نتایج جستجو برای: microwave heated polyol method
تعداد نتایج: 1688863 فیلتر نتایج به سال:
Zeolites are nanoporous crystalline alumino-silicates with a rich variety of interesting properties and industrial applications. With over 140 zeolite framework topologies synthetically available—each with its own range of compositions—zeolites offer size-, shapeand electrostaticallyselective adsorption, diffusion and reaction up to remarkably high temperatures. Zeolites are widely used as petr...
Electron paramagnetic resonance (EPR) spectroscopy was used for examination of free radicals in thermally treated vaselinum album (VA). Thermal treatment in hot air as sterilization process was tested. Conditions of thermal sterilization were chosen according to the pharmaceutical norms. Vaselinum album was heated at the following conditions (T--temperature, t--time): T = 160°C and t = 120 min,...
The purpose of this study was to evaluate the occurrence of lipid oxidation in peanut (Arachis hypogaea L) seeds which were heated by microwave irradiation. Peanut seeds were exposed to microwaves for 0, 2.5, 3.5, 4.5, 5.5 and 6.5 min at frequency of 2,450 MHz, 450 watts microwave oven. The quality characteristics of peanut seed (moisture content and color values), extracted peanut oils (PV, TB...
Hydrogen peroxide was encapsulated into a silica xerogel matrix by the sol-gel technique. The composite was tested as an oxidizing agent both under conventional and microwave conditions in a few model reactions: Noyori's method of octanal and 2-octanol oxidation and cycloctene epoxidation in a 1,1,1-trifluoroethanol/Na2WO4 system. The results were compared with yields obtained for reactions wit...
Nickel–zinc ferrites are some of the most interesting soft magnetic materials. They have been extensively used in a number of electronic devices because of their low magnetic coercivity, low eddy current related to their high electrical resistivity, and they are especially suitable for high–frequency applications (large permeability). New low-temperature synthesis methods have been developed to...
A fast one-pot method has been developed for the direct preparation of 3-aryl-1,2-cyclohexanediones from 2,3-epoxycyclohexanone via a microwave-assisted tandem epoxy ketone isomerization-Heck arylation reaction. The preparative microwave-assisted reactions were performed preferentially in 50% aqueous poly(ethylene glycol) utilizing sodium acetate as the base. Within 5-30 min of directed microwa...
Temporary superheating and sustained nucleation-limited "superboiling" of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating) and magnitude (of superheating and superboiling) vary according to system parameters such as volume of the l...
In the present investigation, the oxidizing roasting process of chromite with sodium carbonate to prepare potassium dichromate crystals was studied in the microwave field with air, by heating the chromite and sodium carbonate. The chromite and sodium carbonate heated separately at 1000 ◦C in the microwave oven (frequency: 2.45 GHz; power 1.5 kW) in order to study the microwave absorption proper...
We demonstrate the use of microwave radiation as a tool to accelerate the formation of perfluoroalkylsilane based self-assembled monolayers (SAMs) on silicon oxide surfaces. Surface coverage of these SAMs of monoreactive perfluoroalkylsilanes increased in proportion to the duration over which the solutions were heated by microwave radiation.
Ru/Al2O3 catalysts were prepared by conventional incipient wetness impregnation as well as colloid deposition of RuCl3 precursor via in situ reduction with ethylene glycol (polyol) method on alumina support. The samples were characterized by TEM, XRD and TPR techniques. The catalytic performance tests were carried out in a fixed-bed micro-reactor under diffe...
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