Multicomponent systems supercritical carbon dioxide

The purposes of our research were to evaluate the feasibility of supercritical carbon dioxide extraction of lemon oil near ambient temperature, generate equilibrium data for carbon dioxide with multicomponent essential oil constituents, and evaluate the ability of the Peng-Robinson equation of state ( ) to model this multicomponent supercritical system. 

In this chapter, the possibihty of using late transition metal catalysts to synthesize polyolefins in supercritical carbon dioxide was demonstrated [43]. The multicomponent phase behavior of polyolefin systems at supercritical conditions was studied experimentally by measuring cloud-point curves as well as by modeling polymer systems at supercritical conditions. The cloud-point measurements show that CO2 acts as a strong antisolvent for the ethylene-PEP system, which implies that the polymerization concerned will involve a precipitation reaction. The model calculations prove that SAFT is able to describe the ethylene-PEP-CO2 system accurately. Solubility measurements of the Brookhart catalyst reveal that the maximum catalyst solubility is rather low (in the order of 1x10 mol L ). However, a number of strategies are given to enhance this value. 

In closing, we would like to mention some applications of the GEMC/CBMC approach and very much related combination of CBMC and the grand canonical Monte Carlo technique to other complex systems prediction of structure and transfer free energies into dry and water-saturated 1-octanol [72], prediction of the solubility of polymers in supercritical carbon dioxide [73], prediction of the upper critical solution pressure for gas-expanded liquids [74], investigation of the formation of multiple hydrates for a pharmaceutical compound [75], exploration of multicomponent vapor-to-particle nucleation pathways [76], and investigations of the adsorption of articulated molecules in zeolites and metal organic frameworks [77, 78]. 

Phase Equilibria. From recent research (Schneider and Peters) it became apparent that in the near-critical region of certain ternary carbon dioxide mixtures, due to co-solvency effects of the two solutes relative to each other, the fluid multiphase behavior can be quite complex. Phenomena like immiscibility windows and holes are not unusual, which have their consequences for separations in near-critical processing. Peters stressed that for many applications in supercritical technology carbon dioxide is not an appropriate choice since for many solutes it is a poor solvent that would require the use of a cosolvents. If safety and environmental constraints permit, it is certainly worthwhile to consider alternatives for carbon dioxide. Gulari, Schneider and Peters emphasized the importance of studying representative model systems in order to obtain insight into the systematic variations of the complex phase behavior that may occur in near-critical multicomponent mixtures. Debenedetti stressed the importance of focusing on complex fluids like emulsions. 

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