Catalyst for preparing trimesic acid and method for preparing trimesic acid

Abstract

The invention relates to the technical field of trimesic acid, and discloses a catalyst for preparing trimesic acid and a method for preparing trimesic acid, the catalyst comprises cobalt salt, manganese salt, hafnium salt, lanthanum salt and alkali metal bromide; the method comprises the following step: in the presence of the catalyst, a solvent and an optional dispersing agent, carrying out oxidation reaction on mesitylene to obtain trimesic acid. The reaction is carried out under normal pressure, the reaction temperature is 80-100 DEG C, the reaction is easy to realize, the reaction condition is mild, the operation is facilitated, and the weight yield and the product purity of the trimesic acid are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of trimellitic acid, and particularly relates to a catalyst for preparing trimellitic acid and a method for preparing trimellitic acid. Background Art

[0002] Trimellitic acid, namely 1,3,5-benzenetricarboxylic acid, is an important chemical raw material and an intermediate for the production of special polymers and resins, with very wide applications. It can be used to synthesize alkyd resins with polyols and make water-soluble baking paints; it can be used as a curing crosslinking agent for unsaturated resins; it can be used to manufacture aromatic polyimide-polysulfone reverse osmosis membranes for seawater desalination and the production of ultrapure water; its esters are also a kind of high-grade plasticizers. Therefore, it is of great significance for the production of plastics, synthetic fibers, water-soluble alkyl resins, plasticizers, fungicides, mildew-proof agents, crosslinking agents, etc.

[0003] There have been many studies on the preparation methods of trimellitic acid at home and abroad. There are roughly three methods: the oxidation of mesitylene with potassium permanganate, the oxidation of mesitylene with nitric acid, and the liquid-phase air oxidation of mesitylene. Among them, in the reaction process of the potassium permanganate oxidation method, a large amount of wastewater and waste residue are generated, the post-treatment is difficult, the conversion rate is low, and the purification is complex; for the nitric acid method, the raw material cost is high, the selectivity is poor, the product yield does not exceed 70%, the refining of the crude product is difficult, and the environmental pollution and the production process are highly dangerous.

[0004] In the usual liquid-phase air oxidation method, glacial acetic acid is used as a solvent, and cobalt salt is used as a catalyst at a pressure of 2 - 4 MPa and a temperature of 200°C - 250°C, and air is passed to oxidize mesitylene to obtain trimellitic acid. The production process of this method is relatively mature but complex, the equipment investment is large, and large-scale industrialization has not been achieved. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems of low yield of trimellitic acid and high reaction temperature and pressure existing in the prior art, and to provide a catalyst for preparing trimellitic acid and a method for preparing trimellitic acid.

[0006] To achieve the above purpose, in the first aspect of the present invention, a catalyst for preparing trimellitic acid is provided, and the catalyst includes cobalt salt, manganese salt, hafnium salt, lanthanum salt, and alkali metal bromide.

[0007] In the second aspect of the present invention, a method for preparing trimellitic acid is provided, and the method includes: in the presence of a catalyst, a solvent, and an optional dispersant, subjecting mesitylene to an oxidation reaction to obtain trimellitic acid; wherein, the catalyst is the catalyst described in the first aspect.

[0008] Through the above technical solutions, the present invention has the following beneficial effects:

[0009] (1) The reaction of the present invention is carried out under atmospheric pressure, and the reaction temperature is 80 - 100 °C, which is easy to achieve. The reaction conditions are mild and conducive to operation.

[0010] (2) In the present invention, cobalt acetate and manganese acetate are used as the main catalysts, and hafnium acetate, lanthanum acetate, bromide initiator and dispersant are added to promote the uniform dispersion of mesitylene in the mixed solution and sufficient reaction, which can improve the weight yield and product purity of trimellitic acid. Detailed implementation mode

[0011] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0012] In the present invention, unless otherwise specified, the "room temperature" refers to 20 - 30 °C. The "pressure" refers to gauge pressure.

[0013] The first aspect of the present invention provides a catalyst for preparing trimellitic acid, and the catalyst comprises cobalt salt, manganese salt, hafnium salt, lanthanum salt and alkali metal bromide.

[0014] According to the present invention, in order to improve the yield of trimellitic acid, preferably, the molar ratio of cobalt salt based on Co, manganese salt based on Mn, hafnium salt based on Hf, lanthanum salt based on La and alkali metal bromide based on Br in the catalyst is 1:0.8 - 1.2:0.008 - 0.03:0.015 - 0.06:0.3 - 1, preferably 1:0.8 - 1.2:0.008 - 0.03:0.015 - 0.06:0.65 - 0.9; more preferably 1:0.9 - 1.1:0.01 - 0.02:0.02 - 0.04:0.65 - 0.9.

[0015] According to the present invention, the alkali metal bromide can be the alkali metal bromides commonly used in the art. Preferably, the alkali metal bromide is sodium bromide and / or potassium bromide.

[0016] According to the present invention, preferably, the cobalt salt is cobalt acetate.

[0017] According to the present invention, preferably, the manganese salt is manganese acetate.

[0018] According to the present invention, preferably, the hafnium salt is hafnium acetate. Hafnium acetate can be directly purchased or prepared. The method for preparing hafnium acetate can be as follows: Dissolve hafnium oxychloride in water, then add ammonia water (with a mass fraction of 25 - 28 wt%) to form a Hf(OH)4 precipitate. After washing, dissolve it in acetic acid to obtain hafnium acetate. Among them, relative to every 100 g of hafnium oxychloride, the amount of water used is 200 - 350 g, the amount of ammonia water used is 188 - 241 g, and the amount of acetic acid used is 91 - 135 g.

[0019] According to the present invention, preferably, the lanthanum salt is lanthanum acetate.

[0020] The second aspect of the present invention provides a method for preparing trimellitic acid, which includes: subjecting mesitylene to an oxidation reaction in the presence of a catalyst, a solvent, and an optional dispersant to obtain trimellitic acid; wherein, the catalyst is the catalyst described in the first aspect.

[0021] According to the present invention, preferably, relative to every 100 g of mesitylene, the amount of the solvent used is 600 - 1800 g, the amount of the catalyst used is 2 - 9 g, preferably 4 - 6 g, and the amount of the dispersant used is 0.5 - 1 g, preferably 0.5 - 0.6 g.

[0022] Relative to every 100 g of mesitylene, the amount of the solvent used can be 600 g, 700 g, 800 g, 900 g, 1000 g, 1100 g, 1200 g, 1300 g, 1400 g, 1500 g, 1600 g, 1700 g, 1800 g, and the ranges composed of any two of the above. Preferably, relative to every 100 g of mesitylene, the amount of the solvent used is 1000 - 1200 g.

[0023] Relative to every 100 g of mesitylene, the amount of the catalyst used can be 2 g, 2.2 g, 2.3 g, 3 g, 4 g, 4.5 g, 4.9 g, 5 g, 5.2 g, 5.5 g, 6 g, 7 g, 8 g, 9 g, and the ranges composed of any two of the above. Preferably, relative to every 100 g of mesitylene, the amount of the catalyst used is 2 - 9 g, more preferably 2 - 2.3 g, or more preferably 5 - 5.2 g.

[0024] According to the present invention, the solvent can be a commonly used solvent in the art. Preferably, the solvent is acetic acid.

[0025] According to the present invention, the dispersant can be a commonly used dispersant in the art. Preferably, the dispersant is triethanolamine.

[0026] According to the present invention, preferably, during the oxidation reaction, mesitylene contacts with oxygen to undergo an oxidation reaction. Relative to every 100 g of mesitylene, the flow rate of oxygen is 1.5 - 2 L / min.

[0027] According to the present invention, preferably, the temperature of the oxidation reaction is 80 - 100 °C, and the time of the oxidation reaction is 4 - 6 h. The reaction of the present invention can be carried out under normal pressure or at a higher pressure. In order to reduce the requirements for equipment, preferably, the pressure of the oxidation reaction of the present invention is 0 - 0.2 MPa. In a particularly preferred case, the pressure of the oxidation reaction is normal pressure (0 MPa).

[0028] According to the present invention, preferably, the method further includes cooling, solid-liquid separation, and drying of the product of the oxidation reaction. Among them, the cooling temperature can be 5 - 30 °C.

[0029] According to a particularly preferred embodiment of the present invention, the present invention provides a method for preparing trimellitic acid, which includes: adding 100 g of mesitylene and 1100 - 1200 g of glacial acetic acid solvent into a flask, adding 2 - 2.1 g of cobalt acetate, 2 - 2.1 g of manganese acetate, 0.05 - 0.06 g of hafnium acetate, 0.09 - 0.1 g of lanthanum acetate, 0.9 - 1 g of sodium bromide, and 0.5 - 0.55 g of triethanolamine dispersant under stirring at room temperature, heating to 90 - 95 °C, introducing oxygen at a flow rate of 1.8 - 2 L / min, stirring for 5.5 - 6 h, cooling to 20 - 35 °C, centrifuging and drying to obtain a filter cake, and drying the filter cake to obtain the product.

[0030] The present invention will be described in detail below through examples. In the following examples,

[0031] The catalytic products were analyzed by chromatographic analysis and chemical titration methods;

[0032] The calculation formula for the yield (%) of trimellitic acid is:

[0033]

[0034] M 均苯三甲酸 is the molecular weight of trimellitic acid, 210.1; M 均三甲苯 is the molecular weight of mesitylene, 120.2.

[0035] The reagents used in the following examples are all commercially available products.

[0036] The following examples and comparative examples are all carried out under normal pressure (0 MPa).

[0037] Preparation Example

[0038] This preparation example is used to illustrate the preparation method of hafnium acetate

[0039] Dissolve 1 g of hafnium oxychloride in 3 g of water, then add 2.2 g of ammonia water (mass fraction 25 wt%) to form a Hf(OH)₄ precipitate. After washing, dissolve it in 1.2 g of acetic acid to obtain an acetic acid solution containing 1.56 g of hafnium acetate.

[0040] Example 1

[0041] In a 3000 ml flask, add 100 g of mesitylene and 1200 g of glacial acetic acid solvent. While stirring at room temperature, add 2 g of cobalt acetate, 2 g of manganese acetate, 0.05 g of hafnium acetate, 0.1 g of lanthanum acetate, 1 g of sodium bromide, and 0.5 g of triethanolamine dispersant. Heat to 90 °C, pass oxygen at a flow rate of 1.8 L / min, stir for 6 h, cool to 20 - 35 °C, centrifuge to obtain a filter cake, and dry to obtain the product.

[0042] Example 2

[0043] In a 3000 ml flask, add 100 g of mesitylene and 600 g of glacial acetic acid solvent. While stirring at room temperature, add 1 g of cobalt acetate, 0.8 g of manganese acetate, 0.02 g of hafnium acetate, 0.03 g of lanthanum acetate, 0.4 g of sodium bromide, and 0.5 g of triethanolamine dispersant. Heat to 90 °C, pass oxygen at a flow rate of 1.5 L / min, stir for 6 h, cool to 20 - 35 °C, centrifuge to obtain a filter cake, and dry to obtain the product.

[0044] Example 3

[0045] In a 3000 ml flask, add 100 g of mesitylene and 1800 g of glacial acetic acid solvent. While stirring at room temperature, add 3 g of cobalt acetate, 3.5 g of manganese acetate, 0.2 g of hafnium acetate, 0.3 g of lanthanum acetate, 1.5 g of sodium bromide, and 0.5 g of triethanolamine dispersant. Heat to 90 °C, pass oxygen at a flow rate of 2 L / min, stir for 6 h, cool to 20 - 35 °C, centrifuge to obtain a filter cake, and dry to obtain the product.

[0046] Example 4

[0047] In a 3000 ml flask, add 100 g of mesitylene and 1200 g of glacial acetic acid solvent. While stirring at room temperature, add 1 g of cobalt acetate, 0.8 g of manganese acetate, 0.02 g of hafnium acetate, 0.03 g of lanthanum acetate, 1.5 g of sodium bromide, and 0.5 g of triethanolamine dispersant. Heat to 90 °C, pass oxygen at a flow rate of 1.8 L / min, stir for 6 h, cool to 20 - 35 °C, centrifuge to obtain a filter cake, and dry to obtain the product.

[0048] Example 5

[0049] In a 3000 ml flask, add 100 g of mesitylene and 1200 g of glacial acetic acid solvent. While stirring at room temperature, add 3 g of cobalt acetate, 3.5 g of manganese acetate, 0.2 g of hafnium acetate, 0.3 g of lanthanum acetate, 0.4 g of sodium bromide, and 0.6 g of triethanolamine dispersant. Heat the mixture to 90 °C and introduce oxygen at a flow rate of 1.8 L / min. Stir for 6 h, cool to 20 - 35 °C, and centrifuge to obtain a filter cake. After drying, the product is obtained.

[0050] Example 6

[0051] Carry out according to the method of Example 1, except that the amount of cobalt acetate used is 0.5 g.

[0052] Example 7

[0053] Carry out according to the method of Example 1, except that the amount of manganese acetate used is 3.5 g.

[0054] Example 8

[0055] Carry out according to the method of Example 1, except that the amount of hafnium acetate used is 0.01 g.

[0056] Example 9

[0057] Carry out according to the method of Example 1, except that the amount of lanthanum acetate used is 0.02 g.

[0058] Example 10

[0059] Carry out according to the method of Example 1, except that the amount of sodium bromide used is 0.3 g.

[0060] Comparative Example 1

[0061] Carry out according to the method of Example 1, except that hafnium acetate is replaced with an equal weight of lanthanum acetate.

[0062] Comparative Example 2

[0063] Carry out according to the method of Example 1, except that lanthanum acetate is replaced with an equal weight of hafnium acetate.

[0064] Comparative Example 3

[0065] Carry out according to the method of Example 1, except that manganese acetate is replaced with an equal weight of cobalt acetate.

[0066] Table 1

[0067] Yield of trimesic acid % Purity % Example 1 129.2 99.8 Example 2 121.3 99.5 Example 3 125.6 99.7 Example 4 111.7 99.2 Example 5 108.5 99.3 Example 6 103.2 99.0 Example 7 115.1 98.4 Example 8 112.3 99.2 Example 9 113.8 99.4 Example 10 108.2 99.3 Comparative Example 1 106.9 99.3 Comparative Example 2 114.6 99.7 Comparative Example 3 112.5 99.6

[0068] It can be seen from the results in Table 1 that by using the method of the present invention, it is possible to oxidize mesitylene to prepare trimellitic acid under normal pressure, obtaining relatively ideal weight yield and purity of trimellitic acid.

[0069] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A catalyst for preparing trimellitic acid, characterized in that, The catalyst comprises a cobalt salt, a manganese salt, a hafnium salt, a lanthanum salt and an alkali metal bromide.

2. The catalyst according to claim 1, wherein In the catalyst, the molar ratio of the cobalt salt calculated as Co, the manganese salt calculated as Mn, the hafnium salt calculated as Hf, the lanthanum salt calculated as La and the alkali metal bromide calculated as Br is 1: 0.8 - 1.2: 0.008 - 0.03: 0.015 - 0.06: 0.3 - 1, preferably 1: 0.9 - 1.1: 0.01 - 0.02: 0.02 - 0.04: 0.65 - 0.

9.

3. The catalyst according to claim 1 or 2, wherein The alkali metal bromide is sodium bromide and / or potassium bromide.

4. A method for preparing trimellitic acid, characterized in that, The method includes: in the presence of a catalyst, a solvent and an optional dispersant, subjecting mesitylene to an oxidation reaction to obtain trimellitic acid; wherein, the catalyst is the catalyst described in any one of claims 1 - 3.

5. The method according to claim 4, wherein Relative to every 100 g of mesitylene, the amount of the solvent used is 600 - 1800 g, the amount of the catalyst used is 2 - 9 g, preferably 4 - 6 g, and the amount of the dispersant used is 0.5 - 1 g, preferably 0.5 - 0.6 g.

6. The method according to claim 4 or 5, wherein, The solvent is acetic acid.

7. The method according to claim 4 or 5, wherein The dispersant is triethanolamine.

8. The method according to claim 4 or 5, wherein, During the oxidation reaction, mesitylene contacts with oxygen to undergo an oxidation reaction. Relative to every 100 g of mesitylene, the flow rate of oxygen is 1.5 - 2 L / min.

9. The method according to claim 4 or 5, wherein The temperature of the oxidation reaction is 80 - 100 °C, and the time of the oxidation reaction is 4 - 6 h.

10. The method according to claim 4 or 5, wherein The method further includes cooling, solid-liquid separation and drying of the product of the oxidation reaction.

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