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Process for synthesizing p-methoxy benzaldehyde or p-tertbutyl benzaldehyde

A technology for p-methoxybenzaldehyde and p-methoxytoluene, which is applied in the field of substituted toluene oxidation to prepare substituted benzaldehyde, can solve problems such as complicated separation process, and achieve the effects of reducing pollution, reducing discharge and avoiding sodium sulfate-containing wastewater

Inactive Publication Date: 2014-12-10
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The separation process of this process is complicated. In addition to synthetic wastewater, a considerable amount of high-concentration wastewater containing sodium sulfate and toluene non-condensable gas are produced. The unit consumption of toluene is about 0.068t / t.

Method used

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  • Process for synthesizing p-methoxy benzaldehyde or p-tertbutyl benzaldehyde
  • Process for synthesizing p-methoxy benzaldehyde or p-tertbutyl benzaldehyde
  • Process for synthesizing p-methoxy benzaldehyde or p-tertbutyl benzaldehyde

Examples

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Embodiment 1

[0016] In a 1000mL reaction flask, add 525mL of p-methoxytoluene, 150mL of glacial acetic acid, 50g of cobalt acetate and 30g of sodium bromide, stir, heat to 45°C, and pass oxygen for 4h to complete the reaction; add 800mL of water twice to wash the reaction liquid, to remove catalyst and acetic acid.

[0017] Add 200mL of monomethylbiphenyl to the oil phase after water washing, mix evenly, and desolvate under reduced pressure (-0.09MPa, 85-90℃) to remove p-methoxytoluene; continue to increase the rectification temperature (-0.098MPa, 100 -105°C), gas phase condensation to obtain p-methoxybenzaldehyde (light yellow liquid, acid value: ≤1.0mgKOH / g, content 99.3%); increase the rectification temperature again (-0.098MPa, 118-123°C), distill P-methoxybenzoic acid is discharged, and the gas-phase p-methoxybenzoic acid is passed into the water absorption tower, cooled and crystallized, and p-methoxybenzoic acid (white powder crystals, melting point range 181-185°C) is obtained aft...

Embodiment 2

[0019] In a 1000mL reaction flask, add 700mL of p-tert-butyltoluene, 20mL of glacial acetic acid, 10g of cobalt acetate and 4.5g of sodium bromide, stir, heat to 45°C, and pass oxygen for 4h to complete the reaction; add 1000mL of water twice to wash the reaction liquid , to remove catalyst and acetic acid.

[0020] Add 260mL of biphenyl-biphenyl ether low-melting mixture to the oil phase after water washing, mix well, and carry out desolvation under reduced pressure (-0.09MPa, 80-86°C) to remove excess p-tert-butyltoluene; continue to increase the rectification Temperature (-0.098MPa, 98-104°C), gas phase condensation to obtain p-tert-butylbenzaldehyde (light yellow liquid, content 99.2%); increase the rectification temperature again (-0.098MPa, 114-118°C), remove p-tert-butylbenzaldehyde tert-butylbenzoic acid, p-tert-butylbenzoic acid in the gas phase is passed into the water absorption tower, cooled and crystallized, recrystallized and dried to obtain p-tert-butylbenzoic a...

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Abstract

The invention provides a process for synthesizing p-methoxy benzaldehyde or p-tertbutyl benzaldehyde. The process comprises the following steps of: adding an acidifying agent glacial acetic acid and catalysts cobalt acetate and sodium bromide into p-methoxy methylbenzene or p-tertbutyl methylbenzene, introducing oxygen to perform oxidation reaction under a heating condition, and after the reaction, washing feed liquid with water for twice to remove the catalysts and the acetic acid; adding an oil phase after washing into a high-boiling-point solvent, and then performing rectification under vacuum step by step; unmixing and steaming out excessive p-methoxy methylbenzene or p-tertbutyl methylbenzene, then increasing the vacuum degree and the temperature, and collecting a gas-phase condensate to obtain the p-methoxy benzaldehyde or p-tertbutyl benzaldehyde; and continuously raising the rectification temperature, and receiving the gas-phase condensate with water, and performing recrystallization for twice to obtain p-methoxy benzoic acid or p-tertbutyl benzoic acid. According to the process, the discharge of waste water is reduced, the generation of the waste water containing sodium sulfate is avoided, and meanwhile, methylbenzene is not used for extracting the p-methoxy benzoic acid or p-tertbutyl benzoic acid, so that the pollution of the methylbenzene to the environment is reduced.

Description

technical field [0001] The invention relates to a method for preparing substituted benzaldehyde by oxidation of substituted toluene. Background technique [0002] Using p-methoxytoluene or p-tert-butyltoluene as raw material, the process of synthesizing p-methoxybenzaldehyde or p-tert-butylbenzaldehyde and co-producing p-methoxyl or p-tert-butylbenzoic acid is exactly the same, only The process parameters are slightly different, and the process includes oxidation reaction, distillation to remove acetic acid, washing with water and alkali, separation of p-methoxyl or p-tert-butylbenzoic acid, rectification of p-methoxybenzaldehyde or p-tert-butylbenzaldehyde Separation and other steps. Taking p-methoxybenzaldehyde as an example, its reaction formula is as follows. [0003] [0004] After a sufficient amount of p-methoxytoluene is acidified with acetic acid, catalyst sodium bromide and cobalt acetate are added, and oxygen is passed through at a certain temperature for oxi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C27/00C07C27/12C07C45/36C07C45/82C07C47/575C07C47/542C07C51/265C07C65/21C07C63/04
Inventor 赵玉明马堂文王利超
Owner NANJING UNIV
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