The Study On The Regulation And Catalytic Performance Of The Surpport And Active Components Of The Loaded Noble Metal Pd And Au

The UV absorbant of benzo three azole is mainly incorporated into some polymer materials,which can effectively protect the polymer by absorbing ultraviolet light.Among benzo three azole azole UV absorbant,UV-P is the most widely used and the largest market demand.Compared to other reduction methods such as zinc powder reduction and hydrazine hydrate,the synthesis of UV-P by catalytic hydrogenation is one of the most environmentally friendly and green synthesis methods reported.At present,there are a series of problems such as serious inactivation and the need to add chips in the system.So finding an efficient and feasible catalyst is the fundamental way to alleviate environmental pollution.However,although the reaction has been produced in a large scale in industry,it is still necessary to have a high catalytic activity in the process of reaction,so it is important to find a highly efficient and strong alkaline catalyst to improve the selectivity of the target product.At present,the adjustable of the support of the hydrotalcite and the high dispersion of the active species make it have a certain application in some solid base catalytic reactions.The alkaline strength of MgAl-LDH itself has certain limitations,and it is possible to add appropriate amount of hydrotalcite to the hydrotalcite and enhance the application of the hydrotalcite support to HAB hydrogenation.Alkyl aromatic compounds are important intermediates in the synthesis of drugs and fragrances.Aromatic alcohols,ketones,aldehydes and carboxylic acids can be obtained by oxidation of alkyl aromatic hydrocarbons.However,the oxidation of alkyl aromatic hydrocarbons in industry is mainly by strong corrosive potassium dichromate and Potassium Permanganate as oxidant,which leads to the strict requirements of the reaction equipment,no trace of reaction route.Due to many reaction byproducts and environmental pollution,it restricts the large-scale production of the compound.Therefore,it is very important to explore a kind of C-H bond which can easily activate alkyl aromatic hydrocarbons and be suitable for more stable and efficient green environmental catalysts with mild conditions.In this research,we have two kinds of ideas:1.We have carried out the first system work on the study of the modulation of hydrotalcite supporter and the study of HAB catalytic hydrogenation;2.By comparing the bimetallic catalysts with different support loads,we carried the second systems.(1)The MgAl-LDH was synthesized by the colloidal milling crystallization separation method,and Pd was loaded on a round piece of hydrotalcite by NaBH4 reduction method.By doping a certain amount of La and Ca elements,We selected out the best catalyst which have the most stonger Alkaline.The size and dispersion of the Pd nanoparticles were modulated by adjusting the amount of NaBH4 added.The optimum catalytic Pd/La5%Ca25%MgAl-LDH was selected by comparison and applied to the catalytic hydrogenation reaction of HAB.The selectivity of UV-P and the conversion rate of HAB was 65.9%and 100%without adding any basic auxiliary agent.When we add the the organic alkaline builder,the yield of the target product can be increased to 73.5%.In addition,the catalyst can be reused more than 4 times,and the catalyst can still maintain relatively good activity.We attribute this high activity to the large amount of Bronsted base on the hydrotalcite surface,the high dispersibility of Pd nanoparticles and more small Pd nanoparticles to activate the N-0 Valence bond of NO compound.(2)Inspired by the studies that have revealed new properties of bimetallic NPs,we developed a new hierarchical marigold-like hollow alumina microsphere(MHAM)supported bimetallic AuPd catalyst.It was found that as-formed supported AuPd catalyst exhibited much better catalytic performance in terms of EB the conversion and the AP selectivity in the liquid phase solvent-free aerobic oxidation of EB using molecular oxygen as an oxidant and TBHP as an initiator,as well as in comparison to corresponding monometallic counterparts and conventional Al2O3 or solid alumina microspheres supported AuPd catalysts.The high catalytic efficiency of the present supported AuPd catalyst was mainly assigned to synergetic effect of active bimetallic components in the catalyst,as well as unique hierarchical marigold-like micro/nanostructure of alumina support being beneficial to close contact of reactants with surface active sites.Moreover,after the pervasive experiment of the catalyst,our catalyst also has better conversion and selectivity for the alkyl aromatic compounds to produce the corresponding ketones.After several times of reuse,the catalyst remains unchanged,indicating that our catalyst has good stability.This high activity is attributed to the special hierarchical lamellar petal structure of the support,the high dispersion of AuPd and the synergistic effect of bimetallic.