三元杂多酸-甲基紫超分子化合物的合成及光谱研究

在水溶液条件下合成了一系列具有Keggin结构的PWxV12 -x MV(x =2 ,4 ,6 ,8,10 )超分子化合物 (PWxV12 -x为具有不同配比的磷钨矾三元杂多酸 ,MV为甲基紫 ) ,并对其紫外光谱 ,红外光谱和荧光光谱进行了研究。结果表明 ,杂多酸阴离子上的端氧与甲基紫阳离子上的N 间通过配合作用相互连结而形成超分子化合物。超分子化合物中仍保持有杂多阴离子的Keggin结构以及甲基紫的基本结构。且随着V的含量增加 ,杂多阴离子的氧化能力增强 ,阴离子PWxV12 -x和阳离子MV的相互作用增强 ,νas(M =Ot) ,νas(M Ob M )和νas(M Oc M )的FTIR吸收峰分别从 96 6 ,886和 80 4cm-1变化至 95 5 ,875和 786cm-1;紫外吸收峰也从 5 19nm移至 5 0 6nm ;用 5 30nm的光激发的荧光发射峰也从 6 92移至 6 4 4nm ,与PWxV12 -x和MV间配合作用的强弱呈现了很好的对应关系。     

甲基蓝双波长光度法测定阿米卡星

在酸性条件下,甲基蓝(MB)与阿米卡星(AMK)反应,生成蓝色离子缔合物,最大吸收波长和负吸收波长分别位于616 nm和676 nm,正负峰吸光度绝对值之和与AMK的浓度线性相关,AMK的浓度在0～1.5×10~(-5)mol·L~(-1)范围内遵从比耳定律,表观摩尔吸光系数ε为7.28×10~4L·mol~(-1)·cm~(-1),据此建立了测定阿米卡星的甲基蓝双波长光度法。方法用于市售药物及人体尿液中阿米卡星含量的测定,结果满意。     

过硫酸钾-甲基紫-银(Ⅰ)催化体系动力学光度法测定痕量银

在醋酸 -醋酸钠缓冲介质中 ,有活化剂邻二氮菲存在时 ,Ag( )对过硫酸钾氧化甲基紫褪色反应有催化作用 ,建立了测定痕量银的新催化光度法。实验优化了反应条件 ,线性范围为 4 .0— 80 μg/ L,检出限为1.5 5× 10 -9g/ m L,相对标准偏差 1.2 % (n=11)。催化反应表观活化能 Ea=4 4.31KJ·mol-1,表观速率常数 k=7.2 7× 10 -4s-1。表观摩尔吸光系数 ε=7.30× 10 5L·mol-1· cm-1。用于洗像废液中银的测定 ,结果令人满意     

甲基环己烷的高温燃烧机理及动力学模拟

本文根据高碳链烷烃和环烷烃高温燃烧的反应类型,开发了高温燃烧反应机理的自动生成程序ReaxGen,并据此建立了甲基环己烷的高温燃烧详细机理。采用激波管反应器模型开展了动力学模拟,研究了燃烧点火温度、点火压力、燃料摩尔分数和当量比对点火延时的影响。通过绝热燃烧平衡计算,得到产物浓度和绝热火焰温度。动力学模拟结果与文献实验结果及国际上同类机理的模拟结果进行了比较和讨论。     

Methyl 2-naphthoates from a traditional Chinese herb Morinda officinalis var. officinalis

Fifteen methyl 2-naphthoate derivatives (1–15), including 11 previously undescribed ones (1–10 and 13), have been isolated from the roots of a well-known Chinese herb, Morinda officinalis var. officinalis. The structures of these isolates were determined on the basis of detailed spectroscopic analyses, and 12 of them were identified as six pairs of enantiomers (1–12). While the relative configurations of 1 and 5 were confirmed by X-ray crystallographic analysis and calculated ¹³C NMR data, respectively, the absolute configurations of 1–12 were established via interpretation of experimental and computed ECD data. Compounds 1–4 possessed a novel heterocylic bridge ring system incorporating a 2,6-dioxabicyclo[3.2.1]oct-3-ene motif. Our biological evaluations revealed that (−)-mornaphthoate E (9) showed significant cytotoxicity against a panel of human cancer cell lines (MDA-MB-231, MCF-7 and A549, IC₅₀ 1–10 μM), while (−)-mornaphthoate A (2) displayed mild inhibition against butyrylcholinesterase (IC₅₀ 37.98 ± 1.98 μM).     

A facile and efficient synthesis of new fluoroalkylsulfonates and the corresponding tetrabutylammonium salts

A useful synthetic methodology towards new fluoroalkylsulfonates was developed. Grignard addition to an inexpensive and commercially available fluorine-containing ester, methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (1) gave the mono-adduct (2) as the only product in high yield. The scope and limitation of this method were thoroughly investigated and it was found that it works for most Grignard reagents except electron-poor ones. Interestingly, the resulting fluoroalkylsulfonates exhibit substituent-dependent hydration behavior due to the presence of carbonyl group in these compounds. Converting the fluoroalkylsulfonate to the acid form and then neutralizing it with tetra-n-butylammonium hydroxide gave the corresponding tetra-n-butylammonium salts, which shows good solubility in common organic solvents, some of which might be suitable for copolymerization with other hydrophobic monomers.     

新型芳香三嗪超交联多孔聚合物去除水溶液中甲基橙

Organic dyes, especially the harmful cationic dye methyl orange (MO), are emerging pollutants. The development of new materials for their efficient adsorption and removal is thus of great significance. Porous organic polymers (POPs) such as hyper-cross-linked polymers, covalent organic frameworks, conjugated microporous polymers, and polymers with intrinsic microporosity are a new class of materials constructed from organic molecular building blocks. To design POPs both with good porosity and task-specific functionalization is still a critical challenge. In this study, we have demonstrated a simple one-step method for the synthesis of the hyper-cross-linked aromatic triazine porous polymer (HAPP) via the Friedel-Crafts reaction. The resultant porous polymer was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, elemental analysis (EA), thermo-gravimetric analysis (TGA), solid-state ¹³C nuclear magnetic resonance (¹³C NMR), and nitrogen adsorption-desorption isotherms. The results show that HAPP is a rough, irregular morphology, porous organic polymer that is amorphous in nature. The novel polymer showed high Brunauer-Emmett-Teller surface area (of up to 104.36 m²∙g⁻¹), porosity, and physicochemical stability. Owing to the presence of N heteroatom pore surfaces in the network, the material exhibited a maximum adsorption capacity of 249.3 mg∙g⁻¹ for MO from aqueous solutions at room temperature. This is higher than that of some reported porous materials under the same conditions. To explain this phenomenon more clearly, theoretical quantum calculations were performed via the DFT method using Gaussian 09 software and Multiwfn version 3.4.1. It is performed to analyze the properties and electrostatic potential (ESP) of the HAPP monomer and MO. The results indicated that the N heteroatom of HAPP can easily develop strong interactions with MO, supporting the efficient adsorption of MO. The parameters studied include the physical and chemical properties of adsorption, pH, contact time, and initial concentrations. The percentage of MO removal increased as the pH was increased from 2 to 4. The optimum pH required for maximum adsorption was found to be 5.6. Adsorption kinetics data were modeled using the pseudo-first-order and pseudo-second-order models. The results indicate that the second-order model best describes the kinetic adsorption data. The adsorption isotherms revealed a good fit with the Langmuir model. More importantly, the HAPP can be regenerated effectively and recycled at least five times without significant loss of adsorption capacity. Therefore, it is believed that HAPPs with hierarchical porous structures, high surface areas, and physicochemical stability are promising candidates for the purification and treatment of dyes in solution.     

LaCoO_3-TiO_2纳米管阵列的构筑及可见光光催化性能

TiO_2纳米管阵列具有较高的光催化活性,但可见光吸收弱,限制了其太阳能利用和环境应用。窄带隙的钙钛矿(ABO3)型氧化物能够吸收大范围波段的可见光,且稳定性高,但光催化活性低。本文首先采用溶胶-凝胶法合成了LaCoO_3纳米颗粒,然后利用电泳沉积技术将LaCoO_3纳米颗粒修饰于TiO_2纳米管阵列表面,构筑了LaCoO_3-TiO_2纳米管阵列。扫描电子显微镜(SEM)、透射电子显微镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)的表征结果显示溶胶-凝胶法合成的纳米颗粒为LaCoO_3,其尺寸均匀,结晶度高,平均粒径约为100nm。LaCoO_3纳米颗粒与TiO_2纳米管阵列之间的结合力好。紫外可见吸收光谱(DRS)显示,随着电泳沉积时间的延长,LaCoO_3-TiO_2纳米管阵列的吸收带边逐渐红移700nm。可见光下光催化降解甲基橙(MO)的结果表明,电泳沉积15 min制得的LaCoO_3-TiO_2纳米管阵列对MO的光催化效率最高,其降解速率是相同条件下TiO_2纳米管阵列的4倍。光致发光光谱和电化学阻抗谱证实LaCoO_3纳米颗粒的负载有效地促进了光生电荷的分离和传输,可见光光催化活性明显增强。     

极性单体锂系阴离子嵌段共聚物的合成与表征

以酚锂作为副反应抑制剂, 以正丁基锂或1,1-二苯基乙烯盖帽的正丁基锂为引发剂, 通过顺次添加单体的方法, 合成了结构明确的聚异戊二烯-b-聚甲基丙烯酸甲酯(PI-b-PMMA)和聚甲基丙烯酸正丁酯-b-聚甲基丙烯酸甲酯(PBMA-b-PMMA)2种嵌段聚合物. 嵌段聚合反应中甲基丙烯酸甲酯(MMA)的转化率均高于90%, 通过核磁图谱计算的链节摩尔比与理论设计值吻合. PI-b-PMMA和PBMA-b-PMMA的分子量分别达到4×10⁴和1.6×10⁴. 在环己烷中, 通过顺次添加单体的方法, 合成了结构明确的聚苯乙烯-b-聚异戊二烯-b-聚甲基丙烯酸甲酯(PS-b-PI-b-PMMA)三嵌段共聚物, 各单体的转化率均达到100%, 并且产物中的链节摩尔比和理论设计值一致, 最终产物的分子量达到7.4×10⁴, 分子量分布仅为1.28, 为极性三嵌段热塑性弹性体以及有机玻璃透明增韧剂的工业化奠定了基础.     

α-二亚胺镍(Ⅱ)催化甲基丙烯酸甲酯聚合

以4种不同结构的α-二亚胺镍(Ⅱ)催化剂[(t-Bu)—N CH—CH N—(t-Bu)]NiBr₂(C1), [C₆H₅—N C(Me)—C(Me) N—C₆H₅]NiBr₂(C2), [(2,6-C₆H₃(Me)₂)—N C(Me)—C·(Me) N—(2,6-C₆H₃(Me)₂)]NiBr₂(C3)和[(2,6-C₆H₃(i-Pr)₂)—N C(An)—C(An) N—(2,6-C₆H₃(i-Pr)₂)]NiBr₂(An=acenaphthyl)(C4), 在甲基铝氧烷(MAO)作用下, 对甲基丙烯酸甲酯(MMA)进行催化聚合. 以C2为模型催化剂系统研究了Al/Ni摩尔比、 单体浓度、 聚合温度、 聚合时间和反应溶剂对催化活性及聚合物分子量的影响. 在较适合的聚合条件(催化剂用量为1.6 μmol, Al/Ni摩尔比为800, MMA浓度为2.9 mol/L, 甲苯为溶剂, 聚合温度为 60 ℃, 聚合时间为4 h)下, 讨论了催化剂结构对催化活性和聚合物分子量的影响. 研究发现, 催化剂C1~C3催化MMA聚合均得到富含间规结构的聚甲基丙烯酸甲酯(PMMA). 催化剂结构中空间位阻增大导致催化活性降低, 空间位阻最小的 C1催化活性最高[达107.8 kg/(mol Ni·h)]; 而空间位阻最大的C4催化活性仅为7.8 kg/(mol Ni·h). 催化剂结构中给电子效应增加有利于催化活性及聚合物分子量的增加. C2催化活性为62.5 kg/(mol Ni·h), 所得聚合物的分子量为5.0×10⁴; 而具有较强给电子效应的C3催化活性达到96.9 kg/(mol Ni·h), 并得到更高分子量的聚合物(7.6×10⁴).