Method for preparing sodium bisulfate/attapulgite clay composite solid acid catalyst

Abstract

The invention discloses a method for preparing a sodium bisulfate / attapulgite clay composite solid acid catalyst, wherein the solid acid catalyst is respectively prepared through a solution dipping method and a thermal dispersion method by using sodium bisulfate monohydrate and attapulgite clay as raw materials. The solution dipping method comprises the following steps of: intermittently adding asodium bisulfate solution and the attapulgite clay to a cylindrical glass container under the condition of stirring, dipping for a certain time after feeding, introducing the mixture to a dryer or conveying the mixture to the dryer after suction filtering, and stirring and heating until the mixture is dried to obtain the composite catalyst. The thermal dispersion method comprises the following steps of: intermittently adding the sodium bisulfate monohydrate and the attapulgite clay to a cylindrical glass container under the condition of stirring, raising the temperature to be higher than the melting point of sodium bisulfate, and after feeding, stirring the mixture and stopping stirring when the mixture is changed from a viscous state to a powdered state to obtain the composite catalyst. With the adoption of the method, low-cost attapulgite clay resources are fully used, the catalytic effect is improved, and the composite solid acid catalyst is not easy to agglomerate and convenient for shaping, storage, transportation and industrial application.

Description

technical field [0001] The invention relates to a preparation method of a composite solid acid catalyst, in particular to a method for preparing a sodium bisulfate / attapulgite composite solid acid catalyst with attapulgite clay as a carrier by using a solution impregnation method and a thermal dispersion method, and applying it to alcohol dehydration and esterification reaction. Background technique [0002] Sodium bisulfate is a strong ionic compound and a stable crystal. It is cheap and easy to obtain. Because it is easily soluble in water, the aqueous solution is strongly acidic, and insoluble in the reaction system of organic acids and alcohols. Therefore, it can replace sulfuric acid as a catalytic alcohol dehydration reaction. , Esterification reaction of carboxylic acid and alcohol and catalytic condensation reaction, etc. The catalyst has the advantages of simple post-reaction treatment process, direct separation of product and catalyst, less equipment corrosion...

AI Technical Summary

Problems solved by technology

However, there are the following disadvantages in practical applications: (1) When sodium bisulfate is directly used as a catalyst, since the melting point of sodium bisulfate is only 58.5°C, the reaction temperature of acid catalysis such as alcohol dehydration and esterification is generally above this temperature Therefore, sodium bisulfate exists in a molten state. At this time, the viscosity of the fluid is relatively high, and the phenomenon of salt coating is prone to occur, which reduces the active sites that can be catalyzed, which leads to a reduction in the chemical reaction rate, and also increases the amount of catalyst.

(2) Although the generated organic products can be directly separated from the catalyst, when the catalyst is replaced, the agglomeration of the residual salt catalyst and its coating on the wall of the reactor and the pipeline are very serious, and even the pipeline is blocked. These residual catalysts are difficult to Removal at normal temperature will affect the reaction of the next cycle and increase the production cost

(3) Sodium bisulfate monohydrate is easy to agglomerate when left for a long time, and the solid acid catalyst of sodium bisulfate monohydrate is not easy to shape, resulting in difficult and time-consuming loading and unloading, which hinders its industrial application

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