Seeded-MCM-56 Catalyst for Liquid Phase Alkylation
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Solution Overview
Problem
Existing alkylation processes for producing alkylaromatic compounds like ethylbenzene and cumene face challenges in achieving high monoselectivity, leading to the production of polyalkylated species and unwanted by-products, particularly in liquid phase reactions where catalysts lack activity or result in significant by-product formation.
Innovation Solution
A catalyst composition comprising seeded-MCM-56 crystalline aluminosilicate with a binder in a specific weight ratio of 20/80 to 80/20 is used for alkylation, enhancing both activity and monoselectivity by controlling the crystal/binder ratio to minimize di- or polyalkyl product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid phase alkylation is used to produce alkylaromatics, then lower reaction temperature is achieved, but catalyst activity is insufficient and by-product formation increases
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating specific amounts of halogen (0.5-10 wt%) into the zeolite structure, which modifies the catalyst's acid strength and activity to enable effective liquid phase alkylation at lower temperatures
Solution Approach 2:
The patent creates a composite catalyst material combining zeolite crystalline structure with halogen modification and binder components, where the zeolite provides structural framework and the halogen provides enhanced catalytic activity at lower operating temperatures
2Quantity of substance
If conventional catalysts are used for alkylation, then polyalkylated species are produced, but monoselectivity is reduced
Solution Approach 1:
The patent modifies specific local properties of the catalyst by introducing halogen at controlled concentrations (0.5-10 wt%) into the zeolite structure, creating localized active sites that favor monoalkylation while suppressing polyalkylation through controlled acid strength distribution
3Productivity
If catalyst crystal/binder ratio is increased, then catalyst activity improves, but catalyst stability and selectivity may be affected
Solution Approach 1:
The patent optimizes the crystal/binder ratio parameter within the range of 20/80 to 80/20 to balance catalyst activity and stability, where the binder provides structural support and heat dissipation while the zeolite crystals provide catalytic activity
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 process effectively produces monoalkylated benzene with a unique combination of activity and selectivity, reducing unwanted by-products and allowing for capacity expansion and lower capital expenses in existing plants.
Implementation Method 1
A catalyst composition comprising seeded-MCM-56 crystalline aluminosilicate with a binder in a specific weight ratio of 20/80 to 80/20 is used for alkylation, enhancing both activity and monoselectivity
Data Source
AI summary
The present invention provides a process for producing a monoalkylated benzene comprising the step of contacting benzene with an alkylating agent in the presence of a catalyst composition under effective alkylation conditions to form said monoalkylated benzene and polyalkylated benzene, said catalyst composition comprising MCM-56 and a binder, such that the crystal/binder weight ratio in said catalyst composition is from about 20/80 to about 80/20, wherein said polyalkylated benzene comprises dialkylated benzene and trialkylated benzene, and the weight ratio of trialkylated benzene to dialkylated benzene is in the range from about 0.08 to about 0.12.