To overcome the shortage of wood resources as well as to develop novel natural fibers materials,the Chimonobambusa quadrangularis(CQ)and Qiongzhuea tumidinoda(QT)planted in Southwest China were effectively isolated by...To overcome the shortage of wood resources as well as to develop novel natural fibers materials,the Chimonobambusa quadrangularis(CQ)and Qiongzhuea tumidinoda(QT)planted in Southwest China were effectively isolated by the steam explosion(SE).The fine and uniform bamboo microfibers derived from CQ and QT were obtained,and their smallest average widths were 12.62μm and 16.05μm,respectively.The effects of steam explosion on the micro-morphology,chemical composition,thermal stability,crystallinity,surface wettability,and mechanical properties of bamboo microfibers were comprehensively investigated.The results showed that the relative content of cellulose in bamboo microfibers increased but the hemicellulose and lignin contents decreased after SE.The degrees of crystallinity for CQ and QT increased from 40.49%and 39.46%to 68.90%and 55.78%,respectively.The thermal stability and surface hydrophilicity were also improved.The CQ microfibers had a maximum decomposition temperature of 2.79°C,a tensile strength of 58.54 MPa,an elongation at break of 0.6%,and a water contact angle of 2.7°higher than those of the QT microfibers.展开更多
A palladium-catalyzed formal[2+2+1]cyclization of 1-alkynyl-8-iodonaphthalene with double isocyanides is developed herein.The transformation worked well to produce a series of 7 H-acenaphtho[1,2-b]pyrrole with a broad...A palladium-catalyzed formal[2+2+1]cyclization of 1-alkynyl-8-iodonaphthalene with double isocyanides is developed herein.The transformation worked well to produce a series of 7 H-acenaphtho[1,2-b]pyrrole with a broad reaction scope.Isocyanides play a dual role in the reaction.One is a C1 building block,and another is used as C1 N1 component.In the process,the[2+2+1]cyclization involves imidoylation,regioselective addition of imidoylpalladium species into alkyne,double imidoylation,and another addition of the resulting imidoylpalladium species into imine bonds.展开更多
基金This study was financially supported by the National Natural Science Foundation of China(NSFC)(32060381)the Applied Basic Research Programs of Yunnan Province(202201AT070058)+6 种基金the Scientific Research Funds of Educational Committee of Yunnan Province(2022Y552)the Opening Project of Guangxi Key Laboratory of Forest Products Chemistry and Engineering,China(GXFK2209)the High Level Innovative One-Ten-Thousand Youth Talents of Yunnan Province(YNWR-QNBJ-2020-203)the National College Students Innovation and Entrepreneurship Training Program(202110677009)the Major Basic Special Biological Resources Digital Development and Application Project in Yunnan Province(202002AA10007)the USDA National Institute of Food and Agriculture(1012359)“111”Project(D21027).
文摘To overcome the shortage of wood resources as well as to develop novel natural fibers materials,the Chimonobambusa quadrangularis(CQ)and Qiongzhuea tumidinoda(QT)planted in Southwest China were effectively isolated by the steam explosion(SE).The fine and uniform bamboo microfibers derived from CQ and QT were obtained,and their smallest average widths were 12.62μm and 16.05μm,respectively.The effects of steam explosion on the micro-morphology,chemical composition,thermal stability,crystallinity,surface wettability,and mechanical properties of bamboo microfibers were comprehensively investigated.The results showed that the relative content of cellulose in bamboo microfibers increased but the hemicellulose and lignin contents decreased after SE.The degrees of crystallinity for CQ and QT increased from 40.49%and 39.46%to 68.90%and 55.78%,respectively.The thermal stability and surface hydrophilicity were also improved.The CQ microfibers had a maximum decomposition temperature of 2.79°C,a tensile strength of 58.54 MPa,an elongation at break of 0.6%,and a water contact angle of 2.7°higher than those of the QT microfibers.
基金Financial supports from the Natural Science Foundation of Zhejiang Province(No.LY22B020010)the National Natural Science Foundation of China(Nos.21772067,21801096 and 22161043)The Youth Jinggang Scholars Program in Jiangxi Province。
文摘A palladium-catalyzed formal[2+2+1]cyclization of 1-alkynyl-8-iodonaphthalene with double isocyanides is developed herein.The transformation worked well to produce a series of 7 H-acenaphtho[1,2-b]pyrrole with a broad reaction scope.Isocyanides play a dual role in the reaction.One is a C1 building block,and another is used as C1 N1 component.In the process,the[2+2+1]cyclization involves imidoylation,regioselective addition of imidoylpalladium species into alkyne,double imidoylation,and another addition of the resulting imidoylpalladium species into imine bonds.
