Mixed salts of silver and ammonium derivatives of molybdovanadophosphoric acid to improve the catalytic performance in the oxidation of starch

• Heterogeneous catalysts Agx(NH4)5−xPMo10V2O40 have been successfully synthesized.
• The influences of Ag+ and NH4+ on the performances of catalytic oxidation.
• Oxidation of starch catalyzed by Ag3.5(NH4)1.5PMo10V2O40 achieved the highest DO.
• No leaching of catalyst was observed during reused reactions.

Mixed salts of silver and ammonium derivatives Agx(NH4)5−xPMo10V2O40 (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0) were designed and synthesized through ion exchange along with precipitation. Different molar ratio of Ag+ to NH4+ resulted in different surface areas, which could give different oxidative catalytic activity in oxidation of starch. Among all molybdovanadophosphoric salts, Ag3.5(NH4)1.5PMo10V2O40 was found to be the most active catalyst in starch oxidation with the highest degree of substitution (DS = 0.62 mol/100 g). And Ag3.5(NH4)1.5PMo10V2O40 could be reused several times without significant loss of its catalytic activity.

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