Supported Cobalt Sulfide Catalysts for Moderate-Pressure Acids and Esters
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Solution Overview
Problem
Existing methods for producing carboxylic acids and alkyl esters face challenges such as high costs, risks associated with toxic catalysts, and the need for harsh reaction conditions, while gas phase processes have limitations in efficiency and selectivity.
Innovation Solution
A gas phase process using a supported cobalt sulfide catalyst, prepared by depositing cobalt thiocyanate on a catalyst support and converting it to cobalt sulfide, allows for the production of carboxylic acids and alkyl esters with high selectivity and productivity without the need for halides or other co-catalysts, operating at moderate pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid phase hydrocarboxylation using Ni(CO)4 catalyst is used, then carboxylic acid production is achieved, but high pressure (100-300 bar) and toxic catalyst risks increase
Solution Approach 1:
The invention changes the pressure parameter from high (100-300 bar) to moderate (1-50 bar), and transitions from liquid phase to gas phase reaction conditions. This resolves the contradiction by achieving carboxylic acid production while eliminating the need for high pressure and toxic catalysts, as the gas phase process uses a solid catalyst that is non-toxic and operates safely at moderate pressures
Solution Approach 2:
The invention replaces the expensive and hazardous Ni(CO)4 catalyst with a cheap, non-toxic solid catalyst (such as modified metal oxides or metal sulfides). The solid catalyst can be easily handled, does not require special safety precautions, and provides comparable or superior activity, thus resolving the contradiction between productivity and harmful factors
2Object-affected harmful factors
If gas phase hydrocarboxylation is used, then toxic catalyst and high pressure requirements are reduced, but selectivity and productivity are limited
Solution Approach 1:
The invention applies local quality by modifying the surface properties of the solid catalyst with specific promoters (such as alkali metals, alkaline earth metals, or rare earth elements). These local modifications on the catalyst surface enhance the gas phase reaction activity and selectivity, resolving the contradiction by maintaining low toxicity and moderate pressure while improving productivity and selectivity through targeted surface enhancement
Solution Approach 2:
The invention uses composite catalyst materials combining a solid support (metal oxide or metal sulfide) with promotional compounds. This composite structure provides both the safety advantages of gas phase operation and the high productivity of optimized catalytic sites, thus resolving the contradiction between reduced harmful factors and enhanced selectivity/productivity
3Productivity
If liquid phase two-step hydroformylation/oxidation is used, then carboxylic acid is produced, but process complexity and cost increase
Solution Approach 1:
The invention merges the two-step liquid phase process (hydroformylation followed by oxidation) into a single gas phase carbonylation step. This consolidation eliminates the need for separate reaction vessels, catalyst handling, and intermediate product transfer, thus resolving the contradiction by achieving carboxylic acid production with reduced process complexity and lower operational costs
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 achieves selectivity greater than 98% and productivity comparable to or exceeding that of prior bulk cobalt sulfide catalysts, providing a versatile and efficient alternative for producing carboxylic acids and alkyl esters.
Implementation Method 1
heating it to convert the cobalt thiocyanate on the support to cobalt sulfide
Implementation Method 2
contacting an alkene gas, steam, and a carbon-containing gas under hydroxycarbonylation conditions over and in contact with the supported cobalt sulfide catalyst to form a product stream
Data Source
AI summary
The present invention relates generally to gas phase processes for producing carboxylic acids or alkyl esters. In one embodiment, a gas phase process for producing a carboxylic acid or an alkyl ester comprises (a) providing a catalyst support comprising deposits of cobalt thiocyanate on at least a portion of the catalyst support; (b) heating the catalyst support to convert the cobalt thiocyanate on the support to cobalt sulfide to form a supported cobalt sulfide catalyst; and (c) reacting alkene gas, steam or an alkanol gas, and a carbon-containing gas in the presence of the supported cobalt sulfide catalyst in a reactor to form a product stream, wherein the carbon-containing gas comprises carbon monoxide or a mixture of carbon monoxide and carbon dioxide, wherein when steam is used as a reactant, the product stream comprises a carboxylic acid, and wherein when alkanol gas is used as a reactant, the product stream comprises an alkyl ester.