Preparation method of p-methylsulfonylbenzoic acid

A technology of thiamphenicol benzoic acid and p-thiamphenicol, which is applied in the field of preparation of thiamphenicol benzoic acid, can solve the problems of selectivity, low conversion rate and yield, difficult control of reaction degree, poor safety and reliability, etc. Achieve the effects of simple preparation method, convenient large-scale industrialization and process safety

Inactive Publication Date: 2013-09-25
扬州德耀电气有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] (1) The degree of reaction is not easy to control, and the selectivity, conversion rate and yield of the process are low
[0007] (2) The reaction product is complex, difficult to separate and refine, and the product quality is low;
[0008] (3) poor safety and reliability, serious pollution

Method used

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  • Preparation method of p-methylsulfonylbenzoic acid
  • Preparation method of p-methylsulfonylbenzoic acid
  • Preparation method of p-methylsulfonylbenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Main process equipment: stirred tank reactor, flat electrochemical reactor, sedimentation solid-liquid separator, melting equipment, preheating equipment, washing equipment, crystallization equipment, drying equipment, etc.

[0051] like figure 1 As shown, a kind of preparation method of p-methylsulfonyl benzoic acid is to take p-methylsulfonyl toluene as a raw material to carry out selective oxidation to prepare the method for p-methylsulfonyl benzoic acid, and its steps are as follows:

[0052] (1) melting: in the stirring tank, the p-methylsulfonyl toluene is heated to 90 ° C, and the p-methylsulfonyl toluene in a solid state at room temperature is melted into a liquid material;

[0053] (2) preheating: in the stirred tank, add sulfuric acid aqueous solution and oxidant potassium dichromate, heat up to 90 ° C, the concentration of potassium dichromate in the system is 0.5mol / L, and the concentration of sulfuric acid is 0.1mol / L, When the material is mixed with the r...

Embodiment 2

[0066] Main process equipment: static mixing reactor, three-dimensional electrochemical reactor, filtering solid-liquid separator, melting equipment, preheating equipment, washing equipment, crystallization equipment, drying equipment, etc.

[0067] Proceed as follows:

[0068] (1) Melting: in the falling film melting equipment, the temperature of p-methylsulfonyl toluene is raised to 150°C, so that the solid p-methylsulfonyl toluene at room temperature is melted into a liquid material;

[0069] (2) preheating: in the stirring tank, add sulfuric acid aqueous solution and oxidant potassium dichromate, heat up to 120 ° C, the concentration of potassium dichromate in the system is 3.0mol / L, and the concentration of sulfuric acid is 8.0mol / L, When the material is mixed with the raw material p-methylsulfonyltoluene by heating, the system is in a liquid state;

[0070] (3) Chemical oxidation: In the static mixing reactor, the sulfuric acid aqueous solution of potassium dichromate p...

Embodiment 3

[0082] Main process equipment: static mixing reactor, flat electrochemical reactor, centrifugal solid-liquid separator, melting equipment, preheating equipment, washing equipment, crystallization equipment, drying equipment, etc.

[0083] Proceed as follows:

[0084] (1) Melting: in the stirring tank, the p-methylsulfonyl toluene is heated to 120 ° C, and the p-methylsulfonyl toluene that is in a solid state at room temperature is melted into a liquid material;

[0085] (2) preheating: in the stirring tank, add sulfuric acid aqueous solution and oxidant potassium dichromate, heat up to 100 ° C, the concentration of potassium dichromate in the system is 2.0mol / L, and the concentration of sulfuric acid is 4.0mol / L, When the material is mixed with the raw material p-methylsulfonyltoluene by heating, the system is in a liquid state;

[0086] (3) Chemical oxidation: in the static mixing reactor, the sulfuric acid aqueous solution of potassium dichromate preheated in the previous s...

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Abstract

The invention relates to a preparation method of p-methylsulfonylbenzoic acid. The method provided by the invention mainly comprises the following steps: (1) fusing; (2) preheating; (3) chemical oxidation; (4) solid-liquid separation; (5) neutralization for salt formation; (6) solid-liquid separation; (7) adsorption for removal of impurities; (8) solid-liquid separation; (9) acidification and crystallization; (10) solid-liquid separation; (11) washing; (12) dewatering and drying for obtaining a product p-methylsulfonylbenzoic acid; and (13) electrochemical oxidation. The preparation method provided by the invention is simple, has advantages of reasonable technology, low production cost, high product purity and safe process, is convenient to realize large-scale industrialization, and is a clean production technology which is used for preparing p-methylsulfonylbenzoic acid and accords with green chemical development requirements.

Description

technical field [0001] The invention relates to a preparation method of p-methylsulfonyl benzoic acid, in particular to a method for preparing p-methylsulfonyl benzoic acid by direct chemical oxidation of p-methylsulfonyl toluene as a raw material, and belongs to the technical field of fine chemicals. Background technique [0002] The main raw material of the present invention is p-methylsulfonyl toluene, which is an aromatic compound, a white crystalline powder at room temperature, and the molecular formula is C 8 H 10 O 2 S, melting range 88℃~89℃, boiling point 312℃, density 1.154g / cm 3 , soluble in alcohol, ether and other organic solvents, slightly soluble in water. [0003] The product of the present invention is p-methylsulfonylbenzoic acid, which is aliased as p-carboxy-p-methylsulfonyltoluene, p-carboxyphenylmethylsulfone, p-methylsulfonylbenzoic acid and 4-methylsulfonylbenzoic acid, etc., and the English name is 4-methylsulphonylbenzoic acid, 4-(methylsulfonyl)...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C317/44C07C315/04
Inventor 王雅琼李树亮孙黎张小兴许文林
Owner 扬州德耀电气有限公司
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