Paramespri Naidoo

Solubilities of Carbon Dioxide and Oxygen in the Ionic Liquids Methyl Trioctyl Ammonium Bis(trifluoromethylsulfonyl)imide, 1-Butyl-3-Methyl Imidazolium Bis(trifluoromethylsulfonyl)imide, and 1-Butyl-3-Methyl Imidazolium Methyl Sulfate

Ionic liquids (ILs) are being considered as solvents for gas absorption processes as they have the potential, in general, for improved efficiency of gas separations, as well as lower capital and operating costs compared to current commercial processes. In this study the solvent properties of ILs are investigated for use in the absorption of carbon dioxide (CO2) and oxygen (O2). The absorption of these gases in ILs was measured in the temperature range 303.15-333.15 K and at pressures up to 1.5 MPa by gravimetric analysis. The ILs used were methyl trioctyl ammonium bis (trifluoromethylsulfonyl) imide ([MOA][Tf2N]), 1-butyl-3-methyl imidazolium bis (trifluoromethylsulfonyl) imide ([BMIM][Tf2N]), and 1-butyl-3-methyl imidazolium methyl sulfate ([BMIM][MeSO4]). The measurement technique employed in this study is fast and accurate, and requires small quantities of solvent. The results indicated that absorption of both gases increased with a decrease in operating temperature and an increase in pressure. [MOA][Tf2N] had the highest CO2 and O2 solubility. [BMIM][Tf2N] was determined to have the highest selectivity for CO2 absorption. [BMIM][MeSO4] achieved the lowest CO2 absorption with a moderate O2 absorption, revealing this IL to be the least desirable for CO2 and O2 absorption. Calculation of Henrys law constants for all systems confirmed the deductions made from absorption data analysis. Calculation of enthalpy and entropy of absorption for each system revealed CO2 absorption in [MOA][Tf2N] to be the least sensitive to temperature increases. The absorption data was modeled using the generic Redlich-Kwong cubic equation of state (RK-EOS) coupled with a group contribution method.

Can 2-methyl-2-butene and isoprene form clathrate hydrates?

Abstract In order to establish whether 2-methyl-2-butene and isoprene can form hydrates, experimental hydrate dissociation data were measured for the following systems: methane + water, 2-methyl-2-butene + methane + water and isoprene + methane + water. An isochoric pressure search method was used to perform the measurements in the ranges of (274.6 to 288.3) K and (3.25 to 13.35) MPa. The reported results are discussed in terms of the ability of isoprene (2-methyl-1, 3-butadiene) and 2-methyl-2-butene to interfere with methane hydrate dissociation conditions. It is found that the two C5 hydrocarbons are likely not hydrate formers. However, a further confirmation via appropriate analytical tools is recommended.