Preparation of temperature sensitive acidic ionic liquid and method of using the same in catalyzing alcoholic acid esterification

Abstract

The invention discloses preparation of temperature sensitive acidic ionic liquid and a method of using the same in catalyzing alcoholic acid esterification reaction. A general formula (I) represents the structure of the temperature sensitive acidic ionic liquid which is formed by benzothiazole cations and sulfonic acid radical anions. The invention is mainly characterized in that the ionic liquidis in a solid state at room temperature, can be dissolved in polar solvent such as water, alcohol and the like and cannot be dissolved in low-polar or non-polar solvent such as ester, ether and the like; and particularly the solubility of the ionic liquid in alcohol is very sensitive to temperature, the ionic liquid is hardly dissolved in alcoholic solvent at low temperature and can be rapidly dissolved in the alcoholic solvent after temperature is increased, crystals are precipitated after cooling and the solubility of the ionic liquid is very sensitive to temperature. The method of using the ionic liquid in catalyzing esterification comprises that the temperature sensitive ionic liquid is used to catalyze the esterification between monohydric alcohol or polyatomic alcohol and organic carboxylic acid, the ionic liquid is rapidly dissolved in a reaction system after the ionic liquid is heated and homogeneous-phase catalytic esterification reaction is conducted. After the reaction is stopped, the obtained product is cooled, the ionic liquid is crystallized and precipitated from the reaction system and after filtration is conducted, ester products and the ionic liquid are respectively obtained. The invention has the advantage that the transformation process of the temperature sensitive ionic liquid from heterogeneous phase to homogeneous phase to heterogeneous phase in the catalytic system can be realized only through temperature variation. The general formula (I) is shown as the accompanying drawing.

Description

technical field The invention relates to a preparation method of a temperature-sensitive acidic ionic liquid based on a benzothiazole cation and an application thereof in an esterification reaction, and belongs to the technical field of organic chemical catalytic reaction methods. Background technique Organic carboxylic acid esters are an important class of chemical and pharmaceutical intermediates, and their applications cover all aspects of production and life. The synthetic method of organic carboxylate mostly adopts inorganic acid as catalyst. This method has many problems such as poor selectivity, difficulty in separating the product from the catalyst, corrosion of equipment, and pollution of the environment by waste acid. Therefore, the development of efficient and environmentally friendly alkyd esterification catalysts not only has important economic benefits, but also has good social benefits. Ionic Liquids (Ionic Liquids) are a class of low-temperature molten sal...

AI Technical Summary

Problems solved by technology

However, when the esterification system catalyzed by this type of ionic liquid does not involve the participation of polyacids or polyols, the ionic liquid cannot be dissolved in the reaction system and is heterogeneously catalyzed, and cannot achieve crystallization, filtration and separation.

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