Pyrolysis properties of lignin separated from four different kinds of wood （fir, larch, poplar, and eucalyptus） compared with commercial lignin were investigated using a thermogravimetric analyzer coupled to a...Pyrolysis properties of lignin separated from four different kinds of wood （fir, larch, poplar, and eucalyptus） compared with commercial lignin were investigated using a thermogravimetric analyzer coupled to a Fourier-transform infrared spectrometer（TG-FTIR）. Kinetic parameters of lignin thermal cracking reaction, such as activation energy and pre-exponential factor, were calculated using a three-dimensional diffusion model. The carbon residue rate and activation energy of softwood lignin were higher than those of hardwood lignin, showing that the decomposition of the former is relatively more dif？cult than that of the latter during pyrolysis. The distinct characteristic peaks of small-molecule gases and oxygenated chemicals such as ethers, phenols, acids, aldehydes, and alcohols were observed near the maximum weight loss rate by analyzing the 3D IR spectrum of the gas phase products. The formation routes of the main gaseous products were discussed, and the following order of releasing amounts was noted： CO2〉CH4〉H2O〉CO. It is believed that these results will provide valuable information for the thermo-chemical conversion process of lignin from the point of view of feedstock.展开更多
Lignin is a group of phenolic polymers which is abundant in the woody tissues of vascular plants,and is essentially absent from all other living organisms.It has therefore been accepted as a tracer for terrestrial org...Lignin is a group of phenolic polymers which is abundant in the woody tissues of vascular plants,and is essentially absent from all other living organisms.It has therefore been accepted as a tracer for terrestrial organic carbon(TOC) in marine environment since the 1970s.Lignin polymers are not amenable to direct chemical analysis without prior isolation.This review focused on the methods of chemical decomposition,extraction,derivatization and detection of lignin in marine environment.We described and compared several chemical decomposition methods,including nitrobenzene oxidation,alkaline cupric oxide(CuO) oxidation and thermochemolysis,and detection methods such as gas chromatography(GC),gas chromatography-mass spectrometry(GC-MS),high performance liquid chromatography(HPLC) and so on.Possible improvement of lignin analysis and the application prospects of this tracer were also discussed.展开更多
文摘Pyrolysis properties of lignin separated from four different kinds of wood （fir, larch, poplar, and eucalyptus） compared with commercial lignin were investigated using a thermogravimetric analyzer coupled to a Fourier-transform infrared spectrometer（TG-FTIR）. Kinetic parameters of lignin thermal cracking reaction, such as activation energy and pre-exponential factor, were calculated using a three-dimensional diffusion model. The carbon residue rate and activation energy of softwood lignin were higher than those of hardwood lignin, showing that the decomposition of the former is relatively more dif？cult than that of the latter during pyrolysis. The distinct characteristic peaks of small-molecule gases and oxygenated chemicals such as ethers, phenols, acids, aldehydes, and alcohols were observed near the maximum weight loss rate by analyzing the 3D IR spectrum of the gas phase products. The formation routes of the main gaseous products were discussed, and the following order of releasing amounts was noted： CO2〉CH4〉H2O〉CO. It is believed that these results will provide valuable information for the thermo-chemical conversion process of lignin from the point of view of feedstock.
基金supported by National Basic Research Program of China (973 Program 2010CB428901)
文摘Lignin is a group of phenolic polymers which is abundant in the woody tissues of vascular plants,and is essentially absent from all other living organisms.It has therefore been accepted as a tracer for terrestrial organic carbon(TOC) in marine environment since the 1970s.Lignin polymers are not amenable to direct chemical analysis without prior isolation.This review focused on the methods of chemical decomposition,extraction,derivatization and detection of lignin in marine environment.We described and compared several chemical decomposition methods,including nitrobenzene oxidation,alkaline cupric oxide(CuO) oxidation and thermochemolysis,and detection methods such as gas chromatography(GC),gas chromatography-mass spectrometry(GC-MS),high performance liquid chromatography(HPLC) and so on.Possible improvement of lignin analysis and the application prospects of this tracer were also discussed.
