As non-volatile solvents, ionic liquids (ILs) are becoming potential 'green' substitutes of volatile organic solvents. The synthesis and characterization of hydrophilic ILs require the application of basic organic synthesis techniques in conjunction with a wide range of instrumental techniques that will verify and analyze the physicochemical properties of novel organic structures. Our application of the most promising of ILs will be in the field of coal processing and consumption and will ideally produce a novel process of coal (partial) dissolution that is essential for further utilization of low-rank coal.
Brown coal (lignite) is a bulk organic mixture of conjugated hydrocarbons that are complexed together via hydrogen bonds. In order to break the hydrogen bonds and separate the numerous compounds, ILs of specific nature will have to be synthesized and characterized to best break the hydrogen bond network. A series of nitrogen- and phosphorus-based cations have been synthesized via a nucleophilic substitution reaction, the resultant bromide-based IL being converted to acetate-based IL through an ion-exchange procedure in methanol. Water concentration and viscosity measurements, along with thermogravimetric analysis and nuclear magnetic resonance analysis, were conducted to confirm their structures and thermal stability. Hydrogen-bond acidity, basicity, and polarity of these ILs are measured using various dyes. We will further determine the capability of these ILs in dissolving cellulose and brown coal.
Franklin, Michael and Zhao, Hua, "Synthesis and Characterization of Hydrophilic Ionic Liquids: Dissolution and Modification of Brown Coal (Lignite)" (2020). 2020 Graduate Presentations. 14.