Fluorochemicals from fluorspar via a phosphate-enabled mechanochemical process that bypasses HF

Patel C, André-Joyaux E, Leitch JA, de Irujo-Labalde XM, Ibba F, Struijs J, Ellwanger MA, Paton R, Browne DL, Pupo G, Aldridge S, Hayward MA
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All fluorochemicals—including elemental fluorine and nucleophilic, electrophilic, and radical fluorinating reagents—are prepared from hydrogen fluoride (HF). This highly toxic and corrosive gas is produced by the reaction of acid-grade fluorspar (>97% CaF2) with sulfuric acid under harsh conditions. The use of fluorspar to produce fluorochemicals via a process that bypasses HF is highly desirable but remains an unsolved problem because of the prohibitive insolubility of CaF2. Inspired by calcium phosphate biomineralization, we herein disclose a protocol of treating acid-grade fluorspar with dipotassium hydrogen phosphate (K2HPO4) under mechanochemical conditions. The process affords a solid composed of crystalline K3(HPO4)F and K2−xCay(PO3F)a(PO4)b, which is found suitable for forging sulfur-fluorine and carbon-fluorine bonds.