Catalyst with function of preparing trimesic acid by oxidizing mesitylene and application of catalyst

Abstract

The invention relates to the technical field of trimesic acid, and discloses a catalyst with a function of preparing trimesic acid by oxidizing mesitylene and application of the catalyst. The catalyst comprises cobalt acetate, manganese acetate, zinc acetate and alkali metal bromide. The method comprises the following step: carrying out oxidation reaction on mesitylene in the presence of a catalyst, a solvent and an optional dispersing agent 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 of the trimesic acid is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of trimellitic acid, and particularly relates to a catalyst with the function of oxidizing mesitylene to trimellitic acid and its application. 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. Trimellitic acid can also be used in the military industry as a crosslinking agent for rocket solid fuels. 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 potassium permanganate oxidation method, a large amount of wastewater and waste residue are generated during the reaction process, the post-treatment is difficult, the conversion rate is low, and the purification is complex; in 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 salts are used as catalysts 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 in the prior art that the yield of trimellitic acid is low and the reaction temperature and pressure are high, and to provide a catalyst with the function of oxidizing mesitylene to trimellitic acid and its application.

[0006] To achieve the above purpose, in the first aspect, the present invention provides a catalyst with the function of oxidizing mesitylene to trimellitic acid, and the catalyst includes cobalt acetate, manganese acetate, zinc acetate, and alkali metal bromide.

[0007] In the second aspect, the present invention provides a method for oxidizing mesitylene to trimellitic acid, 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 are both easily achievable. The reaction conditions are mild and conducive to operation.

[0010] (2) The present invention uses cobalt acetate, manganese acetate, zinc acetate, and alkali metal bromide as catalysts, and adds a dispersant to promote the uniform dispersion of mesitylene in the mixed solution and sufficient reaction, thereby increasing the weight yield of trimellitic acid. By adopting the preferred implementation mode of the present invention, the weight yield of trimellitic acid can reach more than 120%, and the product purity can reach more than 99%. Detailed implementation mode

[0011] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. 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 with the function of oxidizing mesitylene to trimellitic acid. The catalyst includes cobalt acetate, manganese acetate, zinc acetate, and alkali metal bromide.

[0014] According to the present invention, in order to increase the yield of trimellitic acid, preferably, the molar ratio of cobalt acetate based on Co, manganese acetate based on Mn, zinc acetate based on Zn, and alkali metal bromide based on Br in the catalyst is 1:0.8 - 1.0:0.2 - 0.4:0.4 - 0.6.

[0015] Preferably, when the molar ratio of cobalt acetate based on Co, manganese acetate based on Mn, zinc acetate based on Zn, and alkali metal bromide based on Br is 1:0.85 - 0.95:0.3 - 0.4:0.5 - 0.6, the yield of trimellitic acid can be more than 125%, and the purity can be more than 99.5%.

[0016] According to the present invention, the alkali metal bromide can be a commonly used alkali metal bromide in the art. Preferably, the alkali metal bromide is sodium bromide and / or potassium bromide.

[0017] The second aspect of the present invention provides a method for preparing trimellitic acid by oxidizing mesitylene, the method comprising: 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.

[0018] 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 2.2 - 13.7 g, and the amount of the dispersant used is 0 - 0.65 g, preferably 0.5 - 0.65 g.

[0019] 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 - 1300 g.

[0020] Relative to every 100 g of mesitylene, the amount of the catalyst used can be 2 g, 2.2 g, 3 g, 4 g, 5 g, 6 g, 7 g, 8 g, 9 g, 10 g, 11 g, 12 g, 13 g, 13.7 g, 14 g, 15 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 2.2 - 13.7 g, more preferably 2.2 - 9 g, and further preferably 7 - 8 g.

[0021] Relative to every 100 g of mesitylene, the amount of the dispersant used can be 0.5 g, 0.6 g, 0.65 g, and the ranges composed of any two of the above. Using the catalyst with the specific composition of the present invention can improve the yield of trimellitic acid.

[0022] According to the present invention, the solvent can be a solvent commonly used in the art. Preferably, the solvent is acetic acid.

[0023] According to the present invention, the dispersant can be a dispersant commonly used in the art. Preferably, the dispersant is triethanolamine.

[0024] 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.

[0025] According to the present invention, preferably, the temperature of the oxidation reaction is 80 - 100°C, more preferably 85 - 95°C, the time of the oxidation reaction is 5 - 8 h, preferably 6 - 7 h. The reaction of the present invention can be carried out under normal pressure or under higher pressure. In order to reduce the requirements for equipment, preferably, the pressure of the oxidation reaction of the present invention is 0 - 0.3 MPa. In a particularly preferred case, the pressure of the oxidation reaction is normal pressure (0 MPa).

[0026] According to the present invention, preferably, the method further comprises cooling, solid-liquid separation and drying of the product of the oxidation reaction.

[0027] In a particularly preferred embodiment of the present invention, a method for preparing trimellitic acid from mesitylene by oxidation, the method comprising: in the presence of a catalyst, a solvent and a dispersant, subjecting mesitylene to an oxidation reaction, wherein the catalyst comprises cobalt acetate, manganese acetate, zinc acetate and sodium bromide, and the molar ratio of cobalt acetate based on Co, manganese acetate based on Mn, zinc acetate based on Zn and sodium bromide based on Br is 1:0.85 - 0.95:0.25 - 0.35:0.45 - 0.55; relative to every 100 g of mesitylene, the amount of the solvent used is 1100 - 1200 g, the amount of the catalyst used is 7 - 7.5 g, and the amount of the dispersant used is 0.5 - 0.65 g; the dispersant is triethanolamine and the solvent is acetic acid.

[0028] The present invention will be described in detail below by way of examples. In the following examples,

[0029] The catalytic products were analyzed by chromatographic analysis and chemical titration methods;

[0030] The formula for calculating the yield (%) of trimellitic acid is:

[0031]

[0032] 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.

[0033] The reagents used in the following examples are all commercially available products.

[0034] The following examples and comparative examples are all carried out under normal pressure (0 MPa).

[0035] Example 1

[0036] Add 100 g of mesitylene and 1200 g of glacial acetic acid into a 3000 ml flask. While stirring at room temperature, add 3 g of cobalt acetate, 2.65 g of manganese acetate, 0.94 g of zinc acetate, 0.88 g of sodium bromide, and 0.65 g of triethanolamine dispersant. The molar ratio of Co, Mn, Zn, and Br elements in the catalyst is 1:0.9:0.3:0.5. Heat up to 90 °C, and introduce oxygen at a flow rate of 1.8 L / min. Stir for 6 h. After cooling to room temperature, centrifuge and spin-dry to obtain a filter cake. After drying, the product is obtained.

[0037] Example 2

[0038] Add 100 g of mesitylene and 600 g of glacial acetic acid into a 3000 ml flask. While stirring at room temperature, add 1 g of cobalt acetate, 0.79 g of manganese acetate, 0.21 g of zinc acetate, 0.24 g of sodium bromide, and 0.65 g of triethanolamine dispersant. The molar ratio of Co, Mn, Zn, and Br elements in the catalyst is 1:0.8:0.2:0.4. Heat up to 90 °C, and introduce oxygen at a flow rate of 1.5 L / min. Stir for 6 h. After cooling to room temperature, centrifuge and spin-dry to obtain a filter cake. After drying, the product is obtained.

[0039] Example 3

[0040] Add 100 g of mesitylene and 1800 g of glacial acetic acid into a 3000 ml flask. While stirring at room temperature, add 5 g of cobalt acetate, 4.9 g of manganese acetate, 2.08 g of zinc acetate, 1.75 g of sodium bromide, and 0.65 g of triethanolamine dispersant. The molar ratio of Co, Mn, Zn, and Br elements in the catalyst is 1:1:0.4:0.6. Heat up to 90 °C, and introduce oxygen at a flow rate of 2 L / min. Stir for 6 h. After cooling to room temperature, centrifuge and spin-dry to obtain a filter cake. After drying, the product is obtained.

[0041] Example 4

[0042] Carry out according to the method of Example 1, except that the amount of glacial acetic acid is 1500 g, the amount of triethanolamine is 0.5 g, and the flow rate of oxygen is 2 L / min.

[0043] Examples 5 - 6

[0044] Carry out according to the method of Example 1, except that the amounts of manganese acetate are 2.35 g and 3.0 g respectively, that is, the molar ratios of Co, Mn, Zn, and Br elements in the catalyst are 1:0.8:0.3:0.5 and 1:1.0:0.3:0.5.

[0045] Examples 7 - 8

[0046] It was carried out according to the method of Example 1, except that the amounts of zinc acetate were 0.63 g and 1.25 g respectively, that is, the molar ratios of Co, Mn, Zn, and Br elements in the catalyst were 1:0.9:0.2:0.5 and 1:0.9:0.4:0.5.

[0047] Examples 9 - 10

[0048] It was carried out according to the method of Example 1, except that the amounts of sodium bromide were 0.7 g and 1.05 g respectively, that is, the molar ratios of Co, Mn, Zn, and Br elements in the catalyst were 1:0.9:0.3:0.4 and 1:0.9:0.3:0.6.

[0049] Example 11

[0050] It was carried out according to the method of Example 1, except that sodium bromide was replaced by potassium bromide and the amount of potassium bromide was 3.02 g, that is, the molar ratio of Co, Mn, Zn, and Br elements in the catalyst was 1:0.9:0.3:1.5.

[0051] Example 12

[0052] It was carried out according to the method of Example 1, except that the amounts of cobalt acetate, manganese acetate, zinc acetate, and sodium bromide were 3 g, 1.5 g, 2.8 g, and 1.8 g respectively; that is, the molar ratio of Co, Mn, Zn, and Br elements in the catalyst was 1:0.5:0.9:1.

[0053] Comparative Example 1

[0054] It was carried out according to the method of Example 1, without adding zinc acetate, and the molar ratio of Co, Mn, and Br elements in the catalyst was 1:0.9:0.5.

[0055] Comparative Example 2

[0056] It was carried out according to the method of Example 1, except that zinc acetate was replaced by an equimolar amount of zirconium acetate (1.67 g), and the molar ratio of Co, Mn, Zr, and Br elements in the catalyst was 1:0.9:0.3:0.5.

[0057] Table 1

[0058]

[0059] As can be seen from the results in Table 1, compared with the comparative examples, the method of the present invention can not only improve the yield of trimellitic acid, but also improve the purity of trimellitic acid. By using the preferred embodiments of the present invention (Examples 1-10), the yield of trimellitic acid can be above 120%, and the purity can be above 99%. By using the particularly preferred embodiments of the present invention (Examples 1, 8, 10), the yield of trimellitic acid can be above 125%, and the purity can be above 99.5%.

[0060] 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 with the function of oxidizing mesitylene to trimellitic acid, characterized in that, The catalyst comprises cobalt acetate, manganese acetate, zinc acetate and alkali metal bromide.

2. The catalyst according to claim 1, wherein, In the catalyst, the molar ratio of cobalt acetate calculated as Co, manganese acetate calculated as Mn, zinc acetate calculated as Zn and alkali metal bromide calculated as Br is 1:0.8 - 1:0.2 - 0.4:0.4 - 0.

6.

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 by oxidizing mesitylene, 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 - 15 g, and the amount of the dispersant used is 0 - 0.65 g, preferably 0.5 - 0.65 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 5 - 8 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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