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Characterization for Li 3 PO 4 catalysts toward elucidation of crystalline form and performance relationship
Author(s) -
Ma Weihua,
Li Hao,
Jiang Wei,
Bai Huaping,
Qu Hongxia,
Lu Lude
Publication year - 2015
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22176
Subject(s) - calcination , catalysis , isomerization , lithium (medication) , propylene oxide , chemistry , infrared spectroscopy , inorganic chemistry , alkalinity , selectivity , powder diffraction , crystal structure , nuclear chemistry , oxide , crystallography , organic chemistry , ethylene oxide , medicine , polymer , copolymer , endocrinology
Alkaline lithium phosphates were prepared at different calcination temperatures and their catalytic properties were evaluated. The results showed that the 320 °C‐calcined lithium phosphate had the highest selectivity to allyl alcohol (AA) and higher propylene oxide (PO) conversion among those catalysts calcined from 320 °C to 800 °C. There were two forms of lithium phosphates, β ‐form and γ ‐form, and the transition temperature was 670 °C. The Brunauer‐Emmet‐Teller (BET) surface area and alkalinity of the β ‐Li 3 PO 4 was larger than that of the γ ‐Li 3 PO 4 , and the change of the crystal forms affected catalytic activity a lot. Infrared spectra (IR) and X‐ray powder diffraction (XRD) results showed that the reason of catalyst deactivation might be related to the carbon deposits and the arrangement of the atoms in the two forms of lithium phosphates. Based on structural analysis for Li 3 PO 4 , a new mechanism of PO isomerization was proposed.