Bimodal Cobalt Catalyst for Selective Long-Chain Alcohol Synthesis
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Solution Overview
Problem
Current methods for producing long-chain alcohols from syngas, such as those used in surfactants, face challenges in achieving high yields and selectivity, with existing Fischer-Tropsch synthesis processes requiring multiple steps and not efficiently producing alcohols with 8-22 carbon atoms.
Innovation Solution
A method involving the formation of a bimodal carrier with specific pore size distribution and cobalt support, allowing for the one-step selective production of alcohols with 8-22 carbon atoms by reacting carbon monoxide with hydrogen at controlled pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Fischer-Tropsch synthesis is used to produce long-chain alcohols from syngas, then alcohol production is achieved, but the process requires multiple steps and cannot obtain target alcohol at high yield
Solution Approach 1:
The patent combines multiple synthesis steps into a single Fischer-Tropsch synthesis process by using a bimodal carrier with specific pore size distribution (30-200 nm and 1-25 nm). This allows direct conversion of syngas to long-chain alcohols (C8-C22) in one step, eliminating the need for separate olefin synthesis, hydroformylation, and hydrogenation steps, thereby achieving high yield while reducing process complexity
Solution Approach 2:
The invention employs a bimodal porous carrier with two distinct pore size ranges (30-200 nm and 1-25 nm) to optimize the Fischer-Tropsch synthesis. The larger pores facilitate mass transport of reactants and products, while the smaller pores provide high surface area for catalytic activity. This porous structure enables direct alcohol production with high selectivity and yield in a single step
2Quantity of substance
If existing catalysts are used for Fischer-Tropsch synthesis, then hydrocarbon synthesis is achieved, but long-chain alcohol is not obtained
Solution Approach 1:
The patent changes critical parameters of the catalyst system by using a bimodal carrier with specific pore size distribution (30-200 nm and 1-25 nm) and optimizing cobalt loading (5-20 wt%). These parameter changes transform the catalyst's function from producing only hydrocarbons to selectively producing long-chain alcohols (C8-C22) with high selectivity, while maintaining high conversion efficiency
Solution Approach 2:
The invention creates a composite catalyst system consisting of cobalt metal supported on a bimodal carrier material. This composite structure combines the catalytic activity of cobalt with the optimized pore structure of the carrier, enabling simultaneous achievement of high conversion and selective long-chain alcohol production that neither component could achieve alone
3Manufacturing precision
If cobalt is supported on simple carrier, then catalyst is obtained, but selective production of C8-C22 alcohol is not achieved
Solution Approach 1:
The patent applies local quality by creating regions with different pore sizes within the carrier structure. The bimodal distribution (30-200 nm and 1-25 nm pores) provides different local environments: larger pores for mass transport and smaller pores for selective catalysis. This local differentiation enables precise control over carbon chain growth to produce C8-C22 alcohols selectively
Solution Approach 2:
The invention introduces a new dimension to the carrier structure by implementing a bimodal pore size distribution rather than a uniform structure. This dimensional complexity in the pore size domain (two distinct ranges) enables the catalyst to achieve selective production of specific carbon chain lengths (C8-C22) that cannot be obtained with simple monomodal carriers
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 enables the efficient and selective production of long-chain alcohols, enhancing catalytic activity and yield by optimizing pore structure and catalyst composition, thereby overcoming the limitations of existing synthesis processes.
Implementation Method 1
a method for producing a higher alcohol including synthesizing an olefin by the Fischer-Tropsch synthesis (hereinafter referred to also as the FT synthesis), and subsequent hydroformylation and hydrogenation
Implementation Method 2
forming a porous layer on a surface of a porous material having a pore size mode of 30 nm or more and 200 nm or less to obtain a bimodal carrier
Implementation Method 3
having peaks of pore distribution in a range of 1 nm or more and 25 nm or less and a range of 30 nm or more and 200 nm or less
Data Source
AI summary
A method for producing an alcohol having 8 or more and 22 or less carbon atoms includes the following steps: step 1: forming a porous layer on a surface of a porous material having a pore size mode of 30 nm or more and 200 nm or less to obtain a bimodal carrier; step 2: supporting cobalt on the bimodal carrier obtained in step 1 to obtain a catalyst having peaks of pore distribution in a range of 1 nm or more and 25 nm or less and a range of 30 nm or more and 200 nm or less, respectively; and step 3: reacting carbon monoxide with hydrogen at a gauge pressure of 2 MPa or more and 100 MPa or less in the presence of the catalyst obtained in step 2.