MCM-22 Molecular Sieve Catalyst for Selective Alkylation
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Solution Overview
Problem
Existing catalyst compositions for alkylation and transalkylation of aromatic hydrocarbons produce undesired polyalkylated impurities alongside the desired monoalkylated compounds, leading to reduced selectivity in hydrocarbon conversion processes.
Innovation Solution
A catalyst composition comprising a MCM-22 family molecular sieve with an average crystal agglomerate size of less than or equal to 16 microns, combined with a binder, which enhances the selectivity for monoalkylated aromatic compounds by reducing the crystal size through physical or chemical means such as milling or jet milling, and operating under specific alkylation or transalkylation conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional catalyst compositions with larger crystal sizes are used, then the catalyst activity is maintained, but the selectivity to monoalkylated aromatic compounds decreases due to production of undesired polyalkylated impurities
Solution Approach 1:
The patent applies parameter changes by reducing the crystal agglomerate size of the MCM-22 family molecular sieve from conventional larger sizes to less than or equal to 16 microns. This size parameter modification changes the catalyst's performance characteristics, improving selectivity to monoalkylated aromatic compounds while reducing formation of polyalkylated impurities.
Solution Approach 2:
The patent implements local quality by creating a catalyst composition with non-uniform crystal size distribution, specifically using a binder with particles larger than the molecular sieve crystals. This local structural differentiation optimizes mass transfer and reaction conditions at different locations within the catalyst pellet, enhancing selectivity for monoalkylation.
2Manufacturing precision
If the crystal agglomerate size is reduced to less than or equal to 16 microns, then the selectivity to monoalkylated compounds improves, but the catalyst composition complexity increases
Solution Approach 1:
The patent employs composite materials by combining MCM-22 family molecular sieve crystals with a binder material to form a structured catalyst composition. This composite structure integrates the active catalytic component with a supporting matrix, achieving improved selectivity through controlled crystal size while maintaining mechanical integrity and manageable composition.
3Manufacturing precision
If milling or jet milling is used to reduce crystal size, then the selectivity improves, but the manufacturing process complexity increases
Solution Approach 1:
The patent replaces conventional mechanical milling methods with jet milling technology for crystal size reduction. This substitution uses fluid dynamics and high-velocity gas streams instead of traditional mechanical contact, achieving finer and more uniform crystal size distribution with reduced equipment complexity and improved manufacturing efficiency.
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 catalyst composition achieves a monoalkylated aromatic compound selectivity that is 10% to 60% greater than conventional catalysts with larger crystal sizes, improving the efficiency and selectivity of the hydrocarbon conversion processes.
Implementation Method 1
contacting at least one alkylatable aromatic compound and at least one alkylating agent with a catalyst composition under suitable alkylation or transalkylation conditions, to produce at least one effluent which comprises the monoalkylated aromatic compound
Data Source
AI summary
A catalyst composition comprises (a) a MCM-22 family molecular sieve; and (b) a binder, wherein the MCM-22 family molecular sieve is characterized by an average crystal agglomerate size of less than or equal to 16 microns. The catalyst composition may further have a second molecular sieve having a Constraint Index of less than 12, e.g., less than 2. Examples of molecular sieve useful for this disclosure are a MCM-22 family molecular sieve, zeolite Y, and zeolite Beta. The catalyst composition may be used for the process of alkylation or transalkylation of an alkylatable aromatic compound with an alkylating agent.