Claims
- 1. A catalyst composition which is capable of cracking a heavy bottoms fraction produced as a byproduct in the preparation of isopropylbenzene from benzene and a mixture of propane and propylene, said bottoms fraction consisting essentially of hydrocarbons having 10 or more carbon atoms, the product of said cracking comprising benzene, toluene, xylene and ethylbenzene, said composition comprising a mixture of zeolites, said zeolite mixture comprising:
- (i) from about 10% to about 90% by weight of ZSM-5; and
- (ii) from about 10% to about 90% by weight of ZSM-12, wherein said catalyst is capable of producing more total of said benzene, toluene, xylene and ethylbenzene than a catalyst wherein either ZSM-5 or ZSM-12 is essentially the sole zeolite thereof, said benzene, toluene, xylene and ethylbenzene being produced by cracking equivalent bottoms fractions under equivalent conditions.
- 2. A catalyst composition according to claim 1, wherein the ratio of ZSM-12 to ZSM-5 is 2:1.
- 3. A catalyst composition according to claim 1, wherein said zeolites are composited with porous matrix material.
- 4. A catalyst composition according to claim 1, further comprising an additional hydrogenation/dehydrogenation component.
- 5. A catalyst composition according to claim 1 which is essentially free of an additional hydrogenation/dehydrogenation component.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a division of copending U.S. application Ser. No. 784,965, filed Oct. 7, 1985, now U.S. Pat. No. 4,593,136, which is a division of copending U.S. application Ser. No. 620,590, filed Jun. 14, 1984, now U.S. Pat. No. 4,577,05 which is a continuation-in-part of copending U.S. application Ser. No. 490,624, filed May 2, 1983, now abandoned. The entire disclosures of these applications are expressly incorporated herein by reference.
This invention relates to a catalyst, which is a mixture of ZSM-5 and ZSM-12, and a method for cracking alkylbenzenes over this catalyst mixture.
The Tabak et al. U.S. Pat. No. 4,188,282, the entire disclosure of which is expressly incorporated herein by reference, describes a process utilizing a zeolite catalyst for converting reformer bottoms having at least 8 carbon atoms to hydrocarbon mixtures enriched in benzene, toluene and xylene (BTX).
In the process for alkylation of benzene with propylene or propane/propylene mixtures to produce cumene, di- and poly-propylated benzene derivatives and other alkylated benzene derivatives are produced as side reaction products. These products are presently utilized as relatively low value fuel.
The production of cumene (i.e. isopropylbenzene) is discussed in the Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Volume 7, pp. 286-290, John Wiley and Sons (1979), the entire disclosure of which is expressly incorporated herein by reference.
According to one aspect of the invention, there is provided a catalyst comprising a mixture of zeolites, said mixture comprising:
(i) from about 10% to about 90% by weight of ZSM-5; and
(ii) from about 10% to about 90% by weight of ZSM-12.
According to another aspect of the invention, there is provided a process for converting a first hydrocarbon mixture to a second hydrocarbon mixture, said first hydrocarbon mixture consisting essentially of aromatic hydrocarbons having 10 or more carbon atoms, said first hydrocarbon mixture comprising at least 50% by weight of diisopropylbenzene and less than 5% by weight of the sum of benzene, toluene, xylene and ethylbenzene, said second hydrocarbon mixture comprising at least 30% by weight of the sum of benzene, toluene, xylene and ethylbenzene and less than 20% by weight of diisopropylbenzene, said process comprising cracking said first hydrocarbon mixture over a catalyst comprising a mixture of zeolites, said mixture of zeolites consisting essentially of from about 10% to about 90% by weight of ZSM-5, the remainder being essentially ZSM-12.
According to another aspect of the invention, there is provided an improved method for the preparation of isopropylbenzene from benzene and a mixture of propane and propylene, wherein a heavy aromatic bottoms fraction is produced as a byproduct, said bottoms fraction consisting essentially of hydrocarbons having 10 or more carbon atoms, the improvement comprising cracking said bottoms fraction over a catalyst comprising a mixture of zeolites, said mixture comprising:
(i) from about 10% to about 90% by weight of ZSM-5; and
(ii) from about 10% to about 90% by weight of ZSM-12.
US Referenced Citations (8)
Divisions (2)
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784965 |
Oct 1985 |
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| Parent |
620590 |
Jun 1984 |
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Continuation in Parts (1)
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490624 |
May 1983 |
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Patent Grant
4975401
