UV-Vis Concentration Profiling for Overlapping Metal Catalyst Spectra

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Solution Overview

Problem

Current methods fail to accurately determine the concentrations of multiple transition metal compounds in solutions, especially when their UV-Vis spectra overlap or when one compound is in large excess, hindering real-time monitoring and control in polymerization processes.

Innovation Solution

A method using UV-Vis spectroscopy involves providing reference absorbance profiles for each transition metal compound, irradiating a sample, and calculating a curve to fit the sample absorbance profile, allowing for precise determination of concentrations through least-squares regression, even in overlapping spectra or excess conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional UV-Vis spectroscopy is used to determine transition metal compound concentrations, then measurement can be performed, but accurate determination fails when spectra overlap or one compound is in large excess

Engineering Contradiction:
Improveconcentration determination accuracyVSAvoidspectrum overlap interference
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the overlapping spectrum into individual compound contributions by measuring absorbance at multiple discrete wavelengths and solving a system of linear equations. Each compound's absorbance profile is separated mathematically, allowing accurate concentration determination even when spectra overlap significantly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-wavelength measurement to multi-wavelength measurement, adding the wavelength dimension to the analysis. By measuring absorbance across multiple wavelengths and using least-squares regression, the method resolves overlapping spectra that cannot be distinguished at a single wavelength.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If real-time monitoring of transition metal concentrations is implemented, then process control is improved, but measurement accuracy deteriorates when compounds are in large excess ratios

Engineering Contradiction:
Improvereal-time monitoring capabilityVSAvoidconcentration determination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary characterization of each transition metal compound's absorbance spectrum at multiple wavelengths before actual measurement. These reference profiles are stored and used to construct a calibration matrix that enables accurate concentration calculation even when compounds are present in large excess ratios, allowing real-time monitoring without accuracy loss.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the measured absorbance profile is compared against the calibration matrix, and concentration values are iteratively refined using least-squares regression. This feedback loop ensures accurate determination of concentrations even in challenging conditions where one compound is in large excess.

Inventive Principle:
Principle #23Feedback

3Productivity

If multiple transition metal compounds are analyzed simultaneously, then process control efficiency is improved, but measurement complexity increases due to overlapping spectra

Engineering Contradiction:
Improvesimultaneous measurement efficiencyVSAvoiddata processing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent creates a universal calibration matrix that can simultaneously analyze multiple transition metal compounds using the same measurement protocol and data processing approach. The least-squares regression method provides a unified framework that handles any number of compounds, making the system versatile and efficient without requiring compound-specific procedures.

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

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 precise and real-time monitoring and control of transition metal concentrations in polymerization processes, improving the quality and consistency of polymer products by accurately determining individual concentrations despite overlapping spectra or excess conditions.

Implementation Method 1

irradiating the sample in the chamber with a light beam at a wavelength in the UV-visible spectrum, and generating a sample absorbance profile of the sample

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentEP3922349A1Methods for determining transition metal compound concentrations in multicomponent liquid systems
Publication Date: 2021.12.15 CHEVRON PHILLIPS CHEMICAL COMPANY LP
  • EP3922349A1 patent drawingFigure 1
  • EP3922349A1 patent drawingFigure 2
  • EP3922349A1 patent drawingFigure 3

AI summary

Methods for simultaneously determining the concentrations of transition metal compounds in solutions containing two or more transition metal compounds are described. Polymerization reactor systems providing real-time monitoring and control of the concentrations of the transition metal components of a multicomponent catalyst system are disclosed, as well as methods for operating such polymerization reactor systems, and for improving methods of preparing the multicomponent catalyst system.