WATER AND SOLUTIONS - PowerPoint - PowerPoint by 6zt86X

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									SOLUBILITY AND
 DISTRIBUTION
Molecular Interactions
 Ionic interactions     +   -
                                 - +
 Dipole-dipole interactions     + -
 Induced dipoles      + -             + -   +   -
 Hydrogen bond
Water Miscibility
 Solvents with relatively high polarity are
  miscible in water (e.g. acetic acid,
  ethanol, dioxane, DMSO).
 Solvent with low polarity or non-polar are
  water-immiscible (hexane, petroleum
  ether)
 Ask your advisor for the Solvent
  Miscibility Table
Solvent - Solute Interactions
           Polar solvents (e.g., water): (1) owing to
            high dielectric constant reduce ionic
            attraction between oppositely charged ions in
            crystals; (2) break covalent bonds of strong
            electrolytes resulting in dissociation; (3)
            solvate molecules through dipole interaction
            forces (particularly, hydrogen bond).
           Nonpolar solvents (e.g. hydrocarbons):
            dissolve nonpolar compounds through
            induced dipole interactions.
           Semipolar solvents (ketones, alcohols):
            can induce polarity in nonpolar solvent
            molecules (co-solvents).
Solvent Polarity
 Dielectric           Solvent                           Solute
constant, 
    80                 water                  Inorganic and organic salts

    50                 glycols                      Sugars, tannins

    30        methyl and ethyl alcohols            Caster oil, waxes

    20        Aldehydes, ketones, and Resins, volatile oils, weak electrolytes
               higher alcohols, ethers,   including barbiturates, alkaloids and
                        esters                          phenols
    5         Hexane, benzene, carbon Fixed oils, fats, petrolatum, paraffin,
              tetrachloride, ethyl ether,         other hydrocarbons
                   petroleum ether
    0           Mineral oil and fixed                       -
                    vegetable oils
Liquid-Liquid Systems
         100% A
                                  Miscibility: polar and
                                   semipolar solvents
                                   (e.g. water and
                                   alcohol, glycerin and
          LPS                      alcohol, alcohol and
A                   B              acetone) are
                                   completely miscible in
                                   all proportions.
                                  Partial miscibility:
         Miscible                  With certain
                                   proportions two liquid
                                   layers are formed
                                   (e.g., water-ether,
100% C                  100% B     phenol-water)
            C                     Miscibility is
                                   characterized by the
                                   phase diagram.
Effects on Solubility
 Pressure: increases solubility of gases
  (Henry’s law: PB = PBo. A xB)
 Temperature: solubilty of most gases
  decreases, solubility of liquids and solids
  may be affected both ways
 Co-solvents: increase solubility by
  changing the solvent polarity.
 Salting out: elaboration of gases from
  solutions by electrolytes (NaCl) and highly
  polar nonelectrolytes (glucose)
Doxorubicin and Taxol

                                                O

                           O
                O N
                                                O

                           O
                      OH
                                                    O
                               HO


                                    O
                                    O
                       O                            OH
                                        O   O




  Doxorubicin
                                    Taxol
Cyclodextrin
                            OH
                                                        OH
     HO
       H
                            H
                                             OH                 H             OH
                                                                H

 H
               O
               O            H                       H
                                                  O
                                                   OH               H                        OH
                                                                         O           H
          H                      H
                           HO                                                                      H
                       H             HO
     HO
                                                                             O           HO
                                                                                 H
                                                                                                  OH
                                 O
                                     H
                   H
                                                                                 H                 H
          HO
                                                                                     O
                                 O   H
                                                                    OH
                                                                                                   H
                                                        O                H
                                                                         OH
                                                                         H               O    OH
                                         H          H
                       HO                               H

                                     H                                                        H
                                                            O
                                                                         HO
                                     HO                                    H
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 Ibuprofen            Acetaminophen
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Solubility of Acids/Bases

HAsold = HAsolution                  HAsolution + H2O = H3O+ + A-

 [HAsolution] = so ;                Solubility: s = so + [A-]

                [HA ]solute        Ka
 [A  ]  K a                so
                 [H3O ]         [H3O ]         s

                                                2so
            Ka 
         [H O  ] 
 s  so 1        
            3                                  so

                                                           pKa      pH

								
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