1 / 30

Lecture 47 - Supercritical Fluids

rune
Download Presentation

Lecture 47 - Supercritical Fluids

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. Lecture 47 - Supercritical Fluids

    2. Beyond the Critical Point

    3. If T>Tc, gas can not be liquefied at any pressure

    4. Beyond the Critical Point

    6. Supercritical Fluids Have Unusual Properties 1. Densities are variable (like a gas) 2. Good solvents (like a liquid) 3. Viscosities are low (like a gas)

    7. Density of a SF

    8. Uses of SFs 1. Solvents in analytical chemistry 2. Solvents in the food industry 3. Miscellaneous applications

    9. Analyzing Soil

    10. Analyzing Soil

    11. problems... - analyte may take days to extract - other species are also extracted Solution? Use a supercritical fluid!

    12. Density of a SF

    13. Extraction Using a SF

    14. The Extraction Process

    16. Make the analyte more soluble in the fluid. 2. Make the fluid adsorb more strongly. How to maximize the extraction efficiency

    17. 1. Increase p

    18. 2. Use a different SF

    19. 3. Add a “co-solvent”

    20. Advantages of SFs

    21. Advantages of SFs

    22. Extraction from Water

    23. Other Applications of SFs 1. De-caffeination of coffee, tea The old way: acetone, benzene, ethanol, freons, pentane, hexane, CCl4, CHCl3, CH2Cl2

    24. Other Applications of SFs 1. De-caffeination of coffee, tea The modern way: (a) extract caffeine using SF CO2 (b) contact CO2 with water (c) discard water, recycle CO2

    25. Other Applications of SFs 2. Extraction of other foods - hops - fish oils - butter and eggs - potato chips

    26. 3. Making Ceramics

    27. 3. Making Ceramics Liquid Solvents ? many sizes of particles (not good) Solution? Rapid Expansion of Supercritical Solutions (RESS)

    28. 3. RESS

    29. 4. Supercritical Water Oxidation SF water (T>374oC, p>218 atm) H-bonds break! Kw << 1 x 10-14, non-polars are soluble H2O(SF) + waste ? CO2, N2, Cl-, SO4-2

    30. 5. Contracts I have Known... 1. Extraction of triethylamine from activated carbon. 2. Extraction of Cu, Cr and As from wood 3. Solubility of beclamethasone in SF CO2

More Related