petrochemical

A chemical derived from petroleum or natural gas.

Any of the chemicals derived from petroleum or natural gas. The definition of petrochemicals has been broadened to include the whole range of aliphatic, aromatic, and naphthenic organic chemicals, as well as carbon black and such inorganic materials as sulfur and ammonia.

Petrochemicals are made or recovered from the entire range of petroleum fractions, but the bulk of petrochemical products are formed from the lighter (C₁–C₄) hydrocarbon gases as raw materials. These materials generally occur in natural gas, but they are also recovered from the gas streams produced during refinery operations, especially cracking. Refinery gases are particularly valuable because they contain substantial amounts of olefins that, because of their double bonds, are much more reactive then the saturated (paraffin) hydrocarbons. Also important as raw materials are the aromatic hydrocarbons (benzene, toluene, and xylene) that are obtained from various refinery product streams. For example, catalytic reforming processes convert nonaromatic hydrocarbons to aromatic hydrocarbons by dehydrogenation and cyclization. See also Petroleum.

Thermal cracking processes (such as coking) are focused primarily on increasing the quantity and quality of gasoline and other liquid fuels, but also produce gases, including lower-molecular-weight olefins such as ethylene (CH₂&dbnd;CH₂), propylene (CH₃CH&dbnd;CH₂), and butylenes (butenes, CH₃CH&dbnd;CHCH₃ and CH₃CH₂CH&dbnd;CH₂). Catalytic cracking is a valuable source of propylene and butylene, but it is not a major source of ethylene, the most important of the petrochemical building blocks. See also Cracking; Ethylene.

The starting materials for the petrochemical industry are obtained from crude petroleum in one of two ways. They may be present in the raw crude oil and are isolated by physical methods, such as distillation or solvent extraction; or they are synthesized during the refining operations. Unsaturated (olefin) hydrocarbons, which are not usually present in natural petroleum, are nearly always manufactured as intermediates during the refining sequences. See also Distillation; Petroleum processing and refining; Solvent extraction.

The main objective in producing chemicals from petroleum is the formation of a variety of well-defined chemical compounds, including (1) chemicals from aliphatic compounds; (2) chemicals from olefins; (3) chemicals from aromatic compounds; (4) chemicals from natural gas; (5) chemicals from synthesis gas (carbon monoxide and hydrogen); and (6) inorganic petrochemicals.

A significant proportion of the basic petrochemicals are converted into plastics, synthetic rubbers, and synthetic fibers. These materials, known as polymers, are high-molecular-weight compounds made up of repeated structural units. The major polymer products are polyethylene, polyvinyl chloride, and polystyrene, all derived from ethylene, and polypropylene, derived from propylene. Major raw material sources for synthetic rubbers include butadiene, ethylene, benzene, and propylene. Among synthetic fibers the polyesters, which are a combination of ethylene glycol and terephthalic acid (made from xylene), are the most widely used. They account for about one-half of all synthetic fibers. The second major synthetic fiber is nylon, its most important raw material being benzene. Acrylic fibers, in which the major raw material is the propylene derivative acrylonitrile, make up most of the remainder of the synthetic fibers. See also Polyamide resins; Polyester resins; Polymer; Polymerization; Polyolefin resins; Polyurethane resins; Polyvinyl resins; Rubber.

An inorganic petrochemical is one that does not contain carbon atoms; typical examples are sulfur (S), ammonium sulfate [(NH₄)₂SO₄], ammonium nitrate (NH₄NO₃), and nitric acid (HNO₃). Of the inorganic petrochemicals, ammonia is by far the most common. Ammonia is produced by the direct reaction of hydrogen with nitrogen, with air being the source of nitrogen. Refinery gases, steam reforming of natural gas (methane) and naphtha streams, and partial oxidation of hydrocarbons or higher-molecular-weight refinery residual materials (residua, asphalt) are the sources of hydrogen. The ammonia is used predominantly for the production of ammonium nitrate (NH₄NO₃) as well as other ammonium salts and urea (H₂HCONH₂) that are major constituents of fertilizers. See also Ammonia; Ammonium salt; Urea.

Any material made from substances found in oil or natural gas. Most plastics are petrochemicals.

For more information on petrochemical, visit Britannica.com.

A petrochemical refinery in Grangemouth, Scotland, UK.

Petrochemicals are chemical products made from raw materials of petroleum or other hydrocarbon origin. Although some of the chemical compounds that originate from petroleum may also be derived from coal and natural gas, petroleum is the major source. The largest petrochemical industries are to be found in the USA and Western Europe, though the major growth in new production capacity is in the Middle East and Asia. There is a substantial inter-regional trade in petrochemicals of all kinds. World production of ethylene is around 110 million tons per year, of propylene 65 million tons, and of aromatic raw materials 70 million tons.

The following is a partial list of the major commercial petrochemicals and their derivatives:

• ethylene - the simplest olefin; used as a ripening hormone, a monomer and a chemical feedstock
  • polyethylenes - polymerized ethylene
  • ethanol - made by hydration (chemical reaction adding water) of ethylene
  • ethylene oxide - sometimes called oxirane; can be made by oxidation of ethylene
    • ethylene glycol - from hydration of ethylene oxide or oxidation of ethylene
      • engine coolant - contains ethylene glycol
      • polyesters - any of several polymers with ester linkages in the backbone chain
    • glycol ethers - from condensation of glycols
    • ethoxylates
  • vinyl acetate
  • 1,2-dichloroethane
    • trichloroethylene
    • tetrachloroethylene - also called perchloroethylene; used as a dry cleaning solvent and degreaser
    • vinyl chloride - monomer for polyvinyl chloride
      • polyvinyl chloride (PVC) - type of plastic used for piping, tubing, other things
• propylene - used as a monomer and a chemical feedstock
  • isopropyl alcohol - 2-propanol; often used as a solvent or rubbing alcohol
  • acrylonitrile - useful as a monomer in forming Orlon, ABS
  • polypropylene - polymerized propylene
  • propylene oxide
    • propylene glycol - sometimes used in engine coolant
    • glycol ethers - from condensation of glycols
  • acrylic acid
    • acrylic polymers
  • allyl chloride -
    • epichlorohydrin - chloro-oxirane; used in epoxy resin formation
      • epoxy resins - a type of polymerizing glue from bisphenol A, epichlorohydrin, and some amine
• C4 hydrocarbons - a mixture consisting of butanes, butylenes and butadienes
  • isomers of butylene - useful as monomers or co-monomers
    • isobutylene - feed for making methyl tert-butyl ether (MTBE) or monomer for copolymerization with a low percentage of isoprene to make butyl rubber
  • 1,3-butadiene - a diene often used as a monomer or co-monomer for polymerization to elastomers such as polybutadiene or a plastic such as acrylonitrile-butadiene-styrene (ABS)
    • synthetic rubbers - synthetic elastomers made of any one or more of several petrochemical (usually) monomers such as 1,3-butadiene, styrene, isobutylene, isoprene, chloroprene; elastomeric polymers are often made with a high percentage of conjugated diene monomers such as 1,3-butadiene, isoprene, or chloroprene
• higher olefins
  • polyolefins such poly-alpha-olefins which are used as lubricants
  • alpha-olefins - used as monomers, co-monomers, and other chemical precursors. For example, a small amount of 1-hexene can be copolymerized with ethylene into a more flexible form of polyethylene.
  • other higher olefins
  • detergent alcohols
• benzene - the simplest aromatic hydrocarbon
  • ethylbenzene - made from benzene and ethylene
    • styrene made by dehydrogenation of ethylbenzene; used as a monomer
      • polystyrenes - polymers with styrene as a monomer
  • cumene - isopropylbenzene; a feedstock in the cumene process
    • phenol - hydroxybenzene; of dassdcten made by the cumene process
    • acetone - dimethyl ketone; also often made by the cumene process
    • bisphenol A - a type of "double" phenol used in polymerization in epoxy resins and making a common type of polycarbonate
      • epoxy resins - a type of polymerizing glue from bisphenol A, epichlorohydrin, and some amine
      • polycarbonate - a plastic polymer made from bisphenol A and phosgene (carbonyl dichloride)
    • solvents - liquids used for dissolving materials; examples often made from petrochemicals include ethanol, isopropyl alcohol, acetone, benzene, toluene, xylenes
  • cyclohexane - a 6-carbon aliphatic cyclic hydrocarbon sometimes used as a non-polar solvent
    • adipic acid - a 6-carbon dicarboxylic acid which can be a precursor used as a co-monomer together with a diamine to form an alternating copolymer form of nylon.
      • nylons - types of polyamides, some are alternating copolymers formed from copolymerizing dicarboxylic acid or derivatives with diamines
    • caprolactam - a 6-carbon cyclic amide
      • nylons - types of polyamides, some are from polymerizing caprolactam
  • nitrobenzene - can be made by single nitration of benzene
    • aniline - aminobenzene
      • methylene diphenyl diisocyanate (MDI) - used as a co-monomer with diols or polyols to form polyurethanes or with di- or polyamines to form polyureas
        • polyurethanes
  • alkylbenzene - a general type of aromatic hydrocarbon which can be used as a presursor for a sulfonate surfactant (detergent)
    • detergents - often include surfactants types such as alkylbenzenesulfonates and nonylphenol ethoxylates
  • chlorobenzene
• toluene - methylbenzene; can be a solvent or precursor for other chemicals
  • benzene
  • toluene diisocyanate (TDI) - used as co-monomers with diols or polyols to form polyurethanes or with di- or polyamines to form polyureas
    • polyurethanes - a polymer formed from diisocyanates and diols or polyols
  • benzoic acid - carboxybenzene
    • caprolactam
      • nylon
• mixed xylenes - any of three dimethylbenzene isomers, could be a solvent but more often precursor chemicals
  • ortho-xylene - both methyl groups can be oxidized to form (ortho-)phthalic acid
    • phthalic anhydride
  • para-xylene - both methyl groups can be oxidized to form terephthalic acid
    • dimethyl terephthalate - can be copolymerized to form certain polyesters
      • polyesters - although there can be many types, polyethylene terephthalate is made from petrochemical products and is very widely used.
    • purified terephthalic acid - often copolymerized to form polyethylene terephthalate
      • polyesters

See also

• Petroleum
• Petroleum products
• Organization of the Petroleum Exporting Countries

External links

• Petrochemistry in Europe
• Educational resource on petrochemistry
• Article showing some of the basics of a petchem facility

This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (February 2008)

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
adj. - petrokemisk
n. - petrokemikalie

Nederlands (Dutch)
petrochemisch(e stof)

Français (French)
adj. - pétrochimique, de pétrochimie
n. - produit pétrochimique

Deutsch (German)
n. - Petrochemikalie
adj. - petrochemisch

Ελληνική (Greek)
n. - πετροχημική ουσία
adj. - πετροχημικός

Italiano (Italian)
petrolchimico

Português (Portuguese)
n. - petroquímico (m)
adj. - petroquímico

Русский (Russian)
нефтяной продукт, нефтехимический

Español (Spanish)
adj. - petroquímico
n. - productos petroquímicos

Svenska (Swedish)
n. - petrokemik
adj. - petrokemisk

中文（简体）(Chinese (Simplified))
石化的, 石化产品

中文（繁體）(Chinese (Traditional))
adj. - 石化的
n. - 石化產品

한국어 (Korean)
adj. - 석유 화학(약품)의
n. - 석유 화학 제품

日本語 (Japanese)
adj. - 石油化学の
n. - 石油化学製品

العربيه (Arabic)
‏(الاسم) مواد كيماويه مأخوذم من البترول (صفه) بتروكيماوي‏

עברית (Hebrew)
adj. - ‮של פטרוכימיקל או פטרוכימיה‬
n. - ‮פטרוכימיקל - חומר המופק באופן תעשייתי מנפט או מגז‬

If you are unable to view some languages clearly, click here.

To select your translation preferences click here.