A quantum-chemical study of the mechanism of transesterification reaction carried out in the traditional and supercritical fluid (SCF) conditions has been performed. Samples of biodiesel fuel have been derived from ra...A quantum-chemical study of the mechanism of transesterification reaction carried out in the traditional and supercritical fluid (SCF) conditions has been performed. Samples of biodiesel fuel have been derived from rapeseed oil in the environment of supercritical ethanol using a flow type unit, both in the absence and in the presence of heterogeneous catalysts-metal oxides. Experimental studies of kinematic viscosity of a large array of samples of derived biodiesel have been performed. The viscous correlation allowing determining the content of the desired product-fatty acid ethyl esters (FAEE)-in biodiesel samples, has been made based on the obtained experimental data on the kinematic viscosity of biodiesel samples. The influence of change of the dielectric permittivity of working environments on the rate of reaction of transesterification in the supercritical fluid conditions has been revealed.展开更多
The paper deals with the performing of a critical analysis of the problems arising in matching the classical models of the statistical and phenomenological thermodynamics. The performed analysis shows that some concep...The paper deals with the performing of a critical analysis of the problems arising in matching the classical models of the statistical and phenomenological thermodynamics. The performed analysis shows that some concepts of the statistical and phenomenological methods of describing the classical systems do not quite correlate with each other. Particularly, in these methods various caloric ideal gas equations of state are employed, while the possibility existing in the thermodynamic cyclic processes to obtain the same distributions both due to a change of the particle concentration and owing to a change of temperature is not allowed for in the statistical methods. The above-mentioned difference of the equations of state is cleared away when using in the statistical functions corresponding to the canonical Gibbs equations instead of the Planck’s constant a new scale factor that depends on the parameters of a system and coincides with the Planck’s constant in going of the system to the degenerate state. Under such an approach, the statistical entropy is transformed into one of the forms of heat capacity. In its turn, the agreement of the methods under consideration in the question as to the dependence of the molecular distributions on the concentration of particles, apparently, will call for further refinement of the physical model of ideal gas and the techniques for its statistical description.展开更多
文摘A quantum-chemical study of the mechanism of transesterification reaction carried out in the traditional and supercritical fluid (SCF) conditions has been performed. Samples of biodiesel fuel have been derived from rapeseed oil in the environment of supercritical ethanol using a flow type unit, both in the absence and in the presence of heterogeneous catalysts-metal oxides. Experimental studies of kinematic viscosity of a large array of samples of derived biodiesel have been performed. The viscous correlation allowing determining the content of the desired product-fatty acid ethyl esters (FAEE)-in biodiesel samples, has been made based on the obtained experimental data on the kinematic viscosity of biodiesel samples. The influence of change of the dielectric permittivity of working environments on the rate of reaction of transesterification in the supercritical fluid conditions has been revealed.
文摘The paper deals with the performing of a critical analysis of the problems arising in matching the classical models of the statistical and phenomenological thermodynamics. The performed analysis shows that some concepts of the statistical and phenomenological methods of describing the classical systems do not quite correlate with each other. Particularly, in these methods various caloric ideal gas equations of state are employed, while the possibility existing in the thermodynamic cyclic processes to obtain the same distributions both due to a change of the particle concentration and owing to a change of temperature is not allowed for in the statistical methods. The above-mentioned difference of the equations of state is cleared away when using in the statistical functions corresponding to the canonical Gibbs equations instead of the Planck’s constant a new scale factor that depends on the parameters of a system and coincides with the Planck’s constant in going of the system to the degenerate state. Under such an approach, the statistical entropy is transformed into one of the forms of heat capacity. In its turn, the agreement of the methods under consideration in the question as to the dependence of the molecular distributions on the concentration of particles, apparently, will call for further refinement of the physical model of ideal gas and the techniques for its statistical description.
