Cobalt-Salen Ionic Liquid for Reversible Oxygen Absorption
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Solution Overview
Problem
Current oxygen-absorbing materials are either solid, irreversible, or require high concentrations in organic solvents, making them impractical for industrial and consumer applications, and there is a need for a reversible and selective oxygen-absorbing liquid that can efficiently handle oxygen in various chemical reactions.
Innovation Solution
A cobalt-salen complex coordinated with an ionic liquid having an amine structure and an aliphatic quaternary phosphonium or ammonium cation, which forms a stable liquid solution that selectively and reversibly absorbs oxygen, allowing for efficient oxygen absorption and desorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If solid deoxydants are used for oxygen absorption, then oxygen absorbing ability is achieved, but the materials cannot be used for repeated or continuous use due to irreversible absorption
Solution Approach 1:
The patent changes the chemical state of the oxygen absorption process from irreversible solid-state reaction to reversible coordination chemistry. By using cobalt-salen complex with ionic liquid, the system enables reversible oxygen binding and release through coordination equilibrium, allowing the material to cycle between oxygen-bound and oxygen-free states repeatedly.
Solution Approach 2:
The patent creates a composite system combining cobalt-salen complex (oxygen-binding agent) with ionic liquid (solvent and stabilizer). This composite provides both the reversible oxygen absorption capability of the metal complex and the stability, solubility, and tunable properties of the ionic liquid medium, enabling practical repeated use applications.
2Productivity
If salen complexes are dissolved at high concentration in organic solvent to exploit oxygen absorbing ability, then oxygen absorption efficiency is improved, but solvent contamination occurs in extracted oxygen gas
Solution Approach 1:
The patent changes the solvent type from volatile organic solvent to non-volatile ionic liquid. This parameter change maintains high oxygen absorption efficiency through appropriate complex concentration while eliminating solvent vapor contamination in the extracted oxygen gas, as ionic liquids have negligible vapor pressure.
Solution Approach 2:
The patent replaces traditional volatile organic solvents with ionic liquids that can be reused without degradation or contamination concerns. The ionic liquid medium remains stable throughout repeated oxygen absorption cycles, eliminating the need for frequent solvent replacement or purification.
3Reliability
If ionic liquid comprising cobalt complex is used, then reversible oxygen absorption is achieved, but the liquid has extremely high viscosity requiring dilution in organic solvent
Solution Approach 1:
The patent optimizes the ionic liquid composition and cobalt complex concentration to achieve an optimal balance between oxygen absorption capability and viscosity. By selecting appropriate ionic liquid cations and anions, and controlling the complex loading, the system maintains low enough viscosity for easy handling while preserving reversible oxygen absorption functionality.
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 cobalt-salen complex in liquid form provides a stable and efficient means to selectively absorb and desorb oxygen, overcoming the limitations of existing materials by maintaining oxygen-absorbing ability in a liquid state, enabling repeated use and reducing solvent contamination issues.
Implementation Method 1
Metal complex materials can adsorb and desorb oxygen reversibly and repetitively. A typical example of the mechanism is oxygen transport reaction by heme protein in hemoglobin, which involves adsorption and desorption of oxygen by porphyrin-iron ion complex.
Implementation Method 2
Metal complex materials can adsorb and desorb oxygen reversibly and repetitively.
Implementation Method 3
use of so-called ionic liquid, which is a liquid substance composed only of ion components of cations and anions having a vapor pressure of almost zero
Data Source
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Figure 3~4
AI summary
A liquid having oxygen absorbing ability, comprising a cobalt-salen complex or a derivative thereof and an ionic liquid formed from an anion having an amine structure and a cation of an aliphatic quaternary phosphonium or ammonium having alkyl chains with each 2-20 carbon atoms, wherein the anion of the ionic liquid is coordinated to a cobalt ion of the cobalt-salen complex or a derivative thereof.