ORGANOBISMUTH(III) AND ORGANOBISMUTH(V) CARBOXYLATES AND THEIR EVALUATION AS PAINT DRIERS

A range of bismuth and organobismuth carboxylates has been prepared (e.g. Bi(carboxylate)3; PhBi(carboxylate')2; and Pp3Bi(carboxylate'')2 where carboxylate = octanoate, i.e. 5-ethylhexanoate; carboxylate' = acetate and monomaleate; carboxylate' = acetate, propionate, benzoate, 5-ethylhexanoate, and 0.5 oxalate. A combination of IR (solid) and NMR (solution) studies suggests that in the case of the bismuth(V) compounds the carboxylates may be inequivalent in the crystalline forms but equivalent in solution. The compounds have been tested as driers in two paint formulations, Synolac 50W (linseed-based) and Sorbal P470 (linoleic-rich). Although initially promising results were obtained for Synolac 50W, the shelf life of the bismuth driers was poor. With Sorbal P470, bismuth driers were inferior to established formulations. However, a combination of Bi(OOCH7H15)3 with tris(diethyldithiocarbamato)-bismuth(III) out-performed established driers.