Effect of Co-solvent and Pressure on the Thermal Decomposition of 2,2′Azobis-(isobutyronitrile) in Supercritical CO_2

The thermal decomposition of 2, 2'-azobis (isobutyronitrile) (AIBN) in supercritical CO2 with cosolvent methanol or cyclohexane has been studied by using UV/Vis spectroscopic method at 335.15 K and at 12.0 MPa and 14.0 MPa. Both of the cosolvents can accelerate the decomposition rate, and the effect of methanol is more significant than that of the cyclohexane.

Cosolvent Effect on the Tautomerism of Ethyl Acetoacetate in Supercritical CO_2

The effect of cosolvent cyclohexane, chloroform, and acetonitrile on the keto-enol tautomeric equilibrium of ethyl acetoacetate in supercritical CO2 was studied by UV-Vis spectroscopy over the pressure range from 76 to 110 bar at 308.15 K. It was found that the equilibrium constant decreases with increasing polarity of the cosolvents.

Effect of Dissolved CO_2 on Protein Solubilization in Reverse Micelle

Effect of dissolved CO2 on bovine serum albumin (BSA) solubilization in the reverse micelles of sodium bis (2-ethylhexyl) sulfosuccinate (AOT) in 2,2,4-trimethylpentane (iso-octane) has been studied at 308.2 K. It was found that BSA can be precipitated completely by CO2 while the AOT and water remain in the iso-octane continuous phase. This opens up a possibility for recovery of pure protein solids directly from reverse micellar solutions.

Effect of Molecular Size of Solutes on Their Partial Molar Volumes in Supercritical n-Pentane

The densities of n-pentane, methane-n-pentane, propane-n-pentane, n-heptane-n-pentane, and n-decane-n-pentane binary mixtures were determined at 476.5K in the pressure range from 2 to 5 MPa. The partial molar volumes of the solutes in n-pentane were calculated using the density data. It was found that the partial molar volumes of methane and propane are positive, while those of n-heptane and n-decane are negative.