AFRL: ionic liquid possible cleaning solvent replacement Published Dec. 17, 2014 By Advanced Power Technology Office AFRL Materials and Manufacturing Directorate WRIGHT-PATTERSON AIR FORCE BASE -- A wide range of Air Force platforms and components undergo industrial cleaning processes that are routinely performed at military maintenance, repair, and overhaul facilities, including Air Logistics Complexes (ALCs). To adhere to U.S. Environmental Protection Agency guidelines for solvents containing volatile organic compounds (VOCs), hazardous air pollutants (HAPs), and ozone-depleting substances, these facilities have transitioned to less hazardous cleaning chemicals. However, several of those substances are now subject to reporting, largely due to emitting greenhouse gases (GHGs). As a result, AFRL is looking at new technological solutions for VOC-, HAP-, and GHG-containing solvents which includes ionic liquid (IL) solvents as a potential alternative. Evaluation The Air Force Research Laboratory (AFRL) Energy and Environment (E2) Program has identified and critically evaluated ionic liquid solvents as replacement technology for current cleaning processes at ALCs. AFRL E2 completed a preliminary analysis of ALC requirements and current baseline processes, and a technology assessment was conducted to document currently available IL solvents recommended for cleaning processes. Testing was performed to evaluate alternative solvents in both wiping and immersion cleaning applications. Additionally, substrate and process compatibility testing was conducted with the most promising alternative solvents. The solvents were subjected to the U.S. Army solvent cleaning power test for immersion cleaning with the use of ultrasonic agitation. The 1-ethyl-3-methylimidazolium (EMIM) acetate outperformed the other alternatives and baseline products. It also produced a byproduct of skimmable grease, indicating a potential for solvent recycling at military cleaning facilities which equates to reduced procurement costs. As a result, EMIM acetate is being considered as a safer alternative solvent to vapor degreasing operations at ALCs. About the Systems Support Division The Systems Support Division provides quick reaction materials and processes (M&P) support to a wide range of Air Force customer organizations, including Air Logistics Complexes, Operational Commands, laboratories, product centers and test ranges. The Division conducts development programs to satisfy customer needs and ensure effective and timely use of conventional and advanced M&P.