Ion-Modified Binder for Zeolite Catalyst Selectivity
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Solution Overview
Problem
Zeolite catalysts used in the alkylation of toluene with methanol and/or formaldehyde to produce styrene often result in the formation of unwanted by-products due to high acid site activity and limited selectivity, necessitating a reduction in acid sites and improvement in product selectivity.
Innovation Solution
An ion-modified binder with metal ions such as Co, Mn, Ti, Zr, V, Nb, K, Cs, Ga, B, P, Rb, Ag, Na, Cu, Mg, Fe, Mo, and Ce is used to reduce the number of acid sites and alter the spatial structure of the zeolite catalyst, enhancing mechanical stability and selectivity by forming a zeolite aggregate with amorphous silica or alumina.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If zeolite catalyst with high acid site activity is used for alkylation of toluene, then reaction activity is improved, but by-product formation increases and selectivity deteriorates
Solution Approach 1:
The patent applies local quality by creating zeolite aggregates with non-uniform acid site distribution. The binder material is selectively placed in specific locations within the aggregate structure, creating zones with different acid site densities. This allows high activity in reactant-accessible regions while limiting by-product formation in internal regions, resolving the contradiction between reaction activity and selectivity.
Solution Approach 2:
The binder material acts as an intermediary substance that modifies the catalyst's acid site characteristics. It mediates between the highly active but non-selective zeolite crystallites and the reaction environment, reducing overall acid site activity while maintaining sufficient catalytic function. This intermediary role allows the system to achieve acceptable activity with improved selectivity.
2Power
If zeolite catalyst is used without binder modification, then catalytic activity is maintained, but mechanical stability deteriorates
Solution Approach 1:
The patent employs composite materials by combining zeolite crystallites with binder material to form zeolite aggregates. This composite structure provides the mechanical strength and stability of the binder while maintaining the catalytic activity of the zeolite components. The composite aggregate structure resolves the contradiction between catalytic activity and mechanical stability.
Solution Approach 2:
The catalyst is segmented into discrete zeolite aggregates rather than using bulk zeolite material. This segmentation creates smaller, mechanically more stable units that can be better supported by the binder material. The segmented aggregate structure maintains high surface area and activity while improving mechanical properties compared to bulk zeolite.
3Strength
If conventional binder is used with zeolite catalyst, then mechanical support is provided, but acid site reduction and selectivity improvement are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the binder material's chemical composition and acid site characteristics. The binder is specifically engineered to have certain acid site densities and types that differ from conventional binders. This parameter modification allows the binder to simultaneously provide mechanical support and actively reduce acid site activity, achieving both structural and functional improvements.
Solution Approach 2:
The binder material is designed to perform multiple functions simultaneously: providing mechanical support to the zeolite crystallites, reducing overall acid site activity, and improving product selectivity. This multi-functional binder resolves the contradiction by making the support material itself an active component in controlling catalytic behavior, rather than merely a passive structural element.
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 ion-modified binder reduces acid site activity, increases styrene selectivity, and enhances mechanical stability, leading to improved product yield and reduced by-product formation in the alkylation process.
Implementation Method 1
The metal ions reduce the number of acid sites on the zeolite catalyst component
Implementation Method 2
A zeolite can exchange its native cations for other cations; one example is the exchange of sodium ions for ammonium ions
Data Source
AI summary
An alkylation catalyst having a zeolite catalyst component and a binder component providing mechanical support for the zeolite catalyst component is disclosed. The binder component is an ion-modified binder that can include metal ions selected from the group consisting of Co, Mn, Ti, Zr, V, Nb, K, Cs, Ga, B, P, Rb, Ag, Na, Cu, Mg, Fe, Mo, Ce, and combinations thereof. The metal ions reduce the number of acid sites on the zeolite catalyst component. The metal ions can range from 0.1 to 50 wt % based on the total weight of the ion-modified binder. Optionally, the ion-modified binder is present in amounts ranging from 1 to 80 wt % based on the total weight of the catalyst.