Oils of vegetable origin are of great importance in food, soap, and cosmetic industries and they may also be used as lubricants and raw materials for biodiesel production depending on their viscosity and thermal stability. This work provides insight into the fatty acid components, physicochemical properties and thermal stability of some refined vegetable oils. The Saponification values, peroxid...

A mixed proton–electron conducting perovskite was synthesized by liquid-citrate method and the corresponding membrane was prepared by pressing followed by sintering. The hydrogen permeability of BaCe0.9Yb0.1O3-δ was studied as a function of temperature and hydrogen partial pressure (PH2) gradient. Using 100% dry hydrogen at 1173 K, the hydrogen permeation rate of dense membranes (1.63 mm thick)...

the aim of this paper is to study the kinetic study carbonylation of methanol using of the homogeneous rhodium catalyst and ch3i as the promoter in acid media based on monsanto process. the reaction was carried out in liquid media in the constant pressures 20,28 and 40 atm. and temperatures 170 to185oc, espect to the  initial  reactant concentrations and co pressure.  it was identified that the...

the kinetics and mechanism of the reaction of 5-nitro-1h-benzo[d] imidazole to produce 6-nitro-1h-benzo[d] imidazole was studied by employing hybrid meta-density functional theory. mpwblk/6-31+g** level calculations were carried out to obtain energies and optimize the geometries of all stationary points along the pes, and determine the harmonic vibrational frequencies. two transition states (ts...

In heterogeneous catalysis, rates with Arrhenius-like temperature dependence are ubiquitous. Compensation phenomena, which arise from the linear correlation between the apparent activation energy and the logarithm of the apparent pre-exponential factor, are also common. Here, we study the origin of compensation and find a similar dependence on the rate-limiting surface coverage term for each Ar...

The H/D primary kinetic isotope effect (KIE) for the hydride transfer reaction catalyzed by Escherichia coli dihydrofolate reductase (ecDHFR) is calculated as a function of temperature employing ensemble-averaged variational transition-state theory with multidimensional tunneling. The calculated KIEs display only a small temperature dependence over the temperature range of 5 to 45 degrees C. We...

The kinetics and mechanism of the reaction of 5-nitro-1H-benzo[d] imidazole to produce 6-nitro-1H-benzo[d] imidazole was studied by employing hybrid meta-density functional theory. MPWBlK/6-31+G** level calculations were carried out to obtain energies and optimize the geometries of all stationary points along the PES, and determine the harmonic vibrational frequencies. Two transition states (TS...

Self-diffusion coefficient measurements were performed for pure n-alkyl ketone liquids using the pulsed field gradient NMR spin-echo technique. Ionic conductivities and dielectric constants of 0.0055 mol·L-1 tetrabutylammonium trifluoromethanesulfonate in 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, and 2-decanone were also measured. The temperature-dependent conductivities and...

in this research the drying of four kinds of vegetables was investigated in a vacuum dryer. the effect of temperature on drying rate of samples at various temperatures (30, 35 and 45 °c) was studied. six thin-layer drying models were fitted to drying data and suitable model was selected from them. then effective moisture diffusivity and activation energy of samples were calculated. the diffusio...

In the present work, the effective moisture diffusivity and activation energy were calculated using an infinite series solution of Fick’s diffusion equation. The results showed that increasing drying temperature accelerated the drying process. All drying experiments had only falling rate period. The average effective moisture diffusivity values varied from 2.807x10 to 6.977x10m s over the tempe...