Exploring the Impact of Persistent Chemical Vortices on Solution Homogeneity in Laboratory-Scale Reactions

Abstract

Abstract This study investigates the impact of persistent chemical vortices in lab scale reactions involving drop-wise addition of reagent, utilising pH indicators to visualise the vortex. Through the comparison of different indicators, Yamada universal indicator emerged as the superior choice. A protocol for acidifying a magnetically stirred solution was developed, allowing precise comparisons of chemical vortex lifetimes across various variables. The study examines the effects of container geometry, bulk solution pH, dropping position, stirring speed, and solution viscosity on vortex dynamics. Notable findings include the significant increase in chemical vortex persistence with larger beaker sizes, a direct relationship between acid concentration and vortex lifetime, and the effect of dropping position on vortex stability which fits the Rankine vortex model. Furthermore, the study reveals a nuanced relationship between stirring speed and vortex persistence, with a loss of dependence observed at higher velocities. Additionally, a significant increase in vortex lifetime was observed with higher solution viscosity, which is explained by the diffusion of momentum expressed by the Javier-stokes equation. Opportunities for further research include refining experimental setups to optimise vortex dynamics and comparative studies between cylindrical beakers and round-bottom flasks to assess their resistance to vortex formation. These insights have implications for improving chemical mixing processes, particularly in small-scale research and development settings.