Small Pore Molecular Sieve Catalyst Impregnation
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Solution Overview
Problem
Existing methods for pre-treating molecular sieves with organic material to enhance catalytic activity in oxygenate-to-olefins conversion reactions often result in a wide distribution of non-catalytic or detrimental organic materials, and are limited by the small pore size of the molecular sieves, which restricts the types of organic precursors that can be used.
Innovation Solution
Impregnating small pore molecular sieves with specific aromatic co-catalysts and polar impregnation agents, such as diisopropylethylamine, to achieve a uniform distribution of catalytically active organic material within the molecular sieve pores, even for compounds with larger kinetic diameters, by temporarily manipulating the porous framework structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-treatment with organic material is used to enhance catalytic activity, then catalytic activity is improved, but a wide distribution of non-catalytic or detrimental organic materials is formed
Solution Approach 1:
The patent applies preliminary action by pre-impregnating the molecular sieve with specific aromatic co-catalysts and polar impregnation agents before the actual oxygenate conversion reaction. This pre-treatment step ensures that only desired catalytically active organic materials are present in uniform distribution, avoiding the formation of non-catalytic or detrimental organic materials during the reaction process.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the composition ratios (at least 50 wt% aromatic co-catalyst and 0.1-50 wt% polar impregnation agent), temperature (200-450°C), and pressure (250-3000 psig) during impregnation. These controlled parameters ensure uniform distribution and catalytic activity while preventing formation of detrimental organic materials.
2Reliability
If small pore molecular sieves are used for MTO/OTO conversion, then selectivity to light olefins is improved, but the types of organic material precursors that can be used are limited
Solution Approach 1:
The patent uses polar impregnation agents (such as water, alcohols, amines, carboxylic acids, esters, ethers, or sulfones) as intermediaries to facilitate the impregnation of aromatic co-catalysts into the small pore molecular sieve structure. These polar agents temporarily modify the pore environment, enabling entry of aromatic compounds with kinetic diameters up to 2.0 Å larger than the pore diameter, thus expanding precursor options while maintaining small pore selectivity.
Solution Approach 2:
The patent applies parameter changes by utilizing temperature (200-450°C) and pressure (250-3000 psig) conditions during impregnation to temporarily alter the porous framework structure. This allows aromatic co-catalysts with larger kinetic diameters to enter and be retained within the small pore structure, expanding the range of usable organic precursors while preserving the size-selective properties of small pore molecular sieves.
3Reliability
If aromatic co-catalysts with larger kinetic diameters are impregnated, then catalytic activity is enhanced, but the pore size limitation prevents entry into small pore molecular sieves
Solution Approach 1:
The patent employs polar impregnation agents as intermediaries that facilitate the entry and retention of aromatic co-catalysts with larger kinetic diameters into small pore molecular sieves. These polar agents temporarily modify the pore environment, creating pathways that allow bulkier aromatic molecules to access and be retained within the pore structure, thereby enabling enhanced catalytic activity despite size mismatch.
Solution Approach 2:
The patent utilizes parameter changes by applying elevated temperature (200-450°C) and pressure (250-3000 psig) during impregnation to temporarily expand or modify the porous framework structure. This dynamic structural modification allows aromatic co-catalysts with kinetic diameters exceeding the normal pore size to enter and be retained within the molecular sieve, achieving enhanced 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
This approach allows for the selective impregnation of catalytically active organic molecules, enhancing the conversion of oxygenates to olefins and improving selectivity to ethylene and propylene, while maintaining catalyst stability and activity.
Implementation Method 1
contacting the molecular sieve primary catalyst with a combination of from at least 50 wt % to about 99.9 wt % of an aromatic co-catalyst and from about 0.1 wt % to less than 50 wt % of a polar impregnation agent under conditions sufficient to impregnate the porous framework structure of the primary catalyst with the aromatic co-catalyst
Implementation Method 2
methods of converting oxygenates to olefins using said integrated catalyst systems
Data Source
AI summary
The invention includes a method for impregnating a molecular sieve primary catalyst with an aromatic co-catalyst, the method comprising contacting the small pore molecular sieve primary catalyst having a porous framework structure with a combination of from at least 50 wt % to about 99.9 wt % of an aromatic co-catalyst and from about 0.1 wt % to less than 50 wt % of a polar impregnation agent containing one or more heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, and boron, under conditions sufficient to impregnate the porous framework structure of the primary catalyst with the aromatic co-catalyst (and optionally also with the polar impregnation agent), thus forming an integrated catalyst system. Methods for converting oxygenates to olefins using said integrated catalyst system are also described herein.