MEP Ionic Fluid Preparation With Ethyl Bromide Phase Separation
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Solution Overview
Problem
Existing methods for producing quaternary ammonium compounds for use in battery electrolytes require solvents that need to be removed post-creation, leading to inefficiencies and potential hydrolysis issues.
Innovation Solution
A method is developed to produce quaternary ammonium compounds, such as MEP, by using ethyl bromide as both a solvent and reactant, followed by a solvent swap with water to create a two-phase system, allowing for the separation and purification of MEP without the need for additional solvent removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water is used as a solvent in the reaction, then the reaction can proceed, but hydrolysis of ethyl bromide occurs lowering the pH to less than 2
Solution Approach 1:
Acetonitrile is introduced as an intermediary solvent that mediates between the reactants. It dissolves both the tertiary amine and ethyl bromide, allowing the quaternization reaction to proceed efficiently while preventing hydrolysis of ethyl bromide, thus maintaining pH above 2
Solution Approach 2:
The solvent system parameters are changed from water alone to a mixture of acetonitrile and water. This parameter change modifies the reaction environment to prevent hydrolysis while maintaining reaction feasibility, achieving both goals simultaneously
2Ease of manufacture
If a solvent is used in the reaction, then the reaction can proceed, but the solvent requires removal after creation of the compounds
Solution Approach 1:
The harmful component (excess ethyl bromide) is extracted from the reaction mixture by exploiting its immiscibility with water. The two-phase system allows selective removal of ethyl bromide in the organic phase, leaving the ionic liquid in the aqueous phase without requiring additional solvent removal steps
Solution Approach 2:
The process utilizes phase transition from a single-phase reaction mixture to a two-phase system upon water addition. This phase separation enables easy removal of excess reactants and solvent without complex purification equipment, simplifying the overall process
3Object-affected harmful factors
If ethyl bromide is used in excess to prevent hydrolysis, then pH is maintained, but additional separation steps are required
Solution Approach 1:
The addition of water triggers phase separation, creating distinct aqueous and organic phases. Excess ethyl bromide partitions into the organic phase which can be easily separated by decantation or phase separation equipment, making the separation process simple and efficient
Solution Approach 2:
The reaction mixture is segmented into two distinct phases based on solubility differences. The aqueous phase contains the desired ionic liquid product while the organic phase contains excess ethyl bromide and other organic-soluble impurities, enabling straightforward separation
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 approach yields high-quality MEP with minimal hydrolysis, reduces the need for solvent recovery, and maintains a neutral pH, enhancing the efficiency and cost-effectiveness of the process.
Implementation Method 1
adding N-methylpyrrolidine to an excess amount of ethyl bromide located in a reactor, wherein the N-methylpyrrolidine will react with the ethyl bromide forming MEP
Implementation Method 2
adding water to the reactor creating a two phase system to develop which includes: (i) a top layer containing aqueous MEP and (ii) a bottom layer containing ethyl bromide
Data Source
AI summary
A method of preparing MEP including the steps of: (a) adding N-methylpyrrolidine to an excess amount of ethyl bromide located in a reactor, wherein the N-methylpyrrolidine will react with the ethyl bromide forming MEP, wherein the reaction will have a reaction temperature that can varies over time; (b) stopping addition of N-methylpyrrolidine when the excess of ethyl bromide to the N-methylpyrrolidine falls within a range of 3:1 to 1.5:1; (c) adding water to the reactor creating a two phase system to develop which includes: (i) a top layer containing aqueous MEP and (ii) a bottom layer containing ethyl bromide; (d) separating the top layer from the bottom layer yielding a first aqueous solution of MEP and a second solution of ethyl bromide; and (e) removing N-methylpyrrolidine and ethyl bromide from the first aqueous solution of MEP.