Preparation method and application of silicotungstic acid shell coating and core intercalation zeolite imidazole framework

Abstract

The invention relates to biomass energy utilization technology and aims to provide a preparation method and application of silicotungstic acid shell coating and core embedded zeolite imidazole framework. It includes: dissolving silicotungstic acid in methanol solution of cobalt nitrate, adding it to dimethylimidazole methanol solution, stirring continuously at room temperature, centrifuging after sufficient complexation reaction; filtering out, cleaning and drying the solid product to obtain silicon Tungsten acid core embedded zeolite imidazole framework; added to silicotungstic acid aqueous solution, after ultrasonic treatment, continuous stirring at room temperature, centrifugation after full reaction; the solid product is filtered, washed, and dried to obtain the product. The zeolite imidazole skeleton of the present invention can maintain the structural integrity of uniform pore size during high temperature and high pressure reaction processes, and at the same time provides active catalytic sites for Lewis acids and Lewis bases. The uniform distribution of silicotungstic acid is achieved at higher loadings, the catalyst has good stability when recycled, the conversion efficiency is high after the catalyst is regenerated, and the catalyst has a long cycle life.

Description

technical field [0001] The invention relates to biomass energy utilization technology, in particular to a preparation method and application of silicotungstic acid shell coating and core embedding zeolite imidazole framework. Background technique [0002] Microalgae have unique advantages such as high oil content and fast growth rate, and are considered as an important choice for biodiesel feedstock. Homogeneous catalysts are often used in the traditional microalgae oil conversion method to produce biodiesel. Although high conversion efficiency has been achieved, the difficulty in recycling acid-base catalysts has caused problems such as equipment corrosion and environmental pollution that are difficult to solve, hampering the sustainable and healthy development of the industry. The heterogeneous catalyst developed in recent years to convert bio-oil to biodiesel can solve the above problems, and has become a research hotspot of catalysts at home and abroad. Heteropolyacid i...

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Problems solved by technology

[0003] Malkar et al. loaded phosphotungstic acid inside the zeolite imidazole framework ZIF-8 centered on zinc atoms to make a catalyst for the esterification reaction of benzoic anhydride and cinnamyl alcohol, but the catalyst structure has a limited amount of phosphotungstic acid loading (less than 18%) leads to a catalytic efficiency of only 60%, in order to improve the catalytic efficiency it is necessary to load more phosphotungstic acid but it will lead to the collapse of the zeolite imidazole framework

Jeon et al. loaded phosphotungstic acid on the surface of zeolite imidazole framework ZIF-8 particles centered on zinc atoms to make a catalyst for the transesterification reaction of soybean oil, but the agglomeration of phosphotungstic acid on the periphery of the zeolite imidazole framework caused the specific surface area of ​​the catalyst to increase. drop (only 457m 2 / g), although a higher loading of phosphotungstic acid (50%) has been achieved, the catalytic efficiency of transesterification has not been significantly improved (only 73%)

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