Lipase-catalyzed enantioselective esterification of glycidol in supercritical carbon dioxide

Phase equilibria for {2,3-epoxypropanol (Glycidol) + carbon dioxide} fromT= 292 K toT= 343 K at pressures up to 27 MPa

“…Direct comparison with our results cannot be performed because it would require knowledge of the molar volume of the solution. This quantity has not been measured, but can be calculated from the combination of our results and those of Martins et al (2)(3)(4) A subsequent calculation of the excess molar volumes of the solutions was performed. The molar volumes of pure carbon dioxide were taken from the compilation of Angus et al (12) Those of Glycidol were based on the value of 66.76 cm 3 ·mol −1 at T = 298 K, extrapolated to higher pressures and temperatures by means of the compressibility and expansion coefficient of propanol.…”

“…The solubilities of Glycidol in carbon dioxide given by Martins et al (4) were obtained, at T = 308 K, as amount of solute per unit volume solution. Direct comparison with our results cannot be performed because it would require knowledge of the molar volume of the solution.…”

“…dioxide, (4) at the same temperature and p = 14 MPa. They obtained good selectivity (the reaction product in supercritical CO 2 had enantiomeric purity of (80 to 85) per cent at a conversion rate 130 per cent).…”

“…The only results so far published on this system are those of Mei-Shen et al, (5) which describe this three-phase line, and Martins et al (4) which give the solubilities of Glycidol in supercritical CO 2 at T = 308.1 K Several cubic equations of state were fitted to the VLE isotherms, using different mixing and combining rules. Those that better represented, simultaneously, the liquid and vapour phase compositions were proposed by Soave, (6) Mathias,…”

Enzymatic catalysis in cosolvent modified pressurized organic solvents

“…The rate and selectivity of enzymatic reactions in organic solvents may be directly affected by solvent strength (Chaudhary et al, 1996) or influenced by indirect measures of solvent strength including thermodynamic water activity (a w ) and the solubility of the substrate (e.g., Kamat et al, 1993;Martins et al, 1992;Marty et al, 1990;Rantakylä and Aaltonen, 1994;Valivety et al, 1991). Enzymatic catalysis in SCFs exploits the ability to dramatically alter solvent strength with small changes in temperature and pressure in the near-critical region.…”