Scale-up How do we get it right first time?

Scale-up in the context of fast moving process development can be problematic. Getting scale-up right requires an understanding of the way in which physical and chemical process parameters interact to determine overall performance. Multiphase systems are particularly difficult. The most common types of scale-up problem at the reaction stage will be shown, and the root causes will be discussed and exemplified. Common root causes are: increases in overall processing time on scale-up, with possible adverse effects on yield and quality; differences in heat transfer capability, which can feed back to increases in cycle time; changes in mass transfer rates, which can impact on reaction time and selectivity; poor dispersion of solids (mass transport), leading to low reaction rates and stalled reactions; and changes in mixing efficiency in homogeneous reactions, with implications for reaction selectivity. A procedure for identification of potential scale-up problems will be described.