What is a Supercritical Fluid?

What is a supercritical fluid, anyway? At last summer's ACS Green Chemistry show, Rolf Schlake was asked to speak about supercritical fluids and their uses.



http://www.ustream.tv/recorded/15545951

Non-Toxic Enzymatic Esterification

Esters of fatty acids and alcohols are used in the food, beverage, cosmetic and pharmaceutical industries as flavor and fragrance compounds. Applied Separations has recently synthesized fatty acid esters using an immobilized lipase in a carbon dioxide medium without the use of toxic organic solvents. Various esters have been synthesized using the “green” supercritical process including citronellol laurate, isoamyl acetate, and octyl oleate.

For more information, visit the Applied Separations website.

Aerogel Drying with Supercritical Fluids

Because a supercritical fluid has no surface tension, it can be used to dry the aerogel without consequence. The end result removes all liquid from the gel and replaces it with gas, without allowing the gel structure to collapse or lose volume.

For more information, visit the Applied Separations website.

Supercritical Fluids in 2012

Happy New Year! How are you going to use supercritical fluid in 2012? The Applied Separations team of engineers can guide you through the process of converting your process to environmentally friendly supercritical fluids.

Use supercritical fluids for: Aerogel drying, medical implant cleaning, metal injection molding, natural products extractions, critical cleaning, textile dyeing, essential oils, critical point drying and much much more. Visit the Applied Separations site to explore the possibilities.

http://appliedseparations.com/Supercritical/SCF_Uses/default.asp

Counter Current Separations Using Supercritical Fluids

Applied Separations has constructed a unique counter current extraction column that uses supercritical carbon dioxide to fractionate components contained in a liquid. Counter current extraction using supercritical carbon dioxide is an alternative to conventional distillation and solvent extraction processes and offers the use of a “green solvent” with enhanced selectivity and mild operating conditions. Many applications of this technology are applicable to edible oils, including the removal of free fatty acids, separation of glycerides, and the removal of free fatty acid ethyl esters.

For more information about how supercritical fluids can improve your process, visit the Applied Separations website.

Aerogel Drying Software

Applied Separations, Inc. has developed new software to be used with its aerogel drying system. Complete automated control of conditions now ensures that the aerogel is free of defects usually associated with the drying process. The system dries silica aerogels as well as other inorganic and polymeric aerogels.

Click for more information about the aerogel drying system.

Environmentally Friendly Method of Drying Aerogels

Aerogels are highly porous materials with large internal surface area and large pore volumes. Their densities are as low as 3 kg/m3 and have porosities as high as 99.9%. This makes them excellent thermal insulators.

Although there are other types of aerogels, such as carbon and alumina, silica aerogels are the most common. They are made with a liquid alcohol like ethanol which is mixed with a silicon alkoxide precursor to form a silicon dioxide sol gel (silica gel). However, removing the aerogels from the solvent bath for common use can be problematic.

Since the structure is so fine, normal drying at atmosphere collapses the network rendering to dust. This is caused by normal capillary pressure at the liquid/vapor interface on the inside of the pore. The energy of vaporization is greater than the wall strength of the pore.

Because a supercritical fluid has no surface tension, it can be used to dry aerogels without consequence. The end result removes all liquid from the gel and replaces it with gas, without allowing the gel structure to collapse or lose volume.

For more information: http://appliedseparations.com/Supercritical/SCF_Uses/SCF_for_Aerogels.asp