“…It means that, the Mn ion of Mn More important is that, the two actions resulted in the BE increment (dBE: 1.7 eV and 0.4 eV) of Mn ion in Mn TPFPP/mCS. This means that the Mn ion of Mn TPFPP/ mCS carried more positive charges to bind and activate oxygen molecules, exhibiting its higher catalytic activity than before 48 . Summarily, after grafting and coordinating Mn TPFPP to mCS, the other two of three internal influencing factors on the catalytic performance of Mn TPFPP/mCS had been modulated well.…”
Section: Resultsmentioning
confidence: 98%
“…More important is that, the two actions resulted in the BE increment (dBE: 1.7 eV and 0.4 eV) of Mn ion in Mn TPFPP/mCS. This means that the Mn ion of Mn TPFPP/mCS carried more positive charges to bind and activate oxygen molecules, exhibiting its higher catalytic activity than before 48 . Figure 4 XPS spectra of Mn 2p, N 1 s and Cl 2p for mCS, Mn TPFPP, and Mn TPFPP/mCS.…”
in order to make full use of the impact of internal and external factors on the performance of title catalyst for ethyl benzene oxidation, the key internal influencing factors on the catalytic performance were modulated by coordinating and grafting manganese porphyrin to mesoporous and macroporous chitosan, and the important external factors (i.e. oxidation reaction conditions) were optimized using Response Surface Methodology. Under the Response Surface Methodology optimized oxidation reaction conditions (176.56 °C, 0.59 MPa, and 0.25 mg amount of manganese porphyrin), the catalyst could be used at least five times. The ethyl benzene conversion, catalyst turnover numbers, and yields reached up to 51.2%, 4.37 × 10 6 and 36.4% in average, respectively. Compared with the other optimized oxidation reaction conditions, the corresponding values increased 17%, 26% and 53%. Relative to the manganese porphyrin, the catalytic performance and efficiency of the immobilized catalyst had notably increased. High-efficiency and high-selectivity oxidation of ethyl benzene (EB) has been still paid a great attention 1-6. There were so many advanced catalysts and catalytic ethyl benzene oxidation technologies 1-25 , some of which could even offer high yields of products 1-6. However, up to date the oxidation techniques used are not very satisfactory yet: There were mainly lack of cleaner production techniques, for examples, O 2 was not used as oxidant, toxic solvents were used, some energy saving and emission reduction had not been done, and so on. Therefore, the catalyst preparation 21-25 , the catalytic oxidation system and the oxidation conditions 7-20 , which are satisfactorily meeting to the cleaner production process should be comprehensively considered. Based on the above considerations, the internal influencing factors on the catalytic performance of catalyst should be further reasonably tuned, and the external influencing factors should be optimized via Response Surface Methodology (RSM). Because RSM has been successfully used in other catalysis fields: It has been used for optimization of the various reaction conditions and prediction of interactions between the influencing reaction condition parameters based on constructing a suitable model, evaluating the effects of key factors and searching the optimum reaction conditions. The better catalysis responses have achieved 26-29. These considerations and the various optimizations above will probably bring the advanced catalysis techniques 7-25 forwards better catalytic results and excellent various applications in practical chemistry industry. Due to a great deal of attention to the environmental issues, for modern companies which are manufacturing the products of acetophenone and phenylethanol via ethyl benzene oxidation, a set of strict modern technique of cleaner production has to be requested. Under the preconditions, the immobilized metalloporphyrins and their catalysis systems, which are usually not added any additives, co-reductants, and solvents, but oxygen molecules...
“…It means that, the Mn ion of Mn More important is that, the two actions resulted in the BE increment (dBE: 1.7 eV and 0.4 eV) of Mn ion in Mn TPFPP/mCS. This means that the Mn ion of Mn TPFPP/ mCS carried more positive charges to bind and activate oxygen molecules, exhibiting its higher catalytic activity than before 48 . Summarily, after grafting and coordinating Mn TPFPP to mCS, the other two of three internal influencing factors on the catalytic performance of Mn TPFPP/mCS had been modulated well.…”
Section: Resultsmentioning
confidence: 98%
“…More important is that, the two actions resulted in the BE increment (dBE: 1.7 eV and 0.4 eV) of Mn ion in Mn TPFPP/mCS. This means that the Mn ion of Mn TPFPP/mCS carried more positive charges to bind and activate oxygen molecules, exhibiting its higher catalytic activity than before 48 . Figure 4 XPS spectra of Mn 2p, N 1 s and Cl 2p for mCS, Mn TPFPP, and Mn TPFPP/mCS.…”
in order to make full use of the impact of internal and external factors on the performance of title catalyst for ethyl benzene oxidation, the key internal influencing factors on the catalytic performance were modulated by coordinating and grafting manganese porphyrin to mesoporous and macroporous chitosan, and the important external factors (i.e. oxidation reaction conditions) were optimized using Response Surface Methodology. Under the Response Surface Methodology optimized oxidation reaction conditions (176.56 °C, 0.59 MPa, and 0.25 mg amount of manganese porphyrin), the catalyst could be used at least five times. The ethyl benzene conversion, catalyst turnover numbers, and yields reached up to 51.2%, 4.37 × 10 6 and 36.4% in average, respectively. Compared with the other optimized oxidation reaction conditions, the corresponding values increased 17%, 26% and 53%. Relative to the manganese porphyrin, the catalytic performance and efficiency of the immobilized catalyst had notably increased. High-efficiency and high-selectivity oxidation of ethyl benzene (EB) has been still paid a great attention 1-6. There were so many advanced catalysts and catalytic ethyl benzene oxidation technologies 1-25 , some of which could even offer high yields of products 1-6. However, up to date the oxidation techniques used are not very satisfactory yet: There were mainly lack of cleaner production techniques, for examples, O 2 was not used as oxidant, toxic solvents were used, some energy saving and emission reduction had not been done, and so on. Therefore, the catalyst preparation 21-25 , the catalytic oxidation system and the oxidation conditions 7-20 , which are satisfactorily meeting to the cleaner production process should be comprehensively considered. Based on the above considerations, the internal influencing factors on the catalytic performance of catalyst should be further reasonably tuned, and the external influencing factors should be optimized via Response Surface Methodology (RSM). Because RSM has been successfully used in other catalysis fields: It has been used for optimization of the various reaction conditions and prediction of interactions between the influencing reaction condition parameters based on constructing a suitable model, evaluating the effects of key factors and searching the optimum reaction conditions. The better catalysis responses have achieved 26-29. These considerations and the various optimizations above will probably bring the advanced catalysis techniques 7-25 forwards better catalytic results and excellent various applications in practical chemistry industry. Due to a great deal of attention to the environmental issues, for modern companies which are manufacturing the products of acetophenone and phenylethanol via ethyl benzene oxidation, a set of strict modern technique of cleaner production has to be requested. Under the preconditions, the immobilized metalloporphyrins and their catalysis systems, which are usually not added any additives, co-reductants, and solvents, but oxygen molecules...
“…This class of bioinspired N-ligands, for instance metalloporphyrins, which allow the selective epoxidation of olefins with multiple scaffolds has, however, an intrinsic instability problem, as it is considered to be one of the main drawbacks for the implementation of these epoxide synthetic processes to the pharmaceutical industrial scale. Nevertheless, strategies to overcome this issue, such as the immobilization of metalloporphyrins onto solid supports, namely polymers [45,46,47], clays [48], silica [49,50], mesoporous materials [51,52], or magnetic nanoparticles [43,53,54], is currently the target of particularly active research, as it is considered one of the most promising approaches.…”
In the present study, we developed a green epoxidation approach for the synthesis of the diastereomers of (−)-isopulegol benzyl ether epoxide using molecular oxygen as the oxidant and a hybrid manganese(III)-porphyrin magnetic reusable nanocomposite as the catalyst. High activity, selectivity, and stability were obtained, with up to four recycling cycles without the loss of activity and selectivity for epoxide. The anticancer effect of the newly synthesized isopulegol epoxide diastereomers was evaluated on a human osteosarcoma cell line (MG-63); both diastereomers showed similar in vitro potency. The measured IC50 values were significantly lower than those reported for other monoterpene analogues, rendering these epoxide isomers as promising anti-tumor agents against low prognosis osteosarcoma.
“…1) Metalloporphyrins as active centers. Metalloporphyrins are recognized as well‐known analogs of the heme cofactor and most metalloenzymes, which have been extensively used as oxidation catalysts in the fine‐chemicals syntheses of epoxides, alcohols, ketones, and aldehydes …”
It is a big challenge to homogenize heterogeneous catalysts with molecular catalytic performance. With this target in mind, herein, we describe a facile strategy for direct incorporation of single catalytic sites in 3D open porous aromatic frameworks (PAFs). The synthesis of the PAF (denoted as PAF‐76) as well as its derivatives (PAF‐76‐M, M=Fe, Mn, Zn) was achieved by the use of tetrakis(4‐bromophenyl)methane as tetrahedral nodes and tetrakis(4‐bromophenyl)porphyrin as planar nodes. The connection of monomers into an extended network of PAF‐76 was monitored by 13C NMR and FTIR spectroscopies. The prepared PAF‐76s showed 3D porous structures with surface areas of 450–700 m2 g−1, pore volumes of 0.3–0.4 cm3 g−1, and pore sizes around 1.2 nm. The direct incorporation of metalloporphyrin components into the PAF‐76‐M frameworks has allowed the uniform distribution of metal ionic sites throughout the PAF‐76‐M particles. The combined merits of isolated metal sites and suitable pore size make PAF‐76 a good candidate for heterogeneous catalysis. The catalytic performances of the porphyrin/metalloporphyrin‐based active sites in the PAF‐76s were evaluated by aerobic oxidation reactions of styrene, which are usually carried out with homogeneous systems. Metal‐functionalized PAF‐76s (PAF‐76‐M) exhibit enhanced turnover frequencies for styrene conversion (16.9–50.9 mol mol(M)−1 h−1) compared with molecular catalysts (0–35.0 mol mol(M)−1 h−1), and improved selectivity toward phenylacetaldehyde (85.7–99 %) in contrast to their corresponding monomers (0–75.5 %). The robustness of PAF‐76 in terms of high thermal stability, good recyclability, and excellent solvent resistance showed that these PAF‐76 materials hold great promise for developing heterogeneous catalysts.
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