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Characterization of moisture-sensitive raw materials with simple spectroscopic techniques.
1Merck and Co., Inc., Merck Research Laboratories, P.O. Box 2000, RY818-C306 Rahway, NJ 07065, USA.
Talanta
|October 31, 2008
Summary
Spectroscopic techniques offer efficient analysis of air and water-sensitive raw materials. This study demonstrates FT-IR and NIRS methods for quantifying critical reagents in chemical synthesis, ensuring product quality and reaction efficiency.
Area of Science:
- Analytical Chemistry
- Process Chemistry
- Spectroscopy
Background:
- Controlling raw material quality is crucial for synthetic processes.
- Air and water-sensitive materials present significant quantitative analysis challenges.
- Spectroscopic methods offer rapid, cost-effective analysis for reactive materials.
Purpose of the Study:
- To demonstrate the utility of spectroscopic techniques for analyzing air and water-sensitive raw materials.
- To develop and validate methods for quantifying specific reactive impurities and reagents.
- To ensure optimal reaction conversion and product quality in chemical synthesis.
Main Methods:
- Fourier Transform Infrared (FT-IR) spectroscopy for acetic acid quantification in acetic anhydride.
- Near-Infrared Reflectance Spectroscopy (NIRS) for diisobutyl aluminum hydride (DIBAL-H) concentration in toluene.
- NIRS with Partial Least Squares (PLS) regression for p-toluenesulfonic acid in p-toluenesulfonic anhydride.
Main Results:
- A one-frequency calibration method accurately quantified 2-35 wt.% acetic acid in acetic anhydride.
- A one-frequency calibration method determined 0-1.5 mol/L DIBAL-H in toluene.
- A PLS-NIRS method was developed for quantifying p-toluenesulfonic acid, which is not suitable for chromatography.
Conclusions:
- Spectroscopic methods provide effective solutions for analyzing challenging air and water-sensitive raw materials.
- Developed methods ensure accurate quantification, preventing issues like reaction quenching and incomplete conversion.
- These techniques enhance process control and product quality in chemical manufacturing.
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