Important Terms from A to Z
Chemicals are all chemical compounds produced by chemical processes in the lab or industrially. They can be pure substances or mixtures of substances. Chemicals are divided into organic and inorganic chemicals. Organic chemistry covers practically all the carbon-containing compounds, while inorganic chemistry (inorganic matter) relates to the other elements of the periodic table and their compounds. Petrochemicals are an important subsection of organic chemistry.
The term “organic chemistry” was coined in 1806 by the Swedish chemist Jöns Jakob Berzelius and in the early 19th century was limited to compounds that can be built by living organisms. However, the assumption that organic compounds cannot be synthetically manufactured was ultimately disproved by Friedrich Wöhler in 1828. Wöhler succeeded in synthesizing urea (producing urea from inorganic substances).
It wasn’t until the mid-19th century that scientists realized that carbon content is the defining characteristic of an organic compound, and the boundaries of the two disciplines – organic and inorganic chemistry – are now becoming increasingly blurred. Nevertheless, a distinction is still useful because the reaction mechanisms and material structures often differ in inorganic and organic chemistry.
Organic chemistry covers approximately 19 million known carbon compounds, greatly exceeding the number of known inorganic compounds (about 500,000). This is attributable to carbon’s special ability to form branched chains and ring structures with other carbon atoms. The naming of organic compounds is determined by International Union of Pure and Applied Chemistry (IUPAC) rules and are is set out in its “Blue Book.” (Anorganic compounds are listed in the “Red Book.”).
Organic chemicals are very diverse. They range from the gaseous methane (natural gas, see also gases), the simplest hydrocarbon compound, to macromolecular plastics. They are sub-classified by material groups, e.g. by their functional groups or carbon chains/skeletons. Functional groups include, for example:
- Oxygen and hydroxy compounds (alcohols, aldehydes, carboxylic acids, ketones)
- Nitrogen compounds (amines, amides, nitro compounds, nitriles)
- Sulfur compounds (alkanethiolates, sulfates)
- Phosphorus compounds (phosphates, phosphines)
- Organometallic compounds (ferrocene)
When classifying by carbon chain/skeleton, the chemicals can be further differentiated into aliphatic hydrocarbons (e.g. alkanes, alkenes), aromatic hydrocarbons (aromatics), heterocycles and biochemical compounds (amino acids, proteins, etc.).
Depending on the properties of substances or chemicals, they must be accordingly classified, labeled and packaged. Likewise, the chemical compatibility – i.e. how various chemicals will react with each other – must be considered in their storage; see detailed comments under Chemicals.
Organic chemistry has radically changed people’s lives in the last 150 years. Almost all goods used on a daily basis contain organic chemicals. Currently, most organic chemicals are produced from crude oil, with crude oil and natural gas also used as feedstock in the production of petrochemicals. In our daily lives we are surrounded by all sorts of petroleum-based products, which we often take for granted – including soaps, plastics, paints, cars, frames for eye glasses, and disposable diapers, etc. Approximately 5% of the oil and gas consumed each year is needed to make petrochemical products. In the U.S., the world’s largest market for petrochemicals, the per-capita consumption of petrochemical products is 58kg a year. Due to the vast worldwide demand for chemical products, the storage and handling of organic chemicals such as petrochemicals in tank terminals also plays an important role in the value and processing chain.
Status: December 2015
All information subject to change. Errors and omissions excepted.