Investigation of Poly(ether-b-amide)/Nanosilica Membranes for CO2/CH4Separation

The results of molecular dynamics （MD） simulations on transport process of CO2 and CH4 gases in poly（ether-b- amide） （PEBAX）/nanosilica membranes are discussed. The diffusion coefficients for CH4 and CO2 gases at 6 cases with different amounts of nanosilica loading in the simulation boxes are presented. The results show that diffusion coefficients for CO2 gas in all cases are larger than those for the CH4 one. Moreover 10% nanosilica loading case shows maximum effects on diffusion coefficients and improves them by more than 68% and 157% for CO2 and CH4 gases, respectively. Additionally, the results of 3-D Cartesian trajectories and displacements curves are presented and the jumping attempt of CO2 is significantly more than that of CH4. Due to the rubbery state of PEBAX membranes in ambient temperature, the results confirm that channel lifetimes are very short and then back diffusion is not observed for this polymer.     

Connectionist intelligent model estimates of convective heat transfer coefficient of nanofluids in circular cross-sectional channels

Journal of Thermal Analysis and Calorimetry - The effect of Na2CO3 additive on the steam gasification characteristics of Sunjiahao (SJH) coal char was studied in the present paper. Na2CO3-catalyzed...     

An efficient synthesis of pentasubstituted pyrroles: one-pot four-component reaction of arylamine,acetylenedicarboxylate, arylglyoxal,and symmetrical 1,3-dicarbonyl compounds

An efficient and catalyst-free for the synthesis of dialkyl 5-(aryl)-4-(1,3-dicarbonyl)-1-(aryl)-1H-pyrrole-2,3-dicarboxylate via a novel one-pot four-component reaction of arylamine, acetylenedicarboxylate, arylglyoxal, and 1,3-dicarbonyl compounds in ethanol is reported. All the products were obtained in excellent yields and their structures were established from their spectroscopic data.     

Facile synthesis of 4-nitro-N-substituted-1,8-naphthalimide derivatives using ultrasound in aqueous media

This study describes the ultrasound-assisted synthesis of 4-nitro-N-substituted-1,8-naphthalimide derivatives from 4-nitro-1,8-naphthalic anhydride and related amines by irradiating at 35 KHz in a sonic bath in aqueous media at room temperature. The results obtained by this method are comparable to those obtained by a common reflux method. The imidation reaction under ultrasound irradiation preceded 8 and 20 times faster than the common method and produced higher yields.     

A novel approach for the synthesis of aryl amides

A novel and highly efficient approach for the synthesis of aryl amides in high yields by the reaction of carboxylic acids and isocyanides in methanol at ambient temperature is reported.     

Useful chemical information obtained by use of common counterions as internal calibrants in X-ray photo-electron spectra of inorganic complex ions

It is shown that the accuracy and precision, and hence the value for bonding-structure studies, in relative binding energy measurements can be enhanced if a common counterion is employed. The differences in chemical shifts between the peaks for the atoms under consideration and for a common counterion in twenty-nine compounds are measured. This technique reduces charging effect errors, which otherwise often occur when non-conducting samples (e.g., salts) are measured relative to a traditional external calibrant. The improvements in accuracy and precision are demonstrated by using the cesium salt of twenty-nine heteropoly and isopoly anions in more than seventy-five different runs. Oxygen 1s, tungsten 4d, and molybdenum 3d binding energies are measured relative to the cesium 3d ionization potential. In this work the cesium counterion is assumed to be chemically invariant. For the relative binding energies that are studied, no dependence on the charge of the anion is observed. A linear relation seems to exist between the oxygen Is binding energies (measured relative to Cs) and the oxygen-to-tungsten ratio in five isopoly anions. This latter finding may serve as a useful aid in studies related to the synthesis of new compounds.     

o-Phenylenediamine as a New Catalyst in the Highly Regioselective Conversion of Epoxides to Halohydrins with Elemental Halogens

The regioselective ring opening of epoxides using elemental iodine and bromine in the presence of o-phenylenediamine as a new catalyst affords vicinal iodo alcohols and bromo alcohols in high yields. The major advantages of this method are versatility, high regioselectivity, a cheap and commercially available catalyst, mild and neutral reaction conditions, and short reaction times. Fourier transform Raman spectroscopy was used to study the reaction of iodine with o-phenylenediamine. The results indicate that the complex [(Diamine)I]⁺·I₅^– is formed, and we suggest that the major nucleophile is the pentaiodide ion. This bulky nucleophile has a fundamental role in the high regioselectivity observed attacking the less sterically hindered epoxide carbon.     

Excess volumes of the binary mixtures of trichloroethylene withn-alcohols at 30 and 40°C

Volumes of mixing binary systems formed by trichloroethylene with n-alcohols (1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) were measured as a function of composition at 30 and 40°C, by dilatometric measurements. All the systems show a change of sign for V ^E from negative to positive as the mole fraction trichloroethylene increases at both temperatures The positive value of the excess volumes increase as carbon chain length increases. The results are explained in terms of depolymerization of hydrogen bonded alcohol aggregates and weak hydrogen-bonding interaction of the type Cl-H–O between unlike molecules.