Configurational-bias Monte Carlo simulations in the Gibbs and isobaric-isothermal ensembles using the transferable potentials for phase equilibria force field were carried out to investigate the thermophysical properties of mixtures containing supercritical carbon dioxide and methanol. The binary vapor-liquid coexistence curves were calculated at 333.15 and 353.15 K and are in excellent agreement with experimental measurements. The self-association of methanol in supercritical carbon dioxide was investigated over a range of temperatures and pressures near the mixture critical point. The temperature dependence of the equilibrium constants for the formation of hydrogen-bonded aggregates (from dimer to heptamer) allowed for the determination of the enthalpy of hydrogen bonding, DeltaHHB, in supercritical carbon dioxide with values for DeltaHHB of about 15 kJ mol(-1) falling within the range of previously proposed values. No strong pressure dependence was observed for the formation of aggregates. Apparently the decrease of the entropic penalty and of the enthalpic benefit upon increasing pressure or solvent density mostly cancel each other's effect on aggregate formation.

Download full-text PDF

Source
http://dx.doi.org/10.1063/1.1763842DOI Listing

Publication Analysis

Top Keywords

supercritical carbon
16
carbon dioxide
16
methanol supercritical
8
monte carlo
8
binary phase
4
phase behavior
4
behavior aggregation
4
aggregation dilute
4
dilute methanol
4
supercritical
4

Similar Publications

Preparation of curcumin submicron particles by supercritical antisolvent method with external adjustable annular gap nozzle.

Sci Rep

January 2025

Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Ministry of Education), National Demonstration Center for Experimental Mechanical Engineering Education (Shandong University), School of Mechanical Engineering, Shandong University, Jinan, 250061, People's Republic of China.

The supercritical antisolvent (SAS) method can effectively improve the bioavailability of poorly water-soluble drugs. However, the current supercritical equipment and processes were not fully developed, making industrialization difficult to achieve. Therefore, an externally adjustable annular gap nozzle and its supporting equipment were designed.

View Article and Find Full Text PDF

Awakening n-π* electron transition in structurally distorted g-CN nanosheets via hexamethylenetetramine-involved supercritical CO treatment towards efficient photocatalytic H production.

J Colloid Interface Sci

January 2025

International Research Center for Renewable Energy (IRCRE), State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University (XJTU), Xi'an 710049 PR China.

Graphitic carbon nitride (g-CN) has been regarded as highly potential photocatalyst for solar energy utilization. However, the restricted absorption of visible light for pristine g-CN significantly limits the solar-light-driven chemical reaction efficiency. Herein, structurally distorted g-CN nanosheets with awakened n-π* electron transition were successfully synthesized through hexamethylenetetramine (HMTA)-involved supercritical CO (scCO) treatment and following pyrolysis of melamine precursor.

View Article and Find Full Text PDF

One-step high-pressure and high-temperature direct aqueous mineral carbonation of tailings derived from mining of Platinum Group Metals in South Africa requires a fundamental understanding of the reactivity of the most dominant mineral phases, i.e. pyroxene and plagioclase (66 wt.

View Article and Find Full Text PDF

Ensuring long-term wellbore integrity is critical for carbon dioxide geological storage. Ordinary Portland cement (PC) is usually used for wellbore primary cementing and plug operation, and set cement is easily corroded by acidic fluids, such as carbon dioxide, in underground high-temperature and high-pressure (HTHP) environments, resulting in a decrease in the mechanical properties and an increase in permeability. In order to achieve long-term wellbore integrity in a CO-rich environment This study introduces materials such as thermosetting vinyl ester resin (TSR), filler composite resin (FCR), and low-cost resin cement (RC).

View Article and Find Full Text PDF

Using the Ordos Basin dry sandstone and sandstone saturated with different saline concentrations as research subjects, a self-developed constant temperature and pressure CO2 injection simulation device was employed to conduct permeability tests on sandstone under varying effective stresses and CO2 injection pressures. The test results indicated that during the CO2 injection process, the permeability of dry sandstone was two orders of magnitude higher than that of sandstones saturated with different saline concentrations. When the effective stress increases from 10 MPa to 28 MPa, the fissure compressibility of reservoir sandstone is influenced by the saturation of different saline concentrations, with the compressibility coefficients for 0%, 15%, and 30% saline-saturated sandstone being 0.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!