Rare earth oxides
AssigneeRhone-Poulenc Chimie
InventorsClaire David, Francoise Seon
Life of this patent
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Abstract
Novel rare earth oxides having a large specific surface of at least 40 m.sup.2 /g, well adapted for catalysis, are prepared (i) by reacting at least one rare earth salt with a strong base in the presence of carboxylate ions, or by reacting at least one rare earth carboxylate with a strong base, to produce a true rare earth hydroxide, (ii) separating the precipitate thus produced, and then (iii) washing and (iv) calcining such precipitate.
Claims26
Particulates of a calcined trivalent rare earth oxide, the rare earth oxide being selected from the group consisting of yttrium oxide, lanthanum oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, lutecium oxide and thulium oxide, the rare earth oxide having a specific surface of at least 44 m.sup.2 /g measured after calcination for at least two hours at a temperature of from 350.degree. to 600.degree. C., a pore volume of at least 0.2 cm.sup.3 /g, and a mean pore diameter of greater than 50 .ANG..
Particulates consisting essentially of a calcined trivalent rare earth oxide, the rare earth oxide being selected from the group consisting of yttrium oxide, lanthanum oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, lutecium oxide and thulium oxide, the rare earth oxide having a specific surface of at least 44 m.sup.2 /g, measured after calcination for at least two hours at a temperature of from 350.degree. to 600.degree. C., a pore volume of at least 0.2 cm.sup.3 /g and a mean pore diameter of greater than 50 .ANG..
Particulates of a calcined trivalent rare earth oxide, the rare earth oxide being selected from the group consisting of yttrium oxide, lanthanum oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, lutecium oxide and thulium oxide, the rare earth oxide having a specific surface ranging from 70 to 110 m.sup.2 /g, measured after calcination for at least two hours at a temperature of from 400.degree. to 450.degree. C., a pore volume of at least 0.2 cm.sup.3 /g, and a mean pore diameter of greater than 50 .ANG..
Particulates consisting of a calcined trivalent rare earth oxide, the rare earth oxide being selected from the group consisting of yttrium oxide, lanthanum oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, lutecium oxide and thulium oxide, the rare earth oxide having a specific surface ranging from 70 to 100 m.sup.2 /g, measured after calcination for at least two hours at a temperature of from 400.degree. to 450.degree. C., a pore volume of at least 0.2 cm.sup.3 /g, and a mean pore diameter of greater than 50 .ANG..
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