Catalyst – solid sorbent – or support therefor: product or process – Zeolite or clay – including gallium analogs – And additional al or si containing component
Reexamination Certificate
1999-12-20
2001-05-29
Dunn, Tom (Department: 1754)
Catalyst, solid sorbent, or support therefor: product or process
Zeolite or clay, including gallium analogs
And additional al or si containing component
C502S060000, C502S071000, C502S077000
Reexamination Certificate
active
06239056
ABSTRACT:
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved process for the disproportionation of aromatic hydrocarbons to yield desirable alkylaromatic isomers. A specific objective is to obtain a high yield of paraxylene by disproportionation of toluene.
This invention is based on the discovery that high activity with potential for selectivity to paraxylene is obtained by disproportionation of toluene using a catalyst, having a particular X-ray diffraction pattern, comprising a zeolite oil-dropped with an aluminum phosphate binder.
The present invention therefore is directed to an oil-dropped spherical catalyst comprising a zeolitic aluminosilicate having a pore diameter of from about 5 to 8 A and an aluminum phosphate binder. The catalyst has an X-ray powder diffraction pattern such that the ratio of peak intensities at respective two-&THgr; Bragg angle values of 48.5:46.5 is at least about 1.1, and optimally the ratio of peak intensities at respective two-&THgr; Bragg angle values of 48.5:47.5 is at least about 1.0. The preferred catalyst of the present invention comprises a zeolitic aluminosilicate preferably selected from MFI, MEL and MTW, and most preferably comprises MFI. In one embodiment, the catalyst has a particle size of no more than about 1 mm.
The invention also comprises a process for the disproportionation of a toluene feedstock using the present catalyst to obtain a product comprising paraxylene. Preferably the product contains paraxylene in excess of its equilibrium concentration at disproportionation conditions. The catalyst preferably is subjected to a precoking step prior to its use for disproportionation/transalkylation in order to deposit a controlled concentration of carbon on the catalyst and increase its selectivity to paraxylene in the product. A process combination optionally comprises a xylene-separation zone using adsorptive separation.
These as well as other objects and embodiments will become apparent from the detailed description of the invention.
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Boldingh Edwin P.
Gajda Gregory J.
Holmgren Jennifer S.
Dunn Tom
Spears, Jr. John F.
Tolomei John G.
UOP LLC
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