Alkali-Promoted Catalyst Uniform Deposition via Non-Aqueous Impregnation
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Solution Overview
Problem
Existing methods for depositing promoters onto catalysts are limited by the need for volatile forms, ionic requirements, weak adsorption forces, and potential surface chemistry issues, leading to non-uniform dispersion and inefficient promoter use.
Innovation Solution
A method involving the reaction of alkali metals with alcohols in a non-aqueous medium to produce an alkoxide promoter solution, which is then contacted with a starting catalyst to achieve uniform deposition and intimate contact with active sites, enhancing catalyst activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If promoter deposition is performed from gas phase, then uniform dispersion is achieved, but the promoter must be in volatile form which limits the choice of promoters
Solution Approach 1:
The patent changes the physical state parameter of the promoter from gas-phase volatile to liquid-phase soluble, enabling deposition of non-volatile promoters while maintaining uniform dispersion through solution impregnation methods
Solution Approach 2:
The patent introduces a liquid solvent as an intermediary medium to carry the promoter from the liquid phase to the catalyst surface, replacing the gas phase as the transport medium and enabling broader promoter selection
2Manufacturing precision
If ion exchange method is used, then ionic promoters can be deposited, but the catalyst precursor must have ionic groups which restricts catalyst design
Solution Approach 1:
The patent introduces a liquid solvent as an intermediary that can dissolve ionic promoters without requiring ionic groups on the catalyst precursor, allowing deposition of ionic promoters on any catalyst surface through solution impregnation
Solution Approach 2:
The patent changes the deposition mechanism from ion exchange (requiring ionic groups) to solution impregnation (requiring only solvent solubility), enabling promoter deposition on a broader range of catalyst precursors
3Ease of manufacture
If adsorption is used, then promoter can be attached to catalyst surface, but the attachment force is too weak for stable promotion
Solution Approach 1:
The patent changes the attachment mechanism from weak physical adsorption to stronger chemical interaction by using solution impregnation where the promoter forms chemical bonds or strong interactions with the catalyst surface during the deposition process
4Manufacturing precision
If excess water is used for impregnation, then promoter can be deposited, but surface chemistry becomes less beneficial
Solution Approach 1:
The patent changes the solvent parameter from water (which creates excessive surface moisture and alters surface chemistry) to organic solvents or other non-aqueous solvents that provide controlled deposition without compromising surface chemistry for syngas-to-alcohol catalysis
Solution Approach 2:
The patent uses a temporary liquid solvent medium that is evaporated or decomposed after deposition, leaving only the desired promoter on the catalyst surface without the harmful effects of excess water remaining
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 method results in a uniformly distributed alkali-promoted catalyst with improved activity and selectivity for syngas conversion to alcohols, specifically C1-C4 alcohols, by controlling alkali metal concentration and deposition depth.
Implementation Method 1
reacting, at least in part, the alkali metal with an excess of the alcohol, thereby producing a promoter solution comprising the alcohol and the alkoxide of the alkali metal
Implementation Method 2
contacting at least some of the promoter solution from step (c) with the starting catalyst, under effective conditions to deposit at least some of the alkali metal onto the starting catalyst
Data Source
AI summary
Improved methods of introducing promoters to catalysts are described. The present invention provides a convenient method of uniformly distributing a catalyst promoter, to provide for intimate contact between the promoter and the active catalyst sites. This intimate contact can enhance the activity and/or product selectivity of the promoted catalyst. In some embodiments, the method includes reacting an alkali metal with an alcohol in a non-aqueous medium, contacting the resulting solution with a starting catalyst, and depositing the alkali metal onto the starting catalyst to form an alkali-promoted catalyst.