Investigation Of Thioporphyrazin In Thermo-catalytic Oxidation Of Cyclohexane And Photocatalytic Degradation Of Organic Pollutants

Metal thioporphyrazine compounds and their derivatives can simulate cytochrome P450,is a kind of highly secure,environmentally friendly catalysts.These metal thioporphyrazines,can not only be as catalysts for activation of C-H bond of alkane in petrochemical industry,but also provide an effective way to eliminate organic pollutants under solar light and oxygen in the air as the oxidant.So it indicates that the metal thioporphyrazines are potential and efficient biomimetic catalysts.The main works in this paper can be summarized as follows:Chapter 1 mainly introduces different kinds of porphyrazines,advances in porphyrin-carbon nanotube hybrid systems and the catalytic progress on porphyrin.In chapter 2,Iron（II）tetra（1,4-dithiin）porphyrazine（FePz（dtn）4）was prepared following the procedure reported by our group and characterized by UV-Vis,and then taken it as a biomimetic catalyst,oxygen molecules in the air as the oxidant,to catalyze oxidation of cyclohexane into cyclohexanol or cyclohexanone under heating conditions.Also the effect of the reaction solvent,temperature and time on this catalytic oxidation process was investigated.The preliminary experiment results showed that the optimal reaction parameters are acetonitrile as a solvent,reaction temperature 100 °C and reactive time 12 h,the molar ratio 30:1 between substrate and catalyst,in which cyclohexane conversion is up to 52%,the yield and selectivity of cyclohexanol is 42%,81% respectively.In chapter 3,two monobenzo porphyrazines were synthesized successfully with a yield of 7.8% and 34.1% respectively then characterized by 1H-NMR,UV-Vis,EA,MALDI-TOF MS,the substituents on penzyl ring were nitryl and methoxyl.Four kinds of metal nitrobenzeneporphyrazine(M=Co²⁺,Mn²⁺,Ni²⁺ and Zn²⁺)and Cobalt methoxyporphyrazine have also been synthesized and characterized by MALDI-TOF MS UV-Vis and CV.Their biomimetic catalytic activities were evaluated by the cyclohexane oxidation.Several important reaction parameters were optimized for the oxidation of cyclohexane.Under the optimal reaction conditions,MnPz shown the highest activity,the conversion and selectivity of cyclohexane catalyzed by MnPz towards cyclohexanol for 12 h reached 38% and 53%,respectively.Other metalloporphyrazines also showed good conversion and excellent selectivity.The order of the catalytic activity of metalloporphyrazine were obtained as PhNO₂Pz（SBu）₆Mn > PhNO₂Pz（SBu）₆Co > PhNO₂Pz（SBu）₆Zn > PhNO₂Pz（SBu）₆Ni.In the end,the activity of these synthesized catalysts was compared and the effect of ring structure and substituent were investigated.The results showed that the activity of metalloporphyrazine is enhanced after change of substituents in periphery.And the periphery of the porphyrazine with an electron donor group is better than the periphery with an electron withdrawing group.In chapter 4,the covalence composite octkis（butylthio）porphyrazinepyridine-single wall carbon nanotubes（FePz（SBu）8-Py-SWCNTs）was synthesized successfully and characterized by XPS,SEM,TEM.Their biomimetic catalytic activities were evaluated by the degradation of Methylene Blue（MB）using activated molecular oxygen.The results demonstrated that the efficiency of the composite catalyst has a remarkable enhance and up to 80% of MB can be degradated under pH=9.18 in 5h,almost completely（98%）for 12 h.The activity remains even after 5 cycles,which indicated excellent repeatablity.The active oxygen species（AOPs）,1O₂ and HO·,were detected by ESR technology.A possible mechanism using catalyst transfer active oxygen was presented.