Combining enabling techniques in organic synthesis: continuous flow processes with heterogenized catalysts

The concepts article describes enabling techniques (solid-phase assisted synthesis, new reactor design, microwave irradiation and new solvents) in organic chemistry and emphasizes the combination of several of them for creating new synthetic technology platforms. Particular focus is put on the combination of immobilized catalysts as well as biocatalysts with continuous flow processes. In this context, the PASSflow continuous flow technique fulfils both chemical as well as chemical engineering requirements. It combines reactor design with optimized, monolithic solid phases as well as reversible immobilization techniques for performing small as well as large scale synthesis with heterogenized catalysts under continuous flow conditions.     

3D Graphene Foam by Chemical Vapor Deposition: Synthesis,Properties, and Energy-Related Applications

In this review, we highlight recent advancements in 3D graphene foam synthesis by template-assisted chemical vapor deposition, as well as their potential energy storage and conversion applications. This method offers good control of the number of graphene layers and porosity, as well as continuous connection of the graphene sheets. The review covers all the substrate types, catalysts, and precursors used to synthesize 3D graphene by the CVD method, as well as their most viable energy-related applications.     

基于杯芳烃主体的分子自组装研究进展

分子自组装是超分子化学最重要的研究内容之一. 杯芳烃作为继冠醚、环糊精之后的第三代人工合成受体分子已在分子自组装研究方面取得了重要进展并显示了广泛的应用前景. 主要综述杯芳烃衍生物通过氢键、金属诱导配位、π-π作用、疏水作用等非共价键弱相互作用力在溶液状态、固态和界面的分子自组装方面的研究进展.     

Chemical reaction and Soret effects on MHD convective flow of second grade fluid through an absorbent medium with ramped wall temperature as well as ramped surface concentration

In the present paper, the heat generating and/or absorption as well as thermo-diffusion on the unsteady free convection MHD gyrating flow of radiation and chemical reactive second grade fluid past an unbounded perpendicular plate during absorbent medium have been discussed. Here, it is assumed that, the confining plate has the ramped wall temperature with ramped surface concentration and isothermal temperature with ramped surface concentration. The analytical solutions for the governing equations are found by utilization of Laplace transformation methodology. The velocity, temperature and concentration profiles are analyzed with quite few figures. It is determined that, velocity, temperature and concentration distribution sketches in case of ramped temperature as well as ramped surface concentration are not as much of as those of isothermal temperature as well as ramped surface concentration. In addition to the idioms of skin friction, Nusselt number as well as Sherwood number are achieved and characterized numerically with tabular format.     

Nitraza-/Oxa-Propylene- and Hydrazonemethylene-Bridged 1,2,4-Nitraminotriazoles and Selected Salts

Two new bridged nitraminotriazoles with bridging oxapropylene and nitrazapropylene moieties were synthesized, and converted into several salts, as well as from the hydrazonemethylene bridged nitraminotriazole. All compounds were fully characterized by NMR and IR spectroscopy, elemental analysis as well as differential thermal analysis. The sensitivity towards friction and impact were determined according to BAM standard technics and the energetic properties were calculated by using the EXPLO5 computer code. The neutral compounds as well as the various salts were examined in terms of their physicochemical properties and detonation performance to each other and compared to the commonly used secondary explosive RDX.     

The determination of trace metals in lubricating oils by atomic spectrometry

The determination of trace metals in lubricating oils using atomic spectrometric methods is reviewed. The importance of such analyses for technical diagnostics as well as the specific sample characteristics related to the analyte form (metallo-organic and metal particles) is discussed. Problems related to sample pre-treatment for appropriate sample introduction and calibration are addressed as well as the strategies to overcome them. Recent trends aimed at simplifying sample manipulation are presented. The applications and scope of AAS, ICP OES and ICP MS techniques for the determination of trace metals in lubricating oil is individually discussed, as well as some present instrumental trends.     

Modification of aqueous polyurethanes by forming latex interpenetrating polymer networks with polystyrene

A series of latex particles with interpenetrating polymer network structure have been synthesized from waterborne polyurethane (PU) and polystyrene (PS). The effect of PU/PS composition, cross-linking density in the PS domain as well as in PU have been studied in terms of dispersion size, transmission electron microscopy morphology, mechanical and dynamic mechanical properties in addition to swellability in water and toluene of the dispersion cast film. It was found that inverted core (PS)–shell (PU) morphology was well defined and that the domain size as well as the film properties were well controlled by the latex composition and cross-linking density of both phases. Received: 15 March 2000 Accepted: 21 February 2001     

Two-mode Fluorescent Detection of Cyanide by a Simple AIE-based Chemosensor with Red Emission

TPE-TCF, a simple TPE-derivative with red-emission was used to detect cyanide in the condition of single dispersion as well as under aggregate state. It could be found that TPE-TCF exhibited excellent fluorescent response to cyanide in both situations, and the mechanism was supposed to be the reaction between cyanide and the double bond in TPE-TCF as well as the aggregation induced emission property of the reacted TPE-TCF molecules. What's more, TPE-TCF could distinguish cyanide with other species, such as common anions and biotiol well, which indicated it as a potential indicator for cyanide with good selectivity and specificity.     

Theory and practice of a powerful technique for electrochemical investigation of solid solution electrode materials

The theory and practice of a solid-state electrochemical technique which allows measurement of the chemical diffusion coefficient and partial conductivities of the mobile species in a mixed ionic-electronic conductor, as well as the equilibrium partial thermodynamic quantities, are described. The theory incorporates nonideal thermodynamic behavior of the carriers as well as cross terms in the flux equations. Once the cell is assembled, all parameters can be measured as a function of composition without any further physical manipulation, so that the experiments are well suited to automatic control.     

Aspects of Electrochemical Behavior of Aldehydes and Ketones in Protic Media

Reduction of carbonyl group in aldehydes and ketones, as well as oxidation of numerous aldehydes is discussed, as well as those reductions of organic compounds where the C?O group activates cleavage of an adjacent C? X bond where X is a good leaving group like halogen, OH, NH₂ or SR or activates hydrogenation of an adjacent C?C group. Survey involves aliphatic and aromatic aldehydes, aryl alkyl and diaryl ketones, as well as α‐ketoacids, 1,2‐diketones and compounds where the carbonyl group is a part of a ring. The role of acid–base, hydration–dehydration and in some cases keto–enol equilibria on electrochemical behavior is pointed out, as well as the role of buffer kind and concentration and the nature of the cation of supporting electrolyte. Better understanding of these factors promises finding of best conditions for electroanalytical procedures.     

光诱导钌配合物的几何异构和结构异构反应研究进展

金属钌(Ru)的配合物具有丰富的基态和激发态的光物理、光化学性质,在太阳能转换、光催化以及分子识别等方面都得到了广泛深入的研究.光诱导的钌配合物的异构反应是其颇具特色的一类光反应,研究光异构反应对于光能量转化、信息储存以及"分子光开关"和"分子马达"的设计具有重要的意义.本文小结和综述了钌配合物的光诱导几何异构和结构异构反应的特性和机理以及最新的研究进展.     

Comparison of HDS of Dibenzothiophene and HDN of Quinoline Over Supported MO and CoMo Nitrided and Sulfided Catalysts

Catalytic activities of sulfided and nitrided forms of alumina supported molybdenum as well as cobalt-molybdenum catalysts were compared in the reactions of hydrodesulfurization of dibenzothiophene and hydrodenitrogenation of quinoline. Effect of catalyst composition as well as of the method of its activation on the reaction pathways and catalyst selectivity is discussed.     

4. Characteristics of cellulose acetates 4.1 Characterization and physical properties of cellulose acetates

An overview is provided of the basic features of cellulose acetate of various degree of substitution in the solid and liquid crystalline state as well as in solution. These features represent a necessity for an understanding of the properties of these cellulose derivatives and further for mixed esters, which are not presented in this paper. Specifically, the crystal structure of cellulose triacetate will be addressed as well as structures in dilute and semi-dilute solutions. Thermal, viscoelastic and further properties in the solid state are discussed as well as flow behavior of solutions and their application in molecular weight determination, including false viscosity of commercial 2.5 cellulose acetates.     

Stereospecific synthesis of optically active phenylpropylene oxides

The stereospecific lithiation of diastereomeric phenylpropylene oxides has been studied as well as the trapping reaction with electrophiles. The reduction of the cis-alpha-benzoylpropylene oxide to give prevalently the anti-epoxy alcohol has been investigated as well.     

Metal On‐Line Voltammetric Analyzer for On‐Site Monitoring of Iron Speciation in Acid Mine Drainage Waters: Development and Characterization

The development of a simple, low cost, portable metal on‐line voltammetric analyzer (MOVA) for the iron analysis, as well as other species, in mining effluents is presented. It consists of a voltammetric cell based on an impinging jet flow configuration, a fluidic system controlled by gravity and electronics. Laboratory tests were performed to optimize the system as well as the analytical conditions for Fe speciation measurements. MOVA was then tested in the laboratory, in samples of both mining effluents. The results showed that iron in both mining effluents, as well as copper and arsenic, can be measured in oxygenated samples.     

Advances and challenges of MOF derived carbon-based electrocatalysts and photocatalyst for water splitting: A review

Environmental pollution and energy shortage are substantial fears to the modern world's long-term sustainability. Water splitting is an essential technique for eco - friendly and sustainable energy storage, as well as a pollution-free method to produce hydrogen. In this regards Metal–organic frameworks have emerged as the most competent multifunctional materials in recent times, due to its large surface areas, adjustable permeability, easy compositional alteration, and capability for usage as precursors with a wide range of morphological forms. Further, MOF-derived carbon-based nanomaterials also offer significant benefits in terms of tunable morphological features and hierarchical permeability, as well as ease of functionalization, making them extremely effective as catalysts or catalysts supports for a wide variety of important reactions. Recent developments in carbon-based MOFs as catalysts for overall water splitting are discussed in this review. We explore how MOFs and carbon-based MOFs might well be beneficial, as well as which methods should be explored for future development. We divided our review into two sections: photocatalytic and electrocatalytic water splitting, and we gathered published literature on carbon-based MOFs materials for their outstanding activity, offers helpful methods for catalysts design and analysis, as well as difficulties This study highlights the developments in MOF derived materials as photo and electro catalysts by explaining respective approaches for their use in overall water splitting.     

THE VISUAL PROCESS: PHOTOPHYSICS and PHOTOISOMERIZATION OF MODEL VISUAL PIGMENTS and THE PRIMARY REACTION

Abstract— A systematic comprehensive consideration of the emission spectroscopy, emission lifetimes, transient spectroscopy, as well as quantum yields of fluorescence, triplet occupation and photoisomeriz-ation is given for a wide variety of polyene derivatives including retinyl and longer, as well as shorter chainlength homologs. Absorption spectral properties and the results and significance of theoretical calculations are also included. Chainlength, solvent and temperature effects on state order and photophysical as well as photoisomerization properties are evaluated. The mechanism for the primary light step in vision is considered in light of photophysical and photoisomerization data on model visual pigments and rhodopsin.     

Reaction of thiocyanates with ironcyanogen compounds of silver

Silver fenocyanide as well as Silver ferricyanide are converted into silver thiocyanate by treating with thiocyanate ions, while feirocyanide ions or ferricyanide ions are formed at the same time. Silver ferrocyanide as well as silver ferricyanide are dissolved by solutions of thiocynates of higher concentrations.     

普鲁士蓝修饰生物传感器的研究进展

文中叙述了普鲁士蓝(PB)结构特征和电化学特性,PB在过氧化氢传感器中的应用。综述了PB葡萄糖传感器及其他基于PB的生物氧化酶传感器的研究进展。引用文献52篇。     

Adsorption of silver on cellobiose and cellulose studied with MIES, UPS, XPS and AFM

Metastable induced electron spectroscopy, ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy as well as atomic force microscopy were employed to study the adsorption of silver on cellulose as well as its precursor cellobiose. The formation of silver nanoparticles encapsulated by the organic film previously found for the monomer glucose is well reproduced for the dimer cellobiose. For the polymer cellulose on the other hand, no nanoparticle formation is found even though the surface is covered with silver atoms. No significant chemical interaction is found in any of these cases.