JOURNAL OF PHYSICAL AND THEORETICAL CHEMISTRY
Year:2011 | Volume:7 | Issue:4|Papers Count:12

Hybrid nanocomposites of binary Pt-Ru/Polyaniline were prepared by oxidative polymerization of aniline and formation Pt and Ru nanoparticles. The polymerization of aniline was carried out in the presence of Potassium hexa cyano Platinate (IV) andRuthenium (III) nitrosyl nitrate as oxidizing agents. During the reaction aniline monomers undergo oxidation and form polyaniline (PANi) whereas the reduction of cations, result the formation of Pt and Ru nanoparticles. Nano-sized Pt and Ru particles were prepared by controlled reduction of precursors in micro emulsion medium, stabilized with the Sodium Dodecyl Sulfate. Micro emulsion solution acts as both emulsifier and dopant to obtain stable nanocomposite. Pt-Ru/PAn nanocomposites are characterized by cyclic voltammetry (CV), FT-IR spectroscopy and scanning microelectronic microscopy (SEM).

In this work, theoretical investigations on carbon nanotube with oxygen atom have been carried out by first-principles calculations and density functional theory and hartree fock theory in 3-21G and 6-31G basis sets. The interaction energy of the oxygen atom to a CNT is calculated. The effects of this substitutions have been investigated on the during transplantation (10, 0) single-walled carbon nanotube with 120 atoms and the effect of method and basis sets have been investigated on the reaction energy. We observe the interaction energy increase with increasing oxygen atoms.

Vapor-phase methylation of toluene using methanol and its isopropylation with 2-propanol has been investigated in a down flow reactor under atmospheric conditions using N2 carrier over a series of surface modified and unmodified ZSM-5 (Si/Al=60–170) loaded with H3PO4, differing in the external surface treatment of the zeolites.The feed molar ratios of toluene/methanol and toluene/2-propanol were varied over a wide range (8–0.125), and the optimum feed ratio of toluene/alcohol was less than 0.5 in both cases. Space velocity employed in toluene methylation reported as WHSV (toluene) =1.2h-1, and the space velocity employed in toluene isopropylation reported as WHSV (toluene) =0.8 h-1. The methylation reactions were carried out in the temperature range of 623–773 K, and the isopropylation reactions were carried out in the temperature range of 483–583 K. Atmospheric pressures was maintained in all runs. Catalysts containing 0–4.9 wt.% P were prepared using modified and unmodified ZSM-5 zeolites, and their catalytic performance for vapor-phase alkylation of toluene with methanol and 2-propanol were investigated. The optimum phosphorous content for methylation was 2.1 wt.% P which was greater than the optimum phosphorous loading for isopropylation (0.7 wt.% P).

New type of heterogeneous nanocatalyst for deoximation based on Tungsten oxide supported on mesoporous molecular sieve MCM-41 was developed. This new system representes inexpensive and highly active heterogeneous nanocatalyst for deoximation under green and mild reaction conditions.

We have performed density functional theory (DFT) calculations to investigate the properties of defect in a representative armchair model of silicon nanotubes (SiNTs). To this aim, the structures of pristine and defective (5, 5) SiNTs have been optimized and the properties such as bond lengths, total energies, binding energies, formation energies, gap energies, and dipole moments have been evaluated for the optimized structures. The results indicate that the evaluated properties could yield the effects of the defect on the properties of pristine SiNT.

TiO2 nanoparticles were synthesized by modified sol–gel method using pure room temperature ionic liquid (RTIL) 2-hydroxyethylammonium formate as a reaction medium. The structure and morphology of TiO2 nanoparticles were characterized with X-ray powder diffraction (XRD), BET surface analysis and scanning electron microscopy (SEM). TiO2 nanoparticles were synthesized in open and closed vessels. The TiO2 nanoparticles prepared in open vessel present only anatase crystal phase after calcination at 500oC but the TiO2 prepared in closed vessel presents anatase and rutile phases after calcination at 500oC. The photocatalytic efficiency decreases with increasing of ethanol and water as molecular solvent in preparation step of nanoparticles. The degradation percent can reach over 97% at the optimal catalyst concentration (2.0 g/L) in 120 minutes irradiation.

Transesterification, one of the most effective methods for ester synthesis, is usually conducted under acid or basic conditions. Although quite a few methods have been reported for transesterification, they are not general as far as b-ketoesters are concerned. Some of these methods used toxic, expensive reagents and in relatives large amount. In this research, transesterification reaction six types b-ketoesters achieved in present of Cu powder and Cu nanoparticles as catalyst and b-ketoesters prepared using this method. Copper Nanoparticles is an efficient catalyst for the transesterification of b-ketoesters with several kinds of alcohols, leading to good yields with high selectivity.

In this study, a series of laboratory tests were conducted to investigate the efficiency of hydroxyapatite (HAP) nanopowders towards adsorption of lysozyme from aqueous solution. In the present research, HAP nanopowders synthesized from egg-shell characterized using SEM and FT-IR. The adsorption of lysozyme was 1 mg/mL using 0.1 g adsorbent in 100 mL of lysozyme solution. Adsorption data were fitted to a linearly Langmuir isotherm.Thermodynamics parameters were also calculated to study the effect of temperature on adsorption process. An adsorption kinetic study revealed that the adsorption process followed first order kinetics.

An azobenzene bridge was introduced into the lower (or smaller) rim of p-tert-butylcalix [8] arene to form 1, 5-singly bridged calix [8] arene derivatives, respectively. Bridged calix [8] arene of conformationally rigid were isolated. The stability of the two structures of bridged calix [8] arenes have been compared.The study of organic structure to form nanoporous structures is a well known in chemistry phenomena to finding crystal structure of calix [8] arene as supramolecular chemistry. The effect of hydrogen bonding on calix [8] arene was reported at Density Functional Theory by Gaussian 98 of program package. The self assembled nanotubes in solid state through network hydrogen bonds between the chains of this structure were investigated.

Single walled nanotubes (SWNT) are common interested nanovehicle to make biosensors more sensitive.Carbon nanotubes (CNTs) have many distinct properties make them to be exploited to develop the next generation of such nano sensors.The Keto-Enol tautomerization is one of the most common investigated subjects of isomerism in this regards, sensors are devices that are able to detect and change the physical properties of such reactions to measurable electrical signal. Some chemicals with the properties to do Keto-Enol tautomerization are substituted to CNTs and the physico chemical properties are simulated. Hyperchem is used as main software to design the CNT Sensor and the main physical properties are calculated after monte carlo simulation. The systems have been optimized at first by UFF method. In all situation the energy minimization have been done by MM+ and the fully optimized systems have transferred to Guassian98, after final optimization with 6-31G, HF method. The stability, electrical changes and physico chemical properties were calculated and compared to find in which situation Caffeic Acid and SWNT have the most stability state.