Synthesis Of Conjugated Fe/Mn Porphyrin Polymers And Their Catalytic Performance For Aerobic Oxidation Of Cyclohexane

It is difficult to recycle and reuse metalloporphyrins in the catalytic oxidation of hydrocarbons. To solve this problem, people try to make metalloporphyrins immobilized on inorganic carriers or organic polymeric carrier, but studies show that the immobilized metalloporphyrins does not fundamentally solve the above problems. This paper proposed and studied the synthesis of porous conjugated polymer metalloporphyrins that chemical properties is stable and can be reused without weakening the catalytic activity, achieving the application of metalloporphyrins in heterogeneous catalysis.On the basis of a large number of research literature, we synthesized T(p-Br)PPFeCl and T(p-Br)PPMnCl, then used them as raw materials to synthesis Mn/Fe porphyrin polymers. Its surface area aperture test found that the surface area of MnP-CMP and FeP-CMP is325m2/g and296m2/g, the contribution of the microporous pore volume are44%and36%. We concluded that MnP-CMP and FeP-CMP are insoluble conjugated microporous structure porphyrin polymer. FE-SEM images showed that the monoliths consist of100-200nm sized elementary platelets.Catalytic properties of Mn/Fe porphyrin polymers and the corresponding single metalloporphyrins was studied. The experimental results showed that the catalytic activity of porphyrin polymer is significantly better than the metal porphyrin, mainly in the cyclohexane conversion rate, and good selectivity of alcohol and ketone. The relative catalytic activity:MnP-CMP> FeP-CMP> T(p-Br)PPMnCl> T(p-Br)PPFeCl.We used MnP-CMP as the preferred catalyst, studying different factors in the reaction, such as effect of various of reaction pressure, effect of the concentration of the catalyst, effect of the flow rate of air and effect of the temperature. The results showed that when the reaction is catalyzed by12mg (200ml cyclohexane) MnP-CMP at150℃,0.8MPa with the air flow rate being1000mL/min, the conversion of cyclohexane is up to29.87%, total yield of alcohol and ketone is21.89%after3.5h. Under same conditions, we used FeP-CMP as the catalyst, conversion of cyclohexane is up to27.51%after4h, total yield of alcohol and ketone is19.21%, the yield of acid is1.93%. Acid selectivity is significantly lower than that of MnP-CMP. It is very beneficial to the targeted synthesis of alcohol and ketone.We mainly studied reuse performance of MnP-CMP and FeP-CMP, experimental results showed that their structure are stable, not easily broken down to destruction, cyclohexane conversion rate is still above25%in MnP-CMP catalyst system and that is23%in FeP-CMP catalyst system after recycling five.