With the assistance of different solvents, self-crosslinked acetic acid lignin-containing polyurethane (LPU) membranes were synthesized. Compared with tetrahydrofuran and dioxane, N, N-dimethylacetamide with stronger ...With the assistance of different solvents, self-crosslinked acetic acid lignin-containing polyurethane (LPU) membranes were synthesized. Compared with tetrahydrofuran and dioxane, N, N-dimethylacetamide with stronger polarity together with higher boiling point was demonstrated to be beneficial for preparing LPU particles of smaller size and enhanced binding force. It was also found that lignin domain can interpenetrate into polyurethane domain well with 43.3% lignin addition, resulting in enhanced phase mixing and better performance. In addition, relative homogeneous and smooth LPU membrane can be obtained with 2% TMP addition, while stress crack took place when TMP content was greater than 3%.展开更多
Hydrothermal pretreatment of poplar wood chips was performed in an acetic acid/sodium acetate buffer medium.To characterize the structural changes of lignin in the pretreatment process,milled wood lignin(MWL)was isola...Hydrothermal pretreatment of poplar wood chips was performed in an acetic acid/sodium acetate buffer medium.To characterize the structural changes of lignin in the pretreatment process,milled wood lignin(MWL)was isolated from both the un-treated and treated poplar wood chips,and analyzed by ^(1)H-NMR,^(13)C-NMR,^(31)P-NMR,FT-IR,and GPC-MALLS.Results showed that the lignin in the pretreated wood chips had more phenolic OH groups,less aliphatic OH groups,higher molecular weight,and narrower polydispersity,in comparison with the lignin in the un-treated wood.The acetic acid-sodium acetate buffer pretreatment facilitated the removal of-OCH_(3) groups and the cleavage of the inter-unit linkages ofβ-O-4 bond in the lignin.Furthermore,the re-polymerization of lignin in the acetic acid-sodium acetate buffer pretreatment was found to be less than that in autohydrolysis.展开更多
The production of formic and acetic acids （or salts） by hydrothermal oxidation of syringol, a model compound for lignin, was investigated using a batch reactor. Results show that the highest yields of formic and ace...The production of formic and acetic acids （or salts） by hydrothermal oxidation of syringol, a model compound for lignin, was investigated using a batch reactor. Results show that the highest yields of formic and acetic acids were, respectively, 59.6% and 11.3% at the reaction condition of 0.5 mol/L NaOH, 120% H2O2 supply and 280 ℃. These results will inform studies aiming to develop more enviromnental friendly lignin conversion processes by obtaining products beyond a CO2 end product.展开更多
文摘With the assistance of different solvents, self-crosslinked acetic acid lignin-containing polyurethane (LPU) membranes were synthesized. Compared with tetrahydrofuran and dioxane, N, N-dimethylacetamide with stronger polarity together with higher boiling point was demonstrated to be beneficial for preparing LPU particles of smaller size and enhanced binding force. It was also found that lignin domain can interpenetrate into polyurethane domain well with 43.3% lignin addition, resulting in enhanced phase mixing and better performance. In addition, relative homogeneous and smooth LPU membrane can be obtained with 2% TMP addition, while stress crack took place when TMP content was greater than 3%.
基金support from the National Natural Science Foundation of China (31540009 and 31370581)the Yellow River Mouth Scholar Program (DYRC20120105).
文摘Hydrothermal pretreatment of poplar wood chips was performed in an acetic acid/sodium acetate buffer medium.To characterize the structural changes of lignin in the pretreatment process,milled wood lignin(MWL)was isolated from both the un-treated and treated poplar wood chips,and analyzed by ^(1)H-NMR,^(13)C-NMR,^(31)P-NMR,FT-IR,and GPC-MALLS.Results showed that the lignin in the pretreated wood chips had more phenolic OH groups,less aliphatic OH groups,higher molecular weight,and narrower polydispersity,in comparison with the lignin in the un-treated wood.The acetic acid-sodium acetate buffer pretreatment facilitated the removal of-OCH_(3) groups and the cleavage of the inter-unit linkages ofβ-O-4 bond in the lignin.Furthermore,the re-polymerization of lignin in the acetic acid-sodium acetate buffer pretreatment was found to be less than that in autohydrolysis.
基金Project supported by the National Natural Science Foundations of China (Nos. 20976139 and 20777054)the National Key Technology R&D Programs of China (Nos. 2009BAC62B02, 2009AA05Z405, and 2009AA063903)+1 种基金the State Key Laboratory of Pollution Control and Resource Reuse (No. PCRRK08002)the Projects of Shanghai Science and Technology Commission of China (Nos. 09160707900 and 09JC1413900), China
文摘The production of formic and acetic acids （or salts） by hydrothermal oxidation of syringol, a model compound for lignin, was investigated using a batch reactor. Results show that the highest yields of formic and acetic acids were, respectively, 59.6% and 11.3% at the reaction condition of 0.5 mol/L NaOH, 120% H2O2 supply and 280 ℃. These results will inform studies aiming to develop more enviromnental friendly lignin conversion processes by obtaining products beyond a CO2 end product.
