Combining self-modeling curve resolution methods and partial least squares to develop a quantitative reaction...

Area of Science:

• Analytical Chemistry
• Process Chemistry
• Chemometrics

Background:

• Real-time monitoring of chemical reactions is crucial for process optimization and control.
• Traditional methods often require offline sampling and analysis, which can be time-consuming and impractical for certain reaction conditions.
• Developing quantitative models with minimal reference data presents a significant challenge.

Purpose of the Study:

• To develop a quantitative calibration model for real-time in situ UV/ATR measurements during a chlorination reaction.
• To determine the reaction end-point using minimal reference data by combining SMCR methods and PLS.
• To enable real-time process monitoring and control in a large-scale laboratory setting.

Main Methods:

• Utilized evolving factor analysis (EFA) and orthogonal projection approach (OPA) for initial concentration and spectral profile estimation.
• Employed multivariate curve resolution-alternating least squares (MCR-ALS) for refining concentration profiles.
• Constructed a PLS2 model using preprocessed UV spectra and calculated concentration profiles for real-time predictions.

Main Results:

• The combined SMCR-PLS method successfully predicted product concentration in initial batches.
• Qualitative real-time profiles allowed for end-point determination without offline analysis.
• Real-time monitoring identified a process deviation (low temperature) in batch 3, enabling correction and successful completion.

Conclusions:

• The developed method provides a valuable tool for real-time reaction monitoring and end-point determination, especially when traditional sampling is difficult.
• While quantitative prediction accuracy varied, the qualitative insights from real-time profiles significantly enhanced process understanding and control.
• The ability to observe intermediate species and detect process anomalies in real-time offers substantial benefits for industrial chemical manufacturing.