Process for synthesizing p-tert-butylbenzoic acid

A technology of tert-butyl benzoic acid and p-tert-butyl toluene is applied in the field of preparation technology of p-tert-butyl benzoic acid, and can solve the trouble of producing methyl tert-butyl benzoate, large residual amount of product PTA and complicated process steps and other problems to achieve the effect of avoiding complex post-processing, avoiding coloring effects, and changing complex processes

Active Publication Date: 2013-04-03
SUQIAN COSMOS CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But the catalyzer that this method is used is the composite catalyst of cobalt acetate and sodium bromide, has bromide to exist in the production process, and aftertreatment is difficult to handle; Use gac, diatomaceous earth decolorization, process step is complicated, and product PTA residual amount is bigger, It will cause trouble for the subsequent production of methyl p-tert-butylbenzoate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Add 100kg of p-tert-butyltoluene and 0.3kg of cobalt acetate into the reaction kettle, feed oxygen, and start the reaction at a temperature of 150-152°C at the beginning of the reaction, and carry out the oxidation reaction at this temperature for 0.5-1.0 hours; then lower the temperature to 140-143° C. to continue the oxidation reaction, the reaction time is 10-12 hours, and obtain the crude product of p-tert-butylbenzoic acid.

[0041] The solution containing the crude p-tert-butylbenzoic acid is continuously cooled to room temperature, during which the p-tert-butylbenzoic acid is crystallized, centrifugally dried, washed with a small amount of p-tert-butyltoluene, and the centrifuged crude product is obtained. The centrifuged mother liquor is recycled and applied to the next batch of oxidation reactions, and the centrifuged mother liquor can be used repeatedly for 8 to 12 times.

[0042] Add the obtained centrifuged crude product into the dissolution kettle, add tolu...

Embodiment 2

[0045] Add 100kg of p-tert-butyl toluene and 0.2kg of cobalt acetate into the reaction kettle, blow in air, and start the reaction at 151-154°C at the beginning of the reaction, and carry out the oxidation reaction at this temperature of 0.75-1.25°C hours; then lower the temperature to 138-144° C. for the oxidation reaction, and the reaction time is 12-14 hours to obtain crude p-tert-butylbenzoic acid.

[0046] The solution containing the crude product of p-tert-butylbenzoic acid is subjected to gradient cooling, and the temperature is first reduced from the reaction temperature to about 80°C at a rate of 25°C / hour, and then uniformly lowered to about 30°C at a rate of 12°C / hour. Crystals began to precipitate, and then the temperature was uniformly lowered to 12-15°C at a rate of 6°C / hour. The crystallization of p-tert-butylbenzoic acid is complete, centrifuged and dried, and washed with a small amount of p-tert-butyltoluene to obtain a centrifuged crude product. The centrifug...

Embodiment 3

[0050] Add 100kg of p-tert-butyl toluene and 0.40kg of cobalt acetate into the reaction kettle, pass air in, and start the reaction at a temperature of 152-155°C at the beginning of the reaction, and carry out the oxidation reaction at this temperature of 0.25-0.75 Hours; then lower the temperature to 135-142° C. for the oxidation reaction, the reaction time is 8-10 hours, and obtain the crude product of p-tert-butylbenzoic acid.

[0051] Gradient cooling of the solution containing crude p-tert-butylbenzoic acid, first lowering the temperature from the reaction temperature to about 80°C at a rate of 22-24°C / hour, and then uniformly lowering the temperature to about 80°C at a rate of 13-15°C / hour 30°C, at this time, crystals began to precipitate, and then the temperature was uniformly lowered to 13-15°C at a rate of 5-7°C / hour. The crystallization of p-tert-butylbenzoic acid is complete, centrifuged and dried, washed with a small amount of p-tert-butyltoluene to obtain a centri...

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Abstract

The invention relates to a process for synthesizing p-tert-butylbenzoic acid. The process comprises the following steps of: adding p-tert-butyltoluene and cobalt acetate into a reaction kettle, introducing oxygen-containing gas, triggering at the temperature of between 150 and 155 DEG C, performing oxidation reaction for 0.5 to 1 hour, and continuously reacting at the temperature of between 135 and 145 DEG C for more than 5 hours to obtain a p-tert-butylbenzoic acid crude product; cooling the p-tert-butylbenzoic acid crude product to crystallize, performing centrifuge dripping, and striking and washing by using p-tert-butyltoluene to obtain a centrifugation crude product; and adding the centrifugation crude product into a dissolution kettle, adding methylbenzene, raising temperature and dissolving, filtering when a mixture is hot to remove impurities, adding water to wash, transferring materials to a recrystallization kettle, cooling to crystallize, centrifuging, striking and washing by using methylbenzene, and drying to obtain a p-tert-butylbenzoic acid finished product. The prepared p-tert-butylbenzoic acid is white crystals and does not contain mechanical impurities; and the melting point is 164.0 to 167.0 DEG C, the acid value is 312 to 316mgKOH / g, high performance liquid chromatography (HPLC) purity is more than or equal to 99.2 percent, moisture is less than or equal to 0.08 percent, and methylbenzene is less than or equal to 0.05 percent.

Description

technical field [0001] The present invention relates to a kind of synthetic technology of organic intermediate, relate in particular to a kind of preparation technology of p-tert-butylbenzoic acid. Background technique [0002] p-tert-butylbenzoic acid (PTBA) is an important intermediate in organic synthesis. It can be used as a nucleating agent for polypropylene, a modifier for the production of alkyd resin, its amine salt can be used as a preservative, its barium salt, sodium salt, and zinc salt can be used as a lubricating oil additive, and it is also used for the production of p-tert-butylbenzoic acid The main raw material of methyl ester. [0003] The production methods of PTBA mainly include electrochemical oxidation, high temperature gas phase oxidation, and low temperature liquid phase oxidation. The electrochemical oxidation method has little pollution and a yield of less than 30%, which is not suitable for large-scale industrial production. The reaction temperat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C63/04C07C51/265C07C51/43C07C51/42
Inventor 李焕成马瑞
Owner SUQIAN COSMOS CHEM
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