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The Moffatt-Swern oxidation (MSO) is a multistep, versatile, metal-free reaction by which alcohols are transformed into aldehydes and ketones. Batch MSO requires low temperatures (−70 °C) due to a highly exothermic reaction step that generates intermediates. This work shows that a rigorous investigation of the MSO in batch can be used as a stepping-stone to its implementation in a continuous-flow reactor (CFR). This work has two parts: the first part details the investigation of MSO in batch; the second covers the translation of the knowledge derived from batch to a CFR. The MSO batch reaction was performed under cryogenic conditions with real-time process monitoring. The reaction was monitored with Raman spectroscopy and could be tracked throughout the reaction. All concentrations were validated using offline high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). Two configurations of the CFR were produced. Configuration 1 used the traditional batch methodology in...

The pharmaceutical industry has great need to reduce costs and improve manufacturing efficiency while consistently manufacturing quality drug product. Continuous flow reactors (CFRs) offer an option for a flexible, leaner, and cleaner process. CFRs are flow cells optimized for the continuous production of a target compound. Small-volume CFRs avoid some of the reaction control problems associated with scale-up to large-batch chemistry, while still allowing for process intensification through modular scale-out. Compared to batch reactors, CFRs are more energy efficient due to their superior mixing schemes and heat transfer properties. Reactions typically proceed much faster than in batch and require less excess solvent. Currently, CFRs are limited by the technologies available for online monitoring, which require product stream sampling and off-line analytics. This work addresses the analytical challenges inherent to CFRs by demonstrating the ability to assess the quality of product from a reactor stream rapidly, using effective online sampling and monitoring systems. Additionally, following the Quality by Design paradigm, techniques such as statistically based design of experiments, process analytical technologies, and multivariate statistical modeling methods were implemented to facilitate enhanced product and process understanding. An online sampling system that is able to interface with CFRs was developed, with custom software to monitor and control process variables using online analytics. Knowledge of these in-process parameters, combined with appropriate online process analytical technologies, provided a complete understanding of both the physical and chemical system. These improvements reduced the time and effort required to develop and optimize a chemical reaction for large-scale continuous production.

Continuous flow reactors (CFRs) are an emerging technology that offer several advantages over traditional batch synthesis methods, including more efficient mixing schemes, rapid heat transfer, and increased user safety. Of particular interest to the specialty chemical and pharmaceutical manufacturing industries is the significantly improved reliability and product reproducibility over time. CFR reproducibility can be attributed to the reactors achieving and maintaining a steady state once all physical and chemical conditions have stabilized. This work describes the implementation of a smart CFR with univariate physical and multivariate chemical monitoring that allows for rapid determination of steady state, requiring less than one minute. Additionally, the use of process analytical technology further enabled a significant reduction in the time and cost associated with offline validation methods. The technology implemented for this study is chemistry and hardware agnostic, making this approach a viable means of optimizing the conditions of any CFR.