Improvement On TEMPO And Application In The Aerobic Oxidation Of Alcohls

Two methods based on 2,2,6,6-tetramethylpiperidyl-1-oxy (TEMPO) with molecular oxygen for the selective oxidation of alcohols were developed in the paper.A series of 4-substituted TEMPOs were synthesized through 4-OH-TEMPO.Experiment showed that substituents on TEMPO have beneficial effects on the catalytic activity and stability of TEMPO. A variety of 4-substituted TEMPOs have been screened for their ability in the oxidation of primary alcohols to the aldehydes with dioxygen in the NaNO2/FeCl3/4-substituted TEMPO system under mild conditions. Also the effects of various facts (such as solvent, temperature, oxygen pressure, catalyst) on the alcohol oxidation were studied.4-acetamido-TEMPO/NaNO2/FeCl3 has been developed, which could efficiently catalyze the selective aerobic oxidation of a wide range of primary alcohols, which may contain carbon-carbon double bond or N or S heteroatoms, especially primary aliphatic alcohols, to the corresponding aldehydes under mild conditions.Moreover,4-(4-methylbenzenesulfonyloxy)-TEMPO/NaNO2/FeCl3, a cheaper catalytic system, could efficiently oxidize a broad range of alcohols, which may contain carbon-carbon double bond or N or S heteroatoms, or primary aliphatic alcohols to the corresponding aldehydes and ketones under mild conditions.