UV-Vis Spectroscopy for Multicomponent Transition Metal Concentration

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Solution Overview

Problem

Current methods fail to accurately determine the concentration of individual transition metal compounds in solutions containing multiple compounds, especially when their UV-Vis spectra overlap or when one compound is in large excess, hindering precise control of olefin polymerization processes.

Innovation Solution

A method using UV-Vis spectroscopy to irradiate a sample with a light beam in the UV-visible spectrum, generating absorbance profiles, subtracting a reference profile of a second transition metal compound, and correlating the resulting profile to a standard to determine the concentration of the first transition metal compound, allowing for real-time monitoring and adjustment in polymerization reactor systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If UV-Vis spectroscopy is used to determine the concentration of transition metal compounds in multicomponent solutions, then real-time monitoring capability is achieved, but measurement precision deteriorates when spectra overlap or one compound is in large excess

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

Solution Approach 1:

The patent divides the overlapping absorbance spectrum into multiple discrete wavelength measurements. Instead of treating the spectrum as a single overlapping signal, the method selects specific wavelengths where individual compounds have distinct absorbance characteristics, effectively segmenting the measurement to resolve contributions from each compound independently

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the problem from a single-dimension absorbance measurement to a multi-dimensional analysis by measuring absorbance at multiple wavelengths simultaneously. This dimensional expansion allows the system to distinguish between overlapping spectra by analyzing the unique absorbance pattern of each compound across the wavelength spectrum

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

2Device complexity

If conventional UV-Vis spectroscopy is used without spectral deconvolution, then device complexity is minimized, but measurement precision deteriorates in multicomponent systems with overlapping spectra

Engineering Contradiction:
Improvespectroscopy method simplicityVSAvoidindividual compound concentration accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary characterization of each transition metal compound's UV-Vis spectrum before analysis. By pre-identifying the unique absorbance profile and characteristic wavelengths of each compound in advance, the method prepares the measurement strategy beforehand, allowing simple single-wavelength or multi-wavelength measurements to accurately determine concentrations without requiring complex real-time deconvolution algorithms

Inventive Principle:
Principle #10Preliminary 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

Enables precise and real-time monitoring and control of transition metal compound concentrations, even in overlapping spectra or excess conditions, improving the consistency and quality of polymerization processes.

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

PatentEP3655756B1Methods for determining transition metal compound concentrations inc multicomponent liquid systems
Publication Date: 2022.02.23 CHEVRON PHILLIPS CHEMICAL COMPANY LP
  • EP3655756B1 patent drawingFigure 1
  • EP3655756B1 patent drawingFigure 2
  • EP3655756B1 patent drawingFigure 3

AI summary

Methods for determining the concentration of transition metal compounds in a solution containing more than one transition metal compound 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.