Propane + CO2 mixtures as near critical solvents, properties and mixture design
Sustainable process-product development & green chemistry
Selection & Use of Organic Solvents (T1-7)
Keywords: SCF solvents, carbon dioxide, propane, extraction, vegetable oils
The use of mixtures of propane + CO2 for the extraction of natural products can offer special properties regarding solvent power, selectivity and safety. For the case of extraction of vegetable oils from grounded seeds, previous studies have shown that it is possible to obtain complete miscibility of the vegetable oil with the propane + CO2 mixture keeping the mixture below the flammability limits. A strategy for mixture design at different temperatures to comply with the requirements of complete miscibility and non flammability is presented, on the basis of the phase equilibrium properties of the mixtures of vegetable oils + propane + CO2. The predictions are based on an extended version of the Group Contribution Equation of State. The solvent properties of mixtures of CO2 + Propane for the extraction of grounded seed were studied for the extraction of soy oil, sunflower oils and hiprose oil. In a previous work was observed a reduction in mass transfer rate at increasing CO2 concentrations, even in the complete miscibility region. This behaviour is explained in the present work on the basis of the nonideality effects on the effective diffusion coefficients and a mass transfer model for the extraction experiments based on transient diffusion phenoma is presented to quantify the observed experimental results.
Presented Tuesday 18, 09:25 to 09:45, in session Selection & Use of Organic Solvents (T1-7).
