Measurements of Binary Diffusion Coefficients in Supercritical Carbon Dioxide

Abstract

Copyright: © 2014 Kong CY. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. A supercritical fluid (SCF) is an adjustable solvent which is reached at a temperature and pressure higher than its critical point. It can diffuse through solids like a gas, and dissolve materials like a liquid. In addition, close to the critical point, small changes in pressure or temperature result in large changes in density or viscosity, allowing many properties to be tuned. SCFs are suitable as a substitute for organic solvents in a range of industrial processes. Furthermore, there is no surface tension in a SCF, as above the critical temperature there is no phase transition. The applications of SCF is still expanding in the fields of extraction [1,2], food [3], pharmaceutical [4,5], material [6-8] and chemical reaction [9]. The quantitative knowledge of mass transport phenomena such as diffusion coefficients of various compounds in SCF is of considerable important in the design and efficient operation of the newly proposed SCF processes. Experimental methods, compounds and SCFs employed to determine the diffusion coefficients are highlighted in this editorial.