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Composite catalyst and method for preparing trimellitic anhydride

A technology of composite catalyst and trimellitic anhydride, which is applied in the direction of chemical instruments and methods, organic compound/hydride/coordination complex catalyst, physical/chemical process catalyst, etc., can solve the problems affecting the appearance and color number of the final product, and the conversion of trimethylbenzene Low production rate, many impurities in the finished product, etc., to achieve the effect of appearance and color number guarantee, reduction of production cost and high yield

Inactive Publication Date: 2021-08-06
安徽泰达新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved in the present invention is to provide a new method for preparing trimellitic anhydride to solve the problem that the conversion rate of trimellitic anhydride in the traditional production method is low, and there are many side reactions, so that the impurities in the finished product obtained are relatively high. Many problems that affect the appearance and color number of the final product

Method used

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  • Composite catalyst and method for preparing trimellitic anhydride

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] First, add 200kg of mesitylene, 600kg of acetic acid, and 14kg of composite catalyst in the mixing kettle, wherein in the composite catalyst, there are 2.2kg of cobalt acetate, 6.6kg of manganese acetate, 4.2kg of tetrabromoethane, and 1kg of zirconium acetate, start stirring and mixing, and heat up To 80 ℃, so that trimethylbenzene and solvent miscibility;

[0032] Then the mixed material is transferred to the oxidation kettle, and the air is introduced to pressurize. The temperature of the reaction is controlled at 210°C, the pressure is controlled at 1.8Mpa, and the reaction time is 70 minutes. When the oxygen content of the tail gas reaches 15-20%, the oxidation reaction ends;

[0033] Then control the temperature of the anhydride-forming kettle at 180°C, dehydrate the oxidized material into crude anhydride in the anhydride-forming kettle, send the dilute acetic acid produced during the anhydride-forming process into the rectifying kettle, and reuse it after concentr...

Embodiment 2

[0036] First add 200kg of trimethylene, 600kg of acetic acid, and 12kg of composite catalyst in the mixing kettle, wherein in the composite catalyst, 1.5kg of cobalt acetate, 3kg of manganese acetate, 3kg of tetrabromoethane, 4.5kg of zirconium acetate, start stirring and mixing, and heat up to At 80°C, the trimethylbenzene and the solvent are miscible;

[0037] Then transfer the mixed material to the oxidation kettle, feed air to pressurize, the temperature of the reaction is controlled at 180°C, the pressure is controlled at 1.0Mpa, the reaction time is 90 minutes, and the oxidation reaction ends when the oxygen content of the tail gas reaches 15-20%.

[0038]Then control the temperature of the anhydride-forming kettle at 180°C, dehydrate the oxidized material into crude anhydride in the anhydride-forming kettle, send the dilute acetic acid produced during the anhydride-forming process into the rectifying kettle, and reuse it after concentration;

[0039] Rectification step:...

Embodiment 3

[0041] First, add 200kg of mesitylene, 750kg of acetic acid, and 8kg of composite catalyst in the mixing kettle, of which, in the composite catalyst, 1.3kg of cobalt acetate, 2.5kg of manganese acetate, 1kg of tetrabromoethane, and 3.2kg of zirconium acetate are started to stir and mix, and the temperature is raised To 80 ℃, so that trimethylbenzene and solvent miscibility;

[0042] Then transfer the mixed material to the oxidation kettle, feed air to pressurize, control the temperature of the reaction at 200°C, the pressure at 1.5Mpa, and the reaction time is 80 minutes. When the oxygen content in the tail gas reaches 15-20%, the oxidation reaction ends;

[0043] Then control the temperature of the anhydride-forming kettle at 180°C, dehydrate the oxidized material into crude anhydride in the anhydride-forming kettle, send the dilute acetic acid produced during the anhydride-forming process into the rectifying kettle, and reuse it after concentration;

[0044] Rectification st...

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Abstract

A composite catalyst comprises cobalt acetate, manganese acetate, tetrabromoethane and zirconium acetate; and the weight ratio of cobalt acetate to manganese acetate to tetrabromoethane to zirconium acetate in the composite catalyst is 1:(0.3-5):(0.3-5):(0.3-5). A method for preparing trimellitic anhydride takes unsym-trimethylbenzene as a raw material and acetic acid as a solvent, the composite catalyst is used in the method, and air is used as an oxidizing agent; according to the weight ratio of unsym-trimethylbenzene to acetic acid to air of 1:(2.5-10):(0.01-0.08), the preparation method comprises the steps: metering, stirring and mixing the raw materials in a mixing kettle according to the proportion, heating and dissolving; and transferring the mixed material into an oxidation kettle, introducing air to pressurize, controlling the reaction temperature to be 160-220 DEG C and the pressure to be 0.6-2.2 MPa, dehydrating the oxide material into crude anhydride in an anhydride forming kettle, and feeding generated dilute acetic acid into a rectifying kettle to be concentrated and recycled. The invention solves the problem that the appearance and color number of the final product are influenced by more impurities in the obtained finished product due to lower conversion rate of unsym-trimethylbenzene and more side reactions in a traditional production method.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a composite catalyst and a method for preparing trimellitic anhydride. Background technique [0002] Trimellitic anhydride (TMA) is short for partial anhydride, also known as 1,2,4-benzenetricarboxylic anhydride, and its appearance is white or slightly yellow needle-like crystals. The molecular structure of trimellitic anhydride contains carboxylic acid and acid anhydride structure, which has the chemical properties of benzoic acid and phthalic anhydride. It can react with alcohol to form ester or polyester, react with alkali to form salt, and react with ammonia (amine) to form amide-imide. Condensation reactions with hydrocarbons under the action of catalysts, etc., making it suitable for the production of PVC resin plasticizers, polyimide resin paints, water-soluble alkyd resins, epoxy resin curing agents, impregnants for low-voltage and pulse power containers, films, etc. Fi...

Claims

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Application Information

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IPC IPC(8): B01J31/12C07D307/89
CPCB01J31/128C07D307/89
Inventor 柯伯留柯伯成罗建立周晔徐小买柯美松
Owner 安徽泰达新材料股份有限公司
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