Preparation method and application of loaded nano gold catalyst

Abstract

The invention discloses a preparation method and application of a loaded nano gold catalyst. The preparation method includes the following steps of preparing a carrier (Cu-Ce-OY); preparing the supported nano gold catalyst. The application particularly refers to application of the loaded nano gold catalyst in preparation of vanillin and includes the following steps of putting the prepared catalystand vanillyl alcohol in an inner container of a high-pressure reactor, and adding p-xylene and tetrahydrofuran to serve as a mixed solvent; connecting the high-pressure reactor with an argon steel cylinder, introducing argon, adjusting the temperature of an oil bath pot after air in the reactor is removed, placing the reactor in the oil bath pot after the temperature is controlled at reaction preset temperature T+ / -1 DEG C, conducting stirring, conducting cooling through an ice water bath after a reaction is completed, opening the reactor, taking out the inner container, sucking reaction liquid, and filtering the reaction liquid with a nano filter head to prepare the vanillin. Dehydrogenation preparation of the vanillin from vanillyl alcohol can be achieved without oxidants and hydrogen receptors, and the highest yield is up to 99% or above.

Description

technical field [0001] The invention belongs to the technical field of synthesis of vanillin, and in particular relates to a preparation method of vanillin based on vanillyl alcohol dehydrogenation. Background technique [0002] Vanillin, also known as vanillin, is the first flavor synthesized by humans, successfully synthesized by Dr. Harman and Dr. Teiman in Germany in 1874. Vanillin is found in the seeds of the vanilla and has a strong, creamy aroma. Vanillin has a wide range of applications in the food field such as cakes, cold drinks, chocolate, and candies. It can also be used in rubber, plastics, cosmetics, pharmaceuticals, and health products in the fields of fine chemicals. [0003] my country is the world's largest exporter of vanillin. In 2002, the domestic demand was 2,350 tons, accounting for 30% of the output, and the remaining 70% was used for export. The average annual growth rate of my country's vanillin export volume is 12%, and it enjoys a good reputatio...

AI Technical Summary

Problems solved by technology

[0016] The oxidation of vanillyl alcohol to prepare vanillin requires the addition of a large amount of inorganic base and strong oxidizing agent, such as H 2 o 2 and other dangerous oxidizing reagents, and the reaction needs to be carried out under high pressure conditions, the reaction conditions are harsh, the operation is more dangerous, and other by-products will be generated, and the yield is not high

[0017] Fifth, the dehydrogenation route of vanillyl alcohol, there is only one report in the literature (Green Chemistry, 2016, 18, 6136–6142.), using mesoporous silica (SBA-15) to support zero-valent metal Pd 0 As a catalyst, water is used as a reaction solvent, and the reaction is carried out at 80°C under nitrogen protection for 7 hours, and the yield of vanillin reaches 99%.

The dehydrogenation of vanillyl alcohol to prepare vanillin is currently the only relevant literature report. Although the dehydrogenation of an oxidant-free and hydrogen-free acceptor has been realized, the catalyst prepared by assembly of zero-valent palladium and other carrier components has a complicated synthesis process and relatively high cost. In addition, it is necessary to use reagents that seriously pollute water bodies such as organic amines and nitrogen-containing organic substances, and the metal palladium component of the palladium catalyst is prone to loss during the recycling process

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