Two new chiral stationary phases, 2,3 di O acetyl 6 O trimethylsilyl β cyclodextrin (DATBCD) and 2,6 di O trimethylsilyl 3 O acetyl β cyclodextrin(DTABCD), were synthesized, their structures were identified by means...Two new chiral stationary phases, 2,3 di O acetyl 6 O trimethylsilyl β cyclodextrin (DATBCD) and 2,6 di O trimethylsilyl 3 O acetyl β cyclodextrin(DTABCD), were synthesized, their structures were identified by means of infrared and NMR spectra. Capillary columns were coated with the two stationary phases by dynamic method. The chromatographic properties, and enantiomers separation, such as ketone, esters, alcohols and olefines, were investigated on the silylated and acetylated β cyclodextrin stationary phases. The experimental results show that the silylated and acetylated β cyclodextrins are suitable to be used as capillary gas chromatographic stationary phases, the relative polarity of DATBCD and DTABCD stationary phases is respectively 4143 and 3928, the column efficiencies are respectively 3084 and 4198, and DATBCD is of stronger enantioselectivity than DTABCD, capacity factor of the first eluted enantiomer ( k 1) and separation factor(α)of α phenylethanol on DATBCD stationary phase are respectively 8.23 and 1.019.展开更多
硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重...硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重要。本文以β-环糊精为碳源,采用NaCl辅助水热法制备了一系列具有不同微观孔隙结构的硬炭材料,考察了NaCl浓度对硬炭微观孔隙结构的影响,研究了硬炭材料的储纳性能。采用非原位X射线衍射仪、拉曼光谱仪及高倍率透射电镜等进行表征,结果表明,调控NaCl浓度能够优化硬炭材料的孔隙结构,提升硬炭材料闭孔体积。当NaCl浓度为2mol L^(-1)时,制备的硬炭材料(CD-2)的无序程度与石墨微晶尺寸最大,具有最大的闭孔体积与梯度孔隙结构。电化学测试表明,在0.02Ag^(-1)的电流密度下,CD-2硬炭材料具有360 mA hg^(-1)的高储钠比容量及90.2%的首次库伦效率。提出的NaCl辅助水热炭化调控硬炭闭孔结构的策略,为硬炭材料孔隙结构的合理设计提供了有效的技术方法,指导了高性能SIBs硬炭负极材料的开发。展开更多
文摘Two new chiral stationary phases, 2,3 di O acetyl 6 O trimethylsilyl β cyclodextrin (DATBCD) and 2,6 di O trimethylsilyl 3 O acetyl β cyclodextrin(DTABCD), were synthesized, their structures were identified by means of infrared and NMR spectra. Capillary columns were coated with the two stationary phases by dynamic method. The chromatographic properties, and enantiomers separation, such as ketone, esters, alcohols and olefines, were investigated on the silylated and acetylated β cyclodextrin stationary phases. The experimental results show that the silylated and acetylated β cyclodextrins are suitable to be used as capillary gas chromatographic stationary phases, the relative polarity of DATBCD and DTABCD stationary phases is respectively 4143 and 3928, the column efficiencies are respectively 3084 and 4198, and DATBCD is of stronger enantioselectivity than DTABCD, capacity factor of the first eluted enantiomer ( k 1) and separation factor(α)of α phenylethanol on DATBCD stationary phase are respectively 8.23 and 1.019.
文摘硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重要。本文以β-环糊精为碳源,采用NaCl辅助水热法制备了一系列具有不同微观孔隙结构的硬炭材料,考察了NaCl浓度对硬炭微观孔隙结构的影响,研究了硬炭材料的储纳性能。采用非原位X射线衍射仪、拉曼光谱仪及高倍率透射电镜等进行表征,结果表明,调控NaCl浓度能够优化硬炭材料的孔隙结构,提升硬炭材料闭孔体积。当NaCl浓度为2mol L^(-1)时,制备的硬炭材料(CD-2)的无序程度与石墨微晶尺寸最大,具有最大的闭孔体积与梯度孔隙结构。电化学测试表明,在0.02Ag^(-1)的电流密度下,CD-2硬炭材料具有360 mA hg^(-1)的高储钠比容量及90.2%的首次库伦效率。提出的NaCl辅助水热炭化调控硬炭闭孔结构的策略,为硬炭材料孔隙结构的合理设计提供了有效的技术方法,指导了高性能SIBs硬炭负极材料的开发。
