The Synthesis Of NHPI Analogues And Their Application In The Catalytic Aerobic Oxidation

Oxidation is a very important process in chemical industry, through which lots of hydrocarbons could be converted to alcohols, aldehydes, ketones, carboxylic acids and so on. These products are very important and useful chemical intermediates. In the traditional oxidation process, lots of chemical oxidative reagents and metallic compounds are involved which would lead to severe environmental problems. As more and more attention is paid to these problems, alternative green oxidation processes need to be developed urgently.A green oxidation process needs green oxidative reagents and the clean oxygen will be the best choice. As we all know, oxygen is a renewable resource which can make an atom-economy reaction in which byproduct used to be harmless water. However, molecular oxygen is stable in the common conditions. We need suitable catalysts to activate molecular oxygen to realize target process. There needs green catalysts for green oxidations. Ishii’s group has used NHPI systems to catalyze hydrocarbons’ aerobic oxidation for long time, and some of their achievements have been industrialized. Xu Jie’s group is another important work team in this field who have developed some metal free NHPI catalyst systems which can catalyze high selective benzylic oxidations.Herein, started from anhydrides we have achieved the synthesis of corresponding NHPI analogues. These compounds are used to catalyze ethylbenzene’s aerobic oxidation. Through the conversion rate of ethylbenzene and the selectivity of acetophenone, we compare their catalyze ability. We use these compounds to make combinations and find out a powerful system NHQI/Car-NHPI. This new combination can make ethylbenzene’s aerobic oxidation go on smoothly without any initiator. We study the solvent, temperature, reaction time and the amount of catalysts’effect in NHQI/Car-NHPI catalyzed ethylbenzene’s aerobic oxidation. Under the optimized conditions, the conversion rate of ethylbenzene reaches65.7%and the selectivity of acetophenone is75.4%. Overall, we have built a new metal free, initiator free catalyst system which can achieve ethylbenzene’s selective oxidation efficiently. Some organic acid and base are involved in this free radical process, making a good direction for the coming work in this field.