Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
Phys Chem Chem Phys. 2020 Dec 23;22(48):28045-28054. doi: 10.1039/d0cp03157g.
This report outlines the synthesis of an ionic liquid-based pH-responsive indicator to sense acids or bases in non-polar as well as polar solvents. Herein, we have assembled a new ionic liquid (IL) comprised of a group of uniform materials based on organic salts (GUMBOS) by attaching a quaternary phosphonium ionic liquid with a very common acid-base indicator, methyl orange, via simple ion-exchange reaction. This integrated IL-based indicator is highly soluble in less polar solvents and exhibits good sensitivity toward the presence of acids/bases in those media. Furthermore, this indicator has been exploited in determining the dissociation constants of several acids in non-aqueous aprotic solvents by overlapping indicator method and hence this report provides essential information toward the understanding of many fundamental chemical reactions. This report has further scope for the synthesis of novel aqueous suspended nanomaterials, i.e., the nanoparticles derived from GUMBOS (nanoGUMBOS) by a simple flash nano-precipitation method. The nanomaterial has been well characterized by different spectroscopic and microscopic studies. The obtained nanoparticles also exhibit substantial pH-responsive behaviors in aqueous medium and show better susceptibility as compared to the free organic indicator. Thus, this report explores detailed studies on the IL-based indicator in sensing the acidity/basicity of various media.
本报告概述了一种基于离子液体的 pH 响应指示剂的合成，该指示剂可用于检测非极性和极性溶剂中的酸或碱。在此，我们通过简单的离子交换反应，将一种季膦离子液体与一种非常常见的酸碱指示剂甲基橙连接起来，组装了一种新的基于离子液体的指示剂（IL）。这种基于整合离子液体的指示剂在非极性溶剂中具有很高的溶解度，并对这些介质中酸/碱的存在表现出很好的敏感性。此外，该指示剂已被用于通过重叠指示剂法在非水无质子溶剂中测定几种酸的离解常数，因此本报告为理解许多基本化学反应提供了重要信息。本报告进一步探讨了新型水悬浮纳米材料的合成，即通过简单的闪蒸纳米沉淀法从 GUMBOS（nanoGUMBOS）中得到的纳米颗粒。该纳米材料已通过不同的光谱和显微镜研究进行了很好的表征。所得纳米颗粒在水介质中也表现出显著的 pH 响应行为，与游离有机指示剂相比，其敏感性更好。因此，本报告探索了基于 IL 的指示剂在检测各种介质的酸度/碱度方面的详细研究。
