Mobil Oil Corporation

Sowmithri Krishnamurthy

William D McHale

Charles T Kresge

Garry W Kirker

James C Vartuli

Pochen Chu

Albin Huss, Jr

Quang N Le

John P McWilliams

Stephen S Wong

Donald J Klocke

Hans J Schoennagel

David A Pappal

Thomas R Kiliany, Jr

Catherine T Sigal

George R Landolt

There is provided a method for synthesizing layered silicates such as magadiite and kenyaite. The source of silica used in this method is freshly precipitated from a silicate solution. For example, this silica source may be obtained by treating an aqueous solution of sodium silicate with sulfuric acid to form an amorphous silica precipitate. This silica precipitate is not dried to reduce its activity prior to use.

Layered silicate

The dehydrocyclization of a feed containing one or more acyclic hydrocarbons capable of undergoing ring closure to provide aromatic hydrocarbons is accomplished by contacting the feed under dehydrocyclization conditions with a zeolite L dehydrocyclization catalyst which is substantially free of zeolite T and which contains at least one Group VIII metal component, thereby converting at least a portion of the acyclic hydrocarbon content of the feed to aromatic compound(s). Use of the foregoing zeolite L dehydrocyclization catalyst has been found to result in less non-selective hydrocracking of naphtha range materials to gaseous hydrocarbons and greater conversion of low octane paraffins to high octane aromatics than that achieved with a zeolite L synthesized by a prior procedure which results in the co-production of zeolite T contaminant.

Process for the dehydrocyclization of acyclic hydrocarbons and catalyst

The crystallization of a crystalline silicate product from an crystallization mixture is monitored by measuring the specific electrical conductivity of the mixture. The crystallization of metallosilicates, such as aluminosilicate zeolites, may be monitored in this way. Measurement of the electrical conductivity of the crystallization mixture may be carried out on line in a batch or continuous crystallization process. In a continuous process the conductivity may be monitored and used to control the crystallization process parameters in order to achieve a desired degree of crystallinity in the product.

Measurement and control of zeolite synthesis

Abatement of nitrogen oxides in an industrial exhaust gas is effected by reduction of the nitrogen oxides with ammonia in the presence of a catalyst comprising a porous crystalline siliceous solid such as a ZSM-5 type zeolite. Fast responses to changes of NO.sub.x load is achieved with a zeolite of low to moderate acid activity. The catalyst may be virgin catalyst, aged catalyst previously used for the conversion of a hydrocarbon or an organic compound, or artifically aged catalyst.

Abatement of NO.sub.x in exhaust gases

A method is disclosed for flocculating suspensions containing (a) layered oxide materials intercalated with a hydrophobic swelling agent and (b) nonintercalated hydrophobic swelling agent. The suspension is contacted with a ketone, water, and a cationic organic polymer; the resulting mixture is maintained at a sufficiently alkaline pH to prevent removal of the intercalated swelling agent during the flocculation treatment. This method is particularly useful for preparing swelled layered chalcogenide materials for the introduction of interspathic polymeric chalcogenide precursors in order to form a thermally stable product.

Method for flocculating suspensions containing swelled layered

A process is described for rejuvenating a coke-deactivated noble metal-containing zeolite catalyst material which comprises removing coke from a non-sulfided catalyst by contacting the catalyst with oxygen only in the presence of sulfur dioxide, and thereafter reducing the catalyst in the presence of a reducing agent such as hydrogen. The process permits catalyst reactivation by burning off coke from the catalyst while avoiding excessive agglomeration of the noble metal thereon.

Reactivation of noble metal-containing zeolite catalyst materials

A coke-deactivated noble metal-containing catalyst is sulfided with a sulfiding agent, e.g., H.sub.2 S in H.sub.2, then coke is burned from the sulfided catalyst by contacting the catalyst with oxygen, optionally in the presence of sulfur dioxide, and then the catalyst is reduced with a reducing agent, e.g., H.sub.2. The process permits burning off coke while avoiding excessive agglomeration of the noble metals on the catalyst.

Reactivation of noble metal-containing catalyst materials

A process is described for rejuvenating a coke-deactivated noble metal-containing zeolite catalyst material which comprises sulfiding the deactivated catalyst material by contacting with a sulfiding agent such as hydrogen sulfide-containing gas, removing coke from the sulfided catalyst by contacting the catalyst with oxygen in the presence of sulfur dioxide, and thereafter reducing the catalyst in the presence of a reducing agent such as hydrogen. The process permits catalyst reactivation by burning off coke from the catalyst while avoiding excessive agglomeration of the noble metals thereon.

In a process for treatment of a fresh iridium-containing catalyst, the improvement consists of a three step procedure in sequence including treatment with oxygen, treatment with hydrogen chloride, and treatment with a reducing agent such as hydrogen.

Pretreatment of a fresh iridium-containing catalyst

There is provided, in accordance with the present invention, a catalyst composition made up of a mixture of two components, one component comprising a minor proportion of platinum and rhenium on a support and the second component comprising a minor proportion of iridium and rhenium on a separate support. A process for reforming a charge stock, such as naphtha, utilizing such catalyst is also provided.

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Cherry Hill, NJ, United States of America

Sowmithri Krishnamurthy