Modeling of supercritical extraction of mannitol from plane tree leaf.

The objective of this study was to investigate the theoretical feasibility of using supercritical fluid extraction of Mannitol from plane tree leaf as an alternative technology in the pharmaceutical industry. Simulation of an extraction column using dense liquid and supercritical carbon dioxide was modeled involving partial differential equations, using orthogonal collocation on finite elements. The important solvent extraction parameters such as the partition coefficient, mass transfer coefficient, dispersion coefficient, molecular diffusion and extraction efficiency (the amount of Mannitol extracted versus the amount of solvent used) were investigated as a function of the dimensionless Reynold's and Peclet numbers in order to optimize the extraction column geometry and the carbon dioxide operating conditions. The results of this study demonstrated that supercritical extraction is a viable technique for Mannitol production and that the process conditions for a large commercial extraction system do not require a high temperature in order to obtain a high extraction efficiency. However, at low pressures, the solubility of Mannitol in carbon dioxide would limit the success of the extraction process and at very high pressures the extraction technique may not be economically feasible. To investigate the authenticity of the mathematical model, the experimental data for the desorption of hexachlorobenzene from soil was compared with the theoretical results of this research. The model is able to predict the experimental data quite well without any adjustable parameters.