Carbon Monoxide Purity via Formic Acid Decomposition
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Solution Overview
Problem
Current methods for producing carbon monoxide fail to achieve the high purity required by FDA standards, with impurities such as carbonyls and carbon dioxide present in the gas, limiting its use as a pharmaceutical ingredient.
Innovation Solution
A method involving the reaction of degassed formic acid with a mineral acid at elevated temperatures, followed by condensation and scrubbing with a caustic solution, while avoiding contact with metallic nickel and iron-containing materials, to produce gaseous carbon monoxide with purities of at least 99.99%, reducing impurities like Ni(CO)4 and CO2 to extremely low levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods using dehydrating formic acid with phosphoric acid are used, then carbon monoxide can be produced, but impurities such as carbonyls and carbon dioxide remain in the gas
Solution Approach 1:
The patent extracts and removes harmful impurities (carbonyls, carbon dioxide, moisture) from the carbon monoxide gas stream through multiple purification stages including scrubbing with caustic solution, drying with molecular sieves, and selective adsorption, achieving pharmaceutical-grade purity of 99.99% or higher
Solution Approach 2:
The patent introduces intermediary substances and processes between the reaction and final product: phosphoric acid as a catalyst mediator, caustic soda solution as an intermediary scrubbing agent to remove acid fumes, and molecular sieves as intermediary drying agents, each serving to progressively purify the carbon monoxide
2Reliability
If metallic nickel or iron-containing materials are used in the process, then equipment durability is improved, but carbonyl impurities such as Ni(CO)4 and Fe(CO)5 are generated
Solution Approach 1:
The patent applies local quality by using specific material selections in different process zones: glass-lined reactors and stainless steel equipment without nickel or iron components in contact with formic acid and carbon monoxide, while allowing conventional materials in non-contact areas, thereby preventing carbonyl formation where it matters most
Solution Approach 2:
The patent creates an inert environment by eliminating reactive metallic surfaces (nickel, iron) that could catalyze carbonyl formation, using glass-lined or stainless steel equipment that does not generate metallic carbonyls, thus preventing the formation of harmful Ni(CO)4 and Fe(CO)5 impurities
3Manufacturing precision
If multiple purification steps are added to remove impurities, then carbon monoxide purity increases, but process complexity increases
Solution Approach 1:
The patent merges multiple purification functions into integrated process units: combining scrubbing, drying, and filtration operations in a unified flow system, and integrating purification steps directly into the reaction vessel design, thereby achieving high purity while managing process complexity through functional integration
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 process achieves carbon monoxide purity up to 99.999%, significantly exceeding previous standards by minimizing carbonyl and moisture content, ensuring compliance with FDA requirements for pharmaceutical-grade carbon monoxide.
Implementation Method 1
reacting the degassed liquid formic acid or a degassed gaseous formic acid with a liquid mineral acid at an elevated temperature producing a gas phase comprising carbon monoxide gas and water vapor according to the equations: HCOOH (liq.)→CO (g)+H2O (v), or, HCOOH (g)→CO (g)+H2O (v)
Implementation Method 2
condensing the gas phase producing liquid water and carbon monoxide gas
Implementation Method 3
scrubbing and compressing the carbon monoxide gas producing the gaseous carbon monoxide
Data Source
AI summary
Compositions comprising at least 99.99% gaseous carbon monoxide, as well as pressurized cylinders containing such compositions. The compositions can have a Fe(CO)5 content less than 1 ppb, a Ni(CO)4 content less than 10 ppb, a water moisture content less than 5 ppm, and, a CO2 content less than 2 ppm. Gaseous carbon monoxide purities of 99.998% and 99.999% are achieved by removing residual air from the gaseous carbon monoxide.