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Handbook of Solvents - George Wypych - ChemTech - Ventech!

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1444 Aydin K. Sunol and Sermin G. Sunol<br />

where the true potential <strong>of</strong> this technique lies. Typical examples are provided in Table<br />

21.1.9.<br />

Table 21.1.9 Sorption applications <strong>of</strong> supercritical fluids 21,72<br />

Purpose<br />

Supercritical<br />

medium<br />

Environmental<br />

Soil remediation CO 2 + entrainers Soil<br />

Substrate<br />

Regeneration <strong>of</strong> adsorbents CO 2 Polychlorinated biphenyls from adsorbents<br />

Regeneration <strong>of</strong> adsorbents<br />

CO 2<br />

Petrochemical<br />

Benzene, toluene, ethyl acetate from activated<br />

carbon<br />

Regeneration <strong>of</strong> catalysts<br />

CO2, THF, hexane,<br />

ethylbenzene, benzene<br />

Hydrocarbon, coke removal from catalysts<br />

Chromatographic fractionation CO2 Coal tar, mineral oil distillate<br />

Essential oils 78<br />

Chromatographic fractionation CO 2 + alcohol Black pepper, clove extract<br />

Chromatographic fractionation<br />

Polymer processing<br />

CO2, n-pentane+methanol<br />

Biochemical<br />

Styrene oligomer<br />

Chromatographic fractionation CO 2 + alcohol Prostaglandis<br />

Chromatographic fractionation CO 2 + alcohol Vitamins, polyunsaturated fatty acids<br />

Chromatographic chiral separation CO 2 Optical isomers<br />

In synthesis <strong>of</strong> supercritical sorption processes and their operating policies, the synergy<br />

between the characteristics supercritical fluids and the sorption needs to captured. Naturally,<br />

the domain requires good distributed process models and solvers in addition to<br />

physical property models.<br />

21.1.4 REACTIONS IN SUPERCRITICAL SOLVENTS<br />

As stated in the previous sections, supercritical solvents are widely used for separation, especially<br />

for extraction <strong>of</strong> thermally labile compounds. Although the unique properties <strong>of</strong><br />

supercritical fluids make them attractive as a reaction medium as well, the use <strong>of</strong> supercritical<br />

solvents as reaction medium is becoming more and more popular only in the recent<br />

years. The first review on reactions in supercritical fluids was presented by Subramaniam<br />

and McHugh, 79 whereas a more recent and through review was given by Savage et al. 80<br />

The motivations for using supercritical solvents in chemical reactions are many. 81,82 In<br />

this section, the motivations will be stated and explained with examples from each type <strong>of</strong><br />

reaction. Emphasis in this chapter will be given to more recent examples, which were not included<br />

in the previous review papers.

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