7Simple and efficient procedure for the synthesis of 1,4-dihydropyrano[2,3-c]pyrazole 8 derivatives has been developed by one-pot three-component reaction of various aldehydes 9 with malononitrile and 3-Methyl-1-phenyl-2-pyrazoline-5-one in the presence BF 3 /MNPs as 10 a novel nanostructured, heterogeneous and reusable catalyst. In this research, BF 3 /MNPs 11 nanoparticles were prepared at three calcination temperature and characterized by various 12 techniques. The characterization and optimization results show that the catalyst with 13 calcination temperature of 450 °C has the best catalytic activity. The nano-sized magnetite 14 catalyst were recovered by simple separation with an external magnet and reused for several 15 cycles without considerable loss of activity.16 17
Adsorption
of nitrobenzene (NB) from aqueous solution onto mesoporous
silica materials, i.e., pyrolyzed MCM-41 (Si–C), pyrolyzed
Al-MCM-41 (Al–C), MCM-41 containing g-C3N4 (Si–C3), and Al-MCM-41 containing g-C3N4 (Al–C3) were investigated. Results
indicated that NB adsorption was fast, and the adsorption process
reached a steady state in under 5 min. The adsorption data were tested
by Langmuir, Freundlich, and Redlich–Peterson isotherm models,
and the Langmuir isotherm was found to provide a better fit with the
experimental data. The maximum adsorption capacities of various sorbents
Al–C, Si–C, Al–C3, and Si–C3 were 243.9 mg/g, (1982 μmol/g), 217.4 mg/g (1767 μmol/g),
116.3 mg/g (945.1 μmol/g), and 54.95 mg/g (446.5 μmol/g),
respectively.
The oxidation of o‐xylene to phthalic anhydride over Co‐Mn/H3PW12O40@TiO2 was investigated. The experimental results demonstrated that the prepared catalyst effectively catalyzed the oxidation of o‐xylene to phthalic anhydride. Also, the synergistic effect between three metals plays vital roles in this reaction. From a green chemistry point of view, this method is environmentally friendly due to carrying out the oxidation in a fixed‐bed reactor under solvent‐free condition and using molecular oxygen as a green and cheap oxidizing agent. The resulting solid catalysts were characterized by FT‐IR, XRD, XPS, ICP‐OES, FESEM, TEM, EDX, DR‐UV spectroscopy, BET and thermogravimetric analysis. The oxidation of o‐xylene yields four products: o‐tolualdehyde, phthaldialdehyde, phthalide and finally phthalic anhydride as the main product. The reaction conditions for oxidation of o‐xylene were optimized by varying the temperature, weight hourly space velocity and oxygen flow rate (contact time). The optimum weight percentage of phosphotungstic acid (HPW) and Co/Mn for phthalic anhydride production were 15 wt % and 2 wt%, respectively. The best Co/Mn ratio was found to be 10/1. Oxygen flow rate was very important on the phthalic anhydride formation. The optimum conditions for oxidation of o‐xylene were T = 370 °C, WHSV = 0.5 h−1 and oxygen flow rate = 10 mL min−1. Under optimized conditions, a maximum of 88.2% conversion and 75.5% selectivity to phthalic anhydride was achieved with the fresh catalyst. Moreover, reusability of the catalyst was studied and catalytic activity remained unchanged after at least five cycles.
The cover image, by Kianoosh Masoomi et al., is based on the Full Paper Selective vapor‐phase oxidation of o‐xylene to phthalic anhydride over Co‐Mn/H3PW12O40@TiO2 using molecular oxygen as a green oxidant, https://doi.org/10.1002/aoc.4461.
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