Petrochemistry

Petrochemistry is a branch of chemistry that studies the transformation of crude oil (petroleum) and natural gas into useful products or raw materials. These petrochemicals have become an essential part of the chemical industry today.

It may be possible to make petroleum from any kind of organic matter under suitable conditions. The concentration of organic matter is not very high in the original deposits, but petroleum and natural gas evolved in places that favored retention, such as sealed-off porous sandstones. Petroleum, produced over millions of years by natural changes in organic materials, accumulates beneath the earth's surface in extremely large quantities.

The first oil commercial oil well was set up in 1859, two years after which the first oil refinery was set up. The industry grew in the late 1940s. Demand for products from the petrochemical industry grew during the World War II. The demand for synthetic materials increased, and this rising demand was met by replacing costly and sometimes less efficient products with these synthetic materials. This caused petrochemical processing to develop into a major industry.

Before this, petrochemical industry was a tentative sector where various experiments could be carried out. The industry used basic materials: synthetic rubbers in the 1900s, Bakelite, the first petrochemical-derived plastic in 1907, the first petrochemical solvents in the 1920s, polystyrene in the 1930s. After that period, the industry produced materials for a large variety of areas—from household goods (kitchen appliances, textile, furniture) to medicine (heart pacemakers, transfusion bags), from leisure (running shoes, computers) to highly specialized fields like archaeology and crime detection.

Crude oils are compounds that mainly consist of many different hydrocarbon compounds that vary in appearance and composition. Average crude oil composition is 84% carbon, 14% hydrogen, 1%-3% sulphur, and less than 1% each of nitrogen, oxygen, metals and salts.

Crude oils are distinguished as sweet or sour, depending upon the sulphur content present. Crude oils with a high sulfur content, which may be in the form hydrogen sulphides, are called sour, and those with less sulphur are called sweet.

A process called fractional distillation separates crude oil into various segments. Fractions at the top have a lower boiling points than fractions at the bottom. The bottom fractions are heavy, and are thus "cracked" into lighter and more useful products.

Directly from the well, raw or unprocessed ("crude") oil is not useful. Though light sweet oil has been used directly as a burner fuel, these lighter fragments form explosive vapors in fuel tanks, and thus are dangerous. The oil must be separated into various parts and refined before used in fuels and lubricants, and before some of the byproducts form materials such as plastics, detergents, solvents, elastomers, and fibers such as nylon and polyesters.

...
Wikipedia