W. R. Grace & Co.

W.r. Grace & Co. -conn.

Norman R Laine

Moises G Sanchez

Michael V Ernest

Wu-Cheng Cheng

John Allen Rudesill

Jose E Herrera

Charles C Chang

Sandra M Waters

A silica-containing bayerite alumina is prepared by reacting aluminum sulfate, sodium aluminate and sodium silicate at a pH of about 10.5 to 11.5, preferably in the presence of finely divided magnesium hydroxide 'seeds'. The silica-containing bayerite is heated to obtain a hydrothermally stable silica 'stabilized' eta alumina which may be used in the preparation of catalytic compositions.

Silica bayerite/eta alumina

ZSM-5 crystallites are produced with very low levels of blocking tetrapropyl ammonium ions (Q). The reaction mixture contains sources of silica, soda, alumina and trace amounts of Q ions as nucleation agents. Because the crystallites as synthesized from the aqueous medium exhibit only a very small fraction of blocking cations, there is always a diffusion path for the hydrated sodium ions to be exchanged without the need of prior removal of the blocking cations by calcination or otherwise. The small size crystallites can be exchanged, blended with other materials, and formed into catalyst particles. The silica to alumina ratio can be varied and when no aluminum is added, silicalite may be formed. The systhesis can be done in 24 hours or less.

Process for making crystalline siliceous materials

Small size alumina particles of controlled sizes suitable for use as a catalyst support can be made from an acidified alumina slurry by spraying under nonatomizing conditions from a nozzle with a gas or inert fluid used to disperse the slurry into small droplets. The droplets can either be sent through an ammoniated kerosene column or the acidified slurry can be spray dried. Small alumina spheroids are produced, which after calcination, have controlled size diameters from about 0.01 mm. to about 2.0 mm.

Alumina spheroids with controlled small particle size and a process for

Spheroidal alumina particles have a combination of high macroporosity, surface area, crush strength and low attrition loss and bulk density. The particles are prepared by an improved external gelation oil-drop process. In the process a slurry of alumina, preferably a microcrystalline boehmite-pseudoboehmite intermediate, is prepared in an acidic aqueous medium and droplets of the slurry are passed through air into a column containing an upper body of water-immiscible liquid and ammonia and a lower body of aqueous coagulating agent. Catalysts employing the particles as a support and having catalytic agents distributed at controlled depths in the particle have excellent initial and sustained activity and durability, especially for eliminating pollutants in automotive exhaust streams.

Spheroidal alumina particles and catalysts employing the particles as a

An alumina composition comprising a microcrystalline boehmite-pseudoboehmite intermediate having from about 70 to about 85 weight percent of the total amount of Al.sub.2 O.sub.3 present in crystalline form. The composition is prepared by adding aluminum sulfate and sodium aluminate solutions to a mixture of water and aluminum sulfate solution to precipitate alumina and adjusting the pH to a pH higher than the precipitation pH. The reactant concentrations, and rates of addition, temperatures, and pH's in the precipitation are specifically controlled to form the boehmite-pseudoboehmite intermediate.

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Rockville, MD, United States of America

Norman R Laine