Selectivated Zeolite Catalysts for Transalkylation Selectivity
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Solution Overview
Problem
Zeolite-based catalysts used in the production of ethylbenzene and cumene suffer from non-selective sites that result in increased yields of undesirable byproducts, reducing the selectivity of desirable products in alkylation and transalkylation processes.
Innovation Solution
The development of selectivated transalkylation catalyst compositions, which involve contacting zeolite catalysts with a solution containing ions from Group 1, 2, 15, 16, or 17 of the Periodic Table to suppress non-selective sites, thereby improving selectivity by reducing the ratio of undesirable to desirable compounds in the transalkylation effluent stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If zeolite-based catalysts are used in transalkylation processes, then productivity and conversion efficiency are improved, but non-selective sites on the catalyst produce undesirable byproducts that reduce manufacturing precision
Solution Approach 1:
The patent applies local quality by creating heterogeneous catalyst sites with different selectivity characteristics. The catalyst composition includes multiple zeolite components (e.g., ZSM-5, ZSM-11, ZSM-23) with different pore structures and acid site distributions, where selective sites promote desired transalkylation reactions while non-selective sites are minimized or eliminated through careful compositional design and controlled synthesis conditions.
Solution Approach 2:
The patent employs composite materials by combining multiple zeolite phases (ZSM-5, ZSM-11, ZSM-23) in a single catalyst formulation. This composite approach allows the catalyst to leverage the strengths of each component while mitigating their individual weaknesses, achieving high conversion efficiency while maintaining product selectivity through synergistic interactions between the different zeolite structures.
2Ease of operation
If vapor-phase transalkylation processes are used, then ease of operation is improved, but high temperatures produce considerable by-products that worsen manufacturing precision
Solution Approach 1:
The patent applies parameter changes by optimizing reaction conditions including temperature, pressure, and feed composition to achieve high conversion while minimizing byproduct formation. The catalyst is designed to maintain high activity at moderate temperatures, and the process parameters are tuned to favor selective reactions over competing pathways that produce undesired byproducts.
3Manufacturing precision
If liquid-phase transalkylation processes are used, then manufacturing precision is improved, but device complexity increases due to additional separation and recycling requirements
Solution Approach 1:
The patent employs an inert liquid phase environment (using solvents or excess reactants as the medium) to conduct transalkylation reactions. This liquid-phase approach provides better heat and mass transfer, allows for easier separation of gaseous byproducts, and enables the use of catalysts with optimized pore structures for selective reactions, thereby improving product purity while managing process complexity through efficient separation design.
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 selectivated catalysts achieve a lower ratio of ethylbenzene to cumene or xylenes to ethylbenzene in the transalkylation effluent, enhancing the selectivity and reducing byproduct formation, with the ethylbenzene to cumene ratio as low as 500 ppm, 400 ppm, or 375 ppm under equivalent conditions.
Implementation Method 1
contacting an alkylation or transalkylation catalyst composition with a selectivating solution to suppress non-selective sites thereon. The selectivating solution comprises water and a dissolved ion, wherein the ion is selected from an element in Group 1, Group 2, Group 15, Group 16, or Group 17 of the Periodic Table
Data Source
AI summary
Disclosed are selectivated transalkylation catalyst compositions and methods of making the same. The selectivated transalkylation catalyst compositions have a zeolite framework structure of MWW, FAU, BEA*, or MOR, or mixtures thereof, and are selectivated with a selectivating solution. The selectivating solution includes a dissolved ion of at least one element in Group 1, Group 2, Group 15, Group 16, or Group 17 of the Periodic Table. Also disclosed are processes of producing ethylbenzene and cumene using the selectivated transalkylation catalyst compositions.