Trichlorocarbanilide has widely been used in cosmetics and household products, but the extremely low solubility of trichlorocarbanilide in water constrains the development of water-based products. In order to enhance the bioavailability, trichlorocarbanilide were micronized using supercritical fluid. Supercritical carbon dioxide was selected due to relatively low critical temperature and the ra...

Water is not restricted to moderate temperatures and low pressures, but can exist up to very high temperatures, far above its critical point at 647 K. In this supercritical regime, water can be gradually compressed from gas-like to liquid-like densities. The resulting dense supercritical states have extraordinary properties which can be tuned by temperature and pressure, and form the basis for ...

Hydrogen is an important chemical in many industries and it is expected to become one of the major fuels for energy generation in the future. Unfortunately, hydrogen does not exist in its elemental form in nature and therefore has to be produced from hydrocarbons, hydrogen-containing compounds or water. Above its critical point (374.8C and 22.1MPa), water has lower density and viscosity, and a ...

A novel pretreatment method has been developed for determination of toxic metals in plastic materials by their decomposition under supercritical water conditions. Particularly, quantitative analysis of cadmium in polyethylene has been demonstrated using inductively coupled plasma atomic emission spectrometry combined with supercritical water treatment. All the cadmium in a polyethylene sample w...

The nature and extent of hydrogen bonding in water has been scrutinized for decades, including how it manifests in optical properties. Here we report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of subcritical and supercritical water. For subcritical water, the spectrum redshifts considerably with increasing temperature, demonstrating the gradual breakdown of the ...

A measuring method for the distribution behavior between supercritical carbon dioxide and water by a microchip was developed. A surface modification of the microchannel by dichlorodimethylsilane induced a spontaneous phase separation of the supercritical carbon dioxide and aqueous phases in the microchip. The maximum contact time of the aqueous phase to the supercritical carbon dioxide phase wa...

The solvation shell dynamics of supercritical water is analyzed by molecular dynamics simulation with emphasis on its relationship to the translational and rotational dynamics. The relaxation times of the solvation number (tau S), the velocity autocorrelation function (tau D), the angular momentum correlation function (tau J), and the second-order reorientational correlation function (tau 2R) a...

The nuclear isotropic shielding constants sigma((17)O) and sigma((13)C) of the carbonyl bond of acetone in water at supercritical (P=340.2 atm and T=673 K) and normal water conditions have been studied theoretically using Monte Carlo simulation and quantum mechanics calculations based on the B3LYP6-311++G(2d,2p) method. Statistically uncorrelated configurations have been obtained from Monte Car...

The structure and properties of supercritical water is investigated in relation to the energy and environmental issues of the 21 century. Molecular interpretations are given to the temperature dependence of the hydrogen-bonding structure, dynamics, and chemical reactions of supercritical water. The three-dimensional network structure, characteristic of ambient water, is broken down in hot expan...

A new and economically attractive type of geothermal resource was recently discovered in the Krafla volcanic system, Iceland, consisting of supercritical water at 450 °C immediately above a 2-km deep magma body. Although utilizing such supercritical resources could multiply power production from geothermal wells, the abundance, location and size of similar resources are undefined. Here we prese...