Research On Selective Catalytic Oxidation Of Alcohols And Aldehydes By Polyoxometalate

Alcohols,aldehyde,and carboxylic acids are the most vital organic compounds in natural world and in daily life.No matter the organism,medicine,or chemical industry,these three compounds cannot be separated.The preparation of alcohols,aldehydes and carboxylic acids is also one of the important basic chemical industries.The oxidation reaction is the main synthesis method of preparing the above compounds,and the traditional oxidation basically relies on some toxic and hazardous oxidants,such as dichromate,permanganate,periodate,etc.which doesn't fit the concept of“Green Chemistry”.In order to reduce the reaction energy consumption and the use of toxic and hazardous substances,catalytic oxidation has become an effective way to achieve this goal.The purpose of catalysis is to reduce the difficulty and increase the reacting efficiency.At the same time,in the oxidation reaction of the alcohol-aldehyde-carboxylic acid,the addition of a catalyst can reduce the use of traditional strong oxidants,and a more simple and effective way to achieve product conversion.Polyoxometalates which possess excellent redox properties and universal applicability to the substrates are emerging catalysts.In this dissertation,an Anderson-type polyoxometalate was selected as a catalyst to study the catalytic efficiency of the oxidation of alcohols to aldehydes and ketones,and the oxidation of aldehydes to carboxylic acids.?1?We selected the Anderson-type polyoxometalates?NH₄?₄[CuMo₆O₁₈?OH?₆]·5H₂O(Cu^IIIMo₆)with the copper heteroatom center as the catalyst,the molecular oxygen as the oxidants,and realized the transformation of aldehydes to the carboxylic acids.The catalytic system has excellent catalytic activity for various aldehydes,and most of them can be catalytically oxidized to corresponding carboxylic acids with the yields of 99%.The catalyst is green and environment-friendly.Research shows that it can be recycled,and there will be no major changes in the catalytic activity for six cycles,and the structure is stable.?2?Based on the previous research,we investigated the catalytic properties of Cu^IIIMo₆catalytic in the catalytic oxidation of aromatic alcohols to corresponding carbonyl compounds.We determined the optimal reaction conditions after the reaction condition screening,Experiments show that the catalytic system also has good adaptability to aromatic alcohols.Both primary and secondary aromatic alcohols can be efficiently catalyzed and oxidized to the corresponding aldehyde and ketone compounds,and the yields are considerable.Nitrogen,oxygen,and sulfur-containing heterocyclic alcohols can also be quantitatively oxidized toaldehydes and ketones.At the same time,we have inferred the reaction mechanism,and determined the active intermediate(Mo^IV)POMCu^II=O by ESI-Ms,and speculated the catalytic mechanism of this experiment based on the above experiments.It can be seen from this experiment that the Anderson-type catalyst has good catalytic activity,structural stability,simple preparation method,environmental friendly performance,and has great potential in industrial production.