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A kind of technique for preparing p-toluic acid by continuous catalytic oxidation

A technology of p-toluic acid and sodium toluate, applied in the field of chemical technology, can solve the problems of high energy consumption, low output, low yield of catalytic oxidation reaction process, etc., and achieve the effect of low energy consumption

Active Publication Date: 2022-02-11
宁夏德昊科技产业有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] Aiming at the deficiencies in the prior art, the invention provides a process for preparing p-toluic acid by continuous catalytic oxidation, which adopts a two-phase system of p-xylene and caustic soda aqueous solution, adopts cobalt naphthenate as a catalyst, and prepares p-toluic acid in a continuous tubular reactor. Continuous oxidation reaction with oxygen, continuous feeding, continuous extraction of the water phase in the reaction system, water phase cooling crystallization and centrifugation to separate sodium p-toluate, after purification, acidification, centrifugation, vacuum distillation, and slices to obtain the target The product is p-toluic acid; the centrifuged crystallization mother liquor is returned to the reaction system as the water phase, and the whole reaction process forms a continuous feeding and discharging process, which solves the problem of low yield and low yield in the catalytic oxidation reaction process in the prior art , poor product quality, high energy consumption, etc.

Method used

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  • A kind of technique for preparing p-toluic acid by continuous catalytic oxidation

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Embodiment 1

[0027] A process for preparing p-toluic acid by continuous catalytic oxidation, the specific steps comprising:

[0028] (1) Stir and mix p-xylene 20Kg, 32% caustic soda aqueous solution 23Kg and catalyst cobalt naphthenate 1.0Kg in a mixing tank to obtain a feed liquid, and adopt a multiphase pump to feed the feed liquid at 1m 3 / h into the gas-liquid high-efficiency mixer to mix evenly with oxygen to carry out continuous catalytic oxidation reaction, use the pump to circulate through the steam heater on the circulation pipeline to heat the material liquid to 100-110°C, and then enter the continuous tubular reactor to continue Reaction, the reaction temperature is 110°C, and the reaction pressure is 0.3MPa;

[0029] (2) when the massfraction that sodium p-toluate accounts for reaction solution in the reaction solution that enters two-phase continuous separator is 20%, when the massfraction that sodium p-toluate accounts for caustic soda aqueous solution in reaction solution is...

Embodiment 2

[0033] A process for preparing p-toluic acid by continuous catalytic oxidation, the specific steps comprising:

[0034] (1) Stir and mix p-xylene 40.0Kg, 32% caustic soda aqueous solution 46.0Kg and catalyst cobalt naphthenate 2.0Kg in a mixing tank to obtain a feed liquid, and adopt a multiphase pump to feed the feed liquid at 5m 3 / h into the gas-liquid high-efficiency mixer to mix evenly with oxygen to carry out continuous catalytic oxidation reaction, use the pump to circulate through the steam heater on the circulation pipeline to heat the material liquid to 100-110°C, and then enter the continuous tubular reactor to continue Reaction, the reaction temperature is 140°C, and the reaction pressure is 0.6MPa;

[0035] (2) when the massfraction that sodium p-toluate accounts for reaction solution in the reaction solution that enters two-phase continuous separator is 20%, when the massfraction that sodium p-toluate accounts for caustic soda aqueous solution in reaction solutio...

Embodiment 3

[0039] A process for preparing p-toluic acid by continuous catalytic oxidation, the specific steps comprising:

[0040] (1) Stir and mix p-xylene 70Kg, caustic soda aqueous solution 80.5Kg and catalyst cobalt naphthenate 3.0Kg in a mixing tank to obtain a feed liquid, and adopt a multiphase pump to feed the feed liquid at 3m 3 / h into the gas-liquid high-efficiency mixer to mix evenly with oxygen to carry out continuous catalytic oxidation reaction, use the pump to circulate through the steam heater on the circulation pipeline to heat the material liquid to 100-110°C, and then enter the continuous tubular reactor to continue Reaction, the reaction temperature is 130°C, and the reaction pressure is 0.4MPa;

[0041] (2) when the massfraction that sodium p-toluate accounts for reaction solution in the reaction solution that enters two-phase continuous separator is 20%, when the massfraction that sodium p-toluate accounts for caustic soda aqueous solution in reaction solution is 40%...

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Abstract

The invention discloses a process for preparing p-toluic acid by continuous catalytic oxidation, which adopts p-xylene caustic soda aqueous solution / oxygen system, and uses cobalt naphthenate as a catalyst to carry out continuous catalytic oxidation reaction to obtain p-toluic acid. The whole process is short, the production capacity is large, the equipment investment is small, the degree of automation is high, the energy consumption is low, the tail gas is small, the comprehensive cost is low, the product yield is improved, and the labor intensity is reduced. The present invention has good economic and social benefits. It creates conditions to provide high-quality raw materials for the synthesis of related products in the dye industry, such as fluorescent whitening agent OB-1, dyes, pharmaceuticals, and pesticide intermediates, and is suitable for a wide range of promotion and application.

Description

[0001] field of invention [0002] The invention belongs to the field of chemical technology, in particular to a process for preparing p-toluic acid through continuous catalytic oxidation. Background technique [0003] P-toluic acid is a chemical raw material with a wide range of uses. It can be used as an intermediate for medicines, pesticides, organic pigments, whitening agents and other products. It is also an intermediate for the synthesis of drugs, dyes, spices and other substances. It is widely used It is used in many fields such as medicine, pesticide, photosensitive material, organic pigment and so on. [0004] At present, the preparation methods of p-toluene at home and abroad mainly include xylene nitric acid oxidation method, p-cymene nitric acid oxidation method, xylene air oxidation method and toluene carbonylation-oxidation method, etc., wherein xylene air oxidation The method is the most economical and effective method: put p-xylene into the oxidation tower and...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C63/04C07C51/265
CPCC07C51/265C07C63/04
Inventor 袁胜群陈雨晴马洪云徐瑞敏
Owner 宁夏德昊科技产业有限公司