Abstract
Two series of molybdenum phosphate catalysts were synthesized by reacting ammonium heptamolybdate with (1) diammonium hydrogen phosphate and (2) ammonium dihydrogen phosphate. The structural and textural properties of the catalysts, formed during the calcination between 400 and 550 °C, were determined by physico-chemical methods and their catalytic activity evaluated in the ammoxidation of 2-methylpyrazine (MP). The catalysts formed using diammonium hydrogen phosphate displayed higher activity and selectivity during the ammoxidation reaction as compared to those prepared using ammonium dihydrogen phosphate. Formation of a regenerable Mo(OH)
3
PO
4
appears to be responsible for the higher performance of the catalyst.