Modified Na-MOR Catalyst for Dimethyl Ether Carbonylation
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Solution Overview
Problem
Current catalysts for carbonylation of dimethyl ether to produce methyl acetate, such as those with 8-membered ring channels, have limited stability and activity, making them unsuitable for industrial production due to easy deactivation and high costs associated with noble metal catalysts or corrosion-resistant equipment.
Innovation Solution
A molecular sieve catalyst is developed by modifying Na-MOR molecular sieves through treatments like tetraalkyl ammonium chloride exchange, acid treatment, steam treatment, and ammonium ion exchange, which enhances the catalyst's activity and stability, allowing for efficient production of methyl acetate under controlled reaction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If molecular sieve catalysts with 8-membered ring channels (MOR, FER, OFF) are used for carbonylation of dimethyl ether, then the catalyst activity is improved, but the catalyst stability deteriorates (catalyst runs stably for less than 100 hours and is extremely easy to deactivate)
Solution Approach 1:
The patent applies parameter changes by modifying the catalyst's chemical composition and structural parameters. Specifically, it uses a molecular sieve with specific crystal structure (MOR, FER, or OFF) and controls the Si/Al ratio within 5-50, along with introducing metal elements (Cu, Zn, Ga, In, Nb, Ta, Mo, W, or their combinations) at controlled concentrations. These parameter adjustments optimize both the activity and stability, enabling the catalyst to maintain high performance for over 100 hours of continuous operation.
Solution Approach 2:
The patent employs composite materials by combining molecular sieve support with multiple metal elements. The catalyst comprises a molecular sieve base material doped with metal elements such as Cu, Zn, Ga, In, Nb, Ta, Mo, or W, either individually or in combination. This composite structure synergistically enhances both the catalytic activity and the long-term stability, resolving the contradiction between initial activity and operational durability.
2Productivity
If noble metal rhodium catalyst is used for direct production of ethanol from syngas, then the catalytic performance is improved, but the catalyst cost increases (high catalyst cost and limited rhodium output)
Solution Approach 1:
The patent replaces expensive noble metal rhodium catalysts with a cost-effective molecular sieve-based catalyst system. By using abundant materials such as molecular sieves (MOR, FER, OFF) combined with inexpensive metal elements (Cu, Zn, Ga, In, Nb, Ta, Mo, W), the invention achieves comparable or superior catalytic performance without the high cost and supply constraints associated with rhodium, making the process economically viable for industrial scale-up.
Solution Approach 2:
The patent changes the material parameters from noble metals to earth-abundant materials. The molecular sieve catalyst system with controlled Si/Al ratio (5-50) and specific metal element doping achieves high catalytic activity for carbonylation reactions, providing a cost-effective alternative that maintains productivity while dramatically reducing catalyst cost.
3Ease of manufacture
If syngas is converted to ethanol via hydrogenation of acetic acid through liquid phase carbonylation of methanol, then the process maturity is improved, but the equipment cost increases (requires equipment with special alloys that resist corrosion)
Solution Approach 1:
The patent changes the reaction parameters by operating at elevated temperatures (200-400°C) and pressures (1-30 MPa) for the carbonylation of dimethyl ether to methyl acetate. This parameter adjustment enables the use of conventional equipment materials instead of expensive corrosion-resistant alloys, while maintaining high process maturity and catalytic efficiency through the optimized molecular sieve catalyst system.
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 modified catalyst achieves high space-time yield and stability, with a lifetime exceeding 8000 hours, making it suitable for industrial applications and offering a cost-effective solution for methyl acetate production.
Implementation Method 1
a molecular sieve catalyst is provided, which has high activity and stable performance and can meet the requirements of industrial production
Implementation Method 2
The present application provides a catalyst for carbonylation of dimethyl ether to produce methyl acetate, a preparation method therefor and application thereof. The catalyst is prepared by subjecting Na-MOR molecular sieve (sodium-type mordenite molecular sieve) to an exchange treatment of tetraalkyl ammonium chloride and its derivatives
Data Source
AI summary
Provided are a molecular sieve catalyst, a preparation method therefor, an application thereof. The molecular sieve catalyst contains a modified Na-MOR molecular sieve, and the modification comprises: organic ammonium salt exchange, dealumination treatment, and ammonium ion exchange. The catalyst obtained by the method is used in dimethyl ether for one-step production of methyl acetate. The catalyst has high activity and stable performance, and the needs of industrial production can be satisfied.