多孔碳材料的化学气相后处理及其超级电容性能

以廉价的椰壳为原料制备了高比表面积的多孔碳材料,然后在密闭的反应釜中以硝酸蒸汽对多孔碳材料进行了后处理,制备了亲水性更好的多孔碳材料。采用扫描透射电子显微镜(TEM)、物理吸附、X射线粉末衍射(XRD)、拉曼光谱(Raman)和接触角测试对材料的微观形貌、孔道结构、组成和亲水性进行了表征,探究了不同温度下硝酸蒸汽对多孔碳材料的形貌、结构的影响,并采用循环伏安法、恒电流充放电法和交流阻抗法考察了多孔碳材料的超级电容性能。结果表明,经过硝酸蒸汽处理后的多孔碳材料的比表面积和孔体积均有所降低,且随着处理温度的升高,降低得更加明显,而亲水性却越来越好。电化学测试结果表明,经过100℃硝酸蒸汽处理的多孔碳材料(CSC-100)具有最佳的超级电容性能。在以6 mol·L^-1 KOH为电解液的三电极体系中,当电流密度为0.5 A·g^-1时CSC-100的比电容可达452.9 F·g^-1,而未经硝酸蒸汽处理的多孔碳材料(CSC)的比电容仅为350.4 F·g^-1。电容贡献分析表明CSC-100良好的亲水性和表面官能团不仅提高了双电层电容,也提高了赝电容。     

多孔聚合物骨架的超声及微波辅助合成

首次采用超声与微波辅助合成方法制得数种高比表面积吸附纤维和树脂新材料。研究表明,1)分别以4,4’-二氯甲基-联苯(CMDP)、1,4-二氯甲基苯(XDC)以及FeCl3为单体和催化剂,采用超声辅助Fridel-Crafts烷基化自聚合反应制得比表面积可达1320m2/g的超高交联多孔吸附树脂新材料;2)以PP-ST-DVB基纤维为基体,分别采用超声或超声-微波辅助Fridel-Crafts后交联反应制得比表面积可达84.25m2/g和83.96m2/g的超高交联吸附纤维新材料。与现有多孔高分子骨架制备方法相比,这种多孔聚合物合成新技术可有效克服液固相接枝聚合反应中受热不均所带来的种种弊病,且具有促进溶解(溶胀)和反应时间大幅缩短的优点。     

聚酰基氨基脲类多孔有机聚合物的制备及其在糖肽富集中的应用

通过均苯三甲酰肼(BTZ)和对苯二异氰酸酯(PDI)的聚合反应制备了一种新型的聚酰基氨基脲类多孔有机聚合物(POP)。采用傅里叶变换红外光谱(FT-IR)、交叉极化魔角自旋碳13核磁共振(CP-MAS13C NMR)、氮气物理吸附/脱附实验和水接触角等手段对POP-1的物理性质进行表征。其中比表面积为166 m~2/g,水接触角为46.4°,表明这种多孔材料具有良好的亲水性。因此,尝试将POP-1应用于标准蛋白质和复杂生物样品中糖肽的亲水色谱富集。通过基质辅助激光解吸电离飞行时间质谱(MALDI-TOF/MS)分析,从500 fmol人血清免疫球蛋白G(IgG)酶解液中共鉴定到19条典型的N-连接糖肽;通过毛细管液相色谱-串联质谱(c LC-MS/MS)分析,从100μg鼠肝蛋白酶解液中共鉴定到属于605个糖蛋白的1 919个糖肽的1 350个N-糖基化位点。这些结果表明POP-1在糖蛋白质组学研究中具有较强的应用潜力。     

呼吸图法制备聚亚甲基-b-聚甲基丙烯酸甲酯多孔薄膜

首先利用叶立德活性聚合和原子转移活性自由基聚合(ATRP)相结合制备了三个不同链段比的聚亚甲基-b-聚甲基丙烯酸甲酯(PM-b-PMMA)两嵌段聚合物. 接着以它们为原料, 利用静态呼吸图方法在四种不同溶剂中制备了一系列的具有蜂窝状表面的多孔薄膜, 用扫描电子显微镜(SEM)观察了多孔薄膜的形貌. 研究了溶剂、溶液浓度、聚合物链段长度及链段比等因素对多孔薄膜表面孔的大小和分布的影响. 结果表明: 当PM_2k-b-PMMA_2k嵌段聚合物浓度为3 wt%、溶剂为二硫化碳(CS₂)和二氯甲烷(CH₂Cl₂)时, 可以通过静态呼吸图方法制备出孔径为纳米级(520 nm)和微米级(1.1 μm)的较为规整的多孔薄膜. 多孔薄膜表面的孔径随PM-b-PMMA浓度的减小而增大|两嵌段聚合物中两个链段的长度及其链段比的变化对多孔膜表面孔径均产生较大的影响.     

MePEG-b-PCL-b-PDMAEMA的可控合成及性能研究

采用可控开环聚合(ROP)和原子转移自由基聚合(ATRP)相结合的方法制备出一系列单甲氧基聚乙二醇-b-聚(ε-己内酯)-b-聚甲基丙烯酸-N,N-二甲氨基乙酯(MePEG-b-PCL-b-PDMAEMA). 采用核磁(¹H NMR)和凝胶渗透色谱(GPC)研究了聚合物的结构并对聚合物的分子量大小和分布进行了表征. 聚合物的热稳定性能、结晶性能和亲水性能分别由热重分析仪(TGA)、X-衍射仪(XRD)和静态水滴接触角测定. 分别采用荧光光谱法和¹H NMR(以D₂O为溶剂)方法研究了聚合物纳米粒子的形成. 激光光散射(DLS)和透射电镜(TEM)研究结果表明聚合物纳米粒子具有球形结构, 粒子大小在40～70 nm之间并且对外界环境具有pH敏感性能. MePEG-b-PCL-b-PDMAEMA纳米粒子在同时包裹带有正电荷药物以及疏水性药物方面具有潜在的应用前景.     

一锅法Suzuki-Heck反应构筑基于4-乙烯基苯硼酸的发光多孔有机聚合物

多孔有机骨架材料是近年来出现的一类具有较大的比表面积、孔尺寸小于2 nm的多孔有机聚合物材料. 这些材料由较轻质量的C、H、O、N、B等元素组成, 与常规的微孔材料如分子筛和金属-有机骨架化合物相比, 它们具有较低的骨架密度和较高的比表面积等优点. 在本文中, 我们选择4-乙烯基苯硼酸为底物, 通过与芳基卤代物的Suzuki-Heck反应, 发展了一种基于钯催化的一锅法合成发光多孔有机聚合物的新途径. 红外光谱和固体¹³C核磁研究表明, 4-乙烯基苯硼酸在聚合过程中与芳基卤代物之间的Suzuki-Heck反应进行较为完全. 氮气等温吸附曲线表明, 这类材料具有多孔的性质, BET比表面积最高可达552 m²·g^-1. 由于聚合物中存在有较大的共轭基团, 因此具有良好的发光性质. 我们对这些发光有机多孔聚合物在荧光检测硝基化合物方面的应用进行了初步研究, 发现它们对苦味酸(2,4,6-三硝基苯酚)具有良好的选择性检测能力.     

聚合物-纳米金在油水界面的自组装及有序结构的构筑

聚合物-纳米金复合物既具有金纳米粒子的光、电及催化性能,又具有聚合物的可加工性及对外界的刺激响应性,因此已成为高分子科学及材料科学研究的热点。本文主要介绍了我们实验室在聚合物-纳米金在油水界面的自组装及有序结构的构筑研究方面的相关工作:(1)利用界面聚合的方法制备侧链接枝亲水性金纳米粒子的聚苯乙烯及杂化聚合物在水溶液中的自组装;(2)亲水性金纳米粒子及疏水性聚合物(或疏水性磁性纳米粒子)在油水界面的自组装研究;(3)利用金纳米粒子为交联点制备具有温度响应性聚合物微凝胶的研究。     

分级多孔结构ZnO微球的制备及其光电性能

采用简单的低温化学溶液沉积方法制备了分级多孔ZnO微球。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电镜(TEM)、N2吸附脱附以及紫外-可见分光光度计(UV-Vis)等对样品进行了表征。结果显示产物为分级多孔结构的ZnO微球,由直径约10~20 nm ZnO颗粒组装而成,比表面积为40 m2.g-1。把多孔ZnO微球用作染料敏化太阳能电池(DSCs)光阳极,结果表明,该光阳极在增强对入射光的散射作用的同时,为染料分子的吸附提供了较大比表面积,从而提高了DSCs的光伏性能。     

溶胶-凝胶法制备红霉素印迹固相萃取材料及其选择性吸附

以红霉素为模板分子,采用溶胶-凝胶印迹技术,合成对红霉素具有特异选择识别性能的印迹聚合材料.采用红外光谱、扫描电子显微镜、热重分析以及比表面积测定技术对印迹聚合物的结构和表面性能进行详细探讨,结果表明所得印迹聚合物比表面积为266.2m2/g,粒径为600nm左右的颗粒材料.选择3种抗生素类药物进行选择吸附研究,结果表明,该聚合物对红霉素的分离因子最高达到2.20.优化固相萃取条件,结果表明用甲醇:乙酸(75:25,V/V)作为洗脱剂时对红霉素的洗脱效果最好.结合液相色谱技术,该印迹材料成功的分离和富集红霉素肠溶片中的红霉素,回收率达到104.5%。     

硅胶核的性质对分子自组装核壳材料性质的影响

以3种不同比表面积(120、219、289 m2/g)、孔径(10、12、10 nm)、孔体积(0.21、0.70、0.72 m3/g)的硅胶微米球为核,氧化钛或氧化锆为壳,采用分子自组装的方法制备了氧化钛或氧化锆包覆硅胶型核壳材料,探讨了核的性质对核壳材料性质的影响.实验结果表明:在相同的组装条件下,硅胶核的比表面积增大,组装后填料的比表面积也增大;孔径分布范围变窄,大孔减少.因此,硅胶核的性质是影响硅胶核氧化物壳核壳填料性质的因素之一.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.