Bichloride-based ionic liquids for the merged storage, processing, and electrolysis of hydrogen chloride
Gesa H. Dreyhsig, Patrick Voßnacker, Merlin Kleoff, Haralds Baunis, Niklas Limberg, Michael Lu, Reinhard Schomäcker, Sebastian Riedel
Abstract
Hydrogen chloride is produced as a by-product in industrial processes on a million-ton scale. Since HCl is inherently dangerous, its storage and transport are avoided by, e.g., on-site electrolysis providing H 2 and Cl 2 which usually requires complex cell designs and PFAS-based membranes. Here we report a complementary approach to safely store 0.61 kilogram HCl per kilogram storage material [NEt 3 Me]Cl forming the bichloride [NEt 3 Me][Cl(HCl) n ]. Although HCl release is possible from this ionic liquid by heat or vacuum, the bichloride can be used directly to produce base chemicals like vinyl chloride. Alternatively, [NEt 3 Me][Cl(HCl) n ] is electrolyzed under anhydrous conditions using a membrane-free cell to generate H 2 and the corresponding chlorination agent [NEt 3 Me][Cl(Cl 2 ) n ], enabling the combination of these ionic liquids for the production of base chemicals.