Ionic Liquid Purification via Low-Temperature Steam Stripping

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Solution Overview

Problem

Conventional purification processes for ionic liquids containing dialkylimidazolium ions result in partial decomposition, leading to the formation of foul-smelling decomposition products, which are undesirable in air dehumidification systems.

Innovation Solution

A process involving the use of water vapour at a temperature of ≤99°C for stripping to purify ionic liquids of the structure Q+A−, where Q+ is a 1,3-dialkylimidazolium ion and A− is selected from various anions, minimizing decomposition and odour-forming substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional purification processes are used for ionic liquids containing dialkylimidazolium ions, then purification is achieved, but decomposition of the ionic liquid occurs leading to formation of foul-smelling decomposition products

Engineering Contradiction:
Improvepurification qualityVSAvoiddecomposition products
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the temperature parameter of the purification process from conventional high-temperature methods to a low-temperature range (20-99°C). This parameter change prevents thermal decomposition of the ionic liquid while still achieving effective purification through steam stripping at controlled temperatures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces water vapor as an intermediary substance to facilitate purification. The water vapor acts as a stripping medium that selectively removes impurities from the ionic liquid without causing decomposition, serving as a gentle mediator between the purification goal and the sensitive ionic liquid

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If high temperature is used for purification, then purification efficiency is improved, but decomposition of ionic liquid increases

Engineering Contradiction:
Improvepurification efficiencyVSAvoidionic liquid integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent transforms the temperature parameter from high-temperature processing to low-temperature processing (20-99°C range). This parameter inversion maintains purification efficiency through extended contact time and gentle steam stripping while preserving ionic liquid integrity by avoiding thermal degradation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The purification process uses periodic or continuous steam injection at controlled intervals rather than continuous high-temperature heating. This periodic action maintains effective purification through repeated gentle stripping cycles while preventing cumulative thermal damage to the ionic liquid

Inventive Principle:
Principle #19Periodic action

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 effectively purifies ionic liquids while avoiding decomposition products, ensuring a cleaner and safer air dehumidification process by maintaining the integrity of the ionic liquid, as evidenced by the absence of N-methylimidazole in the gas phase during purification.

Implementation Method 1

a process for purifying an ionic liquid by means of stripping with water vapour having a temperature of ≤99° C.

Methodology Applied
Scientific EffectStripping: Distillation

Implementation Method 2

purification of an ionic liquid by means of stripping with water vapour

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS10138209B2Process for purifying an ionic liquid
Publication Date: 2018.11.27 EVONIK OPERATIONS GMBH

AI summary

The invention relates to a process for purifying an ionic liquid comprising dialkylimidazolium ions by means of stripping, wherein water vapor is used at a particular temperature. The process according to the invention is characterized in that the decomposition of the ionic liquid is minimized during the procedure of the process.