SURFACTANT-OIL-WATER SYSTEMS NEAR THE AFFINITY INVERSION. PART X: EMULSIONS MADE WITH ANIONIC-NONIONIC SURFACTANT MIXTURES.

Anionic and nonionic surfactants exhibit opposite changes in hydrophilicity with a change of temperature. This antagonism can be harnessed by the use of mixtures. The phase behavior and emulsion type are mapped on a temperature water-oil/ratio diagram for different anionic-nonionic mixtures. It is shown that the mixing can result in insensitivity to temperature of different kinds of emulsions.     

N‐(2‐Ethylhexyl)carbazole: A New Fluorophore Highly Suitable as a Monomolecular Liquid Scintillator

The synthesis, photophysical properties, and applications in scintillation counting of N‐(2‐ethylhexyl)carbazole (EHCz) are reported. This molecule displays all of the required characteristics for an efficient liquid scintillator (emission wavelength, scintillation yield), and can be used without any extra fluorophores. Thus, its scintillation properties are discussed, as well as its fast neutron/gamma discrimination. For the latter application, the material is compared with the traditional liquid scintillator BC‐501 A, and other liquid fluorescent molecules classically used as scintillation solvents, such as xylene, pseudocumene (PC), linear alkylbenzenes (LAB), diisopropylnaphthalene (DIN), 1‐methylnaphthalene (1‐MeNapht), and 4‐isopropylbiphenyl (iPrBiph). For the first time, an excimeric form of a molecule has been advantageously used in scintillation counting. A moderate discrimination between fast neutrons and gamma rays was observed in bulk EHCz, with an apparent neutron/gamma discrimination potential half of that of BC‐501 A.     

Shearing a glassy material: numerical tests of nonequilibrium mode-coupling approaches and experimental proposals

The predictions of a nonequilibrium schematic mode-coupling theory developed to describe the nonlinear rheology of soft glassy materials have been numerically tested in a sheared binary Lennard-Jones mixture. In this Letter, we focus on the existence, behavior, and properties of an effective temperature T(eff) for the slow modes of the fluid, as defined from a generalized fluctuation-dissipation theorem. New, simple experimental protocols to access T(eff) are proposed, and one such experiment is numerically performed. Our results give strong support to the thermodynamic interpretation of T(eff) and make it experimentally accessible in a very direct way.     

NMR studies of the chalcogen analogues of benzofuran. IV—Proton,carbon-13 and selenium-77 magnetic resonance in nitrobenzo[b]selenophenes

The ¹H, ¹³C and ⁷⁷Se chemical shifts have been measured for mononitrobenzo[ b ]selenophenes. For the homocyclic nuclei, the observed ¹H- and ¹³C-values calculated from the empirical increments of nitrobenzene. Anomalous effects are observed in the 2- and 3-substituted derivatives and the nature of the Se? NO₂ interactions in the former is discussed. ⁷⁷Se chemical shifts of the 4-, 5- and 7-nitro derivatives are approximately correlated with the CNDO calculated electron densities; they also compare well with those of selenoanisoles and other phenyl alkyl selenides. The chemical shifts are also compared with the corresponding values in other heterocycles containing a selenophene moiety.     

Induction asymétrique et réaction des α-hydroxy-oximes avec le bromure de phenylmagnésium. Synthéses stéreoselectives d'alcools aziridiniques et d'aza-bicyclo[3.1.0]oxo-2 oxaisothiazolidines-1,2,3

A facile synthesis of aziridine is describe. It is the reaction between Grignard regents and α-hydroxoximes in toluene. The aziridine alchohols are cyclised into 2-oxo-oxathiazolidines. The use of the nuclear Overhauser effect allows the assignment of the relative configurations of these latter compounds and also the configuration of the aziridine alcohols. A proof of the Grignard reagent complex with the alcoolate id given by action of methylmagensium bromide with 2-phenyl 3-methanol azirine. The asymetrie insuction observed is discussed with a transition state involving this complex.     

Sels d'aziridinium stables c-fonctionnalisés II: Stéréochimie de la quaternisation,synthèses stérèodirigées de composés n-trideutériométhylés et attribution de leurs configurations relatives par el'fet overhauser nucléaire

Aziridines bearing a functionality on a ring carbon and an alkyl or deuteriomethyal group on nitrogen have been quaternized at different temperatures. The configurations of the resulting, stable, diastereomeric aziridinium ions have been assigned by Nuclear Overhauser effect. The stereoselectivity in quaternization is discussed.