Studies On The Oxidation Of 2, 6-di-Substituted-p-Cresol By NO

Phenols are important chemicals and widely existed in various natural products.Their 2,6-di-substituted derivatives are useful intermediates for constructing highly functionalized biologically and medicinally important products.Hindered phenols are a kind of important antioxidants,they are widely used on the antioxidants of plastic.Their other derivatives have been intensely investigated in view of their applications as antibiotics and antitumor agents. Very often,their preparation requires a multistep raction,involves a expensive oxidant,or pollute the environment.This thesis first time takes the nitrous oxide as oxidant,the methanol as solvent,carrying on seleetivity oxidation study on 2,6-di-tert-butyl-4-methylphenol and 2,4,6-trimethylphenol. Their structures were characterized by melting point,LC-MS and ~1H NMR method.The effects of reaction time,reaction temperature and the amount of nitrous oxide on conversion and selectivity were investigated and we found out the optimal condition:temperature 40℃, time 8 hours.The conversion of 2,6-di-tert-butyl-4-methylphenol is 63%,and the selectivity of 2,6-di-tert-butyl-4-methoxymethylphenol is 88%;the conversion of 2,4,6-trimethylphenol is 81%,and the selectivity of 2,6-dimethyl-4-methoxymethylphenol is up to 99%.The other substituted phenols were also studied tentatively.The other solution of alcohol was compared,and we got the corresponding ethers.Their structures were also characterized by melting point,LC-MS and ~1H NMR method.The yield of product is lower as the polarity of O-H weaker.Reaction mechanism was discussed.The conditions of acid and alkali were investigated and we got 4-hydroxy-2,4,6-trimethyl-cyclohexa-2,5-dienone in alkali condition.