Published online by Cambridge University Press: 01 February 2011
Alumina particles were treated under various conditions with different diphenylphosphinate compounds: diphenylphosphinic acid, ethyl diphenylphosphinate, and trimethylsilyl diphenylphosphinate. The balance between surface complexation (namely grafting) and surface phase transformation (formation of bulk aluminum phosphinate phase) was investigated by IR and solid-state 31P MAS NMR spectroscopy, using the model crystalline phase Al(O2PPh2)3 synthesized in a parallel work as a reference. Satisfactory grafting was obtained either by using diphenylphosphinic acid in aqueous medium at pH about 6, or by using ethyl diphenylphosphinate in organic medium as coupling agents.