Topics for Today  From Fats to Soap!

Topics for Today  What is a soap?  Why do soaps clean?  What is dirt?  What is hard water?  How do we make a soap?

Readings for Today  Section – How Hard is Your Water?

Topics for Wednesday  From Soap to Biodiesel!!

Topics for Wednesday  Why biodiesel?  How are soap and biodiesel different? No text readings 

Topics for Friday EXAM 4!!!!

Announcements! HW 5 due Thursday the 10 th !

Final Exam!! Friday, May 18 th

Final Exam!! Can I take it early? Chancellor John Wiley Only if you have 3 finals within 24 hours of each other

Topics for Today  From Fats to Soap!

 Generic term for the soluble salt of a fatty acid What is a soap?

 Generic term for the soluble salt of a fatty acid What is a soap?

Review What is a salt? The product of an acid-base reaction!

Neutralization Reaction HNO 3 + NaOH H + NO 3 - Na + OH - Na + NO 3 - H + OH - Acid + BaseSalt + Water  NaNO 3 + HOH There WILL be a neutralization reaction (in some fashion) on Exam #4!! Can you use carboxylic acids?

Carboxylic Acids C OH O CH 3 Ethanoic/Acetic Acid (Vinegar) CH 3 COO - (Acetate ion)H+H+ Where does the H + come from?

Neutralization Reaction- Review C OHOH O CH 3 + NaOH H2OH2O + C O - Na + O CH 3 Acid + BaseSalt + Water Acetic Acid + NaOHSodium Acetate + H 2 O

Soap  Generic term for the soluble salt of a fatty acid

Review What is a fatty acid?

Fatty Acids + Alcohol Triglyceride + Water H+H+ ThreeTriple FatsOils

Another triglyceride… H | H—C—O—C—(CH 2 ) 16 CH 3 | H—C—O—C—(CH 2 ) 7 CH=CH(CH 2 ) 7 CH 3 | H—C—O—C—(CH 2 ) 14 CH 3 | H = O = O + 3 HOH = O from stearic acid from palmitic acid from oleic acid

Neutralization Reaction C OHOH O CH 3 + NaOH H2OH2O + C O - Na + O CH 3 Acid + BaseSalt + Water Acetic Acid + NaOHSodium Acetate + H 2 O Try another one!!

Stearic Acid CH 3 (CH 2 ) 16 COOH CH 3 (CH 2 ) 16 C O OH

C O CH 3 + NaOH H2OH2O + Na + (CH 2 ) 16 C O-O- O CH 3 (CH 2 ) 16 Acid + Base Salt + Water Review

C OH O CH 3 + NaOH H2OH2O + Na + (CH 2 ) 16 C O-O- O CH 3 (CH 2 ) 16 Fatty Acid + Base Soap + Water Review

Soap  Generic term for the soluble salt of a fatty acid

Salt of a Fatty Acid (Soap!!) CH 3 (CH2) 16 C O O-O- Na +

Salt of a Fatty Acid (Soap!!) CH 3 (CH2) 16 C O O-O- Na + How does a soap work?

Salt of a Fatty Acid (Soap!!) CH 3 (CH2) 16 C O O-O- Na + Polar or nonpolar?

Salt of a Fatty Acid (Soap!!) CH 3 (CH2) 16 C O O-O- Na + Polar or nonpolar?

Salt of a Fatty Acid (Soap!!) CH 3 (CH2) 16 C O O-O- Na + Polar or nonpolar?

Salt of a Fatty Acid (Soap!!) CH 3 (CH2) 16 C O O-O- Na + Polar or nonpolar? NONPOLAR CHAIN POLAR (IONIC) END

Salt of a Fatty Acid (Soap!!) CH 3 (CH2) 16 C O O-O- Na + A molecule with dual personalities! NONPOLAR CHAIN POLAR (IONIC) END Different parts of the molecule behave differently!

REVIEW - TYPES OF BONDS Electronegativity Difference LowHigh IONICPOLARNONPOLAR COVALENT

Salt of a Fatty Acid (Soap!!) Squiggly Notation NONPOLAR CHAIN POLAR (IONIC) HEAD +

What about grease? What are its properties?

What is grease? A bunch of fats and oils!!

Polar or nonpolar?

Another triglyceride… H | H—C—O—C—(CH 2 ) 16 CH 3 | H—C—O—C—(CH 2 ) 7 CH=CH(CH 2 ) 7 CH 3 | H—C—O—C—(CH 2 ) 14 CH 3 | H = O = O + 3 HOH = O from stearic acid from palmitic acid from oleic acid

From Crude Oil Polar or nonpolar?

Dirt and Grease A bunch of nonpolar molecules How does soap clean?

1) The soap traps the grease GREASE Polar Head Nonpolar Tail water

Figure 5.21 (p. 249)

2) The water washes away the soap + grease O H H.. Polar Head Polar Molecule Why?

1) The soap traps the grease GREASE Polar Head Nonpolar Tail water

How do we make a soap?

C OH O CH 3 + NaOH H2OH2O + Na + (CH 2 ) 16 C O-O- O CH 3 (CH 2 ) 16 Neutralize a fatty acid?

We don’t just have fatty acids sitting around in our world… Where can we get them?

Fats! We need to hydrolyze a fat!!

Step 1) Hydrolysis  A chemical reaction where you ADD water!!

PolyesterNylon Opposite of condensation reactions!!

Review - Condensation Carboxylic Acid + Alcohol Ester + Water H+H+

Hydrolysis! Ester + WaterAlcohol + Carboxylic Acid OH - Break the ester into its “original” parts!

Where can we find an ester?

Fats!

Hydrolysis! Ester + WaterAlcohol + Carboxylic Acid OH - Break the ester into its “original” parts!

Hydrolysis! Ester + WaterAlcohol + Carboxylic Acids OH - Break the ester into its “original” parts! Triple Three OR…

Hydrolysis! Fat + WaterGlycerol + Fatty Acids OH - Break the ester into its “original” parts! Three Example

Glycerol Tristearate COH CO OCH H H H C(CH 2 ) 16 CH 3 O O O TRIPLE ESTER! Hydrolyze …

COH CO OCH H H H C(CH 2 ) 16 CH 3 O O O + 3 H 2 O NaOH COH CO OCH H H H H H H + O C(CH 2 ) 16 CH 3 O H 3 Name?Glycerol!! FATTY ACID! Heat

O C(CH 2 ) 16 CH 3 O H 3 This isn’t soap! Now what?

Soap  Generic term for the soluble salt of a fatty acid Neutralize the fatty acid!

C OH O CH 3 + NaOH H2OH2O + Na + (CH 2 ) 16 C O-O- O CH 3 (CH 2 ) 16 Fatty Acid + Base Soap + Water Review

Sopanification  The process of making soap 1) Hydrolysis of the fat 2) Neutralizing the fatty acid

Sopanification  The process of making soap Heating a triglyceride (usually a fat) in the presence of a base

Fat/Oil Glycerol 3 Fatty acids 3 waters Hydrolyzing a fat

Sopanification HEAT / H 2 O COH CO OCH H H H C O C O C O 3NaOH + CHO CH 2 O O H H H + C O-O- O CH 3 (CH 2 ) 16 3 Na + Why is water not in the reaction?

Sopanification  The process of making soap 1) Hydrolysis of the fat (water is used) 2) Neutralizing the fatty acid (water is produced) It’s a wash!!!

When soaps DON’T work… What is hard water?

Water with lots of Ca 2+ and Mg 2+ ions How do these ions get into the water?

Review  Dissolving a salt… 2HCl+Na 2 CO 3 H 2 CO 3 2NaCl + Why the “2”?

Review  Dissolving a salt… 2HNO 3 + CaCO 3  Ca(NO 3 ) 2 + H 2 CO 3 H 2 CO 3  H 2 O + CO 2 A lot of limestone in our area… tend to have very hard water

What does this have to do with soaps?

Soluble in water “Separates” into ions Soap in “normal” water

C O-O- O Na + C O-O- O C O-O- O C O-O- O

 Soap interacts with the Mg 2+ and Ca 2+ ions. Soap in hard water NOT soluble!!!!

Soap in hard water Mg 2+ C O-O- O C O-O- O C O-O- O C O-O- O Na + Soap forms complexes with Mg 2+ and Ca 2+ !! So what?

Soap in hard water Mg 2+ C O-O- O C O-O- O C O-O- O C O-O- O Na + Insoluble in water (soap scum)!!!