Multi-Tasking Processing with Critical Fluids

See also Ionic Liquids, Biphasic Catalysis Posters

Traditionally super- and sub-critical pressurized fluids have used carbon dioxided as the processing fluid in the liquid or supercritical state. The capabilities of the Supercritical Fluid Facility at LANL expand the possibilities for using multiple or linked processing steps; such as extraction, fractionation, or reaction; coupled with interchange of the fluid type. Particular emphasis is placed on using "green" environmentally benign agents such as carbon dioxide and water, coupled when necessary with generally regarded-as-safe (GRAS) co-solvents, such as ethanol. This provides capability for dissolving molecules ranging from non-polar moieties to polar species as illustrated by the figure at left.

When the above approach is coupled with processing options beyond just the extraction mode, a range of useful industrial extracts and products can result as shown by the flow schematic on the right (click to see a larger image). An example of this concept is the SFE of a naturally derived oil, i.e., soybean oil, from its comminuted seed matrix followed by a supercritical fluid reaction (SFR) of the extract with methanol over a naturally derived enzymatic catalyst (see image below left), to yield methyl esters which have applications as bio-diesel or as natural cleaning agents (see image below right).
Similar couplings have yielded fatty alcohol mixtures from consecutive reactions (esterification + hydrogenation) conducted in SF media or custom-designed extracts derivable from thermal gradient fractionationating columns, or preparative supercritical fluid chromatography (SFC).