Method for preparing benzaldehyde, benzyl alcohol and benzyl benzoate through air catalytic oxidation of methylbenzene

Abstract

The invention discloses a preparation method which can improves the content of high added-value product benzaldehyde, benzyl alcohol and benzyl benzoate while not using an organic solvent and producing benzoic acid with high yield on the condition of not changing the existing benzoic acid production process and equipment. The invention has the advantages that through adjusting proportion of a catalyst, under the condition of best proportion of the catalyst, the conversion rate of the benzaldehyde is about 10 percent, the selectivity of the benzoic acid is 40 percent, the selectivity of the benzaldehyde is 30 percent, and the selectivity of the benzyl alcohol is 30 percent; and the content of the high added-value product benzaldehyde and benzyl alcohol are both high, and the catalyst can be repeatedly used, easy to regenerate, so that the production cost is lowered, and the economic benefits of benzoic acid production factories are greatly improved.

Description

technical field

[0001] The invention relates to a preparation method of benzaldehyde, benzyl alcohol and benzyl benzoate, in particular to a method for preparing benzaldehyde, benzyl alcohol and benzyl benzoate through air catalytic oxidation of toluene. Background technique

[0002] Benzaldehyde, benzyl alcohol, and benzyl benzoate have extremely important applications in fine chemical industries such as medicine, pesticides, food and spices. At present, most of the production of benzaldehyde and benzyl alcohol at home and abroad adopts the traditional process method—toluene chlorination and hydrolysis. The method is to chlorinate the side chain of toluene under appropriate conditions to produce benzyl chloride and benzyl dichloride. Benzyl chloride is finally obtained by alkaline hydrolysis and rectification to obtain benzyl alcohol, and benzyl chloride is finally obtained by acid hydrolysis and rectification. Benzaldehyde is obtained; benzyl benzoate is mainly obtained f...

Examples

Embodiment 1

[0020] Add 500 grams of toluene to a 1000 ml pressure reactor, and at the same time add 6 grams of manganese sulfate, 2 grams of manganese acetate, and 1 gram of cerium sulfate to the reactor, close the mouth of the kettle, and when the temperature of the oil bath reaches 180 ° C, gradually introduce compressed air. The molar ratio of the amount of air added to toluene is 8:1, the temperature of the reactor is controlled at about 180°C, the pressure is 1.0 Mpa, and the gas supply is 1000ml / min. After 2 hours of reaction, stop the reaction and cool down to room temperature. The mixture was tested by internal standard method of Wenling 9700 gas chromatography, and the conversion rate of toluene was 11%, benzoic acid was 2%, benzaldehyde was 3.1%, and benzyl alcohol was 5.8%. The oxidizing solution mixture is first separated from toluene at normal pressure, and then reused in the oxidation tower for repeated reactions. The remaining high boilers are fractionated under reduced pres...

Embodiment 2

[0022] Add 500 grams of toluene to a 1000ml pressure reactor, add 5 grams of manganese sulfate and 2 grams of sodium acetate, close the mouth of the kettle, and when the oil bath is heated to 200 degrees, gradually introduce compressed air, and the molar ratio of the amount of air added to toluene is 6: 1. Control the reaction temperature to about 160 degrees, the air flow rate to 800 ml / min, the pressure to 0.6 Mpa, and the oxidation time to 1 hour, stop the reaction, and cool down to room temperature. The mixture was tested by internal standard method of Wenling 9700 gas chromatography, and the conversion rate of toluene was 10.2%, benzoic acid was 1.97%, benzaldehyde was 3.1%, benzyl alcohol was 4.9%. The oxidizing solution mixture is separated from the toluene at normal pressure, and then returned to the oxidation tower for repeated reactions. The remaining high boilers are fractionated under reduced pressure to obtain benzaldehyde, benzyl alcohol, and benzyl benzoate. Pro...

technical field

[0001] The invention relates to a preparation method of benzaldehyde, benzyl alcohol and benzyl benzoate, in particular to a method for preparing benzaldehyde, benzyl alcohol and benzyl benzoate through air catalytic oxidation of toluene. Background technique

[0002] Benzaldehyde, benzyl alcohol, and benzyl benzoate have extremely important applications in fine chemical industries such as medicine, pesticides, food and spices. At present, most of the production of benzaldehyde and benzyl alcohol at home and abroad adopts the traditional process method—toluene chlorination and hydrolysis. The method is to chlorinate the side chain of toluene under appropriate conditions to produce benzyl chloride and benzyl dichloride. Benzyl chloride is finally obtained by alkaline hydrolysis and rectification to obtain benzyl alcohol, and benzyl chloride is finally obtained by acid hydrolysis and rectification. Benzaldehyde is obtained; benzyl benzoate is mainly obtained f...

Examples

Embodiment 1

[0020] Add 500 grams of toluene to a 1000 ml pressure reactor, and at the same time add 6 grams of manganese sulfate, 2 grams of manganese acetate, and 1 gram of cerium sulfate to the reactor, close the mouth of the kettle, and when the temperature of the oil bath reaches 180 ° C, gradually introduce compressed air. The molar ratio of the amount of air added to toluene is 8:1, the temperature of the reactor is controlled at about 180°C, the pressure is 1.0 Mpa, and the gas supply is 1000ml / min. After 2 hours of reaction, stop the reaction and cool down to room temperature. The mixture was tested by internal standard method of Wenling 9700 gas chromatography, and the conversion rate of toluene was 11%, benzoic acid was 2%, benzaldehyde was 3.1%, and benzyl alcohol was 5.8%. The oxidizing solution mixture is first separated from toluene at normal pressure, and then reused in the oxidation tower for repeated reactions. The remaining high boilers are fractionated under reduced pres...

Embodiment 2

[0022] Add 500 grams of toluene to a 1000ml pressure reactor, add 5 grams of manganese sulfate and 2 grams of sodium acetate, close the mouth of the kettle, and when the oil bath is heated to 200 degrees, gradually introduce compressed air, and the molar ratio of the amount of air added to toluene is 6: 1. Control the reaction temperature to about 160 degrees, the air flow rate to 800 ml / min, the pressure to 0.6 Mpa, and the oxidation time to 1 hour, stop the reaction, and cool down to room temperature. The mixture was tested by internal standard method of Wenling 9700 gas chromatography, and the conversion rate of toluene was 10.2%, benzoic acid was 1.97%, benzaldehyde was 3.1%, benzyl alcohol was 4.9%. The oxidizing solution mixture is separated from the toluene at normal pressure, and then returned to the oxidation tower for repeated reactions. The remaining high boilers are fractionated under reduced pressure to obtain benzaldehyde, benzyl alcohol, and benzyl benzoate. Pro...

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