Mesoporous chitosan‐immobilized iron tetrakis(4‐carboxyphenyl)porphyrin as a model of cytochrome P‐450 enzyme for oxidation of ethylbenzene

Abstract

Mesoporous chitosan‐grafted iron tetra (4‐carboxyphenyl) porphyrin catalyst (Fe TCPP/mesp‐CTS) was prepared and investigated as a practical model for the nano‐cavity and coordinate regulation‐catalysis(CRC) function in cytochrome P‐450 enzyme. Fe TCPP/mesp‐CTS was characterized by X‐ray Diffraction(XRD), Thermogravimetry(TG), Ultraviolet–visible spectroscopy(UV‐Vis), Ultraviolet–visible–Diffuse reflectance spectroscopy(UV‐DRS), Scanning electron microscope (SEM), Fourier transform infrared spectroscopy(FT‐IR), and X‐ray photoelectron spectroscopy(XPS) techniques. The catalytic activity of Fe TCPP/mesp‐CTS for ethylbenzene oxidation was investigated and it was proved to be a better catalyst than Fe TCPP/macp‐CTS based on the ethylbenzene conversion, turnover numbers(TON), and the reusability. These results are attributed to the mesocavity and CRC of amino group in Fe TCPP/mesp‐CTS. The highest ethylbenzene conversion and yields of ketone and alcohol were 24.4% and 18.2%, respectively.

Full use of factors promoting catalytic performance of chitosan supported manganese porphyrin

“…All these designs, including the data set in Tables 1 and 2, which were screened from the data (Fig. S1-(1 to 4) obtained via Other Optimization Method (OOM) 34,35 ), were set up based on preliminary experimental test data. Especially, the key effects of the external factors (reaction temperature and pressure) on catalyst turnover number (TON) were remarkably occurred at the ranges of 170-180 °C and 0.5-0.7 MPa respectively.…”

“…immobilized metalloporphyrins and their catalysis systems [31][32][33][34][35] adapting to the cleaner production process. However, the resulting yields (acetophenone and phenylethanol (ONE + OL), less than 25%) were lower than those obtained from the catalytic systems above [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] .…”

“…However, the resulting yields (acetophenone and phenylethanol (ONE + OL), less than 25%) were lower than those obtained from the catalytic systems above [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . In addition, RSM was also seldom used in the catalytic field of metalloporphyrins [14][15][16][17]19,20,[31][32][33][34][35] . Therefore, these are still a challenge.…”

“…For promoting the catalytic activity and the re-usability of metalloporphyrins, and increasing the yields (ONE + OL) of ethylbenzene oxidation catalyzed by the immobilized metalloporphyrins catalysis systems, by investigation of the relative references, we found that, (1) the electron-withdrawing-groups metalloporphyrin grafted and coordinated to porous support could comprehensively enhance the catalytic activity and the reusability for ethylbenzene oxidation 13-15,17,19,20 ; (2) the axial coordination action exerted the most important effect on the catalytic activity, and the covalent grafting action had a decisive effect on the increase of the total turnover frequencies (TOFs) and on the re-usability of the catalyst 36 ; (3) the most key internal effecting factor on the catalytic activity of the immobilized metalloporphyrin was the axial coordination action 37 ; (4) chitosan could be made into nanoporous support material and could provide ammonia groups for the graft and coordination of some metalloporphyrins [34][35][36] . Especially, it is cheap and no harm to our environment.…”

“…Especially, it is cheap and no harm to our environment. Therefore, in order to extend our previous related studies [34][35][36] , manganese (III) 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (Mn TPFPP) acting as catalytic active sites, has been coordinated and grafted on mesoporous and macroporous chitosan (mCS). In the above way, the mainly internal affecting factors on the catalytic performance of the grafted catalyst have been modulated well, because either the strength of coordination bond or the number of grafted bonds both have been tuned 36 at this time.…”