Preparation method and application of tributyrin catalyst

Abstract

The invention discloses a preparation method and application of a tributyrin catalyst, and belongs to the field of tributyrin preparation. The catalyst used in the method is a tantalum-containing compound or an acid-modified tantalum-containing compound, and compared with a traditional method for preparing tributyrin through a protonic acid catalyst, the catalyst is high in activity, capable of achieving the yield of tributyrin of 90% or above, environmentally friendly, not prone to causing equipment corrosion and free of generating a large amount of reaction waste; meanwhile, the catalyst is easy to prepare and low in cost, the product and the catalyst can be separated for recycling through simple filtering operation, the catalytic performance of the catalyst cannot be reduced after recycling, and the yield of 90% or above can still be kept.

Description

Technical Field

[0001] The present invention belongs to the field of the preparation of tributyrin, and particularly relates to a preparation method and application of a catalyst for tributyrin. Background Art

[0002] Tributyrin is a compound formed by the esterification reaction of glycerol and three molecules of butyric acid, belonging to glycerides, and its chemical formula is C 12 H 24 O6. As a plasticizer, it can effectively enhance the flexibility and processability of materials. In addition, tributyrin also has wide applications in the food and pharmaceutical industries.

[0003] Tributyrin is generally prepared by reacting butyric acid and glycerol under the action of an acidic catalyst, and the reaction equation is as follows:

[0004]

[0005] At present, the catalysts used in the synthesis of tributyrin are mostly homogeneous acids such as phosphoric acid, sulfuric acid, p-toluenesulfonic acid, etc. The conditions are harsh, the acidity is strong, and a large amount of waste acid is generated subsequently, which does not meet the requirements of green production and environmental protection.

[0006] In addition, when butyric acid and glycerol carry out the esterification reaction, there are high requirements for both temperature and catalyst. This is because the glycerol molecule structure contains three hydroxyl groups, and there are many side reactions, so the reaction selectivity is low. If the catalyst is not selected properly, side reactions are likely to occur in the esterification reaction, reducing the yield of tributyrin. Therefore, the catalyst for tributyrin must be strictly screened to obtain a catalyst with good catalytic effect on the esterification synthesis of tributyrin, no waste generation, and mild reaction conditions as much as possible. Summary of the Invention

[0007] Technical Problem

[0008] At present, the catalysts in the synthesis of tributyrin have many disadvantages such as harsh reaction conditions and large amounts of reaction waste, so it is necessary to provide a catalyst with good catalytic effect on the esterification synthesis of tributyrin, no waste generation, and mild reaction conditions.

[0009] Technical Content

[0010] For this reason, the present invention has developed a preparation method of tributyrin, which has the advantages of simple operation, green environmental protection, high yield, and suitability for industrial production. To meet the above requirements, the present invention adopts the following technical solutions:

[0011] The present invention provides a catalyst for catalyzing the synthesis of tributyrin, and the catalyst is a tantalum-containing compound or a tantalum-containing compound modified by an acid.

[0012] In one embodiment of the present invention, the tantalum-containing compound includes one or more of tantalum oxide, tantalum hydroxide, tantalate, and tantalum-containing composite oxide.

[0013] In one embodiment of the present invention, the tantalum oxide is Ta2O5.

[0014] In one embodiment of the present invention, the preparation process of the tantalum hydroxide is as follows: Take tantalum chloride, add ammonia water, adjust the pH to neutral, stir for 1 to 10 hours, let it stand for 10 to 20 hours to obtain a precipitate, wash and dry the precipitate, and then calcine it at 300 to 400 °C to obtain tantalum hydroxide.

[0015] In one embodiment of the present invention, the tantalate includes potassium tantalate and / or lithium tantalate.

[0016] In one embodiment of the present invention, the tantalum-containing composite oxide is a composite oxide formed by tantalum and other elements; the other elements include one or more of silicon, tungsten, zirconium, aluminum, cobalt, vanadium, tin, and niobium.

[0017] Specifically, the other element is silicon or zirconium.

[0018] In one embodiment of the present invention, the preparation method of the tantalum-containing composite oxide is specifically as follows:

[0019] Dissolve tantalum chloride in an organic solvent, add other oxides, stir, adjust the pH to neutral, then let it stand and take the precipitate for calcination to obtain a composite oxide formed by tantalum and other metals.

[0020] In one embodiment of the present invention, the organic solvent includes one or more of absolute ethanol, chloroform, carbon tetrachloride, carbon disulfide, and thiophenol.

[0021] In one embodiment of the present invention, the other oxides include one or more of zirconium oxychloride, silicon dioxide, tungsten oxide, zirconium oxide, and aluminum oxide.

[0022] Specifically, the other oxide is zirconium oxychloride or silicon dioxide.

[0023] In one embodiment of the present invention, the molar ratio of tantalum chloride to other oxides is 1:0.1 to 100.

[0024] Specifically, the molar ratio of tantalum chloride to other oxides is 1:0.2 to 70.

[0025] In one embodiment of the present invention, the standing time is 8 to 16 hours.

[0026] In one embodiment of the present invention, the calcination temperature is 200 - 700 °C and the time is 3 - 8 h.

[0027] In one embodiment of the present invention, the acid-modified tantalum-containing compound refers to the acid modification of the tantalum-containing compound with an inorganic acid.

[0028] In one embodiment of the present invention, the inorganic acid includes hydrochloric acid, sulfuric acid, phosphoric acid or nitric acid.

[0029] In one embodiment of the present invention, the specific process of the acid modification is as follows: Immerse the tantalum-containing compound in an inorganic acid solution with a concentration of 0.1-10 mol / L for 1-20 hours, then take out the precipitate and wash it with water until it is neutral, and then activate it at a high temperature of 250-350 °C for 1-5 hours to complete the acid modification.

[0030] In one embodiment of the present invention, the acid-modified tantalum-containing compounds include acid-modified tantalum oxide, acid-modified tantalum hydroxide or acid-modified tantalate.

[0031] Specifically, the acid-modified tantalum-containing compound is acid-modified tantalum oxide.

[0032] Specifically, the preparation process of the acid-modified tantalum oxide is as follows: Immerse tantalum hydroxide in an inorganic acid solution with a concentration of 0.1-10 mol / L for 1-20 hours, then take out the precipitate and wash it with water until it is neutral, and then activate it at a high temperature of 250-350 °C for 1-5 hours to obtain the acid-modified tantalum oxide.

[0033] The present invention also provides a method for catalytic synthesis of tributyrin, and the method includes the following steps:

[0034] Mix butyric acid, glycerol and the above catalyst, and heat for an esterification reaction to obtain tributyrin.

[0035] Furthermore, the molar ratio of butyric acid to glycerol is 3-6:1.

[0036] Furthermore, the addition amount of the catalyst is 1-10 wt% of the mass of glycerol.

[0037] Furthermore, the temperature of the esterification reaction is 120-200 °C, and the time is 1-5 h.

[0038] Beneficial effects

[0039] Compared with the method for preparing glyceryl tributyrate using traditional proton acid catalysts, the catalyst prepared by the present invention has high activity, can achieve a yield of glyceryl tributyrate of over 90%, is environmentally friendly, is not likely to cause equipment corrosion, and does not produce a large amount of reaction waste. At the same time, the catalyst is easy to prepare, has low cost, is insoluble in water, and the product and the catalyst can be separated and recovered by simple filtration operation. Moreover, after recycling and reuse, its catalytic performance does not decline, and it can still maintain a yield of over 90%, meeting the requirements of green and sustainable development. Description of the Drawings

[0040] Figure 1 SEM image of the tantalum oxide catalyst treated with phosphoric acid prepared in Example 1.

[0041] Figure 2 Glyceryl tributyrate obtained in Example 1.

[0042] Figure 3 Results of the catalyst recycling performance in Example 5. Detailed Description of the Invention

[0043] The following further illustrates the specific implementation of the present invention in conjunction with examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that for the processes not specifically described in detail below, those skilled in the art can implement or understand them with reference to the prior art. Reagents or instruments not indicating the manufacturer are regarded as conventional products that can be obtained through commercial purchase.

[0044] Source of Raw Materials

[0045] Tantalum hydroxide and tantalum chloride were purchased from Ningxia Orient Tantalum Industry Co., Ltd., with an analytical purity specification; zirconium oxychloride was purchased from Aladdin Biochemical Technology Co., Ltd., with an analytical purity specification; silicon dioxide was purchased from Jiangsu Qiangsheng Chemical Co., Ltd., with an analytical purity specification.

[0046] Example 1

[0047] Take 1.5 g of tantalum hydroxide, add it to 20 mL of a 1 M phosphoric acid aqueous solution, stir at room temperature for 52 h, stand for aging for 12 h, centrifuge to separate out the white precipitate, then wash it with water until the pH becomes neutral, dry at 60 °C, grind, and then dry in a vacuum drying oven at 110 °C for 2 h, and then slowly heat it to 300 °C in a muffle furnace and activate it for 3 h to obtain the required catalyst, which is a tantalum oxide catalyst treated with phosphoric acid.

[0048] Take 0.01 g of the tantalum oxide catalyst obtained after being treated with phosphoric acid, 20 mL of butyric acid, and 5 mL of glycerol, react at 120 °C for 90 min, then filter the reaction solution to separate out the catalyst, and the reaction solution after removing the catalyst is detected by high-performance liquid chromatography. The yield of glyceryl tributyrate is 92%.

[0049] Example 2

[0050] Take 1 g of tantalum chloride and dissolve it in 10 mL of anhydrous methanol. After it is dissolved, add 0.2 g of zirconium oxychloride. While stirring, dropwise add ammonia water to adjust the pH to neutral, then continue stirring for 4 h, stand for aging for 12 h, wash with water until free of chloride ions, and dry the obtained precipitate at 60 °C for 2 h, and activate and calcine it at 500 °C to obtain ZrO / Ta2O5 with a loading of 20%.

[0051] Take 0.01 g of the above catalyst, 15 mL of butyric acid, and 3 mL of glycerol, react at 130 °C for 60 min, then filter the reaction solution to separate the catalyst, and detect the reaction solution after removing the catalyst by high performance liquid chromatography. The yield of tributyrin is 91%.

[0052] Example 3

[0053] Take 0.2 g of tantalum chloride, add 20 mL of anhydrous ethanol, after it is dissolved, add 2 g of silicon dioxide, stir for 3 h, filter to obtain a precipitate after standing for 5 h, wash with water until free of chloride ions, then dry and calcine at 450 °C to obtain Ta2O5 / SiO2 with a loading of 10%.

[0054] Take 0.02 g of the above catalyst, 15 mL of butyric acid, and 3 mL of glycerol, react at 130 °C for 40 min, then filter the reaction solution to separate the catalyst, and detect the reaction solution after removing the catalyst by high performance liquid chromatography. The yield of tributyrin is 93%.

[0055] Example 4

[0056] Take 3 g of tantalum chloride, add ammonia water, and adjust the pH to neutral with ammonia water, then stir for 5 h, stand overnight for aging to obtain a precipitate, wash the precipitate with water and then dry it, and then calcine it at 350 °C to obtain the required tantalum hydroxide catalyst.

[0057] Take 0.02 g of the above catalyst, 15 mL of butyric acid, and 3 mL of glycerol, react at 130 °C for 60 min, then filter the reaction solution to separate the catalyst, and detect the reaction solution after removing the catalyst by high performance liquid chromatography. The yield of tributyrin is 92%.

[0058] Example 5

[0059] Recover the catalyst after the reaction in Example 1 above, wash it with water and dry it for standby. Take 0.02 g of the recovered catalyst, 15 mL of butyric acid, and 3 mL of glycerol, react at 130 °C for 40 min, then filter the reaction solution to separate the catalyst, and detect the reaction solution after removing the catalyst by high performance liquid chromatography. The yield of tributyrin is 91%.

[0060] Comparative Example 1

[0061] Take 0.2 g of copper nitrate and dissolve it in 30 mL of water. After it is completely dissolved, add 1 g of tantalum oxide, stir at room temperature for 4 h, let it stand for aging for 24 h, dry the obtained precipitate at 60 °C for 2 h, and activate and calcine it at 500 °C to obtain CuO / Ta2O5 with a loading amount of 20%.

[0062] Take 0.05 g of the above catalyst, 15 mL of butyric acid, and 3 mL of glycerol, react at 130 °C for 60 min, then filter the reaction solution to separate the catalyst, and detect the reaction solution after removing the catalyst by high performance liquid chromatography. The yield of tributyrin is 68%.

[0063] The embodiments provided above are not intended to limit the scope covered by the present invention, nor are the described steps intended to limit the order of their execution. Obvious improvements made by those skilled in the art to the present invention in combination with the existing common general knowledge also fall within the protection scope defined by the claims of the present invention.

Claims

1. A catalyst for catalyzing the synthesis of tributyrin, characterized in that: The catalyst is a tantalum-containing compound or an acid-modified tantalum-containing compound; The tantalum-containing compound includes one or more of tantalum oxide, tantalum hydroxide, tantalate, and tantalum-containing composite oxide; The tantalum-containing composite oxide is a composite oxide formed by tantalum and other elements; the other elements include one or more of silicon, tungsten, zirconium, aluminum, cobalt, vanadium, tin, and niobium.

2. The catalyst according to claim 1, characterized in that The tantalum oxide is Ta2O5; the tantalate includes potassium tantalate and / or lithium tantalate.

3. The catalyst according to claim 1, characterized in that The preparation method of the tantalum-containing composite oxide is: Tantalum chloride is dissolved in an organic solvent, other oxides are added, the pH is adjusted to be neutral after stirring, and the precipitate is allowed to stand and roasted to obtain a composite oxide formed by tantalum and other metals; the other oxides include one or more of zirconium oxychloride, silicon dioxide, tungsten oxide, zirconium oxide, and aluminum oxide; the molar ratio of tantalum chloride to other oxides is 1:0.1-100.

4. The catalyst according to claim 3, characterized in that The standing time is 8 to 16 hours, the calcining temperature is 200 to 700° C., and the calcining time is 3 to 8 hours.

5. The catalyst according to claim 3, characterized in that The other oxides are zirconium oxychloride or silicon dioxide, and the molar ratio of tantalum chloride to the other oxides is 1:0.2-70.

6. The catalyst according to claim 1, characterized in that The acid-modified tantalum-containing compound refers to a tantalum-containing compound that is acid-modified using an inorganic acid; the inorganic acid includes hydrochloric acid, sulfuric acid, phosphoric acid or nitric acid.

7. The catalyst according to claim 6, characterized in that The specific process of the acid modification is: immersing the tantalum-containing compound in an inorganic acid solution with a concentration of 0.1-10 mol / L for 1 to 20 hours, then taking out the precipitate and washing it with water until it is neutral, and then activating it at a high temperature of 250 to 350° C. for 1 to 5 hours to complete the acid modification.

8. The catalyst according to any one of claims 1 to 7, characterized in that The acid-modified tantalum-containing compound is acid-modified tantalum oxide; the preparation process of the acid-modified tantalum oxide is: immersing tantalum hydroxide in an inorganic acid solution with a concentration of 0.1-10 mol / L for 1 to 20 hours, then taking out the precipitate and washing it with water until it is neutral, and then activating it at a high temperature of 250 to 350° C. for 1 to 5 hours to obtain the acid-modified tantalum oxide.

9. A catalytic synthesis method of tributyrin, characterized in that: The method comprises the following steps: Butyric acid, glycerol and the catalyst according to any one of claims 1 to 9 are mixed and heated to carry out esterification reaction to obtain tributyrin.

10. A catalytic synthesis method of tributyrin according to claim 9, characterized in that: The molar ratio of butyric acid to glycerol is 3-6:1; the amount of catalyst added is 1-10wt% of the mass of glycerol; the temperature of the esterification reaction is 120-200°C and the time is 1-5h.

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