Hydrogen‐Bonded Organic Frameworks (HOFs): A New Class of Porous Crystalline Proton‐Conducting Materials

Two porous hydrogen‐bonded organic frameworks (HOFs) based on arene sulfonates and guanidinium ions are reported. As a result of the presence of ionic backbones appended with protonic source, the compounds exhibit ultra‐high proton conduction values (σ) 0.75× 10^?2 S cm^?1 and 1.8×10^?2 S cm^?1 under humidified conditions. Also, they have very low activation energy values and the highest proton conductivity at ambient conditions (low humidity and at moderate temperature) among porous crystalline materials, such as metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). These values are not only comparable to the conventionally used proton exchange membranes, such as Nafion used in fuel cell technologies, but is also the highest value reported in organic‐based porous architectures. Notably, this report inaugurates the usage of crystalline hydrogen‐bonded porous organic frameworks as solid‐state proton conducting materials.     

Experimental Study of the Effect of Strong Alkali on Lowering the Interfacial Tension of Oil/Heavy Alkylbenzene Sulfonates System

Experimental studies were conducted to explore the fundamental mechanisms of alkali to lower the interfacial tension of oil/heavy alkylbenzene sulfonates (HABS) system. Sodium hydroxide was used as the strong alkali chemical to investigate the interfacial tension (IFT) of oil/HABS system. The influences of salt and alkali on the interfacial activity were studied by the measurement of interfacial tension and partition coefficient. Moreover, the alkali/surfactant solutions were measured by dynamic laser scattering. The results showed that compared with the salt, the function of alkali to lower the interfacial tension and improve partition coefficient is more significant. The micelles formed by surfactants could be disaggregated because of adding alkali, so the size of micelles decreases and the number of mono‐surfactants increases, then more surfactant molecules move to the interface of oil/surfactant system and the adsorption of surfactants at oil‐water interfaces increases, which can lead to the decrease of IFT.     

Synthesis of 2-amino derivatives of levoglucosenone

2-Amino derivatives of levoglucosenone were prepared by reaction of the 2-methanesulfonyl (or p-toluenesulfonyl) derivatives with ammonia, methylamine, or octylamine under various conditions. The analogous reaction did not occur for saturated derivative 15. The 2-amino-3,4-dihydro derivative was prepared by catalytic hydrogenation of unsaturated amine 9.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 429–432, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

三维有序大孔H3PW12O40-SiO2功能材料的制备、表征及催化性能研究

以杂多酸 H₃PW₁₂O₄₀ (PW₁₂)与正硅酸乙酯(TEOS)混合溶胶, 采用胶晶模板法结合煅烧去除模板工艺, 成功地制备了PW₁₂/SiO₂物质的量比在1/10～1/40之间的三维有序大孔(3DOM) PW₁₂-SiO₂催化剂. 经SEM, N₂吸附, XRD和FTIR等研究表明, PW₁₂含量较低的样品, 大孔结构三维规整性十分好. 在410 ℃氧化分解胶晶的条件下, PW₁₂基本保持一级Keggin结构. PW₁₂在样品中以分子簇或微晶存在, 其大小随含量增加而增大. PW₁₂高含量时, 其含氧键的FTIR振动与纯PW₁₂的基本一致, 但低含量时含氧键振动有一定偏移, 显示PW₁₂/SiO₂相互作用较显著. 样品酸性随杂多酸含量增加而增加, 但PW₁₂/SiO₂物质的量比超过1/30时酸性便减小, 呈火山型曲线变化规律. 对1-十二烯烷基化反应的催化活性随PW₁₂/SiO₂物质的量比的变化与酸性变化有相同的规律. 但所有样品的催化反应活性均远高于纯PW₁₂, 并且有良好的重复使用性能, 使用4次后仍保持新鲜催化剂活性的78%.     

Surface Plasmon Resonance Immunosensor for Anionic Surfactants Based on an Indirect Competitive Immunoreaction

Abstract

A highly sensitive surface plasmon resonance immunosensor for the determination of linear alkylbenzene sulfonate (LAS) was fabricated. The method is based on an indirect competitive reaction of an anti‐LAS antibody in a sample solution with LAS immobilized on a sensor chip and with LAS in the sample solution. A sensor chip immobilized with LAS was prepared by utilizing an electrostatic interaction between an LAS conjugate, LAS–horseradish peroxidase (LAS‐HRP), and a self‐assembled monolayer of 11‐amino‐1‐undecanethiol hydrochloride, which was preliminary prepared on a gold thin film of the sensor chip. The quantitative determination of LAS in the concentration range 10–1000 ppb was achieved by using the proposed immunosensor.     

On-Line coupling of supercritical fluid extraction with high performance liquid chromatography

Supercritical fluid extraction was coupled directly with high performance liquid chromatograph. The system was evaluated for direct injection of supercritical CO₂ and modified supercritical CO₂ at high pressure and temperature onto a HPLC system with varying mobile phase compositions and flow rates. Injection of 9 μL supercritical CO₂ onto the HPLC using methanol/water mobile phases from 100% methanol to 80% with a flow of 1.0 mL/min did not adversely affect the baseline of UV detector. However at higher percentages of water, CO₂ solubility in the mobile phase decreased and caused baseline interferences on the UV detector. At higher HPLC mobile phase flow rates, supercritical CO₂ was injected to higher percentages of water without any effect on the UV baseline. Also, increasing the extraction pressure or modifier concentration did not change the results. Separations of polynuclear aromatic hydrocarbons and linear alkenebenzene sulfonate test mixtures were obtained using on-line SFE/HPLC interfaced system.     

The effects of several sulfonates on thermal and fire retardant properties of poly(methyl methacrylate) and polystyrene

Three different sulfonates (sodium diphenylamine‐4‐sulfonate [SDPAS], 3‐(1‐pyridino)‐1‐propane sulfonate [PPS], and ammonium sulfamate) have been melt blended with polystyrene (PS) or poly(methyl methacrylate) (PMMA) and with clay to make composites. All have been examined by X‐ray diffraction to determine the morphology, by thermogravimetry to determine thermal stabilities, and by cone calorimetry to evaluate fire retardancy. All three sulfonates enhance the thermal stability of the PMMA composites, and SDPAS achieves the greatest improvement. SDPAS also seems to aid in the dispersion of the clay in the polymer. Combination of sulfonates (5 or 10 wt% SDPAS, or 5 wt% PPS) with an organically modified clay exhibit enhanced fire retardancy. The three sulfonates did not enhance the thermal stability of the PS composites; however, there is a reduction in the peak heat release rate. The presence of ammonium sulfamate in PS brings about a 52% reduction in the peak heat release rate. The combination of sulfonates (5 or 10 wt% PPS, or 10 wt% SDPAS) with an organically modified clay provides some fire retardancy to the PS composites. Copyright © 2013 John Wiley & Sons, Ltd.     

Competing Pathways in the Photogeneration of Didehydrotoluenes from (Trimethylsilylmethyl)aryl Sulfonates and Phosphates

The scope of the photochemical generation of α,n‐didehydrotoluene diradicals from aryl sulfonates and phosphates and their chemistry are explored. The thermally inaccessible α,2‐ and α,4‐ intermediates are efficiently obtained by irradiation of ortho‐ and para‐(trimethylsilylmethyl)phenyl triflates through heterolytic splitting of the ester anion from the substrate in the triplet state. Triplet phenyl cations are formed and the loss of trimethylsilyl cation from them affords the desired diradicals (³Me₃SiCH₂C₆H₄‐OZ→³Me₃SiCH₂C₆H₄⁺→ ^? CH₂C₆H₄ ^? ). Triplet sensitization is required, for which acetone is used throughout. Direct irradiation leads, on the contrary, to photo‐Fries fragmentation (¹Me₃SiCH₂C₆H₄O‐Z→Me₃SiCH₂C₆H₄O ^? +Z ^? ). With mesylates, where ester cleavage is less convenient, a further competition from the triplet is direct desilylation. Didehydrotoluenes are also obtained from the corresponding phosphates, although with poor efficiency.     

Aggregation of Sodium 2,4,5-(tri-n-Alkyl)-benzene Sulfonates in Aqueous Solution: Micellization and Microenvironment Characteristics Studied by Electron Paramagnetic Resonance and Steady-State Fluorescence Quenching

The aggregation behaviors and microenvironmental characteristics of five sodium tri-n-alkylbenzene sulfonates (STABS) micelles have been investigated by electron paramagnetic resonance (EPR) and steady-state fluorescence quenching (SSFQ) techniques. The results indicated that the micropolarity of STABS micelles was less sensitive to the increase of the alkyl chain length, and showed slight decrease with the increasing solution concentration. The microviscosity of STABS micelles increased with the increase of the long alkyl chain length, decreased with the increase of the short alkyl chain length, and exhibited little increase when increase the solution concentration. The salinity of added inorganic salt exhibited obvious effect on the decrease of micropolarity and increase of microviscosity of STABS. These results suggested that these different alkyl chains showed different effects on the micellization of STABS and the salinity's effect was even bigger.     

The Effects of Di- or Polysulfonates on Adsorption of Petroleum Sulfonates

Petroleum sulfonates was separated into several fractions with conventional extraction method according to the polarity of extraction solvent. The relative content of mono-, di-, or polysulfonates in each fraction was determined by using high pressure liquid chromatography and then the average sulfonic amount of each fraction can be calculated according to above results. The equivalent weight of each fraction was measured by both two-phase titration method and ESI-MS method, and the results shows the tow methods are comparatively coincident. Furthermore, the mean molecular weight of each fraction can be calculated with the average sulfonic amount and the equivalent weight. Adsorption isotherm and coreflooding adsorption test were both conducted to determine the adsorption amount and adsorption rate of each fraction. It was found that the fraction with the minimum equivalent weight is middle mean molecular weight and its adsorption amount on reservoir sand is maximal. Moreover, two fractions have a tendency to come to saturated adsorption in coreflooding adsorption test, but the time needed for saturated adsorption is distinctly different. However, the total adsorption amount of the other fractions keeps increasing at all time. The mechanisms accounting for the difference of adsorption performance were proposed on the basis of the diverse composition of the fraction.