English

Rapid and isothermal (at room temperature) uptake of CO2 by solutions or, in some cases, organogels comprised of a primary or secondary aliphatic amine (1) and an organic liquid leads to in situ chemical transformation to the corresponding alkylammonium alkylcarbamate (2) based gels. Chemical reversibility is demonstrated by removal of CO2 from 2-based gels upon gentle heating in the presence of nitrogen. This is a general strategy for reversible self-assembly or disassembly of molecular aggregates relying on the initiation or termination of ionic interactions.

Fifteen different low molar mass compounds are assessed as CO2 solvents based on bubble-point loci on the solvent-rich end (0.6 to 1.0 solvent wt fraction) of the CO2-solvent pressure−composition diagram at 298.15 K. Four of the five best solvents (in descending order of solvent strength on a mass fraction CO2 dissolved basis), acetone, methyl acetate, 1,4-dioxane, and 2-methoxyethyl acetate, are oxygen-rich, low molar mass species possessing one or more oxygen atoms in carbonyl, ether, and/or acetate groups that can interact favorably with CO2 via Lewis acid/Lewis base interactions.

Solubility of CO2 and N2O in Twelve Solvents, 18° to 36° C.-Since according to the Lewis-Langmuir theory these two gases have similar molecular structures, it is of interest to compare their solubilities in various liquids. In the method adopted, the air was thoroughly removed from the solvent by boiling and then the gas to be tested, having been carefully purified with the help of liquid air, was admitted and shaken up with the solvent until no further solution took place. Observations accurate to better than one per cent.

Imagine a smart solvent that can be switched reversibly from a liquid with one set of properties to another that has very different properties, upon command. Here we create such a system, in which a non-ionic liquid (an alcohol and an amine base) converts to an ionic liquid (a salt in liquid form) upon exposure to an atmosphere of carbon dioxide, and then reverts back to its non-ionic form when exposed to nitrogen or argon gas. Such switchable solvents should facilitate organic syntheses and separations by eliminating the need to remove and replace solvents after each reaction step.

In recent years, carbon dioxide (CO2) has proven to be an environmentally friendly foaming agent for the production of polymeric foams. Until now, extrusion is used to scale-up the CO2-based foaming process. Once the production of large foamed blocks is also possible using the CO2-based foaming process, it has the potential to completely replace the currently used foam production process, thus making the world-wide foam production more sustainable.

The effects of substituents at the alpha-carbon atom on the donor properties of primary amines and amino alcohols have been studied. Such substituted amino species have important applications in industrially relevant gas separation processes. Qualitative molecular orbital arguments, along with detailed calculations at the MNDO level of theory, show that upon methyl substitution at the alpha-carbon atom the interaction of the methyl group properties of the amino species. Infrared spectroscopic data supporting the calculations are also described.

The basicity of several basic ionic liquids is studied quantitatively for the first time, and the basicity of the ionic liquids can be switched repeatedly by bubbling CO2 and N2 through the solution alternately.