CHAPTER 5. THE CHEMICAL INDUSTRY 5.3
H
H C O C
O
(CH 2 ) 14 CH 3
H C O C
O
(CH 2 ) 14 CH 3
H C O C
O
(CH 2 ) 14 CH 3
H
glycerol fatty acids
Figure 5.7: The structureof a fat, composed of analcohol and three fatty acids
hydrophilic, meaning that it is attracted to water. Let’s imagine that we have
added soap to water inorder to clean a dirty rugby jersey. The hydrocarbon
chain will attach itself tothe soil particles in the jersey, while the carboxylic acid
will be attracted to the water. In this way, the soil is pulled free of the jersey and
is suspended in the water. In a washing machineor with vigorous handwashing,
this suspension can be rinsed off with clean water.
DEFINITION: Soap
Soap is a surfactant thatis used with water for washing and cleaning.
Soap is made by reacting a fat with either sodium hydroxide (NaOH)
or potassium hydroxide(KOH).
- Detergents
DEFINITION: Detergent
Detergents are compounds or mixtures of compounds that are used to
assist cleaning. The termis often used to distinguish between soap and
other chemical surfactants for cleaning.
Detergents are also cleaning products, but are composed of one or more surfac-
tants. Depending on thetype of cleaning that is needed, detergents may contain
one or more of the following:
- Abrasives to scour a surface.
- Oxidants for bleaching and disinfection.