کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6617424 459633 2013 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Conductometric study of binary systems based on ionic liquids and acetonitrile in a wide concentration range
ترجمه فارسی عنوان
بررسی ساختار دوتایی سیستم های مبتنی بر مایعات یونی و استونیتریل در محدوده غلظت گسترده
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی
Although a few groups have recently published transport properties for extensive sets of imidazolium- and pyridinium-based room-temperature ionic liquids (RTILs) and their solutions, there are still no prediction techniques for the conductivity maximum in these systems. We contribute to the discussion by reporting own conductometric data and establishing implicit empirical correlations between ionic structure, concentration and temperature. Our analysis is based on binary systems containing ionic (RTIL) and molecular (acetonitrile) co-solvent. The molar fraction of RTIL in each system ranges from 0 to 50% whereas temperature ranges from 278.15 to 328.15 K. Imidazolium-based RTILs are sampled by 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium and 1-hexyl-3-methylimidazolium tetrafluoroborates, 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, and 1-butyl-3-methylimidazolium bromide. 1-butyl-4-methylpyridinium tetrafluoroborate is employed to distinguish a role of aromatic ring. Ionic association in all RTIL-AN systems poorly correlates with the cation structure, although strongly depends on the anion size and structure. Cation and anion of RTILs form the 'contact ion pairs' (CIPs) where anion is coordinated by imidazole and pyridine rings. Notably, all binary systems exhibit conductivity maximum between χ(RTIL) = 10 and 20%. This maximum slightly shifts towards smaller χ(RTIL), as counterion gets larger. Smaller cations and anions lead to substantial conductivity growth. Conductivity maximum can be boosted and observed at larger χ(RTIL) even at insignificant temperature increase. Our observations provide novel insights into a complicated functional dependence of ionic conductivity versus ionic concentration and temperature. The results may be of extensive practical application, particularly for construction of high-performance electrolyte systems.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electrochimica Acta - Volume 105, 30 August 2013, Pages 188-199
نویسندگان
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