Multikilogram Synthesis of 4-D-Erythronolactone via Batch and Continuous Processing

The conversion of a batch process to continuous (flow) operation has been investigated. The manufacture of 4,D-erythronolactone at kilogram scale was used as an example. Fully continuous processing was found to be impracticable with the available plant because of the difficulty in carrying out a multiphase isolation step continuously, so hybrid batch continuous options were explored. It was found that very little additional laboratory or process safety work other than that required for the batch process was required to develop the hybrid process. A hybrid process was chosen because of the difficulty caused by the precipitation of solid byproduct during the isolation stage. While the project was a technical success, the performance benefits of the hybrid process over the batch were not seen as commercially significant for this system.