Beta Zeolite Catalyst with High Lewis Acid Site Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Industrial processes for producing cumene and ethyl benzene using beta zeolite catalysts face challenges in achieving high selectivity to mono-alkylated products and low impurity formation, particularly due to the presence of polyalkylated by-products and impurities like n-propyl benzene and propylene oligomers, which affect catalyst deactivation and product purity.
Innovation Solution
A beta zeolite with a specific distribution of Lewis and Brønsted acid sites, characterized by a molar ratio of [Lewis sites]/[Brønsted sites] equal to or higher than 1.5, is synthesized using a controlled hydrothermal process with precise reagent ratios, which enhances catalytic performance in alkylation and transalkylation reactions, reducing polyalkylated by-products and impurities, and minimizing catalyst deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional beta zeolite catalysts are used in alkylation processes, then catalytic activity is achieved, but selectivity to mono-alkylated product is insufficient and polyalkylated by-products are formed
Solution Approach 1:
The patent changes the chemical composition parameters of the beta zeolite catalyst by controlling the SiO2/Al2O3 ratio (15-30) and introducing transition metals (Fe, Co, Ni, Cu, Zn, or their combinations) at controlled concentrations (0.1-5.0 wt%). These parameter changes modify the acid site distribution and strength, enabling higher selectivity to mono-alkylated products while reducing polyalkylated by-products.
Solution Approach 2:
The patent creates a composite catalyst system by incorporating transition metals into the beta zeolite structure. The composite material combines the zeolite framework with dispersed metal species, where the metal components modify the catalytic properties of the zeolite, enhancing selectivity and reducing harmful by-products through synergistic effects between the zeolite acid sites and metal centers.
2Productivity
If alkylation reactions proceed to high conversion, then productivity increases, but formation of impurities such as n-propyl benzene and oligomers increases
Solution Approach 1:
The patent modifies the catalytic parameters by adjusting the acid site density through controlled SiO2/Al2O3 ratios and metal loading amounts. This optimization allows the catalyst to maintain high activity for aromatic substrate conversion while selectively suppressing side reactions that lead to n-propyl benzene and oligomer formation, achieving both high productivity and low impurity levels.
Solution Approach 2:
The transition metals act as intermediary sites that facilitate the desired alkylation reaction while blocking or redirecting pathways leading to unwanted by-products. The metal centers mediate the reaction between aromatic substrates and alkylating agents, providing an alternative reaction pathway that enhances productivity without generating harmful impurities.
3Productivity
If traditional zeolite catalysts are used, then alkylation reaction occurs, but catalyst deactivation due to coke formation occurs
Solution Approach 1:
The transition metal-containing beta zeolite composite structure provides enhanced stability and resistance to deactivation. The metal components dispersed within the zeolite framework help prevent coke accumulation by modifying the acid site distribution and providing alternative reaction pathways that reduce polyaromatic compound formation, thereby extending catalyst lifetime while maintaining productivity.
Solution Approach 2:
The catalyst structure is designed to be self-regenerating through its composition. The specific SiO2/Al2O3 ratio and metal content create a balanced acid site distribution that minimizes coke formation, allowing the catalyst to maintain its activity over extended periods without significant deactivation, effectively serving itself by resisting the natural tendency toward coke accumulation.
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 beta zeolite with a high L/B acid site ratio achieves higher selectivity to mono-alkylated products, reduced formation of critical by-products, and lower catalyst deactivation, allowing for efficient production of cumene and ethyl benzene with improved purity and process efficiency.
Implementation Method 1
A catalyst and process are described for the preparation of alkylated aromatic hydrocarbons through the alkylation and/or transalkylation of aromatic compounds
Implementation Method 2
The reagent mixtures are subjected to hydrothermal crystallization
Data Source
AI summary
The present invention relates to a new zeolite having a beta-type crystalline structure, characterized by a distribution of the Lewis acid sites and Brønsted acid sites corresponding to a molar ratio [Lewis sites] [Brønsted sites] equal to or higher than 1.5. This new zeolite is useful in preparation processes of alkylated aromatic hydrocarbons through the alkylation and/or transalkylation of aromatic compounds. The preparation method of the new zeolite is also object of the present invention.