Synthesis And Property Research Of N-Hydroxy -4-Ferrocenylpthalimide

Catalytic aerobic oxidation of hydrocarbons is of fundamental importance in the industrial synthesis of a large variety of oxy-functionalized compounds. In the recent years, there has been an upsurge in research directed toward improving these industrial processes environmentally friendly and highly value-added.As a small molecular free radical catalyst, the excellent catalytic performance and substrate universality of N-hydroxyphthalimide (NHPI) in the catalytic aerobic oxidation of C-H bond in hydrocarbons attracted universal attention. Synthesis of new N-hydroxy compounds and the exploitation of high efficient and selective catalytic systems nowadays become one important part of catalytic oxidation of hydrocarbons.In this paper, we have done the following efforts in the synthesis of new nitroxyl free radical catalyst:(1) A new kind of NHPI derivatives N-hydroxy-4-ferrocenylphthalimide (referred to as 4-FcNHPI) was synthesized through three steps using ferrocene and 4-aminophthalic acid as raw materials. First, the dissolved 4-aminophthalic acid in dilute hydrochloric acid reacted with sodium nitrite in the ice-salt bath. In the presence of phase transfer catalyst, the diazonium salt reacted with ferrocene give the 4-ferrocenylphthalic acid with the maximal yield 34%. Second,4-ferrocenylphthalic acid was dissolved in acetic anhydride and stirred at room temperature for 2 hour, 4-ferrocenylphthalic anhydride was quantitatively formed. At last, we used pyridine as acid depositing agent,4-ferrocenylphthalic anhydride was converted into 4-FcNHPI with a yield of 20.6%. Products of each step were characterized by NMR, MS, IR and other analytical techniques. By searching on Scifinder, we identified that the target molecule of each step were new compounds.(2) Utilizing the aerobic oxidation of ethylbenzene as a template reaction, the catalytic activity of N-hydroxy-4-ferrocenyl phthalimide was preliminary studied. The results showed that the catalytic activity for aerobic oxidation of C-H bond was not satisfying. And if the temperature of the catalytic reaction system is above 60℃, the catalyst undergone an obvious change.(3) We made a preliminary study of the electrochemical properties of N-hydroxy-4-ferrocenyl phthalimide by cyclic voltammetry. Combined with theoretical knowledge of the thermodynamic, instability of the catalyst was explained.