to linoleic acid is 8:1. 17.5 g of product is obtained, the yield is 62.5% (the yield is calculated based on the actual content of oleic acid + linoleic acid), and the azelaic acid product content is 98.37%.

[0043] Comparative Example 2

[0044] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and its scheme is the same as that of Example 1, except that the solvent is water.

[0045] 15.4 g of product was obtained with a yield of 53.1% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the azelaic acid product content was 99.03%.

[0046] Comparative Example 3

[0047] The present invention provides a safe and environmentally friendly method for producing azelaic acid, which is the same as Example 7, except that the concentration of hydrogen peroxide is 15%.

[0048] 10.7 g of product was obtained with a yield of 38.2% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the product content of azelaic acid was 96.98%.

[0049] Comparative Example 4

[0050] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and its scheme is the same as that of Example 7, except that: the concentration of hydrogen peroxide is 40%, the cleavage reaction is obviously exothermic, and the hydrogen peroxide dripping speed should be controlled in the early stage.

[0051] 22.2 g of product was obtained with a yield of 79.3% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the content of azelaic acid product was 99.27%.

[0052] Comparative Example 5

[0053] The present invention provides a safe and environmentally friendly method for producing azelaic acid, which is the same as Example 8, except that the amount of hydrogen peroxide used is 0.9 times the mass of the oleic acid mixture.

[0054] 17.3 g of product was obtained with a yield of 61.8% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the product content of azelaic acid was 97.20%.

[0055] Comparative Example 6

[0056] The present invention provides a safe and environmentally friendly method for producing azelaic acid, which is the same as Example 8, except that the amount of hydrogen peroxide used is 2.1 times the mass of the oleic acid mixture.

[0057] 21.4 g of product was obtained with a yield of 76.5% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the product content of azelaic acid was 99.22%.

[0058] Comparative Example 7

[0059] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and its scheme is the same as that of Example 9, except that: the catalyst is manganese acetate.

[0060] 3.5 g of product was obtained with a yield of 12.5% ​​(the yield was calculated based on the actual content of oleic acid + linoleic acid), and the content of azelaic acid product was 96.40%.

[0061] Comparative Example 8

[0062] The present invention provides a safe and environmentally friendly method for producing azelaic acid, and its scheme is the same as that of Example 1, except that the reaction temperature of the cracking is 70-80°C.

[0063] 6.9 g of product was obtained with a yield of 24.6% (the yield was calculated based on the actual content of oleic acid + linoleic acid), and the product content of azelaic acid was 96.91%.

[0064] It should be noted that according to the standard requirements set by the pharmacopoeia, the prepared azelaic acid needs to meet the relevant quality standard requirements: the content (purity) standard is ≥99.0%; the yield is required to be above 75%.

[0065] Table 1 Experimental comparison data table

[0066]

[0067] From Table 1, we can see that:

[0068] 1. Because linoleic acid is more expensive than oleic acid and has high cost, this application is based on Example 1 and Comparative Example

[0069] Comparison of 1 and 2 shows that the smaller the value of oleic acid:linoleic acid is, the higher the yield tends to be, thereby increasing the yield and saving costs.

[0070] 2. Comparison of Example 1 with Comparative Examples 3 and 4 shows that the oxidation effect is poor and the yield is low when the hydrogen peroxide concentration is low. However, if the hydrogen peroxide concentration is high, the heat released during the reaction is obvious and there is a safety problem.

[0071] 3. Although the oxidation effect is poor when the amount of hydrogen peroxide is low, and the product yield and content are not ideal, the higher the amount, the better. Comparison of Example 1 with Comparative Examples 5 and 6 shows that when the amount of hydrogen peroxide exceeds 2.0 times the mass of the oleic acid mixture, it is not conducive to the reaction and increases the material cost.

[0072] 4. Comparison between Example 1 and Comparative Example 7 shows that when other types of catalysts such as manganese acetate are used, the yield and content are not ideal.

[0073] 5. Comparison between Example 1 and Comparative Example 8 shows that the reaction temperature of pyrolysis also affects the final yield and content of the product. When the reaction temperature is lower than 80°C, it is not conducive to the reaction, and the yield and content are not ideal.

[0074] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing azelaic acid by combining ozone with hydrogen peroxide, characterized in that: The method comprises the following steps: S100. Using nonanoic acid or a mixture of nonanoic acid and water as a solvent, unsaturated fatty acids and their derivatives as raw materials, and adding unsaturated fatty acids and their derivatives to the solvent for mixing; S200. Using ozone as an oxidant, reacting at room temperature and pressure to obtain an ozone compound; S300. Using low concentration hydrogen peroxide as an oxidant, the ozone compound obtained in step S200 is heated and cracked under the action of a catalyst to obtain azelaic acid.

2. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The step S400 is also included: filtering and recovering the catalyst from the azelaic acid prepared in S300, performing thermal stratification, extracting the oil layer with hot water, combining the water layers, cooling them, filtering them, and refining them to obtain a finished product.

3. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The unsaturated fatty acid and its derivatives are oleic acid, linoleic acid or a mixture of oleic acid and linoleic acid, wherein the mass ratio of oleic acid to linoleic acid in the mixture of oleic acid and linoleic acid is (1-7):

1.

4. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The mass ratio of nonanoic acid to water in the mixture of nonanoic acid and water is 1:(1-4).

5. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The concentration of the hydrogen peroxide is 20-30% (w / w).

6. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The amount of hydrogen peroxide used in the step is 1.0-2.0 times the mass of the unsaturated fatty acid and its derivatives.

7. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The catalyst is a transition metal oxide.

8. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The transition metal oxide is one or more of iron oxide, ferrous oxide, molybdenum oxide and copper oxide.

9. The method for preparing azelaic acid by combining ozone with hydrogen peroxide according to claim 1, characterized in that: The reaction temperature of the cracking in step S300 is 80-100°C.

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