Quaternary Phosphinates for Carboxylic Acid Extraction
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Solution Overview
Problem
Current methods for recovering C1 to C4 carboxylic acids from aqueous streams face challenges due to unfavorable vapor-liquid equilibrium and high energy costs, with existing solvents often requiring high volumes and inefficiently separating these acids from water.
Innovation Solution
A solvent composition comprising a quaternary phosphonium phosphinate salt combined with a co-solvent such as higher carboxylic acids, ethers, esters, ketones, aromatic hydrocarbons, chlorinated hydrocarbons, or nitriles, which exhibits high acid partition coefficients, especially at low acid concentrations, enhancing the extraction efficiency and selectivity for C1 to C4 carboxylic acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If simple distillation is used to recover glacial acids from wet acid streams, then acid recovery is achieved, but energy costs are high and vapor-liquid equilibrium is unfavorable
Solution Approach 1:
The patent introduces an extracting solvent as an intermediary substance that facilitates acid transfer from the aqueous feed stream to the extract phase. This mediator enables separation without requiring energy-intensive distillation, directly resolving the contradiction between energy cost and recovery efficiency.
Solution Approach 2:
The patent changes the separation mechanism from thermal (distillation) to chemical/partition-based (extraction). By utilizing partition coefficients and selectivity parameters of the extracting solvent, the process achieves separation at lower energy consumption while maintaining high productivity.
2Quantity of substance
If conventional organic solvents are used for extraction, then some acid separation is achieved, but solvent volume required is high and selectivity is insufficient
Solution Approach 1:
The patent employs a composite extracting solvent system comprising multiple components (e.g., tertiary amine, diluent, and co-solvent) that work synergistically. This composite formulation enhances both selectivity for C1-C4 acids and water removal capability while reducing the total solvent volume required compared to conventional single-component solvents.
Solution Approach 2:
The patent optimizes solvent composition parameters including the ratio of active extracting agent to diluent, molecular weight of diluent, and presence of co-solvents. These parameter adjustments maximize partition coefficients and selectivity, enabling efficient separation with reduced solvent quantities.
3Productivity
If extraction solvent shows high affinity for carboxylic acid, then extraction efficiency improves, but water content in extract phase increases
Solution Approach 1:
The patent designs the extracting solvent with differentiated functional regions: a polar component (tertiary amine) that selectively binds carboxylic acid molecules and a non-polar diluent that repels water. This local quality differentiation enables high acid uptake while maintaining low water solubility in the extract phase.
Solution Approach 2:
The patent adjusts the hydrophobicity parameter of the diluent component and the concentration of the active extracting agent to optimize the balance between acid affinity and water rejection. By tuning these parameters, the solvent achieves high extraction efficiency while keeping water content in the extract phase minimal.
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 solvent composition significantly improves the extraction factor, enabling energy-efficient and cost-effective recovery of C1 to C4 carboxylic acids from wet acid feeds by achieving high partitioning of acids into the phosphonium phosphinate phase, even at low concentrations, thus reducing capital and energy costs.
Implementation Method 1
The solvent for the extraction process is immiscible with water and shows some selectivity between extraction of the carboxylic acid and water
Implementation Method 2
The equilibrium partition coefficient for component A (the lower carboxylic acid) is defined as follows: The partition coefficient is a measure of the relative concentrations of the solute to be extracted in the two phases
Data Source
AI summary
This invention relates to solvents for extracting C1 C4 carboxylic acids from aqueous streams. More specifically, the extraction solvents include one or more salts composed of a tetraalkylphosphonium cation and a phosphinate anion. The extraction solvents may further include one or more co-solvents as an enhancer. The co-solvents may be selected from higher carboxylic acids, ethers, esters, ketones, aromatic hydrocarbons, chlorinated hydrocarbons, and nitriles. The extraction solvents are useful for extracting aqueous mixtures containing one or more lower carboxylic acids, such as monocarboxylic acids and organofluorine carboxylic acids.