Conservation Science Tutorials: SOAPS, SURFACTANTS, AND DETERGENTS Flashcards
What is a soap/ detergent and what are surfactants
Soaps and detergents act in a very similar way but are chemically different. They both work as cleaning agents.
However, both soaps and detergents will act as surfactants when in low concentrations. A surfactant (surface acting agent) acts at the interface between different substances to lower the interfacial tension.
A soap and a detergent are both cleaning agents but are defined by their chemistry. Either a soap or a detergent can also be a surfactant in low concentrations.
What are the three types of soap
Soaps: Three Types
Soap: the sodium or potassium salt of a fatty acid
Metallic soap: the copper, aluminum, lithium, or calcium salt of a fatty acid. Metallic soaps are not water soluble.
Resin soap: alkali salt of a resin
Definition of a fatty acid
What are the oils in soaps
Soaps: Disadvantages
Unfortunately, in hard water soaps will react with the ions of:
Magnesium
Calcium
Iron
They produce complexes that are insoluble in water and precipitate out as soap scum.
One way to overcome this disadvantage is to replace the simple -OH end of the soap with a more complex group that does not form complexes with the ions in hard water. This can be done either at the carboxylic end of the molecule or along the hydrocarbon chain. These are the detergents.
Four broad categories of detergents
Anionic detergents
Anionic Detergents: Sulfates
General Formula of Detergents: Sulfates
Anionic Detergents: Alkyl and Alkane Sulfonates
Anionic Detergents: Benzene Sulfonates
Non-Ionic Detergents
Environmental Impact of Non-Ionic Detergents
There have been some worries about the environmental impact of non-ionic detergents. Although they are often used at very small concentrations in most pharmaceutical or food products, they are present in large concentrations in laundry detergents. The possible breakdown products in sewerage and waste water have caused some concern.
They may be toxic to some bacteria.
They are suspected of being estrogen mimics in waste water.
The result is that, although the amount of non-ionic detergents used in conservation is extremely small, they are being phased out of commercial use.
Cationic Detergents
Cationic detergents are added to shampoos and conditioners. They stick to your hair and are difficult to wash out. The slight positive charge makes the individual hairs repel each other.
Amphoteric (Zwitterionic) Detergents
Structure of Surfactants
Surfactants act at the ______ between different substances. This action lowers the energy of the i______ t______
How a Surfactant Works as a Detergent
How a Surfactant Works (3)
