The preparation of some novel electrolytes: Synthesis of partially fluorinated alkane sulfonic acids as potential fuel cell electrolytes

Abstract : The objective of this research was to prepare some strong acids for evaluation by Fort Belvoir as potential fuel cell electrolytes. The only acid other than phosphoric, H3PO4, currently under investigation by Fort Belvoir as a fuel cell electrolyte is TFMSA, CF3SO3H.H2O, trifluoromethanesulfonic acid monohydrate aqueous solutions and sodium salt mixtures. TFMSA has been found to be superior to H3PO4 from the standpoint of electrode kinetics, but certain undesirable characteristics (volatility; wetting of Teflon) led to this search for a better fuel cell electrolyte. The following acids were prepared: Methanedisulfonic acid; Ethanesulfonic acid; Ethane-1,2-disulfonic acid; Propane-1,3-disulfonic acid; Propane-1,2,3-trisulfonic acid; Chlorotrifluoroethanesulfonic acid; and 1,2,2-trifluoroethane-1,1,2-trisulfonic acid. Yields were low because of purification difficulties and future work will be concerned with scaling up the preparations.