Chemistry of inorganic compounds – Zeolite – Organic compound used to form zeolite
Reexamination Certificate
1997-06-17
2002-04-30
Sample, David (Department: 1755)
Chemistry of inorganic compounds
Zeolite
Organic compound used to form zeolite
C423S705000, C423S707000, C423S712000, C423S306000, C423SDIG002, C423SDIG003, C502S214000
Reexamination Certificate
active
06379646
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to new crystalline, phosphorus-containing molecular sieves, a method for preparing them using a zeolite, and processes employing a catalyst containing them.
2. State of the Art
Because of their unique sieving characteristics, as well as their catalytic properties, crystalline molecular sieves are especially useful in applications such as hydrocarbon conversion. Although many different crystalline molecular sieves have been disclosed, there is a continuing need for new materials with desirable properties for hydrocarbon and chemical conversions, and other applications.
SUMMARY OF THE INVENTION
The present invention is directed to a family of crystalline, phosphorus-containing molecular sieves. The molecular sieves of this invention have some characteristics of zeolites (such as a relatively high mole ratio of silica to alumina in the crystal structure) as well as some characteristics of silicoaluminophosphates (such as having a relatively high phosphorus content in the crystal structure). Because of this duality of characteristics, the crystalline, phosphorus-containing molecular sieves of this invention are termed “zeophosphates” herein.
In accordance with this invention, there is provided a crystalline molecular sieve composition comprising (1) phosphorus oxide; (2) a first oxide comprising an oxide of silicon, germanium or mixtures thereof; and (3) a second oxide comprising an oxide of aluminum, boron or mixtures thereof, said molecular sieve having a mole ratio of the first oxide to the second oxide of greater than 1, containing at least about 10 weight percent phosphorus oxide in the crystal framework, and having pores greater than 5 Å in diameter. The molecular sieves of this invention can have a mole ratio of the first oxide to the second oxide of about 3 or greater, e.g., from about 10 to about 30. The molecular sieves may have the FAU crystal structure.
Further provided by the present invention is an improved method for preparing a molecular sieve comprising (1) phosphorus oxide; (2) a first oxide comprising an oxide of silicon, germanium or mixtures thereof; and (3) a second oxide comprising an oxide of aluminum, boron or mixtures thereof by contacting under crystallization conditions a mixture comprising one or more active sources of said oxides with one or more templating agent capable of forming said molecular sieve, the improvement comprising including a zeolite containing the first oxide and second oxide in the mixture of oxides. The present invention also provides such a method wherein the zeolite is a source of the first oxide and second oxide. The present invention also includes such a method wherein the first oxide is silicon oxide and the second oxide is aluminum oxide. Further provided in accordance with this invention is such a method wherein the zeolite is Y zeolite, and such a method wherein the Y zeolite has a first oxide/second oxide mole ratio of less than about 30, e.g., less than about 15 or less than about 12. Also provided in accordance with this invention is such a process wherein the Y zeolite has an alkali metal content of less than about 1 weight percent. The method of this invention may be conducted such that the mixture used to form the molecular sieve has a starting pH of at least 5. Further provided in accordance with this invention is such a method wherein the molecular sieve formed has the FAU crystal structure.
The present invention also provides such a method wherein the molecular sieve formed has a mole ratio of the first oxide to the second oxide of greater than 1, e.g., 3 or greater, and contains at least about 10 weight percent, e.g., about 10 to about 25 weight percent, phosphorus oxide in the crystal framework.
The present invention additionally provides a process for converting hydrocarbons comprising contacting a hydrocarbonaceous feed at hydrocarbon converting conditions with a catalyst comprising a zeophosphate of this invention.
Further provided by the present invention is a hydrocracking process comprising contacting a hydrocarbon feedstock under hydrocracking conditions with a catalyst comprising a zeophosphate of this invention, preferably predominantly in the hydrogen form.
Also included in this invention is a process for increasing the octane of a hydrocarbon feedstock to produce a product having an increased aromatics content comprising contacting a hydrocarbonaceous feedstock which comprises normal and slightly branched hydrocarbons having a boiling range above about 40° C. and less than about 200° C., under aromatic conversion conditions with a catalyst comprising a zeophosphate of this invention made substantially free of acidity by neutralizing said zeophosphate with a basic metal. Also provided in this invention is such a process wherein the zeophosphate contains a Group VIII metal component.
Also provided by the present invention is a catalytic cracking process comprising contacting a hydrocarbon feedstock in a reaction zone under catalytic cracking conditions in the absence of added hydrogen with a catalyst comprising a zeophosphate of this invention, preferably predominantly in the hydrogen form. Also included in this invention is such a catalytic cracking process wherein the catalyst additionally comprises a large pore crystalline cracking component.
The present invention further provides an isomerizing process for isomerizing C
4
to C
7
hydrocarbons, comprising contacting a catalyst, comprising at least one Group VIII metal and a zeophosphate of this invention, preferably predominantly in the hydrogen form, with a feed having normal and slightly branched C
4
to C
7
hydrocarbons under isomerizing conditions.
This invention also provides a process for alkylating an aromatic hydrocarbon which comprises contacting under alkylation conditions at least a mole excess of an aromatic hydrocarbon with a C
2
to C
20
olefin under at least partial liquid phase conditions and in the presence of a catalyst comprising a zeophosphate of this invention, preferably predominantly in the hydrogen form.
This invention additionally provides a process for transalkylating an aromatic hydrocarbon which comprises contacting under transalkylating conditions an aromatic hydrocarbon with a polyalkyl aromatic hydrocarbon under at least partial liquid phase conditions and in the presence of a catalyst comprising a zeophosphate of this invention, preferably predominantly in the hydrogen form.
This invention also provides a process for converting lower alcohols and other oxygenated hydrocarbons comprising contacting said lower alcohol or other oxygenated hydrocarbon with a catalyst comprising a zeophosphate of this invention, preferably predominantly in the hydrogen form, under conditions to produce liquid products.
Further provided in accordance with this invention is a process for isomerizing an isomerization feed comprising an aromatic C
8
stream of xylene isomers or mixtures of xylene isomers and ethylbenzene, wherein a more nearly equilibrium ratio of ortho-, meta and para-xylenes is obtained, said process comprising contacting said feed under isomerization conditions with a catalyst comprising a zeophosphate of this invention, preferably predominantly in the hydrogen form.
The present invention further provides a process for oligomerizing olefins comprising contacting an olefin feed under oligomerization conditions with a catalyst comprising a zeophosphate of this invention, preferably predominantly in the hydrogen form.
Also provided by the present invention is an improved process for the reduction of oxides of nitrogen contained in a gas stream in the presence of oxygen wherein said process comprises contacting the gas stream with a molecular sieve, the improvement comprising using as the molecular sieve a zeophosphate of this invention. The zeophosphate may contain a metal or metal ions capable of catalyzing the reduction of the oxides of nitrogen, and may be conducted in the presence of a stoichiometric excess of oxygen. In a preferred
Chevron U.S.A. Inc.
Ellinwood Steven R.
Sample David
Sheridan Richard J.
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