Efficient conversion of lignin to fine chemicals and biofuel become more and more attractive in biorefinery. In this work, we used a series of silica-alumina catalysts （i.e., SiO2-Al2O3, HY, Hβ, and HZSM-5） to degr...Efficient conversion of lignin to fine chemicals and biofuel become more and more attractive in biorefinery. In this work, we used a series of silica-alumina catalysts （i.e., SiO2-Al2O3, HY, Hβ, and HZSM-5） to degrade lignin into arenes and phenols. The relationship between the catalyst structure and lignin depolymerization performance was investigated. The results showed that both acidity and pore size of the catalyst could influence the conversion of lignin. In the volatilizable product, phenols were identified as the main phenolic monomers via gas chromatography-mass spectrometer. SIO2-Al2O3 was the most efficient catalyst, giving 90.96% degree of conversion, 12.91% yield of phenols, and 2.41% yield of arenes in ethanol at 280℃ for 4 h. The Fourier transform infrared spectroscopy and ^1H nuclear magnetic resonance spectroscopy analysis demonstrated that deoxygenation and alkylation occurred in this process. The effect of solvents was also investigated and the results showed that ethanol was the most efficient solvent.展开更多
Characteristics of uncondensed lignin reactions in soda cooking of wheat straw were studied. Mild and intense cooking conditions were used to get the pulp sample in which lignin was dissolved physically and the pulp s...Characteristics of uncondensed lignin reactions in soda cooking of wheat straw were studied. Mild and intense cooking conditions were used to get the pulp sample in which lignin was dissolved physically and the pulp sample in which lignin was dissolved chemically respectively. The pulp samples were analyzed by phenolic group determination, alkaline nitrobenzene oxidation and ozonation method. The results indicated that around 90% of lignin in wheat straw is alkali-soluble at the mild conditions, is basically dissolved physically without chemical change. The phenolic group content was not changed greatly, the nitrobenzene oxidation yield only changed slightly during the mild cooking. The phenolic group content was increased obviously and uncondensed lignin content was decreased very much when the intense cooking conditions were applied and the delignification was over 90%. The lignin structure was changed greatly during this period.展开更多
A new method for the preparation of aminated lignin （AEL） through etherification and amination reaction was presented. Chlorine atoms were ？rstly introduced into lignin through its etheri？cation with epichlo...A new method for the preparation of aminated lignin （AEL） through etherification and amination reaction was presented. Chlorine atoms were ？rstly introduced into lignin through its etheri？cation with epichlorohydrin. Then, hydrophilic amine groups were grafted to the modi？ed lignin structure through amination with ethylenediamine to obtain AEL. Subsequent acidi？cation of AEL led to the ionized aminated lignin （IAEL）. The results of our analyses showed that the nitrogen content of AEL was 6.9%. Foaming and emulsifying experiments indicated that AEL had better foamability and emulsifying properties than IAEL. Surface tension tests showed that AEL and IAEL had similar critical micelle concentration （CMC）. However, IAEL had lower surface tension （36.33 mN/m） than AEL （42.89 mN/m） at CMC. These results demonstrate the promising applicability of AEL as an emulsi？er and that of IAEL as feedstock in the production of detergent and dispersant.展开更多
We investigated the role of GA3, uniconazole-P and IAA on tension wood formation, in particular the vessel features, in Fraxinu smandshurica seedlings. Ninety seedlings were used and treated with applications of GA3 a...We investigated the role of GA3, uniconazole-P and IAA on tension wood formation, in particular the vessel features, in Fraxinu smandshurica seedlings. Ninety seedlings were used and treated with applications of GA3 and/or IAA to the apical bud of the stem using a micropipette. Applications of GA3 or GA3 plus IAA with uniconazole-P strongly increased cell number of tension wood in comparison to that of no-uniconazole-P-applied, indicated that GA3 is more efficient than IAA on xylem cell production. Wood quality was also regulated by relative concentration ratio of GA3 to lAA, because of the vessel elements differentiation, density and size were controlled by GA3 and/or IAA on the different levels. These results suggested that the relative concentration ratio of GA3 to IAA and interactions of them are essential in regulating both wood quality and wood quantity, and tension wood formation in this species.展开更多
文摘Efficient conversion of lignin to fine chemicals and biofuel become more and more attractive in biorefinery. In this work, we used a series of silica-alumina catalysts （i.e., SiO2-Al2O3, HY, Hβ, and HZSM-5） to degrade lignin into arenes and phenols. The relationship between the catalyst structure and lignin depolymerization performance was investigated. The results showed that both acidity and pore size of the catalyst could influence the conversion of lignin. In the volatilizable product, phenols were identified as the main phenolic monomers via gas chromatography-mass spectrometer. SIO2-Al2O3 was the most efficient catalyst, giving 90.96% degree of conversion, 12.91% yield of phenols, and 2.41% yield of arenes in ethanol at 280℃ for 4 h. The Fourier transform infrared spectroscopy and ^1H nuclear magnetic resonance spectroscopy analysis demonstrated that deoxygenation and alkylation occurred in this process. The effect of solvents was also investigated and the results showed that ethanol was the most efficient solvent.
文摘Characteristics of uncondensed lignin reactions in soda cooking of wheat straw were studied. Mild and intense cooking conditions were used to get the pulp sample in which lignin was dissolved physically and the pulp sample in which lignin was dissolved chemically respectively. The pulp samples were analyzed by phenolic group determination, alkaline nitrobenzene oxidation and ozonation method. The results indicated that around 90% of lignin in wheat straw is alkali-soluble at the mild conditions, is basically dissolved physically without chemical change. The phenolic group content was not changed greatly, the nitrobenzene oxidation yield only changed slightly during the mild cooking. The phenolic group content was increased obviously and uncondensed lignin content was decreased very much when the intense cooking conditions were applied and the delignification was over 90%. The lignin structure was changed greatly during this period.
基金supported by the Research Project for Hot Tracking Items of Beijing Forestry University(2017BLRD03)the National Natural Science Foundation of China(51603012)+1 种基金the Special Science and Technology Research Program of Beijing Forestry University(2016KJ02)the Fundamental Research Funds for the Central Universities(BLYJ2016-17,BLX2015-06)
文摘A new method for the preparation of aminated lignin （AEL） through etherification and amination reaction was presented. Chlorine atoms were ？rstly introduced into lignin through its etheri？cation with epichlorohydrin. Then, hydrophilic amine groups were grafted to the modi？ed lignin structure through amination with ethylenediamine to obtain AEL. Subsequent acidi？cation of AEL led to the ionized aminated lignin （IAEL）. The results of our analyses showed that the nitrogen content of AEL was 6.9%. Foaming and emulsifying experiments indicated that AEL had better foamability and emulsifying properties than IAEL. Surface tension tests showed that AEL and IAEL had similar critical micelle concentration （CMC）. However, IAEL had lower surface tension （36.33 mN/m） than AEL （42.89 mN/m） at CMC. These results demonstrate the promising applicability of AEL as an emulsi？er and that of IAEL as feedstock in the production of detergent and dispersant.
文摘We investigated the role of GA3, uniconazole-P and IAA on tension wood formation, in particular the vessel features, in Fraxinu smandshurica seedlings. Ninety seedlings were used and treated with applications of GA3 and/or IAA to the apical bud of the stem using a micropipette. Applications of GA3 or GA3 plus IAA with uniconazole-P strongly increased cell number of tension wood in comparison to that of no-uniconazole-P-applied, indicated that GA3 is more efficient than IAA on xylem cell production. Wood quality was also regulated by relative concentration ratio of GA3 to lAA, because of the vessel elements differentiation, density and size were controlled by GA3 and/or IAA on the different levels. These results suggested that the relative concentration ratio of GA3 to IAA and interactions of them are essential in regulating both wood quality and wood quantity, and tension wood formation in this species.
