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Method for preparing benzaldehyde by selective oxidation of methylbenzene

A selectivity and benzaldehyde technology, which is applied in the direction of hydrocarbon oxidation to prepare oxygenates, carbon-based compounds, chemical instruments and methods, etc., can solve the problem of low selectivity of benzaldehyde, achieve mild reaction conditions, high yield, good selectivity

Inactive Publication Date: 2014-11-19
ZHENGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] Patents US3989674, US4137259 etc. adopt the method of gas-phase catalytic oxidation of toluene, the reaction temperature is 250~600°C, and the reactor pressure is 1.0~10.0MPa, but the main product obtained by the reaction is benzoic acid, and the selectivity of benzaldehyde is low. At low conversion (less than 4%), the selectivity of benzaldehyde is 70%

Method used

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  • Method for preparing benzaldehyde by selective oxidation of methylbenzene
  • Method for preparing benzaldehyde by selective oxidation of methylbenzene
  • Method for preparing benzaldehyde by selective oxidation of methylbenzene

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Experimental program
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Effect test

Embodiment 1

[0022] The synthesis of cocatalyst in the present embodiment:

[0023] Add 2.5 grams (0.01mol) of 3,8-dichloro-1,10-phenanthroline, 1.7 grams (0.01mol) of copper chloride dihydrate, 50 mL of absolute ethanol, and 5 mL of water into the reaction flask, and heat to reflux for 5 hours , static, precipitated solids, and dried the solids to obtain 3.0 grams of co-catalysts.

[0024] Catalytic Oxidation of Toluene:

[0025] Add 50mL toluene and 50mL acetonitrile, 2.0 grams of N-hydroxyphthalimide, 2.0 grams of the cocatalyst prepared above, feed oxygen into the reaction kettle, keep the pressure of the reaction kettle at 0.3MPa, and the reaction temperature at 80°C. The time was 360 minutes to obtain the reaction product. After detection by high-pressure liquid chromatography, the benzaldehyde in the product was 14.3%, the benzoic acid was 57.5%, and the benzyl alcohol was 0.2%. The reaction results are shown in Table 1.

Embodiment 2

[0027] The synthesis of cocatalyst in the present embodiment:

[0028] Add 3.3 grams (0.01mol) of 4,7-diphenyl-1,10-phenanthroline, 2.4 grams (0.01mol) of cobalt chloride hexahydrate, 50 mL of acetone, and 10 mL of water into the reaction flask, and heat to reflux for 5 hours. After standing still, a solid precipitated out, and after the solid was dried, 3.5 g of cocatalyst was obtained.

[0029] Catalytic Oxidation of Toluene:

[0030] Add 50mL toluene and 5mL anhydrous acetic acid, 2.0 grams of N-hydroxyphthalimide, 1.0 gram of the cocatalyst prepared above, feed oxygen into the reactor, keep the pressure of the reactor at 0.1MPa, and the reaction temperature at 120 ℃, the reaction time is 120 minutes, promptly obtains the reaction product, detects through high-pressure liquid chromatography, and benzaldehyde is 49.5% in the product, and benzoic acid is 0.4%, and the product obtains 9.7 grams of benzaldehyde through purification separation, and reaction result is shown in T...

Embodiment 3

[0032] The synthesis of cocatalyst in the present embodiment:

[0033] Add 3.7 grams (0.01mol) of 3,8-dibromo-1,10-phenanthroline-5,6-dione, 1.7 grams (0.01mol) of manganese acetate, 40mL of anhydrous acetic acid, 10mL of water into the reaction flask, Heated to reflux for 10 hours, stood still, and a solid precipitated out. After the solid was dried, 2.9 g of a cocatalyst was obtained.

[0034] Catalytic Oxidation of Toluene:

[0035] Add 50mL of toluene and 100mL of dichloroethane, 2.0 grams of N-hydroxyphthalimide, 0.4 grams of the above-mentioned prepared cocatalyst into the reactor, feed oxygen, keep the pressure of the reactor at 1.5MPa, and the reaction temperature is 150°C. The reaction time was 480 minutes, and the reaction product was obtained. The benzaldehyde in the product was 19.0%, and the benzoic acid was 69.0% through high-pressure liquid chromatography detection. The reaction results are shown in Table 1.

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Abstract

The invention belongs to a method for preparing benzaldehyde by selective oxidation of methylbenzene. The method comprises the following steps: adding methylbenzene, N-hydroxyphthalimide, a catalyst promoter and a solvent into a reaction kettle, introducing oxygen, and reacting under the pressure of 0.1-1.5MPa at the temperature of 30-150 DEG C for 60-600 minutes, wherein the catalyst promoter is 1,10-phenanthroline or a metal complex of 1,10-phenanthroline derivative, and the total amount of the catalyst promoter is 0.05%-20% based on the mass percentage of methylbenzene. The method has the beneficial effects that the reaction condition is mild, and benzaldehyde is good in selectivity and high in yield in comparison with benzaldehyde produced by using other catalyst promoters formed by transition metal ions.

Description

technical field [0001] The invention belongs to the technical field of preparation of aldehydes, in particular to a method for preparing benzaldehyde by selective oxidation of toluene. Background technique [0002] Benzaldehyde is an important chemical raw material and an important intermediate in food additives, synthetic drugs and spices. Compared with benzoic acid, it has a higher market price. Compared with the existing method of chlorination and hydrolysis of toluene, the production of benzaldehyde by the method of catalytic oxidation has good product quality and high yield, and is suitable for application in the production of medicine, food, spices and the like. Therefore, by changing the reaction conditions, adding a cocatalyst to increase the content of benzaldehyde in the product is one of the important methods of research and development. [0003] Patent CN200410007341 uses manganese, copper, cobalt, iron and other metals and catalysts composed of sodium, potassiu...

Claims

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Application Information

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IPC IPC(8): C07C27/12C07C45/36C07C47/54C07C51/265C07C63/06B01J31/22
CPCB01J31/006B01J31/183B01J2531/007B01J2531/0241C07C45/36C07C51/265C07C47/54C07C63/06
Inventor 李瑞军李雪洋李彩娟李杰杨贯羽
Owner ZHENGZHOU UNIV
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