NOPR Collection:

Density estimation of normal alkanes from the statistical-thermodynamic perturbation theory based equation of state

2016-07-20T04:17:43Z

Title: Density estimation of normal alkanes from the statistical-thermodynamic perturbation theory based equation of state Authors: Zabeti, Ali Reza; Haghighi, Behzad; Papari, Mohammad Mehdi; Ghiamati, Ebrahim Abstract: An analytical equation of state (EoS) proposed by Ihm-Song-Mason (ISM) is employed to calculate the density of normal alkanes from methane to decane. The best available values of the Lennard-Jones (12,6) parameters have been used to evaluate the second virial coefficient of the EoS for each compound. The second virial coefficient is not very sensitive to the feature of the intermolecular potential. The remaining parameters in the EoS depend only on the repulsive part of the potential. Consequently, they are insensitive to the details of the interaction potential. The calculated second virial coefficients in conjunction with other temperature-dependent parameters of the EoS are employed to predict the density of all alkanes (C1-C10). There is a good agreement comparison between the experimental values of density and the calculated values from ISM EoS for all of the compounds. Page(s): 591-594

Synthesis of nanocrystalline NiO by sol-gel and homogeneous precipitation methods

2016-07-20T04:17:14Z

Title: Synthesis of nanocrystalline NiO by sol-gel and homogeneous precipitation methods Authors: Jeevanandam, P; Pulimi, V Ranga Rao Abstract: Nanocrystalline nickel oxide has been prepared via thermal decomposition of precursors obtained using two methods, sol-gel process and homogeneous precipitation. The precursors and the oxide obtained by calcination are characterized by various analytical techniques such as powder X-ray diffraction, thermal gravimetric analysis, FT-IR spectroscopy, surface area measurements, scanning electron microscopy, transmission electron microscopy and magnetic measurements. The crystallite size of nickel oxide prepared from homogeneous precipitation method is ~ 2 nm whereas that of the nickel oxide prepared from sol-gel process is about 19 nm. The nanocrystalline NiO samples obtained by both the methods exhibit superparamagnetic behavior. Page(s): 586-590

Mineralization of genotoxic Acid Violet 7 by AgBr-ZnO under alkaline conditions using direct sunlight

2016-07-20T04:17:00Z

Title: Mineralization of genotoxic Acid Violet 7 by AgBr-ZnO under alkaline conditions using direct sunlight Authors: Krishnakumar, B; Velmurugan, R; Subash, B; Swaminathan, M Abstract: The photocatalytic degradation of a genotoxic azo dye, Acid Violet 7 (AV 7), using AgBr-ZnO in aqueous solution has been investigated under solar irradiation at pH 12. The photocatalytic activity of AgBr-ZnO is higher than that of bare ZnO (prepared ZnO), commercial ZnO, TiO₂ and Degussa TiO₂-P25 in the degradation of AV 7. Mechanism of degradation by AgBr-ZnO is proposed to explain its higher activity under solar light. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH, cations, anions and oxidants, on photomineralization by AgBr-ZnO have been analyzed. The degradation of AV 7 follows pseudo-first order kinetics according to the Langmuir-Hinshelwood model. Based on the intermediates formed during the photodegradation, a degradation pathway is proposed. The mineralization of AV 7 has also been confirmed by chemical oxygen demand measurements. Page(s): 580-585

Model chemistries of hydrazides. III: SEMO computations of isonicotinic acid hydrazide, its valence isomers and their isopropyl derivatives

2016-07-20T04:14:01Z

Title: Model chemistries of hydrazides. III: SEMO computations of isonicotinic acid hydrazide, its valence isomers and their isopropyl derivatives Authors: Krishna, K Rama; Rao, Ch V Kameswara; Ramam, V Ananta; Rao, R Sambasiva; Rao, M Venkata Subba Abstract: The computational quantum chemistry of isonicotinic acid hydrazide (INH), an antitubercular drug, is studied at SEMO level of theory. AMPAC 6.7 package is employed to invoke six hamiltonians, viz., MNDO, MNDO3, MNDO/C, AM1, PM3 and SAM1, to arrive at the optimized geometries in the gaseous phase. Picolinic acid hydrazide (PAH), a valence isomer of INH, and benzoic acid hydrazide (BAH) without a hetero atom in the aromatic ring and their isopropyl derivatives are also investigated. PAH and INH are found to be more stable as compared to BAH, based on electronic and total energies. However, heat of formation is positive (endothermic) and increases in the order: BAH < INH < PAH. The HOMO concentrates on the hydrazide fragment, while LUMO extends over the ring. The orbital-based interactions are more probable with isopropyl derivatives as FMOs spread on either side. Isopropyl derivatives have higher. (E_LUMO - E_HOMO) and electron affinity values, while ionization potential and hardness have lower values compared to parent compounds. The static dipole moment of INH (1.13 Debye) is substantially increased to 1.87 Debye in isop-INH and to 4.46 Debye in PAH. For INH, the second order hyperpolarizability is higher than that of PAH. The electrophilic centers are the terminal nitrogens of hydrazide fragment and the pyridine nitrogen in INH and PAH. The isopropyl analogues have higher electrophilic character. The 3D-surface and 2-D contours of total electron density (TED) on TED, electrostatic potential (ESP) on TED and ESP on ESP along with Mullikan and ESP charges are analysed. The quantum chemical computed bond characteristics of INH are in agreement with the X-ray crystallographic data. Page(s): 571-579