Study On Selective Oxidation Of Allyl Alcohol By Manganese Dioxide

??-unsaturated aldehydes and ketones are important intermediates in organic synthesis reactions and are widely found in fine chemicals such as pharmaceuticals,perfumes,and chemical materials.The preparation of ? ?-unsaturated aldehydes and ketones by selective oxidation of allylic alcohol has been the focus of chemists.In the study of traditional allylic alcohol oxidation,most of the oxidants use rare metal complexes or some heavy metal compounds.These oxidants are expensive,have harsh reaction conditions,and are difficult to recycle,which limits their application.The research on the preparation of ? ?-unsaturated aldehyde and ketone compounds by the oxidation of allylic alcohol with low-cost and high-efficiency,mild reaction conditions and environmentally friendly oxidants will have important value in practical application.The oxidation state of manganese in manganese dioxide is positive tetravalent,in the middle valence state of manganese,which could be both oxidizing and reducing.Research precedent show that manganese dioxide has certain oxidation activity and has been applied in the oxidation of allyilic alcohol due to its novel properties such as being stable,non-toxic,harmless,cheap and readily available.In addition,its reaction condition usually are mild and easy to operate.Due to the existence of various crystal forms of manganese dioxide,their properties are quite different,which resulted very different oxidizing ability and selectivity.Although there are reports of oxidation of allylic alcohol with manganese dioxide,there is absence of studies on the relation between the oxidation ability and the crystal form of manganese.In this research,manganese dioxide with different crystal forms was prepared for the investigation of oxidizing ability of manganese dioxides in the oxidation of allylic alcohol.The aim of the research is to establish an objective relationship between the manganese dioxide crystal form and the selective oxidation ability,which provided a scientific basis for the study of manganese dioxide in the application of allyl alcohol oxidation.