Optimization of the operative conditions for heteropolyacids synthesis through ion exchange

phospho-tungstic and phospho-molybdic wells-dawson heteropolyacids, h6p2w18o62 .xh2o and h6p2mo18o62 .xh2o respectively, were synthesized through ion exchange with a higher yield (~ 90%) than the conventional organic route (~ 70%). pure, non-degraded heteropolyacids are obtained when the corresponding ammonium salt [(nh4)6p2w18 o62.13h2o or (nh4)6p2mo18 o62.12h2o] is kept in contact with an acid resin [about (1:0.8) salt:resin weight ratio] up to three days. the use of an organic media instead of an aqueous media greatly favors the completeness of the exchange.