Direct CO2 Hydrogenation to Formic Acid in Acidic Media
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Solution Overview
Problem
Current methods for producing formic acid from hydrogen gas and carbon dioxide in acidic media are inefficient, requiring additives like bases, salts, and formate, leading to high costs and complex purification processes, which are not suitable for industrial-scale hydrogen storage and discharge applications.
Innovation Solution
A method involving a catalysed chemical reaction in an acidic medium with a polar solvent, using catalysts like [RuCl2(PTA)4] and [RhCl(PTA)3], which operates at moderate pressures and temperatures without additives, achieving high yields of pure formic acid and allowing for catalyst recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If base additives are used in the hydrogenation reaction, then the reaction efficiency is improved, but the purification cost and complexity increase significantly
Solution Approach 1:
The invention removes base additives from the reaction system entirely, extracting the problematic component that causes purification complexity. By conducting the hydrogenation reaction in acidic medium without bases, formates, or carbonates, the process eliminates the need for complex purification steps to remove salt byproducts, while maintaining high reaction efficiency through the use of water-soluble metal phosphine catalysts
Solution Approach 2:
Instead of using the conventional basic medium for CO2 hydrogenation, the invention inverts the approach by using acidic medium. This inversion changes the reaction pathway to produce formic acid directly without forming formate salts, thereby eliminating the purification burden associated with salt removal while maintaining productive reaction rates
2Manufacturing precision
If neutralization steps are added to separate formic acid, then the product purity is improved, but the production cost increases
Solution Approach 1:
The reaction system is designed to self-produce pure formic acid directly in the acidic medium without requiring external neutralization agents. The formic acid precipitates or separates naturally from the reaction mixture, and the catalyst can be recycled without additional acidification or neutralization steps, making the purification process self-service and cost-effective
3Adaptability or versatility
If pH modulation is used to switch between formate production and hydrogen delivery, then the reaction versatility is improved, but the salt production and catalyst recycling difficulty increase
Solution Approach 1:
The water-soluble metal phosphine catalyst system is designed to perform multiple functions in the acidic medium: it catalyzes both the hydrogenation of CO2 to formic acid and the reverse reaction of formic acid to H2 and CO2. This multi-functionality eliminates the need for pH modulation to switch between modes, as the same catalyst system operates efficiently in both directions under acidic conditions, preventing salt formation and enabling easy catalyst recycling
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 significantly increases the yield of formic acid, reduces the need for costly purification steps, and enables efficient hydrogen storage and discharge, making it suitable for industrial applications by producing pure formic acid without additives or further separation processes.
Implementation Method 1
a method for producing formic acid in a catalysed chemical reaction from hydrogen gas and carbon dioxide
Implementation Method 2
direct hydrogenation of carbon dioxide into formic acid in acidic medium
Implementation Method 3
in an acidic medium comprising at least one polar solvent
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The present invention relates to a method of producing formic acid in a catalysed chemical reaction from hydrogen gas and carbon dioxide gas, said reaction being conducted in an acidic medium comprising a polar solvent over a wide range of temperatures at total gas pressure of hydrogen and carbon dioxide up to 250 bar without the addition of base, carbonate, hydrogen carbonate or formate. The method of the present invention is advantageous since the reaction may be conducted in a polar solvent such as water or DMSO.