Bimetallic Catalyst and Use in Xylene Production

a technology of bimetallic catalysts and xylene, which is applied in the direction of physical/chemical process catalysts, bulk chemical production, liquid chemical processes, etc., can solve the problems that none of the systems described above are concerned with processing paraxylene-depleted feed streams, and achieves improved selectivity, lower xylene loss, and high ethylene saturation

Inactive Publication Date: 2015-07-16
EXXONMOBIL CHEM PAT INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention is a new catalyst system for making xylenes, which has improved properties such as higher ethylene saturation, lower xylene loss, decreased ring loss, and a decreased susceptibility to poisoning from feedstream impurities. The new system also operates at less severe conditions. This patent aims to provide a simple and reproducible method for making the catalyst system that avoids problems of the prior art such as xylene loss by ring saturation and sulfur poisoning.

Problems solved by technology

Unfortunately, an equilibrium mixture of xylenes contains roughly twice as much metaxylene as para- or orthoxylene.
However, none of the systems described above are concerned with processing paraxylene-depleted feed streams through multiple bed systems where the functions of dealkylation and isomerization can be separately managed for improved performance.

Method used

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  • Bimetallic Catalyst and Use in Xylene Production
  • Bimetallic Catalyst and Use in Xylene Production
  • Bimetallic Catalyst and Use in Xylene Production

Examples

Experimental program
Comparison scheme
Effect test

example 1

Top-Bed Catalyst Preparation: 0.1 wt % Pt and 1:0 Pt / Ag Molar Ratio

[0046]The catalyst used for top-bed catalyst preparation was H-ZSM-5 with 35% silica binder in a 1 / 16″ (approximately 0.16 cm) cylindrical extrudate form. The H-ZSM-5 was selectivated three times with silicone before metal impregnation. An impregnation solution made with 1.41 g of tetraamine platinum nitrate solution (an aqueous solution with 3.55 wt % Pt) and 16.7 g of de-ionized (DI) water was slowly added to 50 g of the catalyst. The mixture was tumbled thoroughly until completely loose. The mixture was air-dried first at ambient conditions then at 250° F. for four hours. The mixture was calcined at 660° F. (352° C.) for 3 hours with a mixture of 40% air and 60% nitrogen at a flow rate of 5 vol / vol / min.

example 2

Top-Bed Catalyst Preparation: 0.1 wt % Pt and 1:1 Pt / Ag Molar Ratio

[0047]The same procedure described in Example 1 was followed except that the impregnation solution was made with the composition below:[0048]1.41 g of tetraamine platinum nitrate solution (an aqueous solution with 3.55 wt % Pt)[0049]0.0446 g of chemical grade silver nitrate, solid[0050]16.7 g of DI water

example 3

Top-Bed Catalyst Preparation: 0.1 wt % Pt and 1:2 Pt / Ag Molar Ratio

[0051]The same procedure described in Example 1 was followed except that the catalyst used was 100 g and the impregnation solution was made with the composition below:[0052]2.83 g of tetraamine platinum nitrate solution (an aqueous solution with 3.55 wt % Pt)[0053]0.175 g of chemical grade silver nitrate, solid[0054]26.2 g of DI water

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Abstract

The invention is directed to a bimetallic catalyst system adapted for the manufacture of xylenes, a process for making said catalyst system, and to the process of manufacture of xylenes using said catalyst system, providing, in embodiments, improved selectivity by at least one of higher ethylene saturation and low xylene loss, decreased susceptibility to poisoning from feedstream impurities, and ability to operate at less severe conditions.

Description

PRIORITY CLAIM[0001]This application claims the benefit of Provisional Application No. 61 / 604,926, filed Feb. 29, 2012, the disclosure of which is incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]The invention relates to bimetallic catalysts used in the production of xylenes, and more specifically in ethylbenzene dealkylation-xylene isomerization systems to make paraxylenes.BACKGROUND OF THE INVENTION[0003]A typical aromatic hydrocarbon stream found in petrochemical plants and refineries, such as may be produced by reforming and cracking naphtha, includes the C8 aromatic hydrocarbon isomers ethylbenzene and the xylene isomers paraxylene, metaxylene, and orthoxylene. Paraxylene is relatively high value as compared with the other isomers because it is used as the main raw material for polyester fibers. Orthoxylene, useful such as for preparing phthalate esters for plasticizers, is relatively more valuable than metaxylene. Unfortunately, an equilibrium mixture of x...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): C07C5/27B01J29/44B01J37/08C07C7/148
CPCC07C2529/44C07C5/2737C07C5/2754C07C5/2708C07C15/08C07C5/2556C07C5/222B01J23/42B01J23/50B01J23/60B01J23/62B01J23/626B01J23/628B01J23/8926B01J29/405B01J29/44B01J29/46B01J37/0018B01J2229/186B01J2229/36B01J2229/42Y02P20/52B01J16/005
InventorROSS, APRIL D.CHENG, JANE C.
OwnerEXXONMOBIL CHEM PAT INC