OIL

[Rev. Allen M. Drago ~ Traveler]

An oil is any substance that is liquid at ambient temperatures and is hydrophobic but soluble in
organic solvents. Oils have a high carbon and hydrogen content and are nonpolar substances. The
general definition above includes compound classes with otherwise unrelated chemical structures, properties and uses, including vegetable oils, petrochemical oils, and volatile essential oils. All oils can be traced back to
organic sources.

Essential oil

An essential oil is a concentrated, hydrophobic liquid containing volatile aroma compounds from plants. An oil is 'essential' in the sense that it carries a distinctive scent, or essence, of the plant. Essential oils do not, as a group, need to have any specific chemical properties in common, beyond conveying characteristic fragrances. In history, oil has been used by Vikings, Spartans, etc. in war as they believed it made them stronger. Essential oils are typically extracted by distillation. Other processes include expression, or solvent extraction. They are used in perfumes, cosmetics and bath products, for flavoring food and drink, and for scenting incense and household cleaning products.

Mineral oil

Mineral oils, found in porous rocks underground, originated from organic material, such as dead plankton, accumulated on the seafloor in geologically ancient times. Through various geochemical processes this material was converted to mineral oil, or petroleum, and its components, such as kerosene, paraffin waxes, gasoline, diesel and such. These are classified as mineral oils because they do not have an organic origin on human timescales, and are instead derived from underground geologic locations, ranging from rocks, to underground traps, to sands. Other oily substances can also be found in the environment; the most well-known of those is asphalt, occurring naturally underground or, where there are leaks, in tar pits. Petroleum and other mineral oils (specifically labelled as petrochemicals) have
become such a crucial resource to human civilization in modern times they are often referred to by the ubiquitous term of "oil" itself.

Organic oils

Organic oils are also produced by plants, animals and other organisms through organic processes, and these oils are remarkable in their diversity. Oil is a somewhat vague term in chemistry; instead, the scientific term for oils, fats, waxes, cholesterol and other oily substances found in living things and their secretions, is lipids. Lipids, ranging from waxes to steroids, are somewhat hard to characterize, and are united in a group almost solely based on the fact that they all repel, or refuse to dissolve in, water, and are however comfortably miscible in other liquid lipids. They also have a
high carbon and hydrogen content, and are considerably lacking in oxygen compared to other organic compounds and minerals.

Synthetic oils

Synthetic oil is a lubricant, consisting of chemical compounds which are artificially made (synthesized) from compounds other than crude oil (petroleum). Synthetic oil is used as a substitute for lubricant refined from petroleum, because it generally provides superior mechanical and chemical properties than those found in traditional mineral oils.

Food

Many edible plant and animal oils and fats are used in cooking and food preparation. In particular, many foods are fried in oil much hotter than boiling water. Oils are also used for flavoring and for modifying the texture of some foods e.g. stir fry. Health advantages are claimed for a number of specific oils such as omega 3 oils, evening primrose oil, olive oil and coconut oil. Trans fats, often produced by hydrogenating vegetable oils, are known to be harmful to health.

Hair

Oil is used on hair to give it a lustrous look. It helps to avoid tangles and roughness to the hair. It also helps the hair to be stabilized and grow faster

Fuel

Almost all oils burn in aerosol form generating heat, which can be used directly, or converted into other forms of fuels by various means. The oil that is pumped from the ground is then shipped via oil tanker to an oil refinery. There, it is converted from crude oil to diesel fuel (petrodiesel), ethane
(and other short-chain alkanes), fuel oils (heaviest of commercial fuels, used in ships/furnaces), gasoline (petrol), jet fuel, kerosene and liquefied petroleum gas.

Lubrication

Due to their non-polarity, oils do not easily adhere to other substances. This makes oils useful as lubricants for various engineering purposes. Mineral oils are more suitable than
biological oils, which degrade rapidly in most environmental conditions.

Painting

Color pigments can be easily suspended in oil, making it suitable as supporting medium for paints. The slow drying process and miscibility of oil facilitates a realistic style. This method has been used since the 15th century

[Rev. Allen M. Drago ~ Traveler]

Emulsifier

An emulsifier (also known as an emulgent) is a substance which stabilizes an emulsion by increasing its kinetic stability. One class of emulsifiers is known as surface active substances, or surfactants. Examples of food emulsifiers are egg yolk (where the main emulsifying chemical is lecithin), honey, and mustard, where a variety of chemicals in the mucilage surrounding the seed hull act as emulsifiers; proteins and low-molecular weight emulsifiers are common as well. Soy lecithin is another emulsifier and thickener. In some cases, particles can stabilize emulsions as well through a mechanism called Pickering stabilization. Both mayonnaise and Hollandaise sauce are oil-in-water emulsions that are stabilized with egg yolk lecithin or other types of food additives such as Sodium stearoyl lactylate.

Detergents are another class of surfactant, and will physically interact with both oil and water, thus stabilizing the interface between oil or water droplets in suspension. This principle is exploited in soap to remove grease for the purpose of cleaning. A wide variety of emulsifiers are used in pharmacy to prepare emulsions such as creams and lotions. Common examples include emulsifying wax, cetearyl alcohol, polysorbate 20, and ceteareth 20. Sometimes the inner phase itself can act as an emulsifier, and the result is nanoemulsion - the inner state disperses into nano-size droplets within the outer phase. A well-known example of this phenomenon, the ouzo effect, happens when water is poured in a strong alcoholic anise-based beverage, such as ouzo, pastis, arak or raki. The anisolic compounds, which are soluble in ethanol, now form nano-sized droplets and emulgate within the water. The colour of such diluted drink is opaque and milky.
[edit] In food

Oil-in-water emulsions are common in food. Notable examples include:

* Vinaigrette – vegetable oil in vinegar; if prepared with only oil and vinegar (without an emulsifier), yields an unstable emulsion
* Mayonnaise – vegetable oil in lemon juice or vinegar, with egg yolk lecithin as emulsifier
* Hollandaise sauce – similar to mayonnaise
* Crema in espresso – coffee oil in water (brewed coffee), unstable