A novel Ni/NiF2‐AlF3 catalyst was prepared by impregnation and following vapor hydrofluorination, and it was used to dehydrofluorination of tetrafluoroethane to trifluoroethylene. BET, SEM, XRD, XPS, NH3‐TPD and Py‐IR techniques were employed to characterize the Ni/NiF2‐AlF3 catalysts. Based on the NH3‐TPD results, it was interestingly found that the strong acidic sites of Ni/NiF2‐AlF3 catalyst transformed into the mid‐strength acidic sites with the increase of Ni loading, attributing to the roles of Ni on the catalyst surface. Compared with the NiF2‐AlF3 catalyst, the added Ni particles can improve the catalyst activity and stability for dehydrofluorination of 1, 1, 1, 2‐tetrafluoroethane. The best performance was obtained at Al/Ni=2 over the Ni/NiF2‐AlF3 catalyst, with high trifluoroethylene selectivity(99%) and CF3CFH2 conversion of 21.3%, after the reaction for 20 h on‐time stream at 500 °C, which showed the better application possibility as a heterogeneous dehydrofluorination catalyst. It was suggested that catalytic performance was related with the mid‐strength Lewis acidity on the catalyst surface. And the Ni/NiF2‐AlF3 catalyst (Al/Ni=2) possessed the good catalytic stability due to the mild‐strength Lewis acid sites.
This study represents the first report on the chemical composition and antimicrobial activity of the essential oil from the branches of Jacaranda cuspidifolia Mart. Thirty-three compounds were identified by Gas Chromatography-Mass Spectrometry (GC-MS) and the major constituents of the essential oil were Palmitic acid (31.36%), (Z) - 9,17-Octadecadienal (12.06%), Ethyl palmitate (3.81%), Perhydrofarnesyl acetone (2.07%), γ-Maaliene (1.88%), and Cedro (1.42%) and 9,12-Octadecadienoic acid ethyl ester (1.42%). The in vitro antimicrobial activities of the essential oil were evaluated by the disc diffusion method, and the inhibition zones against Escherichia coli, Staphylococcus aureus and Candida albicans were 7.10, 8.20 and 7.25 mm, respectively. The oil showed moderate activities against E. coli, S. aureus and C. albicans with minimum inhibition concentration (MIC) values of 17.3 mg/mL, 12.9 mg/mL and 16.0 mg/mL, respectively.
Vinylidene fluoride (VDF) is a crucial monomer for manufacturing polyvinyl fluoride. Catalytic pyrolysis is an ideal route to dispose of 2‐chloro‐1,1‐difluoroethane (HCFC‐142) byproduct derived from the industrial manufacture of 1‐chloro‐1,1‐difluoroethane (HCFC‐142b). The activated carbon catalysts treated by nitric acid and further supported by potassium, were employed to catalytic pyrolysis of HCFC‐142 to synthesize VDF. The prepared K/C catalysts were characterized by BET, X‐ray diffraction (XRD), SEM‐EDX, Raman, NH3‐ and CO2‐ Temperature Programmed Desorption (TPD). With the increase of potassium loading, the surface areas of K/C catalysts reduce gradually, whereas their amounts of surface base sites increase. When the potassium loading reaches up to 1.0%, the 1 K/C catalyst possesses the superior catalytic performance, with the highest conversion of 47.7% and selectivity to VDF of 48.4% at 600 °C. The potassium species improved the catalytic performance of activated carbon is associated with the suitable amounts of surface base sites.
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