Solubilization of endocrine disruptors in micellar media

The interaction of endocrine disruptor chemicals (EDCs) such as nonylphenol (NP) and β-estradiol with cationic micelle of hexadecyltrimethylammonium ion (HTA⁺) and a monolayer of HTA⁺ ion adsorbed at the electrode surface has been investigated in the presence of hydrophilic modified (2-hydroxypropyl)-β-cyclodextrin. NP, which has a similar structure to HTA⁺, decreased the critical micelle concentration (cmc) of hexadecyltrimethylammonium bromide more effectively. At the low HTA⁺ concentration, HTA⁺ inhibited the adsorption of I₂. However, as the HTA⁺ concentration increased, a monolayer of HTA⁺ was formed at the electrode surface and caused the adsorption of iodine molecule (I₂). In the presence of micelle, the I₂ was dissolved in the micelle. Both EDCs caused the formation of HTA⁺ monolayer even at the HTA⁺ concentration below the cmc.     

Kinetics and mechanism of the reaction of chlorine atoms with n-pentanal

The kinetics and mechanism of the reaction Cl + CH3(CH2)3CHO was investigated using absolute (PLP-LIF) and relative rate techniques in 8 Torr of argon or 800-950 Torr of N2 at 295 +/- 2 K. The absolute rate experiments gave k[Cl+CH3(CH2)3CHO] = (2.31 +/- 0.35) x 10(-10) in 8 Torr of argon, while relative rate experiments gave k[Cl+CH3(CH2)3CHO] = (2.24 +/- 0.20) x 10(-10) cm3 molecule(-1) s(-1) in 800-950 Torr of N2. Additional relative rate experiments gave k[Cl+CH3(CH2)3C(O)Cl] = (8.74 +/- 1.38) x 10(-11) cm3 molecule-1 s(-1) in 700 Torr of N2. Smog chamber Fourier transform infrared (FTIR) techniques indicated that the acyl-forming channel accounts for 42 +/- 3% of the reaction. The results are discussed with respect to the literature data and the importance of long range (greater than or equal to two carbon atoms along the aliphatic chain) effects in determining the reactivity of organic molecules toward chlorine atoms.     

Lithium ion conduction in an organoborate zwitterion-LiTFSI mixture

An organoborate zwitterion-lithium salt mixture, prepared via selective borate formation of N-ethylimidazolium salt, exhibited ionic conductivity of 3.0 x 10(-5) S cm(-1) at 50 degrees C and a lithium transference number of 0.69.     

Regiospecific synthesis of 2‐substituted furanonaphthoquinones

The naturally‐occurring furanonaphthoquinones 1a‐d have been synthesized from 3‐furancarboxylic acid and 2,3‐dimethoxybenzaldehyde via the Birch reduction‐elimination.     

Interactions and influence of α-cyclodextrin on the aggregation and interfacial properties of mixtures of nonionic and zwitterionic surfactants

The interactions of α-cyclodextrin (α-CD) with the nonionic surfactant decanoyl-N-methyl-glucamide (Mega-10) and the zwitterionic surfactant dimethyldodecylammoniopropanesulfonate (DPS) in their mixed system have been studied using interfacial tension, fluorescence, and nuclear magnetic resonance measurements. From the plots of interfacial tension vs. log of total surfactant concentration, we have obtained values of the surface excess of surfactant, the critical micellar concentration (cmc), the standard free energy of micelle formation, and association constant of surfactant/α-CD inclusion complexes (assuming a 1:1 stoichiometry). A comparison of the K _a values obtained for the interaction between α-CD and DPS and Mega-10, respectively, shows that DPS interacts stronger with α-CD than Mega-10. The experimental mixed cmc was analyzed by the pseudophase separation model and regular solution theory for the evaluation of ideality or nonideality of the mixed micelle formation. The interaction parameters in the mixed micelle and the micelle composition at different mole fractions of DPS were also computed. The fluorescence anisotropy (r) values of rhodamine B decreases with the increase of α-CD concentrations.     

Approach to thermal equilibrium in atomic collisions

The energy relaxation of fast atoms moving in a thermal bath gas is explored experimentally and theoretically. Two time scales characterize the equilibration, one a short time, in which the isotropic energy distribution profile relaxes to a Maxwellian shape at some intermediate effective temperature, and the second, a longer time in which the relaxation preserves a Maxwellian distribution and its effective temperature decreases continuously to the bath gas temperature. The formation and preservation of a Maxwellian distribution does not depend on the projectile to bath gas atom mass ratio. This two-stage behavior arises due to the dominance of small angle scattering and small energy transfer in the collisions of neutral particles. Measurements of the evolving Doppler profiles of emission from excited initially energetic nitrogen atoms traversing bath gases of helium and argon confirm the theoretical predictions.     

Measurement of the rate of nu(e) + d --> p + p + e(-) interactions produced by (8)B solar neutrinos at the Sudbury Neutrino Observatory

Solar neutrinos from (8)B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of nu(e)'s is measured by the CC reaction rate to be straight phi(CC)(nu(e)) = 1.75 +/- 0.07(stat)(+0.12)(-0.11)(syst) +/- 0.05(theor) x 10(6) cm(-2) s(-1). Comparison of straight phi(CC)(nu(e)) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3 sigma difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- nu(e) component in the solar flux. The total flux of active 8B neutrinos is determined to be 5.44+/-0.99 x 10(6) cm(-2) s(-1).