From batch to continuous processes: a good answer, but what is the question?
Part I – General considerations and the reaction unit perspective


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The switch from batch to continuous process is a major topical question in the fine chemical, pharmaceutical and biopharmaceutical industries. In spite of a genuine interest, as shown by the profusion of recent literature and symposia on the topic, batch remains the widely accepted standard in these industries and the steps taken toward continuous remain somewhat shy. A paradox? Here, we propose a fresh look at the question through the chemist’s eyes but with process engineer glasses. In this first part, general considerations and simple reaction unit operations are investigated. The second part of the article (1) will propose general considerations on the purification unit operations, less simple reaction unit operations, and the overall process perspective.


Many recent articles, symposia and initiatives show that moving processes from batch to continuous is a topic raising serious considerations in fine chemical, pharmaceutical and biopharmaceutical industries.
As a matter of fact, many industries implemented continuous processes decades ago, but the fine chemical, pharmaceutical and biopharmaceutical processes are still largely operated in a batch mode.
Nowadays, several leading companies (Novartis, GSK, AstraZeneca, Pfizer, Eli Lilly, Genzyme, Sanofi, Lonza, etc.) have disclosed their interest and activities in the field and the FDA is clearly pushing in that direction.
In addition, major successes have also been achieved, like Novasep installing their first large scale continuous chromatographic processes (including solvent recycling) almost 20 years ago (2).
Nevertheless, despite genuine interests and significant achievements, examples of continuous processes in the fine chemical, pharmaceutical industries are still rather limited. Historically the priority has been set to the ability to produce and characterize high quality molecules, much less to producti ...