Catalytic oxidative desulfurization(ODS) of model oil and commercial oil samples was investigated using an air-assisted performic acid oxidation system with a phase transfer or emulsion catalyst comprising a quaternar...Catalytic oxidative desulfurization(ODS) of model oil and commercial oil samples was investigated using an air-assisted performic acid oxidation system with a phase transfer or emulsion catalyst comprising a quaternary ammonium salt-based heteropolyoxometalate.Different emulsion catalysts with a Keggin type heteroployoxometalate anion(containing W,Mo,and V) and cetyltrimethylammonium bromide cation were prepared and characterized by X-ray fluorescence,Fourier transform infrared spectroscopy,and scanning electron microscopy.[C16H33N(CH3)3]3[PW9Mo3O40] was the most effective catalyst in the current oxidation system,which reduced the sulfur content of the model oil from 1275 μg/g to 57 μg/g.The reactivity order of different model sulfur compounds was thiophene < dibenzothiophene < 4,6-dimethyldibenzothiophene. The ODS of model sulfur compounds followed first order kinetics with apparent activation energy from 29 to 27 kJ/mol.The catalysts also performed efficiently in the ODS of the industrial oil samples,including untreated naphtha,light gas oil,heavy gas oil,and Athabasca oil sands derived bitumen,for which sulfur removal rates were 83%,85%,68% and 64%,respectively.展开更多
Objective:To isolate and identify the undescribed compounds from the fruits of Cinnamomum migao and evaluate its nitric oxide inhibition potential.Methods:The chromatographic techniques of silica gel,Sephadex,and HPLC...Objective:To isolate and identify the undescribed compounds from the fruits of Cinnamomum migao and evaluate its nitric oxide inhibition potential.Methods:The chromatographic techniques of silica gel,Sephadex,and HPLC were used for isolation and purification of the compounds,while HR-ESI-MS,1D NMR,2D NMR,ECD,and X-ray diffraction techniques were used to characterize and confirm the isolated compounds.Moreover,the antiinflammatory activity of the isolated compounds was carried out to check inhibitory potential against the production of nitric oxide with RAW264.7 cells stimulated by LPS.Results:Camganoid A(1),a novel sesquiterpene possessing an unprecedented skeleton,and camganoid B(2),containing a unique eight-membered sesquiterpene moiety with a new carbon skeleton,were isolated and identified from the fruits of C.migao.The absolute configurations of 1 and 2 were confirmed by single crystal X-ray diffraction and electronic circular dichroism(ECD)calculations.Among these compounds,compound 1 exhibited potent inhibitory activity against the production of nitric oxide with IC50value of 4.59μmol/L in RAW264.7 cells stimulated by LPS.Conclusion:The isolation of two new skeletons from the fruits part of C.migao possessed unique skeletons which have not been reported before.展开更多
基金Financial support from the Higher Education Commission(HEC) Pakistan,under the International Research Support Initiative Program(IRSIP)
文摘Catalytic oxidative desulfurization(ODS) of model oil and commercial oil samples was investigated using an air-assisted performic acid oxidation system with a phase transfer or emulsion catalyst comprising a quaternary ammonium salt-based heteropolyoxometalate.Different emulsion catalysts with a Keggin type heteroployoxometalate anion(containing W,Mo,and V) and cetyltrimethylammonium bromide cation were prepared and characterized by X-ray fluorescence,Fourier transform infrared spectroscopy,and scanning electron microscopy.[C16H33N(CH3)3]3[PW9Mo3O40] was the most effective catalyst in the current oxidation system,which reduced the sulfur content of the model oil from 1275 μg/g to 57 μg/g.The reactivity order of different model sulfur compounds was thiophene < dibenzothiophene < 4,6-dimethyldibenzothiophene. The ODS of model sulfur compounds followed first order kinetics with apparent activation energy from 29 to 27 kJ/mol.The catalysts also performed efficiently in the ODS of the industrial oil samples,including untreated naphtha,light gas oil,heavy gas oil,and Athabasca oil sands derived bitumen,for which sulfur removal rates were 83%,85%,68% and 64%,respectively.
基金supported by NSFC(81973191)Natural Science Foundation of Shanghai(19ZR1428100)+1 种基金Project supported by the Department of Science and Technology of Guizhou(Grant No.[2018]2831)the Horizontal Research Project of Shanghai Jiao Tong University(SA1700111,SA1700118)。
文摘Objective:To isolate and identify the undescribed compounds from the fruits of Cinnamomum migao and evaluate its nitric oxide inhibition potential.Methods:The chromatographic techniques of silica gel,Sephadex,and HPLC were used for isolation and purification of the compounds,while HR-ESI-MS,1D NMR,2D NMR,ECD,and X-ray diffraction techniques were used to characterize and confirm the isolated compounds.Moreover,the antiinflammatory activity of the isolated compounds was carried out to check inhibitory potential against the production of nitric oxide with RAW264.7 cells stimulated by LPS.Results:Camganoid A(1),a novel sesquiterpene possessing an unprecedented skeleton,and camganoid B(2),containing a unique eight-membered sesquiterpene moiety with a new carbon skeleton,were isolated and identified from the fruits of C.migao.The absolute configurations of 1 and 2 were confirmed by single crystal X-ray diffraction and electronic circular dichroism(ECD)calculations.Among these compounds,compound 1 exhibited potent inhibitory activity against the production of nitric oxide with IC50value of 4.59μmol/L in RAW264.7 cells stimulated by LPS.Conclusion:The isolation of two new skeletons from the fruits part of C.migao possessed unique skeletons which have not been reported before.
