Uop Lcc

Union Carbide Corporation

Thomas R Cannan

Edith M Flanigen

Brent M Lok

Richard J Hinchey

Robert L Patton

Richard T Gajek

Celeste A Messina

Nanette Greenlay

Alan P Cohen

Maryellen Lavin

Alex J Caglione

A process for regenerating spent zeolite composites. The process involves contacting the composite, either as a shaped article or a fine powder, with a caustic solution, e.g., sodium hydroxide at treating condition. Once the contacting is completed, the composite is isolated, washed with water, dried and calcined to give a regenerated composite.

Regeneration of spent zeolite compositions

Low silica forms of faujasite-type zeolites are prepared from more siliceous forms of the same zeolite species by contacting the starting zeolite with a highly caustic concentrated sodium aluminate solution at elevated temperatures. In view of the fact that the process does not favor the formation of undesirable impurity phases such as zeolite A and thus does not require the presence of zeolite A nucleation inhibitors, the process is particularly advantageous in the production of forms of zeolite X having Si/Al.sub.2 molar ratios below 2.5.

Process for preparing low silica forms of zeolites having the faujasite

Difluoromethane (R32) is of current interest as a partial replacement for chlorodifluoromethane (R22) refrigerant heretofore widely used in vapor compression refrigeration systems. R32 has, however, proved to be more reactive than is desirable with the zeolite A adsorbent-desiccant compositions used in such systems to prevent corrosion and freeze-up problems. The sodium cation form of a zeolite having the crystal structure of zeolite B is found to be an effective adsorbent for that purpose and to be significantly less reactive with the R32.

Process for drying CH.sub.2 F.sub.2 refrigerant utilizing zeolite

Zeolite beta is synthesized hydrothermally from an aqueous reaction mixture containing the conventional reactive sources of SiO.sub.2, Al.sub.2 O.sub.3 and Na.sub.2 O tetraethylammonium halide as the source of the crystallization directing tetraethylammonium ions and diethanolamine as the agent providing the increased basicity necessary for the formation of zeolite beta crystals. Seed crystals of zeolite beta are optionally employed to shorten the crystallization period.

Synthesis of zeolite beta

The catalytic conversion of hydrocarbon feedstocks is affected under effective conversion process conditions in the presence of silicoaluminophosphate-based catalyst compositions.

Hydrocarbon conversions using catalysts silicoaluminophosphates

A novel crystalline aluminosilicate composition denominated 'zeolite LZ-133' or simply 'LZ-133' and having uniform pore dimensions of approximately 4.3 Angstroms is prepared hydrothermally from a reaction mixture containing as essential reagents, water, alkali or alkaline earth metal oxide, alumina, silica and a quaternary ammonium compound.

Zeolite LZ-133

The crystalline omega-type zeolite LZ-202 can be prepared by a novel process that eliminates the prior art requirement of a templating agent. Unlike prior art omega-type zeolites, the as-synthesized form is totally ion-exchangeable and can be enriched with silicon by treatment with ammonium fluorosilicate to produce a product which is substantially crystalline.

Crystalline zeolite LZ-202 and process for preparing same

A novel class of crystalline microporous silicoaluminophosphates is synthesized by hydrothermal crystallization of silicoaluminophosphate gels containing a molecular structure-forming templating agent. The class comprises a number of distinct species, each with a unique crystal structure. The compositions exhibit properties somewhat analogous to zeolitic molecular sieves which render them useful as adsorbent or catalysts in chemical reactions such as hydrocarbon conversions.

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Congers, NY, United States of America

Thomas R Cannan