Polysilicone Modified POMs@alumina Catalytic Materials And Their Catalytic Properties

The polyoxometalates have a variety of adjustable structure types,the valence of the POM are the highest oxidation state,and the POM themselves are Bronsted acid,so they are extremely widely used in the field of catalysis.Alumina as a catalyst carrier has a low cost and is simple to prepare.In this paper,based on the covalent modification of Dawson-type POM on the surface of alumina as the research object,two types of catalysts were prepared and their catalytic properties were investigated.1.SOx produced by the combustion of sulfur compounds in oil products has great harm to the atmosphere and human body.The demand for sulphur content in vehicle oils has become more and more demanding throughout the world,and the production of highly efficient and rapid desulfurization catalysts is an inevitable trend.Based on the POMs@alumina system,the Cs,C12 and C18 organic carbon long chains were covalently modified to hydrophobically modify the materials,and the catalytic materials were systematically characterized by different techniques.We designed a variety of chemical models to demonstrate the affinity of substrates and products with organic carbon chains in the desulfurization of oil products.The polarity of the reaction substrates is relatively weak and is easily adsorbed to the surface of the polyacid active sites via the hydrophobic long chains.At this point,the increased polarity of the product can easily leave the active site through long chain desorption,greatly increasing the overall rate of the catalytic reaction.In the catalytic reaction,the simulated oil and the real oil are almost completely desulfurized under the mild reaction conditions in 9 min and 60 min respectively,and the catalytic material shows a high recycling effect,which has potential industrial application prospects.2.Acid-catalyzed reactions are a large class of reactions in the industry and include a wide variety of reactions such as alkylation reactions and esterification reactions.Homogeneous catalysts are commonly used in the industry to catalyze acid reactions.However,traditional acid catalysts have limitations such as dehydration,difficulty in separation,many side reactions,and corrosion equipment.Therefore,the preparation of green,efficient and environment-friendly solid acid catalysts is an alternative to conventional liquid acid catalysts.The direction of development of the catalytic reaction.Based on the POMs@alumina system,the sulfonic acid group was used to synthesize catalyst Al2O3-P2W15-SO3H.At the same time,the catalysts were tested by various techniques.The esterification reaction of citric acid and n-butanol was used as a probe reaction to investigate the activity of the catalyst.The catalytic reaction achieved 99%conversion within 180 minutes,and the catalytic material had high cycling stability.