Synthesis and characterisation of ionic liquids based on 1-butyl-3-methylimidazolium chloride and MCl4, M = Hf and Zr

Abstract

Dialkylimidazolium chlorometallate molten salts resulting from the combination of zirconium or hafnium tetrachloride and 1-butyl-3-methylimidazolium chloride, [C(1)C(4)Im][Cl], have been prepared with a molar fraction of MCl(4), R = n(MCl4)/n(MCl4) + n([C1C4IM][Cl]) equal to 0, 0.1, 0.2, 0.33, 0.5, 0.67. The structure and composition were studied by Differential Scanning Calorimetry (DSC), (35)Cl (263 to 333 K), (1)H and (13)C solid state and solution NMR spectroscopy, and electrospray ionisation (ESI) mass spectrometry. The primary anions of the MCl(4)-based ILs were [MCl(5)], [MCl(6)] and [M(2)Cl(9)], whose relative abundances varied with R. For R = 0.33, pure solid [C(1)C(4)Im](2)[MCl(6)], for both M = Zr and Hf are formed (m.p. = 366 and 385 K, respectively). For R = 0.67 pure ionic liquids [C(1)C(4)Im][M(2)Cl(9)] for both M = Zr and Hf are formed (T(g) = 224 and 220 K, respectively). The thermal dissociation has been attempted of [C(1)C(4)Im](2)[HfCl(6)], and [C(1)C(4)Im](2)[ZrCl(6)] monitored by (35)Cl and (91)Zr solid NMR (high temperature up to 551 K).

Halometallate ionic liquids – revisited

“…96 It seems to be a reoccurring theme that MS results can lead to confusion and erroneous conclusions about speciation. Campbell et al 97 studied chlorohafnate(IV) and chlorozirconate(II) ionic liquids using a multi-technique approach, which unfortunately did not include vibrational spectroscopy. Based on DSC and known coordination chemistry of both metals, they hypothesised the predominance of [MCl 6 ] 2À , [M 2 Cl 10 ] 2À and (unknown in the literature) [M 2 Cl 9 ] À at w MCl 4 = 0.33, 0.50 and 0.67, respectively.…”

Solubility Behaviour of TiCl4, ZrCl4, and HfCl4 in Chloroaluminate Ionic Liquids

“…The same behaviour was reported for ionic liquids containing excess aluminium chloride 12,16. Ionic liquids solely based on NbCl 5 ,17 TaCl 5 ,18 TiCl 4 ,19 ZrCl 4 ,20 or HfCl 4 21 were already reported. However, their mixtures with neutral chloroaluminate melts have not been described yet.…”

Experimental investigations on the regeneration of desulfurized 1‐butyl‐3‐methylimidazolium tetrachloroferrate [Bmim][FeCl4] and 1‐butyl‐3‐methylimidazolium thiocyanate [Bmim][SCN] ionic liquids: A raman spectroscopic study

“…The thermal stability of both ionic liquids, that is, [Bmim][FeCl 4 ] and [Bmim][SCN] under harsh thermal conditions was investigated by using the TGA analysis, and the results are illustrated in Figure . With the reference of [Bmim][FeCl 4 ] (Figure ), the TGA analysis revealed that initially, the significant weight loss of the ionic liquid [Bmim][FeCl 4 ] was identified at a temperature within the range of 43.8°C with loss in weight of approximately 7.8% . This initial loss in weight of the [Bmim][FeCl 4 ] sample can be directed to the evaporation of the trapped water molecules present in the [Bmim][FeCl 4 ], which were absorbed from the atmosphere during the experimentation.…”