An efficient and eco-friendly protocol for the chemoselective N-benzyloxycarbonylation of amines was described.The reaction of amines with benzyl chloroformate（Cbz-Cl） in the presence of PEG-600 at room temperature ...An efficient and eco-friendly protocol for the chemoselective N-benzyloxycarbonylation of amines was described.The reaction of amines with benzyl chloroformate（Cbz-Cl） in the presence of PEG-600 at room temperature afforded the corresponding N-Cbz derivatives in excellent yields.The method is applicable to the N-Cbz protection of aliphatic（acyclic and cyclic） and aromatic amines.展开更多
采用碳端到氮端依次连接策略,以天冬氨酸、甘氨酸、精氨酸为起始原料,以HBTU为缩合剂,Asp(OBzl)-OAllyl顺次分别与Boc-甘氨酸和Cbz-Arg(Cbz)2偶联生成碳端和氮端保护的RGD。进一步在N-甲基吗啉存在下以Pd(PPh3)4催化脱去烯丙基,得到目...采用碳端到氮端依次连接策略,以天冬氨酸、甘氨酸、精氨酸为起始原料,以HBTU为缩合剂,Asp(OBzl)-OAllyl顺次分别与Boc-甘氨酸和Cbz-Arg(Cbz)2偶联生成碳端和氮端保护的RGD。进一步在N-甲基吗啉存在下以Pd(PPh3)4催化脱去烯丙基,得到目标产物。中间产物和目标产物的分离、提纯采用重结晶和柱层析法,应用1 H NMR,13C NMR和MS等对其结构进行了表征。展开更多
We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanopartic...We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanoparticles(NPs)predominantly exposing{200}facets,termed Pd/CN11-2.This facet-specific configuration significantly boosted hydrogen adsorption,leading to notable improvements in catalytic activity.Compared to Pd/XC-72-2 and Pd/g-C_(3)N_(4)-2,Pd/CN11-2 exhibited a remarkable two-fold and nineteen-fold increase in catalytic yield for hydrazo compound hydrogenation,respectively.Pd/CN11-2 also demonstrated robust performance across a range of reaction conditions,maintaining excellent yield.This study emphasizes the critical role of tailored support structures in controlling Pd NPs facets,thereby enhancing hydrogenation efficiency.It provides valuable insights for advancing the industrial application of Pd-based catalysts,underscoring the importance of strategic support modulation for optimizing catalytic performance.展开更多
A mixed oxidant of chlorine dioxide(ClO_(2))and NaClO was often used in water treatment.A novel UVA-LED(_(365) nm)-activated mixed ClO_(2)/NaClO process was proposed for the degradation of micropollutants in this stud...A mixed oxidant of chlorine dioxide(ClO_(2))and NaClO was often used in water treatment.A novel UVA-LED(_(365) nm)-activated mixed ClO_(2)/NaClO process was proposed for the degradation of micropollutants in this study.Carbamazepine(CBZ)was selected as the target pollutant.Compared with the UVA_(365)/ClO_(2) process,the UVA_(365)/ClO_(2)/NaClO process can improve the degradation of CBZ,with the rate constant increasing from 2.11×10^(−4) sec^(−1) to 2.74×10^(−4) sec^(−1).In addition,the consumption of oxidants in the UVA_(365)/ClO_(2)/NaClO process(73.67%)can also be lower than that of UVA_(365)/NaClO(86.42%).When the NaClO ratio increased,both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA_(365)/ClO_(2)/NaClO process.The solution pH can affect the contribution of NaClO in the total oxidant ratio.When the pH range of 6.0-8.0,the combination process can generate more active species to promote the degradation of CBZ.The change of active species with oxidant molar ratio was investigated in the UVA_(365)/ClO_(2)/NaClO process.When ClO_(2) acted as the main oxidant,HO·and Cl·were the main active species,while when NaClO was the main oxidant,ClO·played a role in the system.Both chloride ion(Cl^(-)),bicarbonate ion(HCO_(3)^(-)),and nitrate ion(NO_(3)^(-))can promote the reaction system.As the concentration of NaClO in the reaction solution increased,the generation of chlorates will decrease.The UVA_(365)/ClO_(2)/NaClO process can effectively control the formation of volatile disinfection by-products(DBPs),and with the increase of ClO_(2) dosage,the formation of DBPs can also decrease.展开更多
药品和个人护理产品(Pharmaceuticals and Personal Care Products,PPCPs)在水环境中的存在对生态系统和人体健康构成了潜在威胁.光催化技术因其高效的催化氧化能力而备受关注.本研究采用煅烧法制备了g-C_(3)N_(4)/MXene(MCN)复合光催...药品和个人护理产品(Pharmaceuticals and Personal Care Products,PPCPs)在水环境中的存在对生态系统和人体健康构成了潜在威胁.光催化技术因其高效的催化氧化能力而备受关注.本研究采用煅烧法制备了g-C_(3)N_(4)/MXene(MCN)复合光催化材料,并探究了其对水体中卡马西平(CBZ)的光催化降解性能.通过X射线衍射、扫描电子显微镜和X射线光电子能谱表征,证明了g-C_(3)N_(4)与MXene的成功复合.同时,实验系统考察了pH值、CBZ初始浓度、催化剂用量和光强对光催化降解效果的影响.结果表明,在光照条件下,MCN催化体系对CBZ的去除效果最为显著,30 min内可去除超过90%的CBZ污染物.降解过程符合一级动力学模型,与g-C_(3)N_(4)相比,动力学常数提高3.3倍.稳态荧光光谱、瞬态光电流测试和电化学阻抗谱图结果表明,MXene的复合能提高g-C_(3)N_(4)中载流子的分离效率,从而促进更多活性氧物种的生成.自由基捕获实验和电子顺磁共振实验确认超氧自由基(·O_(2)^(-))在该催化反应中起主导作用.本研究的相关结果可为光催化降解PPCPs,尤其是卡马西平污染物提供新的策略.展开更多
基金the National Science and Technology Project of China(No.2009ZX09102-054)for financial support
文摘An efficient and eco-friendly protocol for the chemoselective N-benzyloxycarbonylation of amines was described.The reaction of amines with benzyl chloroformate（Cbz-Cl） in the presence of PEG-600 at room temperature afforded the corresponding N-Cbz derivatives in excellent yields.The method is applicable to the N-Cbz protection of aliphatic（acyclic and cyclic） and aromatic amines.
文摘采用碳端到氮端依次连接策略,以天冬氨酸、甘氨酸、精氨酸为起始原料,以HBTU为缩合剂,Asp(OBzl)-OAllyl顺次分别与Boc-甘氨酸和Cbz-Arg(Cbz)2偶联生成碳端和氮端保护的RGD。进一步在N-甲基吗啉存在下以Pd(PPh3)4催化脱去烯丙基,得到目标产物。中间产物和目标产物的分离、提纯采用重结晶和柱层析法,应用1 H NMR,13C NMR和MS等对其结构进行了表征。
基金supported by the National Natural Science Foundation of China(21503264,22179081 and 22076117)Natural Science Foundation of Shanghai(20ZR1422500).
文摘We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanoparticles(NPs)predominantly exposing{200}facets,termed Pd/CN11-2.This facet-specific configuration significantly boosted hydrogen adsorption,leading to notable improvements in catalytic activity.Compared to Pd/XC-72-2 and Pd/g-C_(3)N_(4)-2,Pd/CN11-2 exhibited a remarkable two-fold and nineteen-fold increase in catalytic yield for hydrazo compound hydrogenation,respectively.Pd/CN11-2 also demonstrated robust performance across a range of reaction conditions,maintaining excellent yield.This study emphasizes the critical role of tailored support structures in controlling Pd NPs facets,thereby enhancing hydrogenation efficiency.It provides valuable insights for advancing the industrial application of Pd-based catalysts,underscoring the importance of strategic support modulation for optimizing catalytic performance.
基金supported by the National Natural Science Foundation of China (No.52170006)。
文摘A mixed oxidant of chlorine dioxide(ClO_(2))and NaClO was often used in water treatment.A novel UVA-LED(_(365) nm)-activated mixed ClO_(2)/NaClO process was proposed for the degradation of micropollutants in this study.Carbamazepine(CBZ)was selected as the target pollutant.Compared with the UVA_(365)/ClO_(2) process,the UVA_(365)/ClO_(2)/NaClO process can improve the degradation of CBZ,with the rate constant increasing from 2.11×10^(−4) sec^(−1) to 2.74×10^(−4) sec^(−1).In addition,the consumption of oxidants in the UVA_(365)/ClO_(2)/NaClO process(73.67%)can also be lower than that of UVA_(365)/NaClO(86.42%).When the NaClO ratio increased,both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA_(365)/ClO_(2)/NaClO process.The solution pH can affect the contribution of NaClO in the total oxidant ratio.When the pH range of 6.0-8.0,the combination process can generate more active species to promote the degradation of CBZ.The change of active species with oxidant molar ratio was investigated in the UVA_(365)/ClO_(2)/NaClO process.When ClO_(2) acted as the main oxidant,HO·and Cl·were the main active species,while when NaClO was the main oxidant,ClO·played a role in the system.Both chloride ion(Cl^(-)),bicarbonate ion(HCO_(3)^(-)),and nitrate ion(NO_(3)^(-))can promote the reaction system.As the concentration of NaClO in the reaction solution increased,the generation of chlorates will decrease.The UVA_(365)/ClO_(2)/NaClO process can effectively control the formation of volatile disinfection by-products(DBPs),and with the increase of ClO_(2) dosage,the formation of DBPs can also decrease.
文摘药品和个人护理产品(Pharmaceuticals and Personal Care Products,PPCPs)在水环境中的存在对生态系统和人体健康构成了潜在威胁.光催化技术因其高效的催化氧化能力而备受关注.本研究采用煅烧法制备了g-C_(3)N_(4)/MXene(MCN)复合光催化材料,并探究了其对水体中卡马西平(CBZ)的光催化降解性能.通过X射线衍射、扫描电子显微镜和X射线光电子能谱表征,证明了g-C_(3)N_(4)与MXene的成功复合.同时,实验系统考察了pH值、CBZ初始浓度、催化剂用量和光强对光催化降解效果的影响.结果表明,在光照条件下,MCN催化体系对CBZ的去除效果最为显著,30 min内可去除超过90%的CBZ污染物.降解过程符合一级动力学模型,与g-C_(3)N_(4)相比,动力学常数提高3.3倍.稳态荧光光谱、瞬态光电流测试和电化学阻抗谱图结果表明,MXene的复合能提高g-C_(3)N_(4)中载流子的分离效率,从而促进更多活性氧物种的生成.自由基捕获实验和电子顺磁共振实验确认超氧自由基(·O_(2)^(-))在该催化反应中起主导作用.本研究的相关结果可为光催化降解PPCPs,尤其是卡马西平污染物提供新的策略.
