Basic Ionic Liquid Gels for Catalysis: Application to the Hydrogen Borrowing Mediated Dehydration of 1,3-Propanediol

Abstract

The application of basic ionic liquid gels (BILGs) as recyclable promoters of hydrogen borrowing chemistry was investigated. The hydrogen transfer initiated dehydration of 1,3-propanediol to propanal was catalysed by a [Cp*IrCl2(NHC)] complex promoted by BILGs containing [P6,6,6,14][OH]. Gels comprising a mixture of basic and hydrophobic ionic liquids gave the best results. The reaction proceeded in the ionic liquid [C2mmim][NTf2] enabling the continuous removal of propanal under reduced pressure. Tuning of the composition of the BILG led to a catalytic system that exhibited excellent conversion, selectivity and good recyclability.

Highly biodegradable, thermostable eutectogels prepared by gelation of natural deep eutectic solvents using xanthan gum: preparation and characterization

“…Hydrogels, as a typical type of gel, are extensively applied to the elds of biomedicine and chemistry, 11,12 and ionic gels formed from ionic liquids also have important applications in many elds. [13][14][15] Similarly, since NADESs can be considered as excellent extraction media and delivery systems for bioactive compounds and enzymes, although recent research is still in its infancy, NADES-based gels are expected to have wide application potential in food and medicine. 16 Besides, from the perspective of cell biology, since NADES is presumed to be a possible third liquid in biological cells other than water and oil, 4,17 and as the gel nature of cytoplasm is increasingly recognized, 18,19 the study of gels based on NADES will help to enhance the understanding of cellular metabolism in biological systems.…”

Basic ionic liquids for catalysis: the road to greater stability

“…Further work by Marr, Marr, and co-workers employed the binary approach (Section 3.1) to stabilise the basic ionic liquid gels and enable catalytic applications of basic ionic liquid gels. 111…”

“…McNeice et al built upon the basic ionic gel process described above 103,111 to incorporate Fe-TAML, a biomimetic peroxide activator, 114 within a basic ionic liquid gel for water purification (Figure 26). 115 These soft basic materials provided a protective environment and a more optimum pH for Fe-TAML operation.…”

“…The hydrogen transfer initiated dehydration of 1,3-propanediol promoted by a basic ionic liquid gel 111. …”

Quinine based ionic liquids: A tonic for base instability

“…DMAP ionic liquids have reduced basicity due to withdrawal of electron density from the Lewis base by the cation [7,8]. We have previously had some success stabilising basic ionic liquids by using binary ionic liquids containing small amounts of alkoxide anions [9], and by heterogenising phosphonium hydroxide ionic liquids within silica and titania gels via the sol-gel process [10,11]. This manuscript focusses on a third approach, the use of quinine derived cations.…”