Electrochemical Ionic Liquid Synthesis Using Halide Salts

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Solution Overview

Problem

Current electrochemical methods for producing ionic liquids face safety issues due to the use of perchlorate salts, which are explosive and toxicologically hazardous, and lack versatility in anion exchange and industrial feasibility.

Innovation Solution

An electrochemical method using a reaction mixture with a solvent, a supporting electrolyte that functions as both an anion source and halide salt, such as chloride, to produce aprotic ionic liquids, minimizing the risk of halide anion oxidation and allowing for easy conversion of anions, thereby avoiding perchlorate-related hazards and enhancing selectivity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If perchlorate salts are used as supporting electrolyte and anion source in electrochemical synthesis, then ionic liquids can be produced, but safety risks increase due to explosive and toxicological hazards

Engineering Contradiction:
Improveionic liquid productionVSAvoidsafety risks from perchlorate
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameter of the supporting electrolyte from perchlorate salts to halide salts (chloride, bromide, or iodide). This parameter change eliminates the explosive and toxicological hazards associated with perchlorates while maintaining the electrochemical functionality needed for ionic liquid synthesis. The halide salts provide equivalent electrochemical performance without the safety risks.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If perchlorate salts are used as anion source, then electrochemical synthesis can proceed, but anion exchange versatility is lost

Engineering Contradiction:
Improveelectrochemical synthesis efficiencyVSAvoidanion exchange capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent employs halide salts that serve multiple functions: they act as supporting electrolytes for electrochemical conductivity, as anion sources for ionic liquid formation, and as exchangeable anions for producing different ionic liquid variants. This multi-functionality enables both efficient synthesis and subsequent anion exchange to create diverse ionic liquids with tailored properties.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If conventional heating methods are used for ionic liquid synthesis, then reaction can proceed, but energy efficiency decreases and heat control becomes difficult

Engineering Contradiction:
Improvesynthesis rateVSAvoidenergy efficiency
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent replaces thermal heating (mechanical energy input) with electrochemical synthesis using halide salts as supporting electrolyte. This substitution eliminates the need for conventional heating equipment and associated heat control difficulties, while providing direct electrical energy conversion to chemical products with higher energy efficiency and better process control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 safely produces halide-based ionic liquids with reduced oxidation risks, enabling efficient and selective synthesis while avoiding the formation of explosive compounds and allowing for anion exchange, thus offering a more environmentally friendly and industrially viable process.

Implementation Method 1

an electrochemical oxidation of a reactant

Methodology Applied
Scientific EffectElectrochemical oxidation: Oxidation

Implementation Method 2

electrochemical production of an aprotic ionic liquid

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 3

a supporting electrolyte that functions as both an anion source and halide salt

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP3415662B1A method for producing an ionic liquid
Publication Date: 2022.01.12 VLAAMSE INSTELLING VOOR TECHNOLOGISCH ONDERZOEK NV (VITO)
  • EP3415662B1 patent drawingFigure 1a)~1b)
  • EP3415662B1 patent drawingFigure S1
  • EP3415662B1 patent drawingFigure 2

AI summary

The present invention relates to a method for the electrochemical production of an aprotic ionic liquid of a cation and a halide based anion X- wherein a reaction mixture containing a solvent, a supporting electrolyte, an anion source and a reactant which responds to formula          R'm-Y1-(CR)n-Y2-R"p     (1) wherein - Y1 and Y2 may be the same or different and are selected from the group of N, P and S - m and p may be the same or different and may be 2 or 3, - all R' may be the same or different, all R" may be the same or different, R' may be the same as or different from R" and may, independently of each other be H, a straight chain or a branched saturated alkyl group, a cyclic alkyl group or an aromatic hydrocarbon moiety - At least one R next to Y1 is CH2 - And n is at least 1, preferably at least 2, more preferably maximum 10, most preferably n is 1, 2 or 3, wherein Y is N, P or S is subjected to an anodic electrochemical potential to cause oxidative electrolysis of the reactant, wherein the supporting electrolyte simultaneously functions as anion source and comprises a salt of the halide ion X-, selected from the group of fluoride, chloride, bromide or iodide.