Modeling the Chemical Conversion of Organic Compounds in Sodium Borohydride Reduction Reactions

In this paper we propose a new modeling concept for the prediction of the chemical conversion of reducible species as a function of reductant concentration in sodium borohydride reduction reactions. This concept is applicable to organic compounds of unknown reactive group concentrations, such as mixtures of organic or colloidal materials. In addition to the prediction of chemical conversion, the calculation of model fitting parameters also provides values for an “apparent, conditional equilibrium constant” and an effective reactive group concentration. These models are derived on the basis of simple chemical principles and a chemical equilibrium assumption. The model-fitting parameters can be easily determined with standard mathematical software. Nevertheless, these models capture the overall behavior of the chemical reduction reaction sufficiently well for accurate predictive needs. This modeling concept can be applied in two possible ways. First, model predictions allow the transfer of experimental chemical conversion data to new, similar target compounds, assuming that the necessary requirements are fulfilled. This leads to shorter time-frames required for process development. Second, these models can be applied as heuristic tools in order to test the feasibility of a proposed overall reaction mechanism and/or effective reactive group concentration.