Separation of toluene and heptane by liquid–liquid extraction using z-methyl-N-butylpyridinium tetrafluoroborate isomers (z = 2, 3, or 4) at T = 313.2 K

The (liquid + liquid) equilibrium (LLE) data for three ternary systems containing heptane, toluene, and a z-methyl-N-butylpyridinium tetrafluoroborate ionic liquid ([zbmpy][BF₄] IL, where z = 2, 3, or 4) were determined at T = 313.2 K and atmospheric pressure. The effect of IL cation isomers on the LLE data was evaluated for the first time. The selectivity and extractive capacity from these LLE data were calculated and compared to those previously reported in the literature for the systems (heptane + toluene + [4bmpy][BF₄]) and (heptane + toluene + sulfolane). The results show that the LLE data for the systems comprising the ILs with the metha- and para-substituted cations do not differ significantly from isomer to isomer. On the other hand, significant differences were observed among the systems with the ortho-substituted cation and the other two cation isomers. The degree of consistency of the experimental LLE data was ascertained by applying the Othmer–Tobias correlation. In addition, the LLE data were satisfactorily correlated by means of the thermodynamic NRTL model.     

Sexual differentiation of the zebra finch song system: potential roles for sex chromosome genes

Background  

Recent evidence suggests that some sex differences in brain and behavior might result from direct genetic effects, and not solely the result of the organizational effects of steroid hormones. The present study examined the potential role for sex-biased gene expression during development of sexually dimorphic singing behavior and associated song nuclei in juvenile zebra finches.     

Absolute configuration assignment of 3-indolylacetate esters

Herein we describe a straightforward method for the determination of the absolute configuration of 3-indolyl(bromo)acetate 7, 3-indolyl(alkoxy)acetates 8a–f and 3-indolyl(amino)acetate 8g, based on ¹H NMR spectral analysis. The conformational preferences for two diastereomeric esters were calculated by DFT, which matched very well with the experimental results. X-ray diffraction analysis allowed us to validate the methodology, and independent absolute configuration evidence was obtained by vibrational circular dichroism.     

Study of the aggregation behavior of a π-conjugated dendrimer with a twisted core

A dendrimer having phenylene vinylene and phenylene ethynylene moieties, a twisted core, and eighteen chiral centers on the periphery has been prepared in high yield by using Sonogashira and Horner–Wadsworth–Emmons reactions. UV–visible and fluorescence spectra and circular dichroism measurements have been envisaged to study the aggregation behavior.     

Thermal decomposition of tricyclohexylidene triperoxide

Journal of Thermal Analysis and Calorimetry - The thermal decomposition of tricyclohexylidene triperoxide both pure and in 4% w/w solution of n-dodecane to yield mainly 16-hexadecanolide is studied...     

Synthesis and structure of the molecular complex between N-(N′, N′-dimethylaminopropyl)phenothiazine hydrochloride and 7,7,8,8-tetracyano-p-quinodimethane (DAPP-TCNQ)

Synthesis, spectroscopic, and X-ray structural analysis of the molecular complex between the N-(N, N-dimethylaminopropyl)phenothiazine hydrochloride, monohydrate, (DAPP) and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ), has been carried out. Crystals of C₂₉H₂₇N₆OSCl are monoclinic, P2₁/c,a=12.190(2),b=7.695(2),c=28.928(3)Å, =91.68(1)°. The molecular complex consists of DAPP as donor binding to TCNQ as acceptor by the thiazine central ring and one of the aromatic rings stacking in parallel planes along thec-axis with an interplanar separation of 3.24Å and 3.16Å, respectively. The electronic and epr spectra of the complex are discussed.     

On the Structure and Stability of the Set of Solutions of a Nonlocal Problem Modeling Ohmic Heating

In this work we analyze the existence, structure and stability of the set of positive solutions of a nonlocal elliptic boundary value problem modeling Ohmic heating. By regarding the total electric current flowing through the device by unit of cross-sectional area as the continuation parameter, we show that the set of steady states is constituted by a finite number of differentiable curves. Moreover, the instability index of a steady state changes by 1 when we pass through by a turning point and does not change if we pass through an hysteresis point. Some sufficient conditions so that the model admit a positive steady state for each value of the parameter, as well as for uniqueness and non-existence, will be also given.