Rhone-poulenc Chimie

Axens

Institut Francais Du Pe'trole

Procatalyse S.a.

Jean-Luc Le Loarer

Christophe Nedez

Thierry Chopin

Jean-Yves Chane-Ching

Alain Leveque

Claire David

Denis Guillaume

Thierry Delloye

Stéphane Kressmann

Francoise Picard

Bernard Pacaud

Bernard Taxil

Francis Tastu

Michel Ries

Patrick Dupuis

Hubert Nussbaum

Denis Bortzmeyer

Antoine Dissaux

Georges Dovergne

Jean-François Chapat

Bernard-Antoine Dissaux

The invention provides alumina agglomerates of the type obtained by dehydrating an aluminum hydroxide or oxyhydroxide, agglomerating the alumina obtained, hydrothermally treating the agglomerates and calcining. The invention also provides a catalyst support, an adsorbent material and a catalyst constituted by said agglomerates. The invention also provides methods for preparing said agglomerates.

Alumina and methods for preparing the same

The invention relates to alumina agglomerates of the type obtained by dehydrating an aluminium oxyhydroxide or hydroxide, agglomerating the alumina thus obtained, hydrothermally treating the agglomerates and calcinating same. Said agglomerates are characterised in that: the Vthereof is greater than or equal to 75 ml/100 g, preferably greater than or equal to 80 ml/100 g and, better still, greater than or equal to 85 ml/100 g; the Vthereof is less than or equal to 31 ml/100 g; and the Vthereof is less than or equal to 20 ml/100 g, preferably less than or equal to 15 ml/100 g and, better still, less than or equal to 10 ml/100 g. The invention also relates to a catalyst carrier, an intrinsic catalyst or an absorbent, in particular for use in the petroleum and petrochemical industry, comprising such alumina agglomerates. Moreover, the invention relates to methods for preparing said agglomerates.

Alumina agglomerates and preparation method thereof

Alumina extrudates, methods for preparing and use as catalysts supports

Method for regenerating anthraquinone derivatives during a synthesis

Ceric oxide particulates having a specific surface of at least 190 m.sup.2 /g, measured after calcination at a temperature of from 350.degree. to 450.degree. C., and a specific surface of at least 15 m.sup.2 /g after calcination at 800.degree. C., are prepared by (a) suspending, in an aqueous solution of a decomposable base, a ceric hydroxide of the formula (I):

Ceric oxide particulates having improved morphology

Adsorbent alumina particulates which comprise coagulated droplets, extrudates or crushed alumina particles having a volume of pores with a diameter greater than 80 .ANG. of at least 0.15 cm.sup.3 /g and a particle size of less than 4 mm are well suited for adsorbing chelated organometallic compound values thereon, in particular from a medium of polymerization comprising same.

Adsorption of chelated organometallic compounds onto alumina-based

Heat-stable alumina particulates well suited as catalysts/catalyst supports, notably for the catalytic conversion of vehicular exhaust gases, contain a stabilizing amount of lanthanum values, optionally a costabilizing amount of neodymium values, and have a specific surface area of greater than 40 m.sup.2 /g after calcination at 1,200.degree. C. for 4 hours; these are produced by ripening/rehydrating an alumina powder at least partially into boehmite/pseudo-boehmite state in the presence of a stabilizing amount of at least one lanthanum compound, e.g, lanthanum nitrate, and, optionally, also at least one neodymium compound, the starting alumina powder being the product of rapid dehydration of at least one aluminum hydroxide and/or aluminum oxyhydroxide.

Lanthanum-stabilized alumina particulates

Very finely divided ammonium rare earth double oxalates, readily converted into corresponding rare earth oxides by calcination, such oxides being well adopted, e.g., for the production of luminescent compounds therefrom, are prepared by (a) admixing a second solution of a rare earth compound, e.g., a salt, with a first solution containing oxalate and ammonium ions, (b) then separating the precipitate thus obtained from such mixed solution of reaction, and (c) optionally, drying the separated precipitate.

Production of finely divided rare earth ammonium oxalates/finely divided

Environmental pollution stemming from the industrial discharge and/or storage of water-soluble thorium compounds is avoided by converting same into essentially innocuous water-insoluble thorium phosphates, notably orthorhombic thorium phosphates, by (i) reacting such water-soluble thorium compounds, e.g., the nitrates and/or chlorides, with a base, for example aqueous ammonia, in an aqueous reaction medium, to precipitate a thorium hydroxide therein, (ii) next reacting the precipitate thus formed with a phosphating compound, e.g., phosphoric acid or a soluble phosphate salt, also in an aqueous reaction medium, to precipitate a thorium phosphate therein, and then (iii) separating such thorium phosphate precipitate.

Thorium phosphates prepared by insolubilization of soluble thorium

Neodymium or didymium values are selectively recovered from bastnaesite ores, essentially to the exclusion of cerium and trace amounts of thorium, by (i) calcining the bastnaesite ore, (ii) selectively leaching the calcined bastnaesite with an aqueous solution of nitric acid to solubilize therein neodymium and trivalent rare earth values, and thereby producing an insoluble residue which comprises cerium and thorium values, (iii) separating the insoluble residue, and (iv) liquid/liquid extracting desired neodymium or didymium values from the nitric acid solution.

Recovery of neodymium/didymium values from bastnaesite ores

Thermally stable alumina having a high specific surface at elevated temperatures, well suited as a catalyst support material, e.g., as the support substrate of catalysts useful for the conversion of exhaust gases emanating from internal combustion engines, contain an effective heat stabilizing amount of silica, such silica essentially being distributed within the crystalline network/structure of the alumina, and such silica-stabilized alumina having an isoelectric point above 7 and a reduced capacity for the isomerization of olefins.

Silica-stabilized alumina

A ceric oxide having a specific surface of at least 15 m.sup.2 /g, measured after calcination at a temperature of between 800.degree. and 900.degree. C.

Ceric oxide with new morphological characteristics and method for

Provided is a ceric oxide having a specific surface of at least 85 m.sup.2 /g after calcination between 350.degree. and 550.degree. C., and being further characterized in that it has a pore volume of at least 0.15 cm.sup.3 /g and a median pore diameter greater than 50 .ANG.. The ceric oxide is prepared by destabilizing an aqueous colloidal dispersion of a cerium (IV) compound by the addition of base thereto, separating the precipitate which results and subjecting it to a heat treatment.

Novel ceric oxides and preparation thereof

Novel cerium (IV) compounds having the Formula (I):

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La Rochelle, France

Jean-Luc Le Loarer