Quantitative Raman Spectroscopy for Ionic Liquid A:B Ratio Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

There is a lack of reliable, fast, and quantitative analytical methods for simultaneously determining the acid-to-base molar ratio (A:B) and water content in ionic liquid (IL)/water mixtures, which are critical parameters for the stability and quality of the Ioncell-F process, as these parameters can vary significantly during the process and affect cellulose dissolution and spinning.

Innovation Solution

The use of Raman spectroscopy combined with univariate and multivariate calibrations, particularly Partial Least Squares (PLS) regression, for the quantitative determination of water and protic ionic liquid components in IL/H2O mixtures, allowing for real-time monitoring and control of the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional analytical methods (HPLC, IC, CE, NMR, KF titration) are used to determine anion/cation concentrations and A:B ratio, then measurement precision is improved, but analysis time increases and device complexity increases

Engineering Contradiction:

Improvedetermination of A:B ratio and H2O concentrationVSAvoidanalysis time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces conventional mechanical/chemical analytical methods (HPLC, IC, CE, NMR, KF titration) with Raman spectroscopy, an optical measurement technique. This substitution enables rapid, non-contact measurement of A:B ratio and H2O concentration in ionic liquid mixtures, reducing analysis time from minutes/hours to seconds while maintaining quantitative accuracy through calibration models.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in Raman scattering intensity and spectral characteristics as parameters to quantify A:B ratio and H2O concentration. By monitoring variations in Raman signal intensity and spectral features, the system achieves fast quantitative analysis without requiring complex sample preparation or time-consuming separation processes.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If Refractive Index measurement is used for H2O concentration determination, then ease of operation is improved and analysis time is reduced, but measurement precision deteriorates for A:B ratio detection

Engineering Contradiction:

Improveon-line analysis capabilityVSAvoiddetection of A:B ratio variation

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent employs Raman spectroscopy to simultaneously determine multiple parameters (H2O concentration, A:B ratio, and potentially other composition parameters) using a single measurement technique. This multi-functional capability replaces the need for separate measurements for each parameter, maintaining ease of on-line analysis while achieving precise detection of A:B ratio variations that RI measurement alone cannot detect.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If quantitative Raman spectroscopy with multivariate calibration is used, then productivity is improved through fast analysis, but device complexity and measurement precision requirements increase

Engineering Contradiction:

Improvespeed of quantitative analysisVSAvoidcalibration model complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent transforms complex multicomponent analysis into a series of simplified single-parameter measurements by using Raman spectroscopy. Each component (H2O, acid, base) has characteristic Raman bands that can be measured independently through univariate calibration, while multivariate calibration combines these for simultaneous determination. This approach maintains high productivity while managing device complexity through systematic calibration methodologies.

Inventive Principle:

Principle #35Parameter changes

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

Enables fast and accurate quantification of water, acid, base, and degradation products in IL/H2O mixtures, ensuring process stability and uniform product quality by preventing harmful build-up of degradation products, thus improving operational efficiency and product consistency.

Implementation Method 1

Raman spectroscopy is a well-known vibrational spectroscopy technique, based on the inelastic scattering of the light by a material. The proportional relationship between Raman scattering intensity and analyte concentration is the basis for most of the quantitative analysis done using Raman spectroscopy

Methodology Applied

Scientific EffectRaman scattering: Scattering

Implementation Method 2

Vibrational spectroscopy methods have the big advantages of being fast, non-destructive, and requiring much less efforts and time for sample preparation. In addition to the classical KF titration method as well as to various electrochemical methods, vibrational spectroscopy excels in detecting and analyzing water contained in ILs

Methodology Applied

Scientific EffectInfrared absorption: Absorption (EM radiation)

Data Source

PatentUS12571737B2Quantitative Raman spectroscopy

Publication Date: 2026.03.10 AALTO UNIV FOUND

AI summary

Disclosed is a method for quantification of water and/or one or more ionic liquid components in an ionic liquid (IL)/water (H2O) mixture. The method comprises obtaining one or more Raman spectra for the IL/H2O mixture, and using a quantitative calibration model with the one or more Raman spectra to quantify water and/or one or more ionic liquid components in the IL/H2O mixture.