NITROGEN INCORPORATION IN ALPO4-5 MOLECULAR-SIEVES BY THERMAL AMMONOLYSIS

AlPO4-5 samples were treated with NH3 or NH3/CO mixtures at temperatur es up to 1173 K.The samples were characterized by powder X-ray diffrac tion (XRD), infrared (i.r.) spectroscopy, and high-resolution solid-st ate nuclear magnetic resonance (n.m.r.) spectroscopy (Al-27, P-31, H-1 , and natural abundance N-15). At all temperatures, ammonia was adsorb ed by the molecular sieve through the coordination of one or two NH3 m olecules with aluminum to yield five- and six-fold coordinated Al. Dur ing ammonium treatment above 1073 K, oxygen bridges were broken, leadi ng to -P-NH2 and -Al-OH terminal groups. -Al-NH-P- bridging groups wer e not observed.