The Studies On The Application Of TEMPO In Oxidation Of Alcohols

In recent years,the liquid phase catalytic oxidation of alcohols to aldehydes and ketones by molecular oxygen as a clean oxidant has become a research hotspot.In this work,using TEMPO and its derivatives as catalyst,O2 as the oxidant,acetic acid as solvent,the catalytic oxidation of isosorbide was studied.Then,the optimal catalyst is selected.By changing the different reaction conditions,such as reaction temperature,amount of catalyst,reaction time,the most suitable condition for the catalytic oxidation reaction of isosorbide was obtained.The result showed that the yield is up to 99.6%when the optimal process condition is as follows:reaction temperature is 50℃,reaction time is 3h,rate of O2 is 10 ml/min,3 mol%of AA-TEMPO,6 mol%of HNO3.The product was purified by crystallization and recrystallization and characterized by NMR.In the case of the oxidation of isosorbide,the catalyst was reused twice,and the yield of product is up to 83%.The kinetics of isosorbide and the catalytic mechanism of TEMPO/HNO3 was studied.The kinetics equation was established by analyzing the data obtained in homogeneous environment.The aerobic oxidation of alcohols can be achieved by TEMPO/Ru system.With octanol as a model substrate,the effect of different conditions(such as solvent,temperature,amount of catalyst and so on)on the reaction was studied.The result showed that the conversion and selectivity of octanol are up to 36%,77%by using 4.5 mol%of TEMPO,1.5 mol%of RuCl2(PPh3)3 for 6 h at 100℃ in air.With the addition of BHT,the selectivity can be improved to 95%.The kinetics of octanol and the catalytic mechanism of TEMPO/Ru/BHT are studied.The kinetics equation was established by analyzing the data obtained in homogeneous environment.