Structural Biochemistry/Lipids/Waxes, Soaps, and Detergents

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Waxes[edit]

Chemical Structure[edit]

Wax is a type of long chain apolar lipid which made up of various n-alkanes, ketones, primary alcohol, secondary alcohols, monoesters, beta diketones, aldehydes,etc. Waxes will form protective coating on plants and fruits, and in animal (example: beewax, whale spermaceti, etc.). More commonly, wax is ester of alcohol and fatty acids. They differ from fats since they don’t have triglyceride ester of three fatty acids. Waxes are water resistant, so they are insoluble in water.

Structure of a Wax Ester

Properties[edit]

Due to the versatility of waxes, nature has manipulated them for their water-resistant properties, colligative properties (high melting point, relatively low viscosity at high temperatures, transparency, etc.) and coating properties.

Types of Waxes[edit]

  1. Beeswax – for consumption
  2. Chinese Wax – for polishes
  3. Ear Wax – used as a protective layer over the ear membrane
  4. Lanolin – for rust prevention and cosmetics
  5. Shellac – used as a wood sealant
  6. Spermaceti – for cosmetics and leatherworking
  7. Vegetable (many different types extracted from plants) – used as a protective layer on the plant to prevent loss of water
  8. Mineral – used as fine polishes
  9. Petroleum – fuels, paints, culinary, candles
  10. Synthetic – modified waxes for use in the medical field

Functions and Applications[edit]

Waxes contain many functions in society. Man has manipulated and synthesized many waxes to be used for cosmetics, sealants and lubricants, insecticides, UV protection, energy reserves, food, etc.

Soaps[edit]

Soap is a mixture of sodium salts forming by adding sodium hydroxide or sodium carbonate to natural fatty acids. The density of soap will be decreased by air bubble forming. The general reaction in producing soap:

Fat + NaOH → soap + glycerol

Making Soaps[edit]

An example of making soaps is called Saponification of fats and oils which is the most common method of soap making process. 1) Heat fats and oils 2) React with liquid Alkali

General View of Saponification

Detergents[edit]

Detergent is a material that helps in cleaning. Detergent contains one of more surfactants which are capable of reducing the surface tension of liquid such as water. Commonly, detergent consists of long chain hydrocarbon and ionic group (such as alky sulfate or derivative of ammoniac group).

Types of Detergents[edit]

Anionic

These detergents are man-made and consist of long hydrocarbon chains and a water-soluble ionic group, which is usually negatively charged. These detergents are commonly known as surfactants, or alkyl benzene sulfonates

Cationic

These detergents are also man-made, and they only differ from anionic detergents in that the water-soluble ionic group is positively charged. These detergents are primarily derivatives of ammonium and are commonly used as a germicide and in shampoo.

Neutral

These type of detergents contain the same general set up as all other detergents, except it’s overall charge is neutral. The head of the detergent is polar due to the presence of three hydroxyl groups and an ester group.

Natural

Natural detergents such as bile salts (sodiumglycoholate) are made in the liver. These detergents are derivatives of cholesterol, a type of lipid. Its main function is digestion. The bile salt is capable of emulsifying fats and oils such that enzymes may break them down further.

Function and Application[edit]

Detergents have many functions and applications including cleaning off fats and oils, softening materials, acting as aromas or abrasives, or sanitizing and disinfecting. Though detergent and soap are used interchangeably, people can see the various uses of detergents in common house products including hand soap, laundry detergent, dish and glass detergents, etc.