Refining method of p-tert-butylbenzoic acid

A technology of p-tert-butyl benzoic acid and tert-butyl benzoic acid is applied in the field of preparing p-tert-butyl benzoic acid, can solve the problems of low yield in industrial production, complicated catalyst preparation and high reaction temperature, and achieves low production cost, Eliminate corrosion and post-processing complex and active effects

Inactive Publication Date: 2021-07-13
天津鼎晟新化科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

High-temperature gas-phase oxidation is rarely used due to high reaction temperature (420°C), complex catalyst preparation, and low selectivity (only about 65%); although electrochemical oxidation is non-polluting, the yield is very low (less than 30%) is not suitable for industrial production; the liquid phase solvent oxidation method promotes the sufficient contact of reactant and catalyzer because of the existence of solvent (mainly acetic acid), has prevented the precipitation of late reaction product, makes reaction carry out at lower temperature , and the yield is high, it is currently the main method for the industrial production of tert-butylbenzoic acid
[0004] However, in the process of producing tert-butylbenzoic acid, there is the problem of equipment corrosion caused by the presence of bromide

Method used

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Examples

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Effect test

preparation example Construction

[0035] The preparation method of described supported catalyst comprises the steps:

[0036] The first step is to dry the silica gel at 120-150°C for 3-5 hours to remove the adsorbed moisture and volatile substances, and set aside;

[0037] Preferably, the surface area of ​​the silica gel is 10-700m 2 / g, more preferably the surface area of ​​silica gel is 50-500m 2 / g, most preferably the surface area of ​​the silica gel is 100-400m 2 / g;

[0038] The pore volume of silica gel is 0.1-4.0ml / g, more preferably the pore volume of silica gel is 0.5-3.5ml / g, most preferably the pore volume of silica gel is 0.8-3.0ml / g;

[0039] The average particle diameter of the silica gel is in the range of 0.1-500 μm, more preferably the average particle diameter of the silica gel is 1-200 μm, most preferably the average particle diameter of the silica gel is 10-100 μm.

[0040] In the second step, cobalt acetate and sodium bromide are configured in a molar ratio of 1:3 to form a mixed solu...

Embodiment 1

[0044] 1. Obtain p-tert-butyltoluene: add toluene and concentrated sulfuric acid into the reaction kettle, pass through isobutylene to carry out alkylation reaction, and obtain crude product p-tert-butyltoluene, the temperature of the alkylation reaction is 20°C, and the time is 11 Hour, then the crude product p-tert-butyltoluene is rectified to obtain p-tert-butyltoluene.

[0045] 2, the synthesis reaction of p-tert-butylbenzoic acid: p-tert-butyl toluene and titanium zeolite, supported catalyst are added in the reactor, pass into the gas mixture containing 90% oxygen and other inert gases, at the beginning of the reaction, The temperature was 150°C to start the reaction, and the oxidation reaction was carried out at this temperature for 2h; then the temperature was lowered to 135°C to continue the oxidation reaction, and the reaction time was 5h to obtain the crude p-tert-butylbenzoic acid.

[0046]3. Gradient cooling crystallization

[0047] The solution containing the cru...

Embodiment 2

[0051] 1. Obtain p-tert-butyltoluene: add toluene and concentrated sulfuric acid into the reaction kettle, pass through isobutylene to carry out alkylation reaction, and obtain crude product p-tert-butyltoluene. The temperature of the alkylation reaction is 24°C, and the time is 9 Hour, then the crude product p-tert-butyltoluene is rectified to obtain p-tert-butyltoluene.

[0052] 2, the synthesis reaction of p-tert-butylbenzoic acid: p-tert-butyl toluene and titanium zeolite, supported catalyst are added in the reactor, pass into the gas mixture containing 90% oxygen and other inert gases, at the beginning of the reaction, The reaction was started at 155°C, and the oxidation reaction was carried out at this temperature for 0.25h; then the temperature was lowered to 145°C to continue the oxidation reaction, and the reaction time was 5h to obtain crude p-tert-butylbenzoic acid.

[0053] 4. Gradient cooling crystallization

[0054] The solution containing the crude product of p...

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Abstract

The invention provides a refining method of p-tert-butylbenzoic acid. The refining method comprises the following steps: 1, obtaining p-tert-butyltoluene; 2, adding the p-tert-butyltoluene obtained in the step 1 and a supported composite catalyst into a reaction kettle, introducing oxygen, and carrying out an oxidation reaction at a certain temperature to obtain a p-tert-butylbenzoic acid crude product; 3, cooling and crystallizing the p-tert-butylbenzoic acid crude product obtained in the step 2, performing centrifugal spin-drying, and washing with p-tert-butyltoluene to obtain a centrifuged crude product; and 4, adding the centrifuged crude product into a dissolving kettle, centrifuging, and drying to obtain a p-tert-butylbenzoic acid finished product. The method has the beneficial effects that the high-quality product can be obtained by simply washing the crude product with water, the post-treatment process is simplified, the quality of the product can be improved, and the production cost can be reduced.

Description

technical field [0001] The invention relates to the field of preparation of p-tert-butylbenzoic acid, more specifically to a method for refining p-tert-butylbenzoic acid. Background technique [0002] 4-tert-butylbenzoic acid is an organic synthesis intermediate, mainly used in polypropylene nucleating agent, polyvinyl chloride heat stabilizer, metal processing cutting and lubricating oil additive, antioxidant, alkyd resin modifier, flux and Many special functions such as dyes. [0003] The production routes of p-tert-butylbenzoic acid mainly include high-temperature gas-phase oxidation, electrochemical oxidation, liquid-phase solvent oxidation, and liquid-phase solvent-free oxidation. High-temperature gas-phase oxidation is rarely used due to high reaction temperature (420°C), complex catalyst preparation, and low selectivity (only about 65%); although electrochemical oxidation is non-polluting, the yield is very low (less than 30%) is not suitable for industrial producti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/265C07C51/43C07C51/47C07C63/04B01J31/26B01J31/38B01J31/04B01J29/89
CPCC07C51/265C07C51/43C07C51/47C07C2/70B01J29/89B01J31/04B01J31/26B01J31/38B01J2231/70C07C63/04C07C15/02
Inventor 任荣
Owner 天津鼎晟新化科技有限公司
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