Verfahren zur Darstellung von Oniumfluoriden

Onium fluorides (fluorides of substituted ammonium, phosphonium, arsonium and stibonium ions) are prepared by (i) reacting an onium chloride, bromide or iodide with HF under anhydrous conditions to form an onium fluoride/hydrogen fluoride addition compound, reacting this with a metal alkoxide to produce the corresponding alcohol addition compound, and thermally degrading the latter; or (ii) reacting an onium chloride, bromide or iodide with a metal alkoxide, reacting the product with HF under anhydrous conditions to form an onium fluoride/alcohol addition compound, and thermally degrading the latter. Examples prepare [CH3)4N]F, 1-benzylpyridinium fluoride, [(CH3)4Sb]F, trimethylbenzylammonium fluoride, [(C2H5)4N]F, [(CH3)3(C2H5)N]F, C3\H7)4N]F, [(n-C3H7)4N]F, trimethylcetylammonium fluoride, cetylpyridinium fluoride, [(CH3)3(C6H5)N]F [(C6H5)4P]F, [(C6H5)4As]F and [CH3(C6H5)3-As]F. The fluorides may be thermally cracked to give alkyl or aryl fluorides, e.g. benzyl fluoride from trimethylbenzylammonium fluoride, and methyl fluoride from [(CH3)4N]F. The onium fluorides are good conductors and may be used in condensers (see Division Hl) or electrolytic processes (see Division C7). They also react with metal alkyls to produce organometallic complex salts.ALSO:Solvate free substituted ammonium, phosphonium, arsonium or stibonium fluorides (see Division C2) can be reacted with metal alkyls to form organometallic complex salts for use as molten electrolytes, e.g. for refining aluminium or they can be used for the anodic production of fluoride layers on metal surfaces.