Electrophilic fluorination methodology

Chapter One This chapter reviews the historical background of the fluorination using both elemental fluorine and N-F reagents. It relates the properties and preparations of these electrophilic reagents. And finally it discusses the use of these reagents in selective electrophilic fluorination (formation of C-F bond from C-H bond) of organic compounds. Chapter Two, Three and Four These chapters present our investigations into the fluorination of hydrocarbon systems containing an electron withdrawing group (ewg).Chapter Two shows the difference in reactivity of elemental fluorine and Selectfluor(^TM) towards aldehydes and ketones. Select fluor gives rise to a-fluorinated compound when reacting with ketones (acyclic and cyclic ones) whereas different results were observed using fluorine. In Chapter Three aldehydes are submitted to fluorination which occurred at the carbonyl and not on the chain. Finally, Chapter Four review the fluorination of nitriles using both fluorinating reagents. Chapter Five In this last Chapter we explore the fluorination of cyclic ethers (hydrocarbon systems containing an electron donating group) using both elemental fluorine and Selectfluor(^TM). Unexpected derivatives were identified. Chanter Six to Nine Experimental details relating to Chapter Two-Five

Multidimensional separation prior to mass spectrometry: Getting closer to the bottom of the iceberg

While prefractionation has previously been shown to improve results in MS analysis, a novel combination provides an additional dimension of separation: protein fractionation by SDS-PAGE followed by IEF of tryptic peptides before separation by RP-LC [Atanassov and Urlaub, Proteomics 2013, 13, 2947-2955]. This three-step separation procedure prior to MS/MS substantially increases proteome coverage and represents a further step toward a more comprehensive analysis of complex proteomes

Study of the mechanical properties of a ceramics of orthopedic and dental use

The study of the preparation of ceramics is consisted in sintering a hardened cement, wich is composed of mixture of three calcium phosphates : tetracalcium phosphate (Ca4(PO4)2O), -tricalcium phosphate (-Ca3(PO4)2) and monocalcium phosphate (Ca(H2PO4)2.H2O).After wetting, the cement evolved towards an apatitic phase while hardening. To check the effect of certain factors on the resulting ceramics, a complete central composite design of four variables (liquid/solid ratio, stoichiometric coefficient of monocalcium phosphate, rate of increase in temperature and duration of landing of termpertaure) was set up. The equation of the model and optimal conditions were defined

Frustration-induced exotic properties of magnetic molecules

Geometric frustration of interacting spin systems is the driving force of a variety of fascinating phenomena in low-dimensional magnetism. In this contribution I will review recent results on frustration-induced effects in magnetic molecules, i.e. zero-dimensional magnetic systems, as well as in a recently synthesized frustrated molecule-based spin tube, i.e. a one-dimensional spin system.Comment: 5 pages, 9 eps figures; proceedings of the symposium on "Spin- and charge-correlations in molecule-based materials", October 2005, Koenigstein (Taunus), German

Stoichio-kinetic modeling and optimization of chemical synthesis: Application to the aldolic condensation of furfural on acetone

The condensation reaction of furfural (F) on acetone (Ac) gives a high added value product, the 4-(2-furyl)-3-buten-2-one (FAc), used as aroma in alcohol free drinks, ice, candies, gelatines and other products of current life. This synthesis valorises the residues of sugar cane treatment since furfural is obtained by hydrolysis of sugar cane bagasse followed by vapor training extraction. In the face of numerous and complex reactions involved in this synthesis, it is very complicated to define the kinetic laws from exact stoichiometry. A solution allowing to cope the problem consists in identifying an appropriate stoichiometric model. It does not attempt to represent exactly all the reaction mechanisms, but proposes a mathematical support to integrate available knowledge on the transformation. The aim of this work is the determination of stoichiometric and kinetic models of the condensation reaction of furfural on acetone. Concentrations of reagents and products are determined by gas and liquid chromatography. Concentration profiles obtained at different temperatures are used to identify kinetic parameters. The model is then used for the optimization of the production of FAc. The interest of such tool is also shown for the scale up of laboratory reactor to a large scale. The anticipation of the reaction behaviour in large scale is crucial especially when the reactor presents important limitations of thermal exchange capacity

Self-assembled metallic nanoparticle template --- a new approach of surface nanostructuring at nanometer scale

In the present work, the formation of silver and copper nanostructures on highly oriented pyrolytic graphite (HOPG) modified with self-assembled gold nanoparticles (Au NPs) is demonstrated. Surface patterning with nanometer resolution was achieved. Different methods such as field emission scanning electron microscopy (FEGSEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) were used to illustrate a selective deposition of silver and copper on Au NPs. The mechanism of silver and copper ions reduction on Au NP with $n$-dodecanethiol coating is discussed.Comment: 6 pages, 3 figure

The World Before 1907: Searching for Chemical Literature before Chemical Abstracts.

An overview of early abstracting sources for historical chemical literature prior to the launch of Chemical Abstracts in 1907.UT Librarie