TY - JOUR
T1 - Phase behaviour and conductivity study of electrolytes in supercritical hydrofluorocarbons
AU - Bartlett, Philip N.
AU - Cook, David C.
AU - George, Michael W.
AU - Ke, Jie
AU - Levason, William
AU - Reid, Gillian
AU - Su, Wenta
AU - Zhang, Wenjian
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011/1/7
Y1 - 2011/1/7
N2 - The purpose of this work was to characterise supercritical hydrofluorocarbons (HFC) that can be used as solvents for electrodeposition. The phase behaviour of CHF3, CH2F2, and CH 2FCF3 containing [NBun4][BF 4], [NBun4][B{3,5-C6H 3(CF3)2}4] and Na[B{3,5-C 6H3(CF3)2}4] was studied and the conditions for forming a single supercritical phase established. Although all three HFCs are good solvents for [NBun 4][BF4] the results show that the CH2F 2 system has the lowest pr for dissolving a given amount of [NBun4][BF4]. The solubility of Na[B{3,5-C6H3(CF3)2}4] in CH2F2 was found to be unexpectedly high. Studies of the phase behaviour of CH2F2 containing [NBun 4][BF4] and [Cu(CH3CN)4][BF 4] showed that the copper complex was unstable in the absence of CH3CN. For CHF3, [Cu(hfac)2] was more soluble and more stable than [Cu(CH3CN)4][BF4] and only increased the phase-separation pressure by a moderate amount. Studies of the conductivity of [NBun4][B(C6F5) 4], [NBun4][B{3,5-C6H 3(CF3)2}4], [NRfBu n3][B{3,5-C6H3(CF3) 2}4] (Rf = (CH2)3C 7F15), and Na[B{3,5-C6H3(CF 3)2}4] were carried out in scCH 2F2. The results show that these salts are more conducting than [NBun4][BF4] under the same conditions although the increase is much less significant than that reported in previous work in supercritical CO2 + CH3CN. Consequently, either [NBun4][BF4] or the corresponding BARF salts would be suitable background electrolytes for electrodeposition from scCH 2F2.
AB - The purpose of this work was to characterise supercritical hydrofluorocarbons (HFC) that can be used as solvents for electrodeposition. The phase behaviour of CHF3, CH2F2, and CH 2FCF3 containing [NBun4][BF 4], [NBun4][B{3,5-C6H 3(CF3)2}4] and Na[B{3,5-C 6H3(CF3)2}4] was studied and the conditions for forming a single supercritical phase established. Although all three HFCs are good solvents for [NBun 4][BF4] the results show that the CH2F 2 system has the lowest pr for dissolving a given amount of [NBun4][BF4]. The solubility of Na[B{3,5-C6H3(CF3)2}4] in CH2F2 was found to be unexpectedly high. Studies of the phase behaviour of CH2F2 containing [NBun 4][BF4] and [Cu(CH3CN)4][BF 4] showed that the copper complex was unstable in the absence of CH3CN. For CHF3, [Cu(hfac)2] was more soluble and more stable than [Cu(CH3CN)4][BF4] and only increased the phase-separation pressure by a moderate amount. Studies of the conductivity of [NBun4][B(C6F5) 4], [NBun4][B{3,5-C6H 3(CF3)2}4], [NRfBu n3][B{3,5-C6H3(CF3) 2}4] (Rf = (CH2)3C 7F15), and Na[B{3,5-C6H3(CF 3)2}4] were carried out in scCH 2F2. The results show that these salts are more conducting than [NBun4][BF4] under the same conditions although the increase is much less significant than that reported in previous work in supercritical CO2 + CH3CN. Consequently, either [NBun4][BF4] or the corresponding BARF salts would be suitable background electrolytes for electrodeposition from scCH 2F2.
UR - http://www.scopus.com/inward/record.url?scp=78650103704&partnerID=8YFLogxK
U2 - 10.1039/c0cp01202e
DO - 10.1039/c0cp01202e
M3 - Article
C2 - 21072413
AN - SCOPUS:78650103704
SN - 1463-9076
VL - 13
SP - 190
EP - 198
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 1
ER -