Formation and catalytic characterization of various rare earth phosphates
2002; Royal Society of Chemistry; Volume: 12; Issue: 6 Linguagem: Inglês
10.1039/b110121h
ISSN1364-5501
AutoresHiroaki Onoda, Hiroyuki Nariai, Ai Moriwaki, Hideshi Maki, Itaru Motooka,
Tópico(s)Chemical Synthesis and Characterization
ResumoVarious rare earth phosphates [rare earth elements: R = La, Ce, Pr, Nd, Sm, Yb, and Y; phosphates: Monazite-type, Xenotime-type, Rhabdophane-type, and Weinshenkite-type orthophosphates RPO4, polyphosphate R(PO3)3, and ultraphosphate RP5O14] were synthesized by heating the mixtures of each rare earth oxide and diammonium hydrogenphosphate or phosphoric acid. The compositions of rare earth phosphates were determined by XRD, FT-IR, and TG–DTA. Catalytic properties were studied as one of properties of various rare earth phosphates. Specific surface areas of samples were measured by the BET method. Acid strengths and amounts of acidic sites were measured using several indicators by n-butylamine titration. Acidic properties were also confirmed by adsorption of ammonia. Various rare earth phosphates were characterized by catalytic activities on dehydration reaction of 2-propanol, cracking/dehydrogenation reaction of cumene, and isomerization reaction of butene. The characterization of catalysts was discussed with regard to type of rare earth elements, type of phosphates, and type of phosphorus resources.
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