Chapter 3 - Hydrogenation Using Critical Fluids

Abstract

Hydrogenation processes have employed pressure as a variable to provide higher reaction yields and to affect better contact between the hydrogen, substrates, and catalyst components during the hydrogenation reaction. However, the variable of pressure is also prominent in processes that employ supercritical fluids as a medium for extractions and reactions, particularly when supercritical carbon dioxide (SC-CO2) is utilized with its capability of readily dissolving fat, oil, and associated lipid moieties. This chapter on hydrogenation using critical fluids discusses a logical progression starting with fundamental material on why supercritical and subcritical fluids can facilitate hydrogenations advantageously, including a background discussion on characteristics of critical fluids. It also explains the merits and advances in using supercritical fluids for primarily the hydrogenation of fats or oils and additional lipid moieties. However, unlike some applications of supercritical fluids, very high pressures are not necessarily required to affect a successful hydrogenation when using SC-CO2, the lower compressed alkanes, or dimethyl ether as hydrogenation media.