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					            Ecuador Sustainable
            Practices Pt. 4d: Soap




C. Henry, UWB
                Why would we make
                     soap???
       • Because it's fun chemistry!
       • Because you can make better soap
         than you can buy!
       • Because it's natural!

       • And at Black Sheep Inn, the women’s
         group can make it and sell it to the
         lodge!

C. Henry, UWB
                                         Hydrophylic,
                                         water soluble
                      Detergents
            C C C C C C C
             \ / \ / \ / \ / \ / \ / \
             C C C C C C               +-
   Hydrophobic,
   oil soluble             The "tails"
                           Carboxyl (-COO-Na+)
                           Sulfonate (-SO3-Na+)
                           hydroxyl (-OH)
                  O
      C17H35 -C             C12H25       SO3-Na+
                  O-Na+
    Natural soaps              Synthetic soaps
C. Henry, UWB
                           •Chains form
                            micelles
                           •Outside solubilizes
                grease      in water
                           •Float freely due to
                            repulsive charges
                           •Trap oil/dirt inside,
                         | removes them from
                            water
          oil


                dirt                How
                                   soaps
                                   work
C. Henry, UWB
        Technical definition of soap
       • the alkali salt of a fatty acid
       • the reaction of a fatty acid and a
         strong base (alkali)
       • the fatty acids come from oils and
         fats
            – the strong alkali base is sodium
              hydroxide, also known as "lye" or
            – potassium hydroxide, also known as
              "potash", (for soft soaps)
C. Henry, UWB
C. Henry, UWB
                 What happens
       • When oils react with OH-, the
         triglycerides release glycerin, so that
         the fatty acids can react with the OH-
         to form the salt (neat soap)
       • Glycerin moisturizes the skin
       • Industrial soap manufactures remove
         the glycerin and sell it as a by-
         product, or use free fatty acids


C. Henry, UWB
                Characteristics of soap
       •   Bar hardness
       •   Fluffiness of the lather
       •   Stability of the lather
       •   These depend upon the fatty acids
           used
            – Palmitic acid (palm oil) = hardness
            – Oleic acid (olive oil) = cleansing &
              conditioning
            – Lauric acid (coconut oil) = fluffy lather
C. Henry, UWB
                                So -
                              Try it!
            Mold Recipe
                        amount      batch Adj amt Adj amt
                          (oz)       size    (oz)      (g)
            Olive oil        2          1        2      57
            Coconut oil      3          1        3      85
            Palm oil        22          1       22    624
            Lye              4          1      4.0    113
            Water          8.5          1      8.5    241
            Scent            2          1        2      57
            or Essential     1          1        1      28
                          42.5                       1205

            heat to 115-125°F           46 °C+
            keep warm on stove
            makes 9-10 cavities
            can put in freezer for 1/2 hour to help out of molds
C. Henry, UWB

				
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