The amphiphilic nanostructure of ionic liquids affects the dehydration of alcohols

Abstract

The effect of the amphiphilic nanostructure of ionic liquids has been investigated on the dehydration of secondary alcohols to alkenes. The influence of these nanostructures was inverted when an acid...

Gold(I)-Catalyzed Direct Alkyne Hydroarylation in Ionic Liquids: Mechanistic Insights

“…This heterogeneity has been experimentally verified in several cases, including imidazolium-based ILs: in particular, ILs involving the BMIM cation invariably exhibit such a microphase separation [35]. This microheterogeneous nature, which is often maintained also upon dilution with conventional liquid reagents/solvents [36], has obvious consequences in the preferential solvation of solutes by either of the two domains, and consequently on reactions carried out in these solvents: very recently, an example has been highlighted, in which changing from a [BMIM][NTf 2 ] to a [BMIM][OTf], as in our case, leads to a complete shutdown of reactivity, which has been explained in terms of the different properties of the microdomains of the IL in the two cases [37]: OTf − , which is a stronger hydrogen bond acceptor compared to NTf 2 − (Table 1), engages in stronger hydrogen bond interactions with the BMIM cation (which acts as an H-bond donor through its C-H moiety in the 2-position) producing polar microdomains with different properties. This influences the partition of the substrate between polar and apolar microdomains and consequently its reactivity.…”

Small-Angle X-ray Scattering Study of the Amphiphilic Bulk Nanostructure of Tetraalkylammonium Deep Eutectic Solvents

“…ILs consisting of at least one sufficiently amphiphilic ion tend to develop a bicontinuous sponge-like nanostructure comprising polar and nonpolar domains. − These nanostructures arise from the strong electrostatic interactions between the charged moieties of the IL cation and anion, often reinforced by hydrogen bonding, forming a polar domain which solvophobically excludes the longer alkyl chains into a separate nonpolar region. − These percolating polar and nonpolar domains in the bulk have been attributed to some of the physicochemical properties of ILs, including their potential to dissolve both polar and nonpolar solutes . These nanostructures can lead to preferential partitioning and varied local solvation effects on reactants, transition states, or products, thus affecting organic reactivity and reaction rates. − The bulk liquid nanostructure of these ILs also impacts its nanostructure at solid interfaces. The ability to tailor this interfacial nanostructure provides greater control over boundary friction, making ILs an interesting choice for use as lubricants and other surface-coating applications. − …”