Method for preparing cyclohexyl formic acid sulfonic acid by using bipolar membrane method

Abstract

The invention provides a method for preparing cyclohexyl formic acid sulfonic acid from cyclohexyl formic acid sulfonate in process wastewater generated when caprolactam is produced by using a toluene method, by using a bipolar membrane electrodialysis technique. The method comprises the following step: converting cyclohexyl formic acid sulfonate in a cyclohexyl formic acid sulfonate solution into cyclohexyl formic acid sulfonic acid through bipolar membrane electrodialysis, wherein the bipolar membrane electrodialysis is achieved through three compartments, bipolar membranes, anode membranes and cathode membranes which are arranged alternatively; specific conditions are that the concentration of the cyclohexyl formic acid sulfonate solution is 5-30% (W/W), the voltage is 25V, the current density is 4-8A/dm<2>, and the reaction time is 3-4 hours. By adopting the method, a conventional concentrated sulfuric acid acidification method for preparing cyclohexyl formic acid sulfonic acid can be completely replaced, high-quality cyclohexyl formic acid sulfonic acid can be prepared, process steps are simple, meanwhile, pollution caused by a great deal of impurity sulfuric acid can be effectively avoided as parameter conditions are optimized, and remarkable industrial application values and environmental benefits can be obtained.

Description

technical field [0001] The present invention relates to a method for preparing cyclohexyl formic acid sulfonic acid by using electrochemical technology, in particular to a method for preparing cyclohexyl formic acid sulfonic acid from cyclohexyl formic acid sulfonate in caprolactam process wastewater produced by the toluene method by using a bipolar membrane electrodialysis process . Background technique [0002] A large amount of waste water is produced in the production process of caprolactam by the toluene method, and cyclohexyl formate sulfonate is the main by-product, which can be converted into high value-added chemical products through subsequent deep processing. Currently, chemical separation methods are mainly used for its recovery and treatment. But the cyclohexyl formic acid sulfonate obtained by separation is a crude product, which cannot meet the needs of industrial applications. In order to turn waste into treasure and improve the industrial value of cyclohexyl...

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Problems solved by technology

[0002] A large amount of waste water is produced in the production process of caprolactam by the toluene method, and cyclohexyl formate sulfonate is the main by-product, which can be converted into high value-added chemical products through subsequent deep processing. Currently, chemical separation methods are mainly used for its recovery and treatment. But the cyclohexyl formic acid sulfonate obtained by separation is a crude product, which cannot meet the needs of industrial applications. In order to turn waste into treasure and improve the industrial value of cyclohexyl formic acid sulfonate, it needs to be purified to obtain a single chemical with industrial use. However, the commonly used process for preparing cyclohexyl formic acid sulfonic acid by concentrated sulfuric acid acidification method has a long flow process, low purity and yield and can consume a large amount of sulfuric acid, accompanied by a large amount of waste acid generation, serious environmental pollution, Therefore, it is of positive practical significance to improve the existing preparation method of cyclohexyl formic acid sulfonic acid or to provide a new alternative method

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