乙二胺和聚乙二醇在纳米介孔氧化铝制备中的协同导向作用

以无机铝盐Al(NO₃)₃为原料, 以乙二胺和聚乙二醇为协同模板导向剂, 与氨水反应, 经过“沉淀-超声-煅烧”等过程, 制得介孔纳米氧化铝. 用TEM, XRD, N₂吸附-脱附等测试技术对样品进行了测试和表征. 研究结果表明, 所得样品具有相当高的比表面积(510 m²•g^－1)、较大孔容(1.13 cm³•g^－1)和较为集中的孔径(5.8 nm)分布. 根据乙二胺和氧化铝表面的溶液化学反应及在不同pH条件下的溶液组分分布, 探讨了它们在介孔氧化铝制备过程中的协同模板作用机理.     

石墨化的有序介孔碳的制备及其作为载体的Pt催化剂对甲醇的电催化氧化

以低分子量的酚醛树脂为碳源, F127为模板剂, NiCl₂为石墨化促进剂, 通过一步模板法辅助合成有序介孔碳. X射线衍射(XRD)、激光拉曼和透射电子显微镜(TEM)等测试结果表明, Ni以金属颗粒的方式进入碳材料的骨架中, 明显提高了有序介孔碳的石墨化程度, 而碳的有序介孔结构几乎没有变化. 在700 ℃热解温度下, Ni含量为5%时, 可以清晰地观察到Ni周围呈现碳的石墨结构. 在硫酸和甲醇溶液中进行循环伏安测试, 结果显示, 碳材料的石墨化有利于提高其电催化活性, 含Ni 5%的碳载Pt催化剂电化学活性面积可达24.84 m²•g^－1, 甲醇氧化峰电流为3.92 mA.     

炭化温度对烟杆基活性炭孔结构及电化学性能的影响研究

以烟杆为原料, 氢氧化钾为活化剂, 通过调节炭化温度(500～800 ℃温度范围)在相同活化条件下制备了具有不同孔隙结构的活性炭材料. N₂吸附测试表明随着炭化温度降低, 活性炭的比表面积和总孔容先增大后减小, 中孔比表面积和平均孔径却一直增大. 其中600 ℃炭化样品经KOH活化后可制得比表面积为3333 m²•g^－1, 总孔容为2.47 cm³• g^－1, 中孔孔容达2.11 cm³•g^－1的高中孔率高比表面积活性炭材料. 采用直流充放电法、交流阻抗法和循环伏安法测定上述多孔炭为电极材料的双电层电容器的电化学性能, 结果表明: 炭化温度不同的烟杆基活性炭电极均表现出良好的功率特性, 充放电流增大50倍, 容量保持率均在80%左右, 其中TS-AC-600活性炭电极在有机电解液中1 mA•cm^－2充放电时, 比电容达到190 F•g^－1. 较高的中孔率和较大的平均孔径使得烟杆基活性炭电极具有良好的高倍率充放电性能.     

活性碳纳米管的制备及其在有机电解液中的电容性能研究

以KOH为活化剂对碳纳米管进行化学活化制备双电层电容器用高比表面积活性碳纳米管. 采用TEM和N₂吸附法表征活性碳纳米管的结构, 采用恒流充放电、循环伏安、交流阻抗等评价其在1 mol•L^－1 Et₄NBF₄/PC中的电容性能. 随活化剂用量增大、活化温度升高和活化时间的延长, 活性碳纳米管的比表面积和比电容都呈增大的趋势. 活化剂用量为3∶1, 800 ℃活化4 h制备的活性碳纳米管的比表面积663 m²•g^－1, 比活化前提高了3倍, 其比电容达57.2 F• g^－1, 比活化前提高了2倍. 将活性碳纳米管的比电容与其比表面积相关联, 发现两者之间具有非常好的线性关系, 并分析了原因.     

介孔TiO2对溶菌酶吸附的动力学和热力学

773.15 K下焙烧二钛酸(H₂Ti₂0₅)制备了介孔结构TiO₂。采用比表面分析仪(BET)、扫描电镜(SEM)、拉曼(Raman)光谱和X射线衍射(XRD)仪进行表征研究了介孔TiO₂对溶菌酶的吸附行为和机理。结果表明,该吸附过程较好地满足Langmuir吸附模型;随着溶液pH值的增高,溶菌酶在介孔TiO₂上的吸附量先增大后减小。在pH = 7.2时,达到最大吸附容量72.5 mg·g^-1。该介孔TiO₂对溶菌酶具有良好的吸附稳定性,经过5次循环后吸附的溶菌酶残余量仍有81.6%。动力学研究表明,介孔TiO₂与溶菌酶间的吸附满足准二级动力学模型,吸附传质过程由膜扩散和粒内扩散共同影响与控制。对热力学参数的计算发现,该过程ΔG⁰ < 0, ΔH⁰ > 0, ΔS⁰ > 0,表明介孔TiO₂对溶菌酶的吸附是一个自发的、吸热的熵增过程。     

具有碱催化活性的有序氮氧化硅MCM-41介孔分子筛的制备与性能研究

以介孔氧化硅MCM-41为氮化前驱体, 以纯的氨气为氮源, 通过调节氮化工艺参数, 制备出了氮含量高达23.01 wt%、比表面积高达665.4 m²•g^－1、平均孔径为2.5 nm的氮氧化硅有序介孔分子筛材料. 采用CNH元素分析、N₂吸附- 脱附分析、小角XRD、高分辨透射电镜(HRTEM)、红外光谱以及²⁹Si 固体核磁共振谱(MAS NMR)等技术对材料的结构进行系统的研究. 并且通过苯甲醛和丙二腈的缩合反应研究了该类材料的碱催化活性. 研究表明, 在30 ℃反应3 h后苯甲醛的转化率达到99.9%.     

有序介孔碳的合成及其相转变机理的研究

采用十六烷基三甲基溴化铵(CTAB)作为模板剂, 正硅酸乙酯(TEOS)为硅源, 在碱性条件下, 用低温合成方法合成了有序介孔硅, 并以此为硬模板, 蔗糖为碳前驱体, 采用液相浸渍方法填充碳源, 制备出有序介孔碳. 通过XRD、TEM、N₂吸附-脱附等测试方法对其表征, 结果表明合成的介孔材料高度有序, 均具有很高的比表面积(介孔硅, 992～1096 m²/g; 介孔碳, 930～1208 m²/g), 较大的孔容和较窄的孔径分布. 还发现随着反应温度的升高, 介孔硅的结构从二维六方相(p6mm)转变为三维立方相(Ia3d); 介孔碳在复制介孔硅后, 其结构也从三维立方相(Ia3d)转变为四方相(I4₁/a), 并对相转变机理做了初步探讨.     

利用均相沉淀剂和形貌导向剂水热一步合成层状镍钴氢氧化物

本文利用在反应过程中同时添加均相沉淀剂六次甲基四胺和形貌导向剂十六烷基三甲基溴化铵,结合水热反应的方法一步合成了镍钴氢氧化物. 随着六次甲基四胺的水解,层状镍钴氢氧化物可以被合成而且避免了额外碱源的使用;同时,由于反应过程中十六烷基三甲基溴化铵参与的孔径调节,合成出来的镍钴氢氧化物具有可控的介孔尺寸13.4 nm以及较大的比表面积93.6 m²•g^-1. X射线衍射图谱表明合成出来的镍钴氢氧化物构型是α-Ni(OH)₂-β-Co(OH)₂. 扫描电镜表明合成出来的镍钴氢氧化物具有层状的结构. 正是因为层状介孔结构的存在,合成出来的镍钴氢氧化物在1A•g^-1电流密度下,比电容可以高达1902 F•g^-1;即使电流密度提高到8 A•g^-1,镍钴氢氧化物的比电容仍然可以保持在1250F•g^-1.     

硅藻土辅助制备有序介孔碳及其电催化性能

以共聚物F127 为软模板, 酚醛树脂为碳源, 引入硅藻土充当暂态支架, 在不同硅藻土与酚醛树脂质量比下, 用蒸发自组装法合成有序介孔碳材料. 利用XRD, TEM, N₂ 吸附-脱附对其结构进行表征, 结果显示, 与单一软模板相比,在硅藻土辅助下获得的介孔碳材料不仅具有高度有序的孔道, 还具有更大的比表面积(717～773 m²·g^-1)和孔径(3.9～11.3 nm). 依据原料比例与介孔碳结构两者间的变化规律, 初步探讨了硅藻土在制备中所起的辅助作用. 采用微波多元醇还原法制备介孔碳载Pt 电催化剂, 在甲醇溶液中进行循环伏安测试, 发现比表面积的增大有利于碳材料的电催化性能提高, 当硅藻土与酚醛树脂的比例为0.5 时, 制备出的有序介孔碳比表面积最大, 载Pt 后呈现的正向氧化峰电流也最大.     

超高交联树脂的氯代烷烃后交联法制备及对咖啡因的吸附研究

以三氯甲烷为外交联剂,以AlCl3为催化剂,经Friedel-Crafts后交联反应将大孔低交联聚苯乙烯（PS）后交联,制备得到超高交联聚苯乙烯树脂HCPS-C₁,树脂的BET比表面积从PS的19.5m²/g提高到HCPS-C₁的522m²/g;再以1,2-二氯乙烷为外交联剂,以FeCl₃为催化剂,将HCPS-C₁后交联,制备得到了比表面积高达791m²/g的超高交联聚苯乙烯树脂HCPS-C₁-C₂。测定了HCPS-C₁和HCPS-C₁-C₂对咖啡因的吸附性能,并与商用树脂XAD4及氯甲基化聚苯乙烯后交联树脂HCPS-CM进行对比,结果表明,HCPS-C₁有着接近于XAD4对咖啡因的吸附量,而HCPS-C₁-C₂对咖啡因的吸附量远高于XAD4,且略高于HCPS-...     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.