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Method for preparing p-toluenesulfonic acid through toluene sulfonation

A technology of p-toluenesulfonic acid and toluene, which is applied in the fields of sulfonic acid preparation, chemical recovery, organic chemistry, etc., can solve the problems of sulfonation microreactor technology without available data, and achieve the effect of safe and continuous process

Active Publication Date: 2014-07-23
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] By searching the prior art literature, toluene liquid phase SO 3 The high-selectivity technology of sulfonation (the selectivity of the product p-toluenesulfonic acid is more than 95%) has not been reported yet, and the toluene liquid phase SO 3 Sulfonated microreactor technology also has no information to check

Method used

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Examples

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Embodiment 1

[0021] Example 1: Low concentration, equimolar reaction process

[0022] Reaction operating conditions: the initial concentration of toluene is 10wt% (solvent is 1,2-dichloroethane), the initial concentration of sulfur trioxide is 5wt% (solvent is 1,2-dichloroethane), adjust the reactant toluene and trichloroethane The flow rate of the sulfur oxide solution is such that the molar ratio of toluene to sulfur trioxide is 1:1, and the ratio of the sum of the total volume flow rate of the two to the volume of the reaction microchannel is 13000 hours -1 (That is, the apparent residence time is 0.28s), and the reaction is performed at a reaction temperature of 28°C. The product is separated by filtration. The separated solid is placed in an oven at 50°C and dried to constant weight. Weigh a certain mass of solid product and dissolve it in triethyl orthoformate, and esterify it at 115°C for 1 hour. The esterified product is analyzed by gas chromatography. Gas chromatographic conditions: ...

Embodiment 2

[0024] Example 2: Isometric, recirculation process

[0025] Referring to Example 1, it can be seen that the toluene concentration is 10wt.%, SO 3 The concentration of 5wt.%, the reaction temperature is close to normal temperature, the content of p-toluenesulfonic acid in the product is nearly 95%. According to this result, the toluene concentration of the reactant is increased to make it excessive. After the reaction, the concentration of toluene in the filtered mother liquor is reduced according to the reaction rate. Reflux continues to react as a reactant without affecting the product concentration. Therefore, the present invention proposes a mother liquor circulation and low-temperature microreaction process.

[0026] The operating conditions are: the initial concentration of toluene is 50wt% (solvent is 1,2-dichloroethane), the initial concentration of sulfur trioxide is 5wt% (solvent is 1,2-dichloroethane), the reaction temperature is 28°C, The residence time is 0.28s. Feed an...

Embodiment 3

[0029] Example 3: High-concentration, equal-volume, recirculation process

[0030] Referring to Example 2, it can be seen that in the toluene concentration of 50wt.%, SO 3 The concentration is 5wt.%, the reaction temperature is close to normal temperature, and the p-toluenesulfonic acid content in the product reaches 96.36% under the operating conditions of the three-cycle reflux process. It is analyzed that the by-product sulfone circulates with the mother liquor as a reaction material, which inhibits the formation of phenylsulfone. Can increase the concentration of p-toluenesulfonic acid product. According to this result and inference, continue to increase the toluene concentration of the reactant to make it excessive and reduce the amount of solvent. After the reaction, the toluene concentration in the filtered mother liquor is gradually reduced according to the reaction rate, and multiple refluxes are used as the reactant to continue the reaction without affecting the product ...

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Abstract

The invention discloses a method for preparing p-toluenesulfonic acid through toluene sulfonation in a micro-reactor. The method is characterized in that a low-concentration liquid SO3 is taken as a sulfonating agent, an excess feeding ratio of toluene to SO3 is employed, and in the sulfonation technology, a high-concentration toluene is used for feeding and a product mother liquor (filtrate) is cycled. Also, a micro-channel in-situ heat exchange technology is employed for precisely regulating the sulfonation reaction temperature. The method has the advantages that liquid sulfur trioxide is taken as the sulfonating agent, no waste acid is basically generated in products, separation is easy to operate, the concentration of the main product p-toluenesulfonic acid is 97%, and the micro-reaction sulfonation technology is safe and continuous in process and high in efficiency.

Description

Technical field [0001] The invention belongs to the technical field of fine chemical raw material synthesis, and specifically relates to a method for preparing p-toluenesulfonic acid by liquid phase sulfonation of toluene in a microreactor. Background technique [0002] The sulfonation reaction occupies an important position in the field of modern industry and is an important step in the synthesis of a variety of organic products. It is widely used in industries such as medicine, pesticides, dyes, detergents, and petroleum. The sulfonation reaction is a kind of reaction that introduces sulfonic acid groups into aromatic hydrocarbon compounds. The introduction of sulfonic acid groups makes the organic compounds have specific functions such as water solubility, easy conversion, and hydrolysis. Accordingly, the sulfonated products can be directly used as surfactants Product application, or as an intermediate product, continue to be converted into intermediates or products containing...

Claims

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Application Information

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IPC IPC(8): C07C309/30C07C303/06
CPCY02P20/582
Inventor 陈光文陈彦全焦凤军韩梅
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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