Triphosgene as an Efficient and Electrophilic Reagent for the One-pot Synthesis of Sulfonylsemicarbazids

1 Results Sulfonylsemicarbazide derivatives are important compounds as blowing agents in cellular rubber and plastics[1]. Different methods for the preparation of these compounds are reported. For example, sulfonylsemicarbazides are prepared by reaction of sulfinic acid salt with azodicarbonamide in water[2] and reaction of sulfonylchloride with semicarbazide[3-4]. In these methods the yields of products are not high[3-4], the solvent such as pyridine is toxic and also the sulfinic acid salt as starting material is not commercially available[2]. Recently, triphosgene [bis(trichloromethyl)carbonate], a crystalline solid which can be easily handled, was reported as a safe stable reagent[5]. It was successfully utilized to the synthesis of large variety of organic compounds[6].     

Syntheses of New Functionalized Monomers for π-Conjugated Polymers

1 Results Tailored monomers based on the activated esters of 2,5-dibromobenzoic (sulfonic) acid derivatives, the 3-substituted 2,5-dibromothiophenes, the 9-substituted 2,7-dibromocarbazoles, and on the brominated 1,10-phenanthrolines suitable for Suzuki, Yamamoto or Grignard metathesis (GRIM) coupling reactions were synthesized and characterized by melting point, elemental analysis, 1H NMR, FTIR and TLC. The Horner-Wadsworth-Emmons reaction mechanism was utilized for the preparation of the 3-[2-(pyren-1-yl)vinyl]- or 3-[2-(quinolin-1-yl)vinyl]-2,5-dibromothiophenes. 4-Nitrophenol or N-hydroxysuccinimide were used for the preparation of activated esters. The Cadogan ring closure was utilized for the synthesis of 2,7-dibromocarbazole derivatives. A monomer with β-diketone structure was prepared and characterized as well. 1,10-Phenanthroline (phen) is a typical β-deficient aromatic compound and experience (and literature) advises that simple bromination is poor and nonselective. Of course, bromo derivatives can be obtained by the Skraup synthesis, but the low-yield and multi-step procedure is tedious. There are two main reasonable procedures available at present for the synthesis of 3,8-dibromo-1,10-phenanthroline. The methods utilize either phen monohydrochloride monohydrate for bromination or phen with addition of pyridine and sulfur chloride S2Cl2. We have found in our laboratory that the replacement of sulfur chloride by sulfur dichloride SCl2 and the use of phen monohydrate gives the possibility to prepare 3-bromo-, 3,8-dibromo-, 3,5,8-tribromo- and 3,5,6,8-tetrabromo-1,10-phenanthrolines in reasonable yields, and these derivatives can be separated by crystallization or by column chromatography.     

Analysis of Conditional Value-at-Risk for Newsvendor with Holding and Backorder Cost under Market Search

We consider a distribution system with one supplier and two retailers. For the two retailers, they face different demand and are both risk averse. We study a single period model which the supplier has ample goods and the retailers order goods separately. Market search is measured as the fraction of customers who unsatisfied with their ＂local＂ retailer due to stock-out, and search for the goods at the other retailer before leaving the system. We investigate how the retailers game for order quantity in a Conditional Value-at-Risk framework and study how risk averse degree, market search level, holding cost and backorder cost influence the optimal order strategies. Furthermore, we use uniform distribution to illustrate these results and obtain Nash equilibrium of order strategies.     

Biomimetic, Catalytic Oxidation in Organic Synthesis

1 Introduction Oxidation is one of the most fundamental reactions in organic synthesis. Owing to the current need to develop forward-looking technology that is environmentally acceptable with respect many aspects. The most attractive approaches are biomimetic oxidation reactions that are closely related to the metabolism of living things. The metabolisms are governed by a variety of enzymes such as cytochrome P-450 and flavoenzyme. Simulation of the function of these enzymes with simple trans…     

Synthesis and Photophysical Properties of Novel Rod-shaped and Star Shaped Fluorescent Phosphane Derivatives

1 Results Over the past few years significant research has been directed toward the development of organic materials for potential application in molecular photonic devices[1] and the development of sensors[2].Interest in these materials is primarily due to the infinite numbers of possible molecular structures with the desired properties,by virtue of the tremendous capabilities of organic synthesis.For the development of a new fluorescent molecular sensor consisting of a recognition moiety linked to a fluorescent moiety,the choice of the fluorophore is of major importance[3] in order to ensure better sensitivity.This presentation will focus on the design,the synthesis and the photophysical investigation on new fluorophores based on phosphane oxide[4] and phosphane sulfide[5] derivatives (See Fig.1).     

Recent developments in homobimetallic reagents and catalysts for organic synthesis

Organometallics are a family of useful organic chemicals because they play important roles in organic synthesis as reagents and as catalysts.They can be classified according to the number of metals they contain.Bimetallic compounds are important organometallics and they are either homobimetallic or heterobimetallic depending on whether the two metals are the same or different.In this paper,we focus on homobimetallic compounds.Homobimetallic compounds are generally used as dianions to react with electrophiles in organic synthesis.Recently,homobimetallics have also been used as catalysts in organic reactions such as in asymmetric reactions.     

Ionic Liquids Derived New Media for from the Chiral Pool： Fine Chemistry

Ionic liquids （Ils） are low melting point salts, which are characterized by properties such as high ability to dissolve organic, organometallic and even inorganic compounds, absence of flammability, lack of measurable vapour pressure and high thermal stability. Due to these peculiar properties, they have recently attracted considerable attention as greener alternatives to volatile organic solvents. A few chiral ionic liquids, which could provide a renewal in the field of chiral solvents, have also been reported recently. Herein, we will present the synthesis of a new family of ionic liquids based on a thiazolinium skeleton. Preliminary results on the use of these chiral ionic liquids in the field of chiral recognition and organic synthesis will also be reported.     

Organosilicon Ion-Exchange and Complexing Adsorbents

1 Introduction Modification of mineral synthetic or natural substrates by organosilicon C-functionally substituted monomers, copolycondensation of the latter with organic and organosilicon compounds, and hydrolytic polycondensation of these monomers are the most widely used methods of synthesis of organosilicon adsorbents.The particular method of synthesis of an organosilicon adsorbent is determined by specific technological objectives that are intended to be accomplished with the use of this …     

Science Letters：Solvothermal synthesis of nanosized CoSb3 skutterudite

Nanostructures enhance phonon scattering and improve the figure of merit of thermoelectric materials. Nanosized CoSb3 skutterudite was synthesized by solvothermal methods using COC12 and SbCl3 as the precursors. A “two-step“ model was suggested for the formation of CoSb3 based on the X-ray diffraction analysis. The first step is the formation of cobalt diantimonide in the earlier stage during the synthesis process. Diantimonide was then combined with antimony atoms to form the skutterudite structured triantimonide, CoSb3, in the later stage of the synthesis process as the second step. The synthesized CoSb3 powders consist of irregular particles with sizes of about 20 nm and sheets of about 80nm.     

Formate and acetate records in the Muztagata ice core, Northwest Tibetan Plateau

Formic and acetic acids (HCOOH, CH3COOH), originating mainly from biosphere (release by plants, combustion of biomass, motor exhaust and oxidation of organism, etc.), are two simple organic chemical com- pounds in troposphere. Though the concentration of these two organic acids is low in atmosphere, they are the main [1] sources of free acidity in precipitation of remote regions , and contribute minor chemical constituents to the balance between anions and cations, especially to some atm…     

Computation speedup in the dynamic simulation of MEMS by macromodels

A doubly clamped microbeam actuated by electrostatic force with squeezed gas film damping is a well-known and standard micro-device in microelectromechanical system (MEMS) for many researchers to demonstrate how reduced-order dynamic macromodel is an effective way to faithfully capture the device behaviors. However it still takes time to directly recompute the time-dependant nonlinear terms in macromodels which are generated by a proper orthogonal decomposition (POD) method with Galerkin procedure at every time step during the macromodel simulation. This paper proposes two methods for speeding up the computation of macromodel simulations. In the first method, the computation speedup is achieved based on the concept of precomputation upon the basis functions are available. In the second method, cubic splines approximation is used to interpolate the basis functions and their first and second derivatives, and spatial integration is performed by application of the Gaussian quadrature. Numerical results show both methods could enhance the efficiency of the macromodel simulation compared with our previous computation results     

Synthesis of Novel Nanocomposites of Silica and Guar Gum:Efficient Zinc Ion Binder

1 Results Adsorption using commercial activated carbon (CAC)[1] can remove heavy metals from wastewater[2-4].However,CAC remains an expensive material for heavy metal removal.Ion exchange techniques are also used but it generates volumetric sludge and increases the cost[5].Using naturally occurring seed polysaccharides can solve these problems but their solubility in water limits its application as an adsorbent.Guar gum is a commercially available,industrially important[6-7] polysaccharide material having backbone of β-D (1→4) mannopyranosyl units with α-D-galactopyranosyl units as side chains.However being water soluble it cannot be used and recycled as metal ion binder under aqueous conditions.Present study describes synthesis of novel nanostructured composite materials out of guar gum[8] and silica which have been evaluated as efficient Zn2 metal binder.Zinc ions could be easily stripped off from the used material by washing with acid and used again for two cycles without any significant change in adsorption capacities.It's composite with silica offer materials with efficient metal ion binding properties due to porosity,water insolubility and outstanding thermal property of silica[9-10].     

Effective adjustment of the optoelectronic properties of organic conjugated materials by synthesizing <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">n</Emphasis> diblock molecules

Because organic conjugated materials offer several advantages relative to their inorganic counterparts,the development of organic conjugated materials has been one of the most active research areas in optoelectronic materials.For almost two decades,the search for organic conjugated materials has represented a major driving force for research concerned with controlling the band gap of extended π-conjugated molecules.In particular,among the parameters affecting the performance of organic light-emitting diodes (OLEDs),the energy levels of organic conjugated materials play an important role because they can affect the driving voltage,wavelength,efficiency,and lifetime of the final device.Balanced injection and transport of electrons and holes are therefore crucial for achieving OLEDs with high quantum efficiency.In this regard,research into adjusting the energy levels of organic conjugated materials is very meaningful for the development of OLEDs.To adjust the energy levels of the organic conjugated materials,Huang et al.have presented a new molecular design and synthesis route that yields p-n diblock conjugated copolymers and oligomers.The present review summarizes and analyzes the progress on adjusting the optoelectronic properties of organic conjugated materials that is due to synthesizing p-n diblock molecules.We discusses primarily work done by Huang et al.,but also discusses work done elsewhere over the past few years.We also point out issues that require attention,and highlight hot spots that require further investigation.     

Alumina as an Efficient Catalyst for the Preparation of Sulfonyl Hydrazides and Sulfonyl Semicarbazides Under Solvent-free Conditions

Sulfonyl hydrazide and sulfonyl semicarbazide derivatives exhibit variety of bactriostatic activity and also are important compounds as blowing agents in cellular rubber and plastics. Different methods for the preparation of these compounds are reported for example, sulfonyl semicarbazides are prepared by reaction of a sul- fonyl hydrazides with urea or cyanic acid , reaction of sulfinic acid salt with azodicarbonamide in water, and reaction of sulfonyl chloride and semicarbazide. In lots of these methods the yields are not high, the solvents are toxic （pyridine） and also the starting materials are not commericaly available. We now report a modified and convenient procedure for the preparation of these compounds under solvent-free condition.     

Reaction Behavior of Unsaturated Compounds in Sub- and Supercritical Water

Much attention has been paid on the chemistry of sub- and supercritical water, because of their unique prosperities such as low viscosity, low polarity, and high solubility to organic compounds. Recently, the unique sub-and supercritical water is applied as reaction media and reaction catalysts for organic reactions. We herein disclose the unique reaction of unsaturated compounds in sub- and supercritical water with specific interaction between unsaturated bond（s） and high-density and high-energy water molecule（s） in sub- and supercritical water.     

Syntheses and Reactions of Novel Oxidized Variants of Sterically-Crowded Chalcogenocarbonyl Compounds

1 Introduction d-Camphor and their derivatives have been widely used as chiral auxiliaries and synthons for organic synthesis, and our attempts are focused onto the new functionalization of these skeletons through the generation of oxidized variants of thiones and selones through in situ generation of novel oxidized variants of bornane-2-thiones and selones. In this paper, a novel generation and chemical conversion of these reactive intermediates are presented.1Introductiond-Camphor andtheir d…     

Numerical simulation of fire development in a single compartment based on cone calorimeter experiments

The burning characteristics of several kinds of wood and polyurethane materials have been studied using cone calorimeter (CONE2A). A new and simple ignition criterion, heat release rate model and mass loss rate model are proposed based on experiments. Combined with these models, the zone-model of fire can be used to predict fire development in a single compartment according to the species of combustibles, their quantities and distribution. Calculated results show that this method is simple and feasible.     

Study of the interaction of DNA and histones by spin-stretching and droplet evaporation

Molecular combing is a powerful and simple method for aligning DNA molecules onto a surface. Using this technique combined with fluorescence microscopy, DNA-histone complexes are stretched on a hydrophobic polymethyl methacrylate (PMMA) surface and observed directly. We have developed a new method to stretch single DNA-histone complexes, termed spin-stretching. The results show that the histones markedly enhance DNA binding to the PMMA surface. DNA winds around the histones and therefore decreases in length. The number of histones that bind to each DNA molecule is found to correlate with the histone concentration. The combed DNA-histone complexes are found to depend on two factors: the binding force on the surface and the centrifugal force at its local position. Na+ ions should compete with histones for binding to DNA; however, the observed competitive binding effect of Na+ ions at low concentrations was negligible.     

Formation of the Inclusion Complex of Orange II with β-Cyclodextrin and Its Photostability

Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated. The molar ratio of inclusion complex of β-Cyclodextrin and Orange Ⅱ is 1∶1. The formation constant K=1.236×103 L/mol was determined by the UV and Fluorescence spectra respectively, which was quite in accordance with the calculation with a modified Benesi-Hildbrand equation. The inclusion complex was characterized by the IR spectra and the molar ratio of inclusion complex is 1∶1 too. The formation constant K=1.266×103 L/mol was determined by 1 H NMR analysis and was nearly the same by UV and fluorescence spectra. The photocatalytic decolorization rate of Orange Ⅱ solutions containing β-CD and TiO2 was smaller by 51.9% than that of the Orange Ⅱ solutions only containing TiO2, while in the case of direct photolysis of Orange Ⅱ solutions, β-CD can lower the photolysis rate by 48.1% under UV-light. This result indicates β-CD can inhibit the photolysis and photocatalytic decolorization of Orange Ⅱ under UV-light. The β-CD inclusion complex was found to be persistent to UV-light photolysis.     

Prospects for Future Application of Fugacity Model to Fate Studying of POPs in China

POPs can stay long enough to diffuse and transfer sufficiently in the environment. Researches indicate that it‘s inadequate to study POPs‘ fate and environmental behavior, in order to get comprehensive knowledge of the POPs‘‘ fate and transfer processes in an area, experiment should be combined with model simulation. Recently multimedia models have become the primary choice in simulating organic pollutant‘‘s fate and assessing exposure risk to ecosystem for they can nearly represent the real environment. Among all models,with simple structure, less required parameters, fngacity model has been an efficient tool used widely on simulating the fate and transport of POPs and put into practice in many countries and areas successfully. On the basis of achievements in scientific research, this paper will emphatically take up the following three questions one by one that consist of fngacity model‘‘s principle, pivotal questions and application prospects in China,