Bimodal Porous Dealkylation Catalyst for C9+ Aromatics
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Solution Overview
Problem
Current methods for producing mesitylene from C9+ aromatic compounds are inefficient due to low conversion rates, high reaction temperatures, and waste production, with existing catalysts exhibiting shape selectivity and low recovery yields.
Innovation Solution
A method involving a dealkylation catalyst with a bimodal porous structure, comprising both mesopores and micropores in a crystalline aluminosilicate, supported with a metal like platinum, which selectively dealkylates C9+ aromatic compounds at low temperatures in the presence of hydrogen, optimizing pore structure and acid site density for enhanced reaction activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional zeolite catalysts with shape selectivity are used for dealkylation, then catalyst specificity is improved, but conversion rates decrease and reaction temperatures must be increased
Solution Approach 1:
The patent employs a bimodal porous catalyst structure combining micropores (5-20 Å) and mesopores (20-100 Å) to resolve the contradiction between shape selectivity and conversion rate. The micropores provide molecular sieving and shape selectivity for specific dealkylation reactions, while the mesopores facilitate mass transport and accommodate larger C9+ aromatic molecules, thereby maintaining high conversion rates without sacrificing catalyst specificity
Solution Approach 2:
The invention creates a composite catalyst system by integrating crystalline aluminosilicate (zeolite) with metal particles (Pt, Pd, Ni, or Ru) on a bimodal porous support. This composite structure combines the shape-selective properties of zeolite with the catalytic activity of metals, achieving both high conversion rates and specific dealkylation of C9+ aromatics at moderate temperatures
2Productivity
If high reaction temperatures are applied to improve conversion, then productivity increases, but energy consumption increases and recovery yields decrease
Solution Approach 1:
The patent optimizes reaction conditions by conducting dealkylation at moderate temperatures (200-400°C) rather than high temperatures, achieving high conversion through the optimized bimodal porous catalyst structure and metal-supported system. This parameter change reduces energy consumption while maintaining productivity through enhanced catalyst activity and selectivity
3Device complexity
If conventional monomodal porous catalysts are used, then catalyst structure is simple, but reaction activity is low due to diffusion limitations
Solution Approach 1:
The patent introduces a bimodal porous structure with both micropores (5-20 Å) and mesopores (20-100 Å) to overcome diffusion limitations in monomodal catalysts. The hierarchical pore system allows efficient mass transport through mesopores while maintaining high surface area and active sites in micropores, significantly enhancing reaction activity without excessive structural complexity
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
This approach significantly improves reaction activity and recovery yields of trimethylbenzenes, allowing for efficient conversion of ethyltoluenes to mesitylene at lower temperatures with reduced waste and energy consumption, while maintaining high purity and economic viability.
Implementation Method 1
a dealkylation catalyst that has a bimodal porous structure including both mesopores and micropores
Implementation Method 2
bimodal porous structure including both mesopores with a diameter of 20 to 100 Å and micropores with a diameter of 4 to 20 Å
Implementation Method 3
dealkylation catalyst includes a crystalline aluminosilicate and a metal supported on the crystalline aluminosilicate
Implementation Method 4
conversions are low due to the shape selectivity of the catalysts
Data Source
AI summary
Disclosed is a method for selective dealkylation of alkyl-substituted C9+ aromatic compounds using a bimodal porous dealkylation catalyst at a low temperature. The catalyst has a bimodal porous structure including both mesopores and micropores. The catalyst includes a crystalline aluminosilicate and a metal. The catalyst is highly active at a low temperature. According to the method, C9+ aromatic compounds substituted with at least one C2+ alkyl group as by-products formed by xylene production can be selectively dealkylated and converted to BTX, etc. on a large scale within a short time. In addition, the method is an environmentally friendly process entailing reduced waste treatment cost when compared to conventional mesitylene production methods. Therefore, high value-added mesitylene can be separated from low value-added C9+ aromatic compounds at lower cost compared to conventional methods. Furthermore, the supported metal catalyst is easy to recover after dealkylation and is recyclable, thereby contributing to reduced cost.