Cesium Tungsten Catalyst Selectivity for Methyl Mercaptan
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Solution Overview
Problem
Current catalysts for synthesizing methyl mercaptan from methanol and hydrogen sulfide have low selectivity and high energy input due to high molar ratios of hydrogen sulfide to methanol, leading to inefficient economic processes.
Innovation Solution
A catalyst with a catalytically active oxidic composition of cesium and tungsten, with a molar ratio of cesium to tungsten between 2:1 and 0.8:1, is used, which is impregnated onto a support material like aluminum oxide to enhance activity and selectivity, allowing for lower hydrogen sulfide to methanol ratios and improved economic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high molar ratio of hydrogen sulfide to methanol is used to increase selectivity, then selectivity towards methyl mercaptan is improved, but energy input increases due to the need to circulate large quantities of gas
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by using cesium tungstate with a specific molar ratio range (0.8:1 to 2:1 of Cs to W) and optimized weight percentage (15-40%), which fundamentally alters the reaction pathway efficiency. This parameter optimization allows achieving high selectivity without requiring excessive hydrogen sulfide molar ratios, thus reducing the energy penalty associated with gas circulation.
2Manufacturing precision
If cesium tungstate concentration is increased to improve selectivity, then selectivity towards methyl mercaptan increases, but catalyst cost and complexity increase
Solution Approach 1:
The patent establishes an optimized parameter range for cesium tungstate concentration (15-40 wt. %) and molar ratio (0.8:1 to 2:1 of Cs to W), which balances selectivity improvement with catalyst simplicity. Within this optimized range, the catalyst achieves high selectivity without requiring complex multi-component formulations or excessive promoter loading, thus avoiding unnecessary complexity.
3Manufacturing precision
If conventional catalysts with stoichiometric alkali to tungsten ratio of 2:1 are used, then good selectivity is achieved, but activity is disproportionately impaired when cesium tungstate concentration is increased
Solution Approach 1:
The patent optimizes the molar ratio of alkali metal to tungsten within the range of 0.8:1 to 2:1, deviating from the conventional fixed 2:1 stoichiometry. This parameter optimization, combined with controlling cesium tungstate concentration at 15-40 wt. %, achieves a balanced state where both high selectivity and maintained activity are realized, overcoming the trade-off present in conventional catalysts.
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 achieves higher selectivity and activity, reducing energy input and costs by maintaining high selectivity even at low molar ratios, resulting in increased yield and cost savings in the separation of methyl mercaptan from reaction mixtures.
Implementation Method 1
A catalyst containing a catalytically active oxidic composition of cesium and tungsten with a molar ratio of cesium to tungsten of 2:1 to 0.8:1, in particular 1.5:1 to 1.2:1, is used for the synthesis of methyl mercaptan from methanol and hydrogen sulfide
Implementation Method 2
which is impregnated onto a support material like aluminum oxide to enhance activity and selectivity
Data Source
AI summary
The invention relates to an oxidic catalyst containing cesium and tungsten for the synthesis of alkyl mercaptans from alkanols and hydrogen sulfide, and to a process for the production of this catalyst, wherein the molar ratio of cesium to tungsten is <2:1.