Sidereactions

Sidereactions refer to unintended reaction pathways that occur concurrently with the desired transformation in a chemical process, leading to byproducts and consumption of reagents. They can reduce yield, complicate purification, and affect selectivity.

They encompass hydrolysis, oxidation, reduction, rearrangements, polymerization, radical processes, dehydration, over-alkylation, and catalyst-induced side steps. Their occurrence depends on substrates, catalysts, solvents, temperature, and trace impurities.

Important factors include solvent choice, temperature, concentration, light exposure, moisture, oxygen, impurities, and the presence of additives or protecting groups. Some sidereactions are promoted by high temperatures or highly reactive intermediates; others are suppressed by mild conditions.

Detection and mitigation rely on analytical monitoring such as NMR, GC-MS, or LC-MS, along with kinetic studies and trapping experiments. Practical strategies include careful stoichiometry, slow or controlled reagent addition, protecting groups, scavengers, alternative catalysts, and optimized solvent systems.

In research and industry, sidereactions influence process design, cost, and safety. Understanding their mechanisms helps in improving selectivity, maximizing yield, and simplifying purification, making sidereactions a central consideration in reaction engineering and pharmaceutical development.