Solubility of CO2 in CO2-philic oligomers; COSMOtherm predictions and experimental results

The solubility of low molecular weight Poly(Dimethyl siloxane) in dense CO2 and its use as a CO2-philic segment

“…A CO 2 -rich vapor phase and a PDMS-rich liquid phase co-exist below these bubble point loci (V-L region of Figure 1). At higher PDMS concentrations (not shown in Figure 9), the bubble point curves would decrease until the vapor pressure of the silicone oil was attained at a concentration of 100% PDMS (Figure 1), as shown in our prior studies for a mixture of CO 2 and low molecular weight PDMS at 25°C [30,49]. For mixtures containing PDMS with an average molecular weight of 2000 or more at 23°C, a CO 2 -rich liquid and a PDMS-rich liquid are in equilibrium (L 2 -L 1 ) at pressures below the cloud point loci, Figures 3 and 9.…”

“…Pressure-composition data at 35°C, Figure 7, mixtures (see Figure 2), remains flat at about 7 MPa. At higher concentrations of PDMS, the bubble point curve would extend to even lower pressures, reaching the vapor pressure of PDMS as its concentration approaches unity [30,49].…”

“…Our group considered PDMS as a pre-combustion CO 2 solvent and presented the entire bubble point curve (0 -100% PDMS) of the two-phase CO 2 -rich vapor -PDMS-rich liquid region (V-L) for mixtures of very low molecular weight PDMS (Mn = 237) and CO 2 at 25°C [29], Figure 1. Our group also measured the CO 2 -rich vapor -PDMS-rich liquid bubble point boundary in the 60 -100% PDMS range for low molecular weight PDMS (Mn = 550) at 25°C, Figure 1, along with the bubble point locus of the CO 2 -rich fluid -PDMS-rich liquid region (F-L) at 40°C [30], Figure 2. There remains a substantial gap in the literature for two-phase boundary pressures for mixtures of CO 2 with low molecular weight PDMS (410 -10000 g/mol), especially at dilute polymer concentrations.…”

“…20 vol.% toluene + 80 vol.% CO 2 ) that is required as a co-solvent is problematic [28]. CO 2 dissolves readily in PDMS, therefore PDMS has been suggested as a pre-combustion CO 2 -selective solvent for the extraction of CO 2 from a warm, gaseous post-water-gas shift reactor stream that also contains hydrogen and water [29,30]. MPa.…”

Isotherms of Fluids in Native and Defective Zeolite and Alumino-Phosphate Crystals: Monte-Carlo Simulations with “On-the-Fly”ab initioElectrostatic Potential

“…The Gibbs excess sorption isotherms of CO 2 in 1, 2, 3 and 4 increase before they drop between 25 and 50 bar when CO 2 becomes liquid. The experimental partial pressure of CO 2 is 64.3 bar at 298 K [31]. The maximum value that is reached in 1 is larger than those in 2, 3 and 4, which are all three rather close.…”