Topics for Today

1
Topics for Today

• From Fats to Soap!

2
Topics for Today

• What is a soap?
• Why do soaps clean?
• What is dirt?
• What is hard water?
• How do we make a soap?

3
Readings for Today

• Section 5.12.1
• How Hard is Your Water?

4
Topics for Wednesday

• From Soap to Biodiesel!!

5
Topics for Wednesday

• Why biodiesel?
• How are soap and biodiesel different?

No text readings?
6
Topics for Friday
EXAM 4!!!!
7
Announcements!
HW 5 due Thursday the 10th!
8
Final Exam!!
Friday, May 18th
9
Only if you have 3 finals within 24 hours of each
other
Final Exam!!
Can I take it early?
Chancellor John Wiley
10
Topics for Today

• From Fats to Soap!

11

• Generic term for the soluble salt of a fatty acid

What is a soap?
12

• Generic term for the soluble salt of a fatty acid

What is a soap?
13
Review
What is a salt?
The product of an acid-base reaction!
14
Neutralization Reaction
Acid Base
Salt Water
? NaNO3 HOH
HNO3 NaOH
H NO3-
Na OH -
Na NO3-
H OH -
Can you use carboxylic acids?
There WILL be a neutralization reaction (in some
fashion) on Exam 4!!
15
Carboxylic Acids
Ethanoic/Acetic Acid (Vinegar)
Where does the H come from?
O
C
CH3
OH
CH3COO- (Acetate ion)
H
16
Neutralization Reaction- Review
Acid Base
Salt Water
Acetic Acid NaOH
Sodium Acetate H2O
O
O

H2O

NaOH
C
CH3
C
CH3
O- Na
OH
17
Soap

• Generic term for the soluble salt of a fatty acid

18
Review
What is a fatty acid?
19
Three
Triple
H
Fatty Acids Alcohol
Triglyceride Water
Fats
Oils
20
(No Transcript)
21
Another triglyceride
from stearic acid
H HCOC(CH2)16CH3
HCOC(CH2)7CHCH(CH2)7CH3
HCOC(CH2)14CH3
H
from oleic acid
from palmitic acid
3 HOH
22
Neutralization Reaction
Acid Base
Salt Water
Acetic Acid NaOH
Sodium Acetate H2O
O
O

H2O

NaOH
C
CH3
C
CH3
O- Na
OH
Try another one!!
23
Stearic Acid
CH3(CH2)16COOH
O
CH3(CH2)16C
OH
24
Review
Acid Base
O

NaOH
(CH2)16
C
CH3
OH
O
H2O

(CH2)16
C
CH3
O-
Na
Salt Water
25
Review
Fatty Acid Base
O

NaOH
(CH2)16
C
CH3
OH
O
H2O

(CH2)16
C
CH3
O-
Na
Soap Water
26
Soap

• Generic term for the soluble salt of a fatty acid

27
Salt of a Fatty Acid (Soap!!)
O
(CH2)16
CH3
C
O-
Na
28
Salt of a Fatty Acid (Soap!!)
How does a soap work?
O
(CH2)16
CH3
C
O-
Na
29
Salt of a Fatty Acid (Soap!!)
Polar or nonpolar?
O
(CH2)16
CH3
C
O-
Na
30
Salt of a Fatty Acid (Soap!!)
Polar or nonpolar?
O
(CH2)16
CH3
C
O-
Na
31
Salt of a Fatty Acid (Soap!!)
Polar or nonpolar?
O
(CH2)16
CH3
C
O-
Na
32
Salt of a Fatty Acid (Soap!!)
Polar or nonpolar?
O
(CH2)16
CH3
C
O-
Na
NONPOLAR CHAIN
POLAR (IONIC) END
33
Salt of a Fatty Acid (Soap!!)
Different parts of the molecule behave
differently!
A molecule with dual personalities!
O
(CH2)16
CH3
C
O-
Na
POLAR (IONIC) END
NONPOLAR CHAIN
34
REVIEW - TYPES OF BONDS
COVALENT
IONIC
POLAR
NONPOLAR
Low
High
Electronegativity Difference
35
Salt of a Fatty Acid (Soap!!)
Squiggly Notation

NONPOLAR CHAIN
POLAR (IONIC) HEAD
36
What about grease?
What are its properties?
37
What is grease?
A bunch of fats and oils!!
38
Polar or nonpolar?
39
Another triglyceride
from stearic acid
H HCOC(CH2)16CH3
HCOC(CH2)7CHCH(CH2)7CH3
HCOC(CH2)14CH3
H
from oleic acid
from palmitic acid
3 HOH
40
From Crude Oil
Polar or nonpolar?
41
Dirt and Grease
A bunch of nonpolar molecules
How does soap clean?
42
1) The soap traps the grease
water
water
Polar Head
water
GREASE
Nonpolar Tail
water
water
water
water
43
Figure 5.21 (p. 249)
44
2) The water washes away the soap grease
Why?
Polar Head
..
..
O
H
H
Polar Molecule
45
1) The soap traps the grease
water
water
Polar Head
water
GREASE
Nonpolar Tail
water
water
water
water
46
(No Transcript)
47
How do we make a soap?
48
O

NaOH
(CH2)16
C
CH3
OH
Neutralize a fatty acid?
O
H2O

(CH2)16
C
CH3
O-
Na
49
We dont just have fatty acids sitting around in
our world
Where can we get them?
50
Fats!
We need to hydrolyze a fat!!
51
Step 1) Hydrolysis

• A chemical reaction where you ADD water!!

52
Opposite of condensation reactions!!
Polyester
Nylon
53
Review - Condensation
H
Carboxylic Acid Alcohol
Ester Water
54
Hydrolysis!
OH-
Ester Water
Alcohol Carboxylic Acid
Break the ester into its original parts!
55
Where can we find an ester?
56
Fats!
57
Hydrolysis!
OH-
Ester Water
Alcohol Carboxylic Acid
Break the ester into its original parts!
58
Hydrolysis!
OH-
Triple
Three
Triple
Ester Water
Alcohol Carboxylic Acids
OR
Break the ester into its original parts!
59
Hydrolysis!
OH-
Three
Fat Water
Glycerol Fatty Acids
Example
Break the ester into its original parts!
60
Glycerol Tristearate
Hydrolyze
TRIPLE ESTER!
H
O
C(CH2)16CH3
C
O
H
O
C
O
H
C(CH2)16CH3
O
O
C
H
C(CH2)16CH3
H
61
H
O
C(CH2)16CH3
C
O
H
O
NaOH
3 H2O
C
O
H
C(CH2)16CH3

O
Heat
O
C
H
C(CH2)16CH3
H
H
FATTY ACID!
C
O
H
H
O
O
H
C(CH2)16CH3
3

C
O
H
H
O
C
H
H
H
Name?
Glycerol!!
62
This isnt soap! Now what?
O
O
H
C(CH2)16CH3
3
63
Soap

• Generic term for the soluble salt of a fatty acid

Neutralize the fatty acid!
64
Review
Fatty Acid Base
O

NaOH
(CH2)16
C
CH3
OH
O
H2O

(CH2)16
C
CH3
O-
Na
Soap Water
65
Sopanification

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

66
Sopanification

• The process of making soap

Heating a triglyceride (usually a fat) in the
presence of a base
67
Hydrolyzing a fat
3 waters
Fat/Oil
Glycerol
3 Fatty acids
68
Sopanification
H
O
C
C
O
H
O

3NaOH
C
O
H
C
HEAT / H2O
O
O
C
H
C
Why is water not in the reaction?
H
O
CH2
O
H
3
(CH2)16
C
CH3

CH
O
H
O-
Na
O
CH2
H
69
Sopanification

• The process of making soap
• 1) Hydrolysis of the fat (water is used)
• 2) Neutralizing the fatty acid (water is produced)

Its a wash!!!
70
When soaps DONT work
What is hard water?
71
Water with lots of Ca2 and Mg2 ions
How do these ions get into the water?
72
Review

• Dissolving a salt

2HCl

Na2CO3

H2CO3
2NaCl
Why the 2?
73
Review

• Dissolving a salt

2HNO3 CaCO3 ? Ca(NO3)2 H2CO3
H2CO3 ? H2O CO2
A lot of limestone in our area tend to have very
hard water
74
What does this have to do with soaps?
75
Soap in normal water
Soluble in water
Separates into ions
76
Soap in normal water
Na
Na
Na
Na
77
Soap in hard water

• Soap interacts with the Mg2 and Ca2 ions.

NOT soluble!!!!
78
Soap in hard water
Soap forms complexes with Mg2 and Ca2!!
So what?
Na
Mg2
Mg2
O-
O-
C
C
O
O
Na
Na
Na
79
Soap in hard water
Na
Mg2
Mg2
O-
O-
C
C
O
O
Na
Insoluble in water (soap scum)!!!
Na
Na