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Solvent extraction

← extractant. ← raffinate (sample was dissolvent in). Solvent extraction. q ： fraction of solute extracted 1-q ： fraction of solute unextracted. is the ratio of total amount (weight) of A in one phase to that in the 2nd phase. partition ratio ： (capacity factor) phase ratio ：.

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Solvent extraction

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  1. ← extractant ← raffinate (sample was dissolvent in) Solvent extraction q：fraction of solute extracted 1-q：fraction of solute unextracted

  2. is the ratio of total amount (weight) of A in one phase to that in the 2nd phase partition ratio ：(capacity factor) phase ratio：

  3. (1) Partition coefficient (2) (3) (4)

  4. (2) Multiple contact (crosscurrent extraction) (3) Multiple contact (countercurrent extraction) 操作模式 • Single contact

  5. Multiple extraction

  6. Effect of pH value on extraction KD ─→ D ( distribution coeff. )

  7. very acid [H+] >>Ka • D=KD (b) at pH (c) [H+] <<Ka D >>KD

  8. Effect of pH value on extraction KD ─→ D ( distribution coeff. )

  9. very acid [H+] >>Ka • D >> KD (b) at pH (c) [H+] <<Ka

  10. Suppose that the partition coefficient for an amine, B, is 0.33 and the acid dissociation constant of BH+ is Ka=1.0x10-9. If 50 mL of 0.010M aqueous amine is extracted with 100 mL of solvent. What will be the formal concentration remaining in the aqueous phase (a) at pH 10.0? (b) 8.0?

  11. Application Extraction of metal ions

  12. HL (aq) HL (o) (1) HL (aq)+ H2O H3O+(aq) +L-(aq) (2) Mn+(aq)+ nL-(aq) MLn(aq) (3) MLn(aq) MLn(o) (4) 加入chelator (HL)

  13. → HL, MLn在有機相中溶解度大 → [L-] is pH dependent (5) >>1 CL：orignal molar conc. of HL in organic phase mass balance → excess chelator CL≈[HL(o)] (6)

  14. (3) (4) 代入(5) (6) (7)

  15. Extraction of Metal Ions with RTIL • 利用RTIL在重金屬離子之萃取,實驗時使用金屬螯合物, RTIL(在此選用不溶於水的1-butyl-3-methylimidazolium hexafluorophosphate , [BMIM][PF6]) 當有機層進行金屬離子的萃取，以便探討RTIL取代揮發性溶劑於金屬離子之萃取的可行性. • Guor-Tzo Wei*, Zusing Yang, Chao-Jung Chen, Anal. Chimica, Acta 2003, 488(2), 183. • Guor-Tzo Wei*, Jin-Chu Chen, Zusing Yang, J. Chin. Chem. Soc. 2003, 50, 1123.

  16. 傳統液-液相萃取: 需使用大量有毒、易燃、高揮發性的有機溶劑. 近代液-液相萃取: a.使用supercritical fluid CO2萃取 b.使用不具揮發性、不可燃、毒性較低的ionic liquid(IL) ，且可回收使用。

  17. Presidential Green Chemistry Challenge Awardshttp://www.epa.gov/greenchemistry/ Mission:To promote innovative chemical technologies that reduce or eliminate the use or generation of hazardous substances in the design, manufacture, and use of chemical products. 1996: Alternative Synthetic Pathways Award: Monsanto Company, The Catalytic Dehydrogenation of Diethanolamine Alternative Solvents/Reaction Conditions Award: Dow Chemical The Development and Commercial Implementation of 100 Percent Carbon Dioxide as an Environmentally Friendly Blowing Agent f or the Polystyrene Foam Sheet Packaging Market Designing Safer Chemicals Award: Rohm and Haas Designing an Environmentally Safe Marine Antifoulant Small Business Award: Donlar Corporation Production and Use of Thermal Polyaspartic Acid Academic Award : Prof. Mark Holtzapple, Texas A&M Univ. Conversion of Waste Biomass to Animal Feed, Chemicals, and Fuels

  18. *Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice, Oxford University Press: New York, 1998, p.30.

  19. What is a Room Temperature Ionic Liquid (RTIL)?(Room Temperature Molten Salt) • Liquid salt consisting of at least one organic component (cation or anion) with melting pointbelow room temperature • Properties: • Negligible vapor pressure • High thermal stability (~250-400°C) • High viscosity • Hydrophobic or hydrophilic • Dissolve many organic, organometallic, and inorganic compounds RTILs are regarding as “Green solvents”

  20. Ethyl ammonium nitrate (EtNH+3)(NO-3), which has a melting point of 12°C, was first described in 1914. P. Walden, Bull. Acad. Imper. Sci. (St. Petersburg) 1800 (1914). Osteryoung & Wilks, late1970, chloroaluminate salts in electrochemistry Sneddon & Hussey, 1980, groups chloroaluminate salts in electrochemistry and organometallic researches. After 1990, used as solvents for synthesis Late 2000, the application in separation

  21. Pure Appl. Chem., 2000, 72, 2275–2287

  22. RTIL Structures • Cations • Anions • PF6-SbF6- • BF4-CF3SO3- (TfO) • Cl-N(CF3SO2)2- (NTf2) R: methyl; R’: n-butyl 1-butyl-3-methylimidazolium, BMIM, C4MIM 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] 1-octyl-3-methylimidazotetrafluoroborate [OMIM][BF4]

  23. General syntheses of ionic liquid: Green Chemistry, 2003. 5. 181-186.

  24. Effect of the nature of anion on physical properties of BMIM salt ----------------------------------------------------------------------------------- Anion m.p. d Viscosity Conductivity oC g/cm3 cP (20oC) S/m ---------------------------------------------------------------------------------- BF4- -82(g) 1.17 233 0.17 PF6- -8 1.36 312 0.14 Cl- 65 1.10 solid solid CF3COO- ~-40(g) 1.21 73 0.32 CF3SO3- 16 1.29 90 0.37 (CF3SO2)N- -4 1.43 52 0.39 C3F7COO- ~-40(g) 1.33 182 0.10 C4F9SO3- 20 1.47 373 0.045 ---------------------------------------------------------------------------------- (g) Glass transition P.S. viscosity of water 1 cP.

  25. Dissolution of Cellulose with Ionic Liquids R.P. Swatloski, R.D. Rogers, et al. J.A.C.S. 124 (2002) 4974.

  26. Room-temperature ionic liquids: a novel versatile lubricantChengfeng Ye , Weimin Liu , Yunxia Chen and Laigui Yu, Chem. Commun., 2001, (21), 2244 - 2245 Alkylimidazolium tetrafluoroborates are promising versatile lubricants for the contact of steel/steel, steel/aluminium, steel/copper, steel/SiO2, Si3N4/SiO2, steel/Si(100), steel/sialon ceramics and Si3N4/sialon ceramics; they show excellent friction reduction, antiwear performance and high load-carrying capacity

  27. Uses of RTILs in Anal. Chem. • Novel solvents in liquid-liquid or micro extractions • Run buffer additives in CE • Matrixes in Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry • Stationary phases in gas-liquid chromatography

  28. Extraction of Metal Ions with RTIL Illustration of various equilibra involved in metal ion extraction with ionic liquid .

  29. 鉛與dithizone結合示意圖 colorless metal complex (red)

  30. + + 2 Cu2+ 2H+ Dithizone Blue Green Violet + + Cu2+ 2 2H+ Oxine Blue Yellow + 2 2H+ + Cu2+ PAN Blue Orange Red

  31. The pH value effect on the extraction of lead ion with dithizone in ( ) ionic liquid, ( ) chloroform.

  32. Comparing the extraction of copper ions with ionic liquid and dichloromethane with PAN

  33. The effect of pH value on the extraction efficiencies of metal ions with dithizone by IL.

  34. The effect of pH value on the extraction efficiencies of metal ions with PAN by IL.

  35. Hg2+ Zn2+ Pb2+ Ca2+ Cr3+ Mn2+ Cd2+ As5+Co2+ Ag+ The effect of 100 ppm cation on the extraction of 5 ppm Cu2+ with dithizone

  36. SCN- citrate Cl- CO32- PO43- CH3COO- The effect of 100 ppm anion on the extraction of 5 ppm Cu2+ with dithizone

  37. SCN- citrate Cl- CO32- PO43- CH3COO- The effect of 100 ppm anion on the extraction of 5 ppm Cu2+ with PAN

  38. Preconcentration of Pb2+

  39. (a) Separation of different metal ions; (b) Reproducibility of Cadmium ions with reusal [C4MIM][PF6] Average = 43.31% RSD = 5.69% (a) (b)

  40. Solute A has a partition coeff. of 1/3 between toluene and water. Suppose that 100 mL of a 0.010 M aqueous solution A is extract with toluene. What fraction of A remains in the aqueous phase (a) if one extraction with 500 mL if performed and (b) if five extractions with 100 mL are performed?

  41. Solute A has a partition coeff. of 1/3 between toluene and water. Suppose that 100 mL of a 0.010 M aqueous solution A is extract with toluene. What fraction of A remains in the aqueous phase (a) if one extraction with 500 mL if performed and (b) if five extractions with 100 mL are performed?

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