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

Abstract

ARTICLEThis journal is © The Royal Society of Chemistry 2013 J. Name., 2013

On the Use of a Protic Ionic Liquid with a Novel Cation To Study Anion Basicity

“…The relationship between acidity and mole fraction of the acids (for the regime where the dominant factor is the anion combination with free acid,0 .5 < c < 1, to form hydrogen bondedd ianions and clusters [A(HA) x ] À ) [54,61] needs more explanation. This association of the free acid and the anion lowers the basicity of the counterion as explained by Polyakov et al [62] It was shown in ar ecent communication [53] that H 0 values of ah ydrogen sulfate ionic liquid's mixtures with H 2 SO 4 changes linearly with mole ratio of the acid over almost the full range of compositions.…”

“…[33] Anion basicity is also factored in equations to describe the polarity [34,35] of solvents in general and ionic liquidsi np articular. [38,39] An umber of qualitative and quantitative spectroscopic scalesa re also reported which are mostly basedo nU V/ Vis, [40][41][42][43][44][45] IR [46,47] and NMR [14,[48][49][50][51][52][53][54][55] spectroscopies. [38,39] An umber of qualitative and quantitative spectroscopic scalesa re also reported which are mostly basedo nU V/ Vis, [40][41][42][43][44][45] IR [46,47] and NMR [14,[48][49][50][51][52][53][54][55] spectroscopies.…”

“…[36,37] Kamlet-Taft multiparameter equationisaw ell-known example. [38,39] An umber of qualitative and quantitative spectroscopic scalesa re also reported which are mostly basedo nU V/ Vis, [40][41][42][43][44][45] IR [46,47] and NMR [14,[48][49][50][51][52][53][54][55] spectroscopies. Most of these methodsa re based on spectroscopic characterization of ap robe, dissolved in ILs at low concentrations, the response of which is found to be correlated to the acidity/basicity of the medium.T he main disadvantage of this approach is the disproportionatee ffect of impurities consequento nt he low concentration of the probe.…”

Applying neutron diffraction with isotopic substitution to the structure and proton-transport pathways in protic imidazolium bis{(trifluoromethyl)sulfonyl}imide ionic liquids

“…15 We have an on-going interest in understanding the role of ionassociation and speciation in ionic liquids [16][17][18] and the nature of the 'complex ions' that can be formed when acids and bases, or salts and acids or bases are mixed. [19][20][21] Here, we compare the liquid structures of 1:1 and 2:1 base:acid mixtures of imidazole with H[NTf 2 ], determined using neutron diffraction with isotopic substitution, in order to identify whether persistent homo-conjugated complex cations can be observed in the basic-rich region of phase space and, if present, to try to understand how these contribute to the liquid structure and proton conductivity. 2 ] was also run to provide isotopic contrast between the C-H and N-H sites in the 2:1 system.…”

Thermodynamic and conductivity properties of acetic acid — EMIMOAc ionic liquid solutions

“…In previous reports we have studied the ionization of several strong Brønsted acids and their H + solvation and transportation mechanisms in AIL solutions using conductivity and viscosity measurements, spectroscopy, and computational simulation. [14][15][16][17] For example, when a strong acid such bis-trifluoromethansulfonylimide acid (HTFSI) dissolves in ILs, HTFSI can partially or completely ionize to produce a proton-bridged TFSIdimer. 18 However, the fundamental solvation and transportation properties of weak Brønsted acids such as HOAc in AILs have not been carefully investigated.…”