Micro-spherical polymer solid acid esterification catalyst and preparation method thereof

Abstract

The invention belongs to the technical field of chemical catalysis and relates to a micro-spherical organic polymer solid acid esterification catalyst and a preparation method thereof. In the invention, the method for preparing the micro-spherical polymer solid acid esterification catalyst comprises the following concrete steps: adding 100 parts by weight of distilled water into a reaction kettle, and then, adding 20-50 parts by weight of vinyl unsaturated monomer, 0.1-3 parts by weight of initiating agent and 1-5 parts by weight of emulsifying agent under the condition of stirring for reacting for 1-6h in a boiling state to form an emulsion; cooling the reactants, and acidifying the reactants with an acidifying agent to obtain white solid precipitates; and drying the white solid precipitates in a vacuum drying oven to obtain the micro-spherical polymer solid acid catalyst. The catalyst of the invention can be recycled and regenerated easily and has the advantages of stable catalytic performance, small alcohol acid ratio, no side reaction, high yield, simple after-treatment of products and lower cost.

Description

technical field [0001] The invention belongs to the technical field of chemical catalysis, and relates to a microspherical organic polymer solid esterification catalyst and a preparation method thereof. Background technique [0002] Carboxylate is an important class of organic compounds. It can not only be used as a raw material for organic synthesis, but also an important fine chemical product, widely used in spices, daily chemicals, food, medicine, rubber, coatings and other industries. Carboxylic acid esters are generally prepared by esterification of alcohols and acids. As we all know, esterification is a reversible reaction. When the esterification occurs, the hydrolysis of the ester also occurs. In order to obtain a high yield of the ester and shorten the reaction The time required to make the reaction proceed under specific conditions, such as using a catalyst, heating, making a certain reactant in excess and reducing the amount of water in the product, etc., wherein ...

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Problems solved by technology

[0005] (1) In the esterification reaction, because sulfuric acid has esterification, dehydration and oxidation at the same time, a series of side reactions occur, so that the reaction product contains a small amount of ether, alkene and sulfuric acid ester, etc., which improves the purification of the product and the recovery of raw materials. Bring difficulties, which also limits its application in the food industry

[0006] (2) The treatment of the reaction product needs to be neutralized by alkali and washed with water to remove sulfuric acid as a catalyst, resulting in complicated process, loss of product and unreacted raw materials, and a large amount of waste liquid which is difficult to handle

[0007] (3) Due to the severe corrosiveness of sulfuric acid, although enamel reactors and high-grade stainless steel pipes are used, the equipment still has to be regularly updated, thereby increasing production costs

However, there are still some problems in using solid acid catalysts instead of sulfuric acid for catalytic esterification.

[0010] (1) The specific activity of solid acid catalyst is lower than that of sulfuric acid, so the production capacity is low;

[0011] (2) Like other heterogeneous catalytic reactions, the surface of the catalyst is prone to carbon formation and loss of activity;

[0017] Existing strong-acid cation-exchange resins, as excellent solid acid catalysts, fully meet the requirements of green chemistry and show broad application prospects, but are not resistant to high temperatures (Amberlyst15 can withstand a maximum temperature of 150°C, and other resins are around 100°C), and their acid strength is low. etc., loaded L acid and with inorganic solids (such as SiO 2 ) to form a composite catalyst, it is from this point of view to make up for the deficiency of the resin itself, the high temperature resistance of the modified resin is indeed enhanced, but the inorganic matter also hinders the activity of the resin (such as water absorption, acidity, etc.) to a certain extent. Failed to realize industrial application

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