Modified EU-1 Zeolite Catalyst for Aromatic C8 Isomerization
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Solution Overview
Problem
Existing zeolitic catalysts for isomerizing aromatic C8 cuts, such as ethylbenzene to xylenes, suffer from low conversion rates and suboptimal xylenes yield, despite achieving advantageous selectivity.
Innovation Solution
A catalyst comprising a modified EU-1 zeolite with more than 20% hexacoordinated aluminium atoms by weight, combined with a matrix and a Group VIII metal, enhances catalytic activity and selectivity for xylenes production during the isomerization of aromatic C8 cuts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional zeolitic catalysts (ZSM-5, mordenite, EUO, MTW) are used for isomerization of aromatic C8 cut, then selectivity for xylenes is improved, but conversion of ethylbenzene is too low
Solution Approach 1:
The patent applies parameter changes by modifying the coordination state of aluminium atoms in the EU-1 zeolite framework. Specifically, it increases the proportion of hexacoordinated aluminium atoms (AlVI) to more than 20% by weight of total aluminium atoms, while maintaining tetracoordinated aluminium atoms (AlIV). This chemical parameter modification of the zeolite structure enhances both the conversion activity and xylene selectivity, resolving the contradiction between selectivity and conversion.
Solution Approach 2:
The patent creates a composite catalyst system combining modified EU-1 zeolite with a matrix material and a Group VIII metal component. This composite structure integrates the shape-selective properties of EU-1 zeolite with the catalytic activity of Group VIII metals and the structural support of the matrix, achieving synergistic effects that simultaneously improve conversion and maintain selectivity for xylene production.
2Manufacturing precision
If unmodified EU-1 zeolite is used as catalyst, then selectivity for xylenes is maintained, but catalytic activity and xylenes yield are insufficient
Solution Approach 1:
The patent modifies the EU-1 zeolite by changing the coordination parameters of aluminium atoms through hydrothermal treatment or chemical modification. The modification increases hexacoordinated aluminium content to >20% by weight, which enhances the acid site density and catalytic activity. This parameter change maintains the pore structure and shape selectivity of EU-1 zeolite while significantly improving xylene yield through enhanced conversion of ethylbenzene.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified EU-1 zeolite catalyst significantly increases the conversion of aromatic C8 cuts and yields xylenes, maintaining selectivity while improving overall process efficiency.
Implementation Method 1
a catalyst which comprises at least one modified EU-1 zeolite containing silicon atoms and aluminium atoms... used in a process for isomerization of an aromatic cut comprising at least one aromatic compound containing eight carbon atoms per molecule
Data Source
AI summary
A catalyst is described which comprises at least one modified EU-1 zeolite containing silicon atoms and aluminum atoms, at least one matrix and at least one metal from group VIII of the periodic table of the elements, the modified zeolite having a number of hexacoordinated aluminum atoms representing more than 20% by weight of the total number of aluminum atoms present in said modified EU-1 zeolite. Said catalyst is used in a process for the isomerization of an aromatic feed comprising at least one compound containing eight carbon atoms per molecule.