Aerobic oxidations have much appeal in organic synthesis for their efficiency, yet they are often avoided in the production of pharmaceuticals because mixtures of O2 and solvents can create a flammable atmosphere. Instead of taking a gamble, process chemists and engineers tend to avoid oxidations altogether and use reagents bought at the required or higher oxidation state. To address this issue, a research team led by Paul M. Osterberg of chemical process safety firm Fauske & Associates, in Burr Ridge, Ill., and Shannon S. Stahl of the University of Wisconsin, Madison, has filled a knowledge gap by experimentally determining safe operating conditions for using O2 with nine common organic solvents (Org. Process Res. Dev. 2014, DOI: 10.1021/op500328f). The research was performed as part of a “precompetitive” consortium involving Eli Lilly & Co., Pfizer, and Merck & Co., formed to promote the development and application of aerobic oxidations for manufacturing. Using an explosion-compatible reactor, the researchers measured the minimum partial pressure of O2 that will support a combustible mixture with each solvent at the elevated temperatures and pressures used in production-scale reactions—values that provide benchmarks for safe application of aerobic oxidations.