Synthesis and characterization of lanthanum acetate for application as a catalyst

Abstract

The use of precursors based upon the rare earths is of considerable interest for the manufacture of catalysts. Starting with a rare earths fraction depleted in cerium (a low cerium carbonate, LCC) produced locally by the industrial processing of monazite sand as raw material, a very pure concentrate of lanthanum was prepared. The rare earth chloride solution was loaded into a strong cationic ion-exchange resin and then eluted using the ammonium salt of EDTA. No barrier ion was used. The lanthanum fraction was separated from the EDTA and then precipitated as oxalate and fired to lanthanum oxide. The lanthanum oxide was fairly easily dissolved using only acetic acid from which lanthanum acetate was crystallized. The solid salt was characterized via thermal analysis, chemical analysis, X-ray diffraction, inductively coupled plasma optical emission spectrometry and infrared spectroscopy. An aqueous solution of lanthanum acetate was prepared to be added to alumina microspheres support, especially sinthesized by the sol–gel process for use as a catalyst. Further work will involve the preparation of a highly specific surface lanthanum oxide via lanthanum acetate to be used as a catalyst and to be compared with the alumina–lanthanum oxide catalyst.