Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficien...Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.展开更多
Replacement of volatile organic compounds （VOCs） by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic...Replacement of volatile organic compounds （VOCs） by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over con- ventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction nilnt nlant studies.展开更多
Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropi...Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropic compressibilityκs,Rao's molar sound function Rm,van der Waals constant b,relaxation strength r,intermolecular free length Lf,internal pressureπ,solvation number Sn,relative association RA,etc.are evaluated,which helps in understanding the molecular interactions occurring in these solutions.展开更多
β-Glucans are biomacromolecules that present biological properties of medical and pharmacological interest, The chemical modification of the primary structure of these carbohydrate biopolymers is a way to enhance or ...β-Glucans are biomacromolecules that present biological properties of medical and pharmacological interest, The chemical modification of the primary structure of these carbohydrate biopolymers is a way to enhance or achieve new biological properties. Acetylated derivatives of （1→6）-β-D-glucan （lasiodiplodan） with different degrees of substitution （0.48, 0.66, 1.03 and 1.26） were obtained and characterized by infra-red and NMR （nuclear magnetic resonance） spectroscopy, thermal analysis, X-ray diffraction and antioxidant capacity. Acetylation was confirmed by FT-IR, and βC NMR spectroscopy. Thermal analysis indicated that unmodified lasiodiplodan and the O-acetylated β-glucan derivative of degree of substitution 0.48 presented three stages of mass-loss, whereas acetylated derivatives of DS （degree of substitution） of 0.66, 1.03 and 1.26 presented four stages of mass-loss. X-ray diffractograms demonstrated that both native and acetylated lasiodiplodan presented crystalline regions in an amorphous polymeric matrix. Scanning electron microscopy revealed that O-acetylation promoted morphologic changes in the biopolymer according to the DS. Acetylation also contributed to improve antioxidant capacity.展开更多
文摘Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.
基金Support from the Australian Research Council (project ID:LP140100650)
文摘Replacement of volatile organic compounds （VOCs） by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over con- ventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction nilnt nlant studies.
文摘Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropic compressibilityκs,Rao's molar sound function Rm,van der Waals constant b,relaxation strength r,intermolecular free length Lf,internal pressureπ,solvation number Sn,relative association RA,etc.are evaluated,which helps in understanding the molecular interactions occurring in these solutions.
文摘β-Glucans are biomacromolecules that present biological properties of medical and pharmacological interest, The chemical modification of the primary structure of these carbohydrate biopolymers is a way to enhance or achieve new biological properties. Acetylated derivatives of （1→6）-β-D-glucan （lasiodiplodan） with different degrees of substitution （0.48, 0.66, 1.03 and 1.26） were obtained and characterized by infra-red and NMR （nuclear magnetic resonance） spectroscopy, thermal analysis, X-ray diffraction and antioxidant capacity. Acetylation was confirmed by FT-IR, and βC NMR spectroscopy. Thermal analysis indicated that unmodified lasiodiplodan and the O-acetylated β-glucan derivative of degree of substitution 0.48 presented three stages of mass-loss, whereas acetylated derivatives of DS （degree of substitution） of 0.66, 1.03 and 1.26 presented four stages of mass-loss. X-ray diffractograms demonstrated that both native and acetylated lasiodiplodan presented crystalline regions in an amorphous polymeric matrix. Scanning electron microscopy revealed that O-acetylation promoted morphologic changes in the biopolymer according to the DS. Acetylation also contributed to improve antioxidant capacity.
