Xylene isomerization
AssigneeUnion Carbide Corporation
InventorsRegis J. Pellet, Gary N. Long, Jule A. Rabo, Peter K. Coughlin
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Abstract
Xylene isomerization is carried out using specific non-zeolitic molecular sieve catalyst, e.g., the silicoaluminophosphate molecular sieves of U.S. Pat. No. 4,440,871, to provide improved production of p-xylene from C.sub.8 aromatic compounds and the conversion of ethylbenzene to a xylene.
Claims30
An isomerization process for manufacture of xylenes from an initial feed stream comprising C.sub.8 aromatics and containing xylenes which comprises contacting said feed stream with a catalyst containing at least one NZMS which has been either calcined, hydrotreated or chemically treated to remove at least a portion of the template used in the manufacture of the NZMS, or, alternatively, is calcined, hydrotreated or chemically treated in situ prior to carrying out the isomerization process at effective isomerization conditions to provide a selected xylene isomer in a greater concentration than the concentration of said xylene isomer initially in said feed stream wherein said NZMS is characterized in the calcined form by an absorption of isobutane of at least 2 percent by weight at a partial pressure of 500 torr and a temperature of 20.degree. C. and is further characterized after removal of the template by an adsorption of triethylamine less than 5 percent by weight at a pressure of 2.6 torr and a temperature of 22.degree. C.
In a process for conversion of a mixture of aromatic compounds having 8 carbon atoms, said mixture containing ethylbenzene and xylenes, to isomerize xylenes contained in said mixture and convert at least part of said ethylbenzene;
- the improvement which comprises contacting such mixture with a catalyst containing at least one NZMS catalyst which has been either calcined, hydrotreated or chemically treated to remove at least a portion of the template used in the manufacture of the NZMS, or, alternatively, is calcined, hydrotreated or chemically treated in situ prior to carrying out the isomerization process, in the presence of added hydrogen at effective process conditions to isomerize xylenes containing in said mixture and to convert at least part of said ethylbenzene, wherein said NZMS is characterized in the calcined form by an adsorption of isobutane of at least 2 percent by weight at a partial pressure of 500 torr and a temperature of 20.degree. C. and is further characterized after removal of the template by an adsorption of triethylamine of less than 5 percent by weight at a pressure of 2.6 torr and a temperature of 22.degree. C.
The process of 7 wherein said inorganic oxide matrix component is selected from the group consisting of clays, silicas, aluminas, and mixtures thereof.
Dependencies are inferred from the claim text.