Highly recyclable, imidazolium derived ionic liquids of low antimicrobial and antifungal toxicity: A new strategy for acid catalysis

Abstract

Imidazolium derived ionic liquid catalysts have been developed which are aprotic and of low antimicrobial and antifungal toxicity, yet which can act as efficient Brønsted acidic catalysts in the presence of protic additives. The catalysts can be utilised at low loadings and can be recycled 15 times without any discernible loss of activity.Over the last decade Ionic Liquids (ILs) have been extensively investigated as potential replacements for volatile organic compounds for use as (inter alia) both tunable reaction media and catalytic solvents.

Brønsted acids in ionic liquids: how acidity depends on the liquid structure

“…[33][34][35][36] HNTf 2 33 Li[NTf 2 ] (1.00 mol eq.) and sulfuric acid, (3.00 mol eq.,) were placed in a cylindrical Kugelrohr flask and fixed to a Kugelrohr distillation apparatus.…”

Comparison of Phytotoxicity of Selected Phosphonium Ionic Liquid

“…With reference to this problem, along with scientific reports on the synthesis, physical and chemical properties and the potential for practical utilization of ionic liquids, a large number of studies have come up, which are concerned with the examination of the potential toxicity of these substances. Studies described in available literature reveal varied influences of ionic liquids on microorganisms [1,2,[17][18][19][20][21][22], plankton [21,[23][24][25][26], invertebrates [27][28][29], vertebrates [27,30], algae [2,21,23,29,[31][32][33], fungi [19,34,35] or higher land plants [8,21,31,[36][37][38][39]. The quoted literature shows that a likely toxic influence of a ionic liquid is determined by a number of factors, of which the primary role is played the cation type and the length of the substituent in the cation (as a rule, the longer alkyl chain, the higher toxicity).…”

Safer and Greener Catalysts – Design of High Performance, Biodegradable and Low Toxicity Ionic Liquids

“…Novel ionic liquids have been extensively prepared and used in organic synthetic applications, but only few research groups have published complementary toxicity and biodegradation data to support its environmental impact. [69,104,113] Connon and co-workers reported an application of pyridinium salts as an effective catalyst in acetalisation reactions. [114][115][116] Ester group substitution at either the 3 or both 3 and 5 positions of the pyridinium ring displayed excellent catalytic activity with very low catalyst loading in the acetalisation of benzaldehyde with methanol.…”

“…On the basis of previous findings, Gathergood, Connon and co-workers reported the design, synthesis and application of imidazolium ionic liquid catalysts in acetalisation reactions. [113] A range of ester and amide side chain imidazolium ionic liquids was prepared. The catalytic activity of all of these imidazolium salts was evaluated in the acetalisation of benzaldehyde in methanol (Scheme 15).…”