Chemical Glossary


Acetaldehyde or ethanal

Acetaldehyde (or ethanal) is a two-carbon aldehyde used as an intermediate in the production of acetic acid. Acetaldehyde is produced by direct oxidation of ethylene. Acetic acid used to be the major derivative for acetaldehyde, but except in China, this is no longer the case. Major end-uses include ethyl acetate, isobutyl acetate, synthetic pyridine derivatives and peracetic acid.

Acetic Acid

Acetic acid is a colourless liquid traditionally made by fermentation (vinegar is mainly acetic acid). It is a raw material for several key petrochemical intermediates and products, including vinyl acetate monomer (VAM) for coatings and adhesives, purified terephthalic acid (PTA) for polyester production, acetate esters, cellulose acetate, acetic anhydride and monochloroacetic acid (MCA). Acetic acid is now mainly produced via methanol carbonylation, but ethane, ethylene or acetaldehyde oxidation processes are also commercially employed.


Acetone is a commodity solvent commonly produced as a co-product during cumene oxidation for phenol, which consumes benzene and propylene, and for this reason on-purpose acetone production has declined. On purpose production consumes either propylene or isopropanol. Acetone is used in the production of bisphenol A and methyl methacrylate, intermediates to PMMA and Polycarbonate engineering resins, respectively, along with methyl isobutyl ketone (MIBK) and others. It also has major use as a solvent in industrial and household applications, e.g., paints and ink. Acetone is produced in all regions.


The Acetyls family are those chemicals derived from acetic acid, the simplest carboxylic acid.

Acrylic Acid

Acrylic acid is used in the production of acrylate esters, superabsorbent polymers, detergents and flocculants. Acrylate esters are mostly used in coatings, adhesives, and elastomers applications, while superabsorbents are used in diapers etc, and most other derivatives are performance chemicals for cleaning or water treatment, also firefighting. Acrylic Acid is a propylene derivative which is produced by propylene vapor-phase oxidation. Acetylene based production of acrylic acid has now ceased, and new processes based on propane are being developed. Acrylic acid tends to be produced close to major consumers as melting of transportable solid can be hazardous. Alternative names for acrylic acid include: acroleic acid, ethylene carboxylic acid, propenoic acid.


Acrylonitrile is used as an intermediate in the production of acrylic fibers as well as acrylonitrile butadiene styrene (ABS) and SAN resins, and as monomer for polyacrylonitrile. Acrylonitrile is a propylene derivative which is produced by the reaction of propylene and ammonia. Acrylonitrile is produced in all regions, although most new projects are either located in Asia where demand growth is strongest, or in the Middle East where there is increasing feedstock availability.

Acrylonitrile butadiene styrene (ABS)

Acrylonitrile butadiene styrene (ABS) is a copolymer made from polymerizing styrene and acylonitrile in the presence of polybutadiene. ABS is stronger than polystyrene, and is used to make light, rigid products such as pipes and toys. It is a high volume engineering polymer that exhibits good strength and high gloss properties and is used widely in the production of electronics and automotive applications.

Alpha Olefins

Alpha olefins are straight chained olefins with a double bond between the end two carbons in a chain (the "alpha" position). These olefins are very reactive and as such have a number of uses. Light alpha olefins (butene-1, hexene-1 and octene-1) are consumed mainly in the production of polyethylene, including LLDPE. Decene-1 is principally used to manufacture polyalpha olefins for the production of high performance lubricants. High alpha olefins are consumed in the manufacture of detergent alcohols. There are two main ways to produce linear alpha olefins - via ethylene oligomerization and via Fischer-Tropsch process via syngas (applicable only to SASOL). In regions of low cost ethylene (eg Middle East) ethylene dimerisation is also used to produce butene-1 and recently ethylene trimerisation has been used to produce hexene-1 Producers either manufacture a specific linear alpha olefin (on-purpose) or a range.


Ammonia is an inorganic compound comprising nitrogen and hydrogen in the ratio 1:3. Ammonia is produced from hydrocarbons, mainly natural gas, and nitrogen extracted from air. Ammonia occurs both in solution and as anhydrous ammonia, the latter finding its main application in fertilizers. Ammonia is also consumed in various other chemical and industrial applications such as the production of nitrate-based explosives, and in aqueous solution as a solvent.


Aniline is an aromatic derivative produced by hydrogenation of nitrobenzene and is used primarily for the production of MDI (methylene diphenyl diisocyanate).

Aromatics Family

The Aromatics are a group of unsaturated hydrocarbons all sharing a common unsaturated six carbon ring. Benzene is the simplest aromatic compound and consists solely of this ring structure, with the other members having hydrocarbon side groups connected to the main ring. Aromatics are named Aromatic after the sharp smell associated with the family and are produced in processes involving the pyrolysis of hydrocarbon streams such as steam crackers and refinery reformer units.


A primary petrochemical building block used in the production of stryene, phenol and caprolactam. Benzene is an aromatic compound consisting of six carbon unsaturated ring structure. Benzene is produced predominantly as a by-product from naphtha or heavy liquid cracking.

Bisphenol A (BPA)

Bisphenol A (BPA) is an intermediate for polycarbonate resins and epoxy resins, and is used in various minor applications of coatings. It is manufactured by from phenol and acetone in the presence of an acid catalyst, and typically in solid form. BPA is produced in all regions. Alternative names for BPA include: 4,4'-(1-methylethylidene)bis-phenol, 4,4'-isopropylidenedi-phenol

Brent Crude Oil

Brent Crude Oil is a blend of crude oil streams produced from the Brent and Ninian Fields in the North Sea. This crude blend is noted as a benchmark crude as it is traded under contract with prices determined by open market activity on the International Petroleum Exchange in London. Brent crude is a light, sweet crude and usually trades at a premium to heavier Middle Eastern grades, and is most suited for the production of gasoline and middle distillates.


Butadiene is the first member for the olefin chemical family with two double bonds, consisting of four carbons joined by alternate single and double bonds (1,2 propadiene which has three carbon atoms separated by two double bonds only is not a useful chemical owing to its high self reactivity) The largest use for butadiene is in the production of synthetic rubbers, with the majority produced as a by-product from steam crackers.


Butane is a gas in the LPG family of petroleum gases that can be separated from the gas stream that is often associated with crude oil as it leaves an oil well. Butane is a four carbon hydrocarbon that can either be arranged as a straight chain (n-butane) or branched (iso-butane). Butane extracted from associated gas is most usually a mixture of these two isomers. N-Butane is more highly valued as a petrochemical feedstock as it yields more ethylene in a steam cracker, while iso-butane has a higher value in gasoline production.

Butyl Acetate

Butyl acetate is most commonly prepared by esterification, the reaction of acetic acid with n-butyl alcohol. The major end-use for butyl acetate is as a medium-boiling solvent for lacquers and enamels. It is also used as an active solvent for cellulosic resins, chlorinated rubber, polystyrene and methacrylate resins.


Caprolactam is a six-carbon one-nitrogen ring that is used to produce nylon 6. The caprolactam ring is opened through hydrolysis and the linear chains are polymerized in a continuous process to produce nylon 6.


Chlorine is a member of the halogen grouping of elements, noted for their high reactivity. Chlorine is also highly toxic and is therefore rarely transported any distance, being produced and consumed at the same site. Chlorine is produced by the electro-chemical separation from brine (concentrated salt-water), which is a highly power-intensive process that also co-produces caustic soda.


Chlorobenzene is produced by the chlorination of benzene in the liquid phase. The major use of chlorobenzene is as an intermediate for the production of nitrochlorobenzenes and diphenyl oxide, which are used to produce herbicides, dyes and rubber.

Crude Oil

Crude oil is a naturally occurring liquid that consists of a wide mixture of hydrocarbons created by the high pressure and temperature decomposition of organic materials. Commercially viable crude oil reserves are found in distinct geographic regions, with the Middle East, the North Sea and Venezuela featuring amongst the key sources of supply. The vast majority of transportation fuels and petrochemical feedstocks are derived from the processing of crude oil.


Cumene is a chemical intermediate almost exclusively consumed in the production of phenol. Cumene is a propylene derivative produced by the reaction of propylene and benzene. Cumene production is widespread geographically, and almost all new plants are integrated with phenol. Alternative names for cumene include: isopropyl benzene, (1-methylethyl)benzene, 2-phenylpropane


Cyclohexane is a six-carbon saturated ring and is an intermediate in the production of nylon. In nylon production, it is used to produce KA oil, which is oxidized with nitric acid to produce adipic acid, which is then reacted with HMDA to produce nylon 6,6. It is also used as a solvent in many chemical processes.


Diesel is a middle distillate product obtained from the processing of crude oil in an oil refinery. Diesel is closely related in composition to Heating Oil, with the former differing by its lower sulphur content. The boiling point and density of diesel is higher than that for gasoline.

Dimethyl Terephthalate (DMT)

Dimethyl terephthalate (DMT) is an intermediate in the production of PET. DMT, an ester of terephthalic acid and methanol, was the main route for the terephthalic acid required for polyester production, but has now been largely superceded by PTA (purified terephthalic acid). DMT is classed as a polyester intermediate, as its main application is PET production. DMT production is now restricted to Europe, North America, East Asia and India. All plants oxidise para-xylene into crude terephthalic acid, which is then esterified with methanol.

Engineering Polymers

The Engineering Polymers are a grouping of specialised polymer materials that have been "engineered" to have specific materials properties. These generally relate to high strength as well as temperature and chemical resistance. These materials are costly to make and rely on their high performance characteristics as cost reduction programs provide OEM producers with a strong incentive to replace them with lower cost commodity polymers


Ethane is a two-carbon hydrocarbon. At standard temperature and pressure, ethane is a colourless, odourless gas. Ethane is produced on an industrial scale either by extraction from natural and associated gas, or as a byproduct of petroleum refining. Its chief use is as petrochemical feedstock in steam crackers for ethylene production.


Ethanol is a two-carbon alcohol which are mainly industrially produced in two ways: by fermentation processes (using starches, sugar crops or lignocellulose as feedstock) which produces fuel grade, or by the catalytic hydration of ethylene (industrial grade). Around 95 percent of globally manufacture ethanol is sourced from the fermentation process. Industrial ethanol is used in the manufacture of several chemicals, acting, in the main, as an intermediate. It is also used as a solvent. The main use for ethanol via fermentation is in fuel. Fuel grade ethanol is used as a substitute for gasoline.

Ethyl Chloride

Ethyl Chloride (chloroethane) is produced by the addition of hydrogen chloride to ethylene over an aluminum chloride catalyst. It is also generated as a co-product of PVC. Ethyl chloride's major use was in the production of tetraethyl lead (TEL) used as an anti-knock additive in gasoline, but its use for this application has been phased-out by most countries since leaded gasoline has been prohibited. The main current application is in thickening of cellulose for making ethyl cellulose, a thickening agent for paints and cosmetics. It is also used as a solvent, refrigerant, aerosol propellant, anesthetic and blowing agent for foam packaging.

Ethylbenzene (EB)

Ethylbenzene (EB), an aromatic liquid hydrocarbon, is a chemical intermediate made from the reaction of benzene and ethylene. It is a precursor to styrene production.


Ethylene is the most basic member of the olefin chemical family, consisting of two carbon atoms joined by a double bond. The ready accessibility and high reactivity of this double bond lends the molecule to many synthesis reactions, including its most common use as a monomer for producing polyethylenes. Ethylene is industrially produced by the pyrolytic cracking in a steam cracker of a wide variety of hydrocarbons, ranging from ethane to gas oil.

Ethylene Dichloride (EDC)

Ethylene dichloride (EDC) is the first molecule produced in the vinyls chain and is a toxic, flammable, and corrosive liquid at room temperature. EDC is most commonly formed from ethylene and chlorine, both of which are costly and difficult to transport, and thus EDC production is normally located close to sources of such raw materials. EDC is principally used for VCM production, with small amounts used for the manufacture of other organic compounds.

Ethylene Oxide (EO)

Ethylene oxide (EO) has widespread uses in the production of surfactants although its largest and fastest growing end-use is in the production of monoethylene glycol (MEG). EO is grouped with polyester intermediates, as the majority is eventually consumed in the production of PET. EO is produced by reacting ethylene and oxygen over mainly silver-based catalysts. Due to its hazardous nature, minimal volumes of EO are transported, and production tends to be from complexes including both ethylene feedstock and EO derivatives. Production is widespread globally, with development mainly in the Middle East and Asia.


Formaldehyde is pungent-smelling gas that dissolves readily in water to form a 37% formaldehyde solution known as formalin. Formaldehyde is produced industrially by the oxidation of methanol over a metal catalyst. Formalin is used as a disinfectant and as a preservative medium for biological specimens. The main industrial application of formaldehyde, however, is in the production of urea-formaldehyde (UF), phenol-formaldehyde (PF) and melamine-formaldehyde (MF) resins for the manufacture of wood adhesives (e.g. for plywood and chipboard) and other applications.

Fuel Oil

Fuel Oil is the term used to define the heavy distillate stream produced from refinery operations. It is used to fuel power stations and in ships and industry. Different fuel oil grades are classified according to their viscosity and sulphur content.

Gas Oil

Gas Oil is the term given to middle distillate streams, generally used as a fuel in heating and air conditioning systems. In refining terms, gas oil comes between fuel oil and the lighter products such as naphtha and gasoline. Its broader definition covers the oil products diesel and jet fuel. Gas Oil can be used as a feedstock in Petrochemical steam cracking, producing ethylene alongside a wide range of co-products.


Gasoline is a relatively light distillate stream produced as one of the principle products from a crude oil refinery. Gasoline specifications vary from region to region with variation in both performance and environmental characteristics. These specifications include octane level, vapour pressure, as well as a wide variety of component limitations such as sulphur, lead, benzene and olefin limitations.

Heavy Crude

Heavy Crude is a term used to define crude oils with a high fraction of high boiling point waxy components such that processing cannot be performed in "normal" refinery operations. Heavy Crude is defined as those crudes having a specific gravity below 28 API and include some Venezuelan oils and oil from Canadian Tar Sand deposits.

Hexamethylene diamine or 1,6-diaminohexane (HMDA)

Hexamethylene diamine or 1,6-diaminohexane (HDMA) is produced by catalytic hydrogenation of adiponitrile. The majority of HMDA is reacted with adipic acid to produce nylon 6,6 in a two-step process.

High Density Polyethylene (HDPE)

High density polyethylene (HDPE) is the name given to the densest member of the polyethylene family. HDPE is more rigid and opaque than the other polyethylenes and is used in many packaging and container applications which benefit from its strength and high temperature resistance. HDPE goods are commonly marked with a 2 following the recycling codes developed by the American Society of the Plastics Industry. HDPE was initially produced by low pressure reaction of ethylene monomers with specialized Ziegler-Natta catalysts in slurry reactors. More recently production has also been obtained by low pressure gas phase HDPE/LLDPE swing plants.

Higher Oxo-alcohols

Higher oxo-alcohols are collectively the heavier, smaller volume oxo-alcohols which are produced in addition to the principal oxo-alcohols 2-ethylhexanol and butanols. Oxo-alcohols are so named because of the “oxo process” process by which they are produced, which involves hydroformulation of an olefin with syngas. Higher oxo-alcohols have a wide variety of end-uses ranging from pesticides to perfumery. Higher oxo-alcohol production is relatively specialised and small volume chemistry and tends to be restricted to large industrial economies.

Hydrodealkylation (HDA)

Hydrodealkylation of toluene to benzene is the most common dealkylation route. The use of toluene dealkylation is sensitive to the producer's alternative value for toluene (i.e. gasoline or chemicals), the hydrogen value (on-purpose or by-product), as well as the benzene market price. As a result the motivation to dealkylate is very different for each producer with some producers dedicated to dealkylate at all times (usually lacking a sufficient gasoline pool or chemical market for toluene) while others are "opportunistic" dealkylators, running their plants at times when the economics fully justify and encourage the process and spot benzene sales are available.


Hydrogenation is a chemical reduction reaction which results in the addition of hydrogen to an unsaturated compound (e.g. alkenes). Metal catalysts are typically used for these reactions, including cobalt-molybdenum or nickel-molybdenum


Iso-butanol is an oxo-alcohol with various uses as a direct process solvent, although is mainly used in the production of various acetates, glycol ethers and amines. It is used as a precursor for isobutyl acetate (a solvent) as a partial replacement for n-butanol in some applications. Iso-Butanol is a propylene derivative, and is produced by catalytically hydrogenated n-butyraldehyde from propylene oxonation (the hydroformulation of propylene with syngas in an oxo-process). Iso-Butanol is produced in all regions.

Isopropanol (IPA)

Iso-propanol (IPA) is a solvent with various applications including printing inks, coatings, de-icer and the manufacture of isopropyl amines, an intermediate to fertilizers. High purity IPA is used in medical and IT solvent applications. It is produced directly by sulphuric acid oxidation of propylene or indirectly by the hydrogenation of acetone. Isopropanol production is widespread globally.


Kerosene was one of the original fuels to be extracted by distillation from crude oil. It is a light to middle distillate and is used in heating, cooking and lighting systems. In its broader definition kerosene includes the fuels used in commercial and military jet engines.

Light Crude

Light Crude is a term used to define crude oils with a higher fraction of lower boiling point components and low wax content. Some definitions have Light Crude defined as a crude with an specific gravity index greater than 28 API, although more commonly this range would include Medium and Light crudes.

Linear Alkyl Benzene (LAB)

Linear alkyl benzene (LAB) is the dominant detergent intermediate. It is mainly produced by the dehydrogenation of n-paraffins to internal olefins followed by alkylation with benzene using hydrofluoric acid catalyst. Almost all LAB is converted to linear alkyl sulfonates, a major surfactant in household cleaning products.

Linear Alpha Olefins (LAO)

Linear alpha olefins (LAO) are produced by two families of processes - full-range and on-purpose. LAOs are produced by the oligomerization of ethylene in full-range processes. On-purpose technologies are used to produce butene-1 (extractive distillation, hydrogenation/fractionation and ethylene dimerization), hexene-1 (fischer-tropsch and ethylene trimerization) and octene-1 (fischer-tropsch). Alpha olefins cover a wide range of products used in diverse applications. The lighter components (butene-1, hexene-1 and octene-1) are used as comonomers in polyethylene production. Decene-1 is principally used to manufacture polyalpha olefins for the production of high performance lubricants. Higher alpha olefins in the C12/C14 range are consumed in the production of detergent alcohols, while those in the C16/C18 range are predominately used in the oilfield chemicals sector and paper industry, and the higher fractions (C20+) are used to manufacture lubricant additives and specialty waxes.

Linear Low Density Polyethylene (LLDPE)

Linear low density polyethylene (LDPE) is a relatively new polyethylene that shares many of the performance characteristics of LDPE. LLDPE is most commonly used in film applications. It is produced by the low pressure catalysed reaction of ethylene with small quantities of higher alpha-olefin (most commonly butene-1). This low pressure technology provides LLDPE with a cost advantage over LDPE, although this advantage is partly surrendered as it is a more difficult polymer to process than LDPE.

Low Density Poly-ethylene (LDPE) - Autoclave

There are two basic processes used for the manufacture of LDPE, autoclave and tubular. ICI developed the first LDPE technology as a stirred autoclave process in the late 1930s. The autoclave process is adiabatic, in that there is no significant heat removal from the reactor during the process. The modern stirred autoclave reactor may have a volume of 3 000 litres and four to six zones, each running at a different temperature, thus enabling direct control of the mix of molecular species and degree of long chain branching. The high-pressure polymerisation of ethylene is a free radical promoted reaction and the autoclave operators almost always use organic peroxides as initiators.

Low Density Poly-ethylene (LDPE) - Tubular

There are two basic processes used for the manufacture of LDPE, autoclave and tubular. The tubular reactor process was originally developed by BASF. In the tubular design, the reactants are cooled along the long jacketed tube reactor. Tubular reactors can have several zones where fresh ethylene and initiator are added. The addition of fresh ethylene both cools the reactants and agitates the mixture so that the molecular weight distribution can be varied.

Low Density Polyethylene (LDPE)

Low density polyethylene (LDPE) was the first polyethylene to be produced and is a member of the polyolefin family. LDPE is used in a wide range of applications, the most common being consumer plastic bags. LDPE goods are commonly marked with a 4 following the recycling codes developed by the American Society of the Plastics Industry. LDPE demand is under pressure from more modern and lower cost polymers including its fellow polyethylene LLDPE. LDPE is formed by the high pressure catalysed reaction of ethylene monomers in either tubular or autoclave reactors.

Maleic Anhydride

Maleic anhydride has traditionally been produced by the oxidation of benzene, but more recently, n-butane has replaced benzene as the main feedstock. Maleic anhydride is a versatile molecule that lends itself to many applications requiring multi-functionality. The main applications for refined Maleic anhydride are unsaturated polyester resins and fine chemicals (alkenyl succinic anhydrides, fumaric acid, polyaspartic acid).

Medium Crude

Medium Crude is a term used to define a crude oil part way between Light Crude and Heavy crude.


Melamine is a white crystaline solid produced by the reaction of ammonia and urea over a catalyst. It is typically shipped in bags and is used mainly as a raw material in the production of melamine formaldehyde resins. These resins are used to produce wood laminates, in textile and paper treatment and as leather tanning agents. Melamine itself also finds applications in flame retardants, speciality fertilizers, ion exchange resins and as a concrete additive.


Methanol, the simplest of the alcohol compounds, is a toxic, flammable liquid with a distinctive odour. Methanol is mainly produced by the reforming of hydrocarbon feedstock syngas, which is mainly derived from natural gas, but can also be derived from coal or refinery residues. As methanol is relatively simple to ship, it provides a means to exploit natural gas reserves which are too remote to be connected to consumers by pipeline, so called "stranded gas". For this reason most of the world's methanol is now produced in remote areas and shipped to consumers in large dedicated methanol carriers. Methanol is a bulk commodity chemical and its major derivatives are formaldehyde, methyl tertiary butyl ether (MTBE), acetic acid, methyl methacrylate (MMA), and di methyl terephthaliate (DMT).

Methyl Tertiary Butyl Ether (MTBE)

Methyl tertiary butyl ether (MTBE) is a volatile, combustible, colourless liquid that is categorised as an oxygenate due to its ability to boost the oxygen content and octane rating of gasoline. It is relatively water soluble and exhibits an unpleasant taste and odour in solution. MTBE is produced from methanol and isobutylene, as is produced both by refiners to meet their own requirements and by major export-based producers in the Middle East, Europe and the United States. MTBE has marginal outlets as a solvent in chemical and medical applications, although its dominant end-use is as a gasoline additive. It is currently being phased out of the gasoline market in the USA due to concerns over groundwater contamination.

Mixed C4

Mixed C4 is the term used to describe the mixture of four carbon compounds that are commonly produced from a steam cracker. Four carbon compounds differ from the shorter olefins in that they can be formed in a variety of structures, being straight or branched and with one or two double bonds. These separate chemicals can either be separated within the steam cracker, or alternatively at separate dedicated extraction units.


Mixed xylenes refers to a mixture of xylene isomers, meta-xylene, ortho-xylene and para-xylene, which are obtained from various sources within a refinery or steam cracker. Although they can be used in a mixture for solvents, they are usually separated and used as feedstock for a limited range of intermediates. They are one of the "aromatic" compounds, along with benzene and toluene. The largest use is para-xylene for polyester production.

Mono Ethylene Oxide (MEG)

Mono ethylene glycol (MEG) is the main constituent of anti-freeze, although consumption of MEG in the production of PET has now overtaken this as the main end-use, and MEG is therefore classed as a polyester intermediate. MEG is produced by the reaction of ethylene oxide and water, and most modern plants are combined EO/MEG units. MEG is produced in all regions, although to an increasing extent in the Middle East.


N-Butanol is an oxo-alcohol mainly used in the production of the butyl acrylate, which finds uses in the coatings industry. Others uses are in smaller volume acetate and glycol ether formulations. It is also used directly as a solvent. Most butanol is manufactured propylene with syngas in an oxo-process, then catalytically hydrogenated. Another major route, developed by Shell involves a one-step reaction with propylene and co-produces 2-ethylhexanol. There are other routes, including fermentation, which is not commercially viable. N-Butanol is a propylene derivative, and is produced in all regions.


Naphtha refers to a range of middle distillate streams whose composition lies part way between gasoline and kerosene. Paraffinic naphtha is a preferred feedstock for petrochemical production via the steam cracking to ethylene and co-products. Naphtha streams with a higher aromatic content are meanwhile processed in reformers to make additional gasoline as well as producing valuable aromatics compounds for the petrochemical industry.

Natural Gas

Natural gas is the name given to dry gas streams composing mainly of methane (CH4). It may also contain small volumes of ethane, propane and butane as well as traces of other gases, such as carbon dioxide. Various components of natural gas is separated via distillation and are used to make methanol and various olefins.


Nitrobenzene is an aromatic derivative produced by nitration of benzene with nitric acid in the presence of sulfuric acid. Almost all nitrobenzene is converted to aniline by hydrogenation.


Nylons (polyamides) are the oldest and largest volume engineering polymers. Nylon refers to a family of a highly versatile materials that are consumed in a variety of applications including fibers, films and molded materials. Nylons are strong, tough polymers with good resistance to elevated temperatures and attack by chemicals.

Nylon Intermediates

The Nylon Intermediates are the family of chemicals used in the production of the nylon family of polymers.

Olefins family

The Olefins are a family of unsaturated hydrocarbons containing a double bond. The double bond provides a target for chemical reaction, both with other chemicals and with other olefins. Catalysed reaction of a pure olefin stream results in the production of polyolefins. Olefins are commonly produced by high temperature pyrolysis of refinery hydrocarbon streams in steam crackers.


Ortho-Xylene is an aromatic compound with two methyl groups substituted onto the benzene ring. Ortho-xylene is recovered from a mixed xylenes stream by fractionation. Its main application is for phthalic anhydride, which is used in plasticiser production.


para-Xylene is an aromatic compound with two methyl groups substituted onto the benzene ring at opposite positions. Para-xylene is recovered from a mixed xylenes stream by adsorption and by isomerisation of C8 aromatics. Almost all para-xylene consumed for chemicals production is used for the production of PTA and DMT, which are used in polyester production.

Petrochemical Feedstocks

Petrochemical Feedstocks are those groupings of feedstock materials that are consumed by the petrochemical industry. Conventionally these feed streams are obtained from refinery operations, however the last 20 years has seen non refinery streams, such as ethane extracted from natural gas, grow in importance as a feedstock.


Phenol is a major commodity chemical intermediate produced from cumene. Phenol is used to produce phenolic resins for wood binding and bisphenol-A for polycarbonate resins. Other engineering applications include the production of caprolactam and adipic acid, which are nylon intermediates. It can also be used directly in some medical and water treatment applications, e.g. anesthetic, disinfectant, exfoliate in cosmetic surgery, acetyl salicylic acid (aspiron) and slimicide. Phenol production is principally from the reaction of propylene and benzene to cumene, then cumene oxidation; hence phenol is classed as a propylene derivative. A white, crystalline powder at room temperature, phenol has for a long time been produced directly from coal distillation, although the volumes from this source are now small relative to propylene-based production. Phenol production is widespread globally with the exception of the Middle East, although capacity is expected to develop there also.

Phthalic Anhydride

Phthalic anhydride is an aromatics derivative produced by the oxidation of ortho-xylene. Phthalic anhydride is used to make phthalate plasticizers, which are used for PVC production. Phthalic anhydride is also used in the production of alkyd resins and unsaturated polyester resins.


Polycarbonate is a resilient engineering resin with excellent optical properties. It is commonly made from bisphenol A linked by carbonate groups (O-CO-O) in the Engineering Polymers family. Polycarbonate is an engineering resin that exhibits good strength and high clarity thus used in technical applications such as optical media and automotive applications such as transparent construction sheet, automotive headlamps, CDs and DVDs. Polycarbonates are also compounded with ABS and used in thin walled electronic applications such as mobile phones and laptop computer cases. PC faces some competition from other glass-like polymers such as PMMA and PS resin. It is stronger than PMMA and has a better light transmission characteristics than glasses.

Polyester Family

The Polyester Intermediates are the family of chemicals used in the production of the polymer polyethylene terephthalate, also known as polyester, which is used for fibre and packaging applications.

Polyethylene Terephthalate (PET) Bottle Grade

PET bottle grade is a transparent polyethylene terephthalate polymer used mainly for bottling carbonated soft drinks and mineral water. The production of PET bottle grade is by solid state polymerisation (SSP) of PET melt phase, which increases the viscosity of the polymer by vacuum treatment, but involves no other raw materials. Due to the ubiquitous usage of PET bottle grade, plants are located in all regions.

Polyethylene Terephthalate (PET) Melt Phase

PET Melt Phase is the basic, amorphous grade of PET (polyethylene terephthalate) which can be used directly for the production of polyester fibre or upgraded to PET bottle grade by solid state polymerisation (SSP). PET Melt phase is produced by the melt-phase polymerisation of terephthalic acid (from PTA or DMT) with MEG. PET melt phase plants for fibre production are increasingly concentrated in Asia, while PET melt phase plants linked to PET bottle grade operations continue to be built around the world.


Polymer is the name given to a solid that is constructed by the repeated addition of simple monomer units. The majority of petrochemical value chains end in the production of a useful polymer material, with examples including polyethylene, polystyrene and polyester.


Polyolefins is the name given to the polymers of the olefin family. By convention these are the single double bond olefins and the grouping does not contain rubber compounds that can be produced by polymerising butadiene.

Polypropylene (PP)

Polypropylene (PP) is the propylene analogue of polyethylene and is also a member of the polyolefin family. PP has a higher chemical and temperature resistance than the polyethylenes. It also has a higher toughness than HDPE and can be used in applications that experience cycling loads. PP's mechanical properties are allowing it to grow into markets that previously specified Engineering Polymers, such as under bonnet applications in the automotive industry. PP goods are commonly marked with a 5 following the recycling codes developed by the American Society of the Plastics Industry. PP is commonly produced using specialized Ziegler-Natta catalysts in slurry reactors.

Polystyrene (PS)

Polystyrene (PS) is a solid aromatic polymer made from the monomer styrene. A commodity polymer used largely for semi/rigid packaging applications, it can be melted at high temperature for molding or extrusion, and then resolidified. It is commonly used as insulation in building structures and packaging. Other applications include electronics housing.


Polyurethanes are made by the reaction of isocyanates (MDI and TDI) with polyols. Polyurethanes can be in the form of flexible or rigid foams, elastomers, coatings, adhesives and low molecular weight additives. MDI is typically used for rigid foams, whereas TDI is used mostly in flexible foams.

Polyvinyl Chloride (PVC)

Polyvinyl chloride (PVC) is a versatile polymer, produced by the polymerisation of VCM. PVC is almost always converted into a compound by the incorporation of additives, allowing it to be used in both rigid and flexible forms as a plastic resin. Extensively used in the construction sector, PVC has a wide variety of applications, including pipe, siding and window/door profiles, wire and cable insulation, rigid film/sheet, and flooring.


Propane is a member of the LPG (Liquified Petroleum Gases) and paraffin families, consisting of three saturated carbon atoms in a straight chain. The term liquified petroleum gas refers to its main production route as a liquified stream produced by the repressurisation of gas that separated from crude oil on extraction from underground. Propane is highly valued as a heating fuel, particularly in developing economies, and hence has a highly seasonal demand and pricing profile.

Propionaldehyde or Propanal

Propionaldehyde (or propanal) is a three-carbon aldehyde commonly produced by reacting syngas with ethylene. Its major use is in the manufacture of trimethylolethane via condensation with methanol. This is used in the manufacture of alkyd resins.


Propylene is the second member of the olefin chemical family, consisting of three hydrocarbons in a chain, linked by one double bond and one single bond. The double bond in propylene is less accessible and less reactive than that in ethylene and hence reaction conditions tend to be harsher for a given synthesis reaction. Propylene is also produced (to a lesser extent than ethylene) from the pyrolytic cracking in a steam cracker of a wide variety of hydrocarbons. Significant volumes of propylene are also produced from refinery FCC units.

Propylene Glycol

Mono, di and tri-propylene glycol are produced commercially. Monopropylene glycol (MPG) is the most widely used, and is found in cosmetics, foods, pharmaceuticals and laundry detergents, as well as substituting for monoethylene glycol in anti-freeze formulations where lower toxicity is required or chiefly to make unsaturated polyester resins used in fibreglass composites for construction applications. Most of polyester based fibreglass, however, are produced from propylene oxide. Di and tri-propylene glycol are mainly used in the production of resins and elastomers. A clear, viscous liquid at room temperature, propylene glycol is produced by the hydrolysis reaction of propylene oxide and water.

Propylene oxide

Propylene oxide is a chemical intermediate mainly used for the production of polyether polyols-which are in turn used in urethane foams, and also in production of propylene glycol, with the remainder consumed in glycol ethers. Propylene oxide is produced from propylene by two routes: mainly chlorohydrin route or to a lesser extent indirect route via hydroperoxidation of isobutane or ethylbenzene producing tertiary butyl alcohol (PO/TBA) or styrene monomer (PO/SM) as co-product respectively. Chlorohydrin route is more energy intensive, produces high by-product yield of little application, and involved chlorine waste disposal. Nevertheless, it remains economically healthy, producing 40 to 50% of PO in the United States. Some propylene oxide is also produced from cumene. Propylene oxide production is widespread outside the Middle East, although projects are now under development in the Middle East.

Purified Terephthalic Acid (PTA)

Purified terephthalic acid (PTA) is produced by the oxidation of terephthalic acid (TA) in acetic acid, and its subsequent purification, often via crystallisation. Prior to the development of the purification process, the crude TA was esterified into DMT, which could then be purified. PTA is the main ingredient in the production of PET melt phase, although much smaller volumes are used in the production of thermosetting resins and coatings. PTA production is highly capital intensive, and tends to be located close to demand centres.


Pygas is the term given to the aromatic rich stream that is extracted within a steam cracker, immediately after the feedstream has been cracked and cooled. It is extracted by washing the stream with water, and is then separated from the water phase. Pygas composition varies according to both the cracker feedstock and the severity of operation, containing valuable quantities of benzene and gasoline components.

Refined Products

Refined products is the term given to the output streams produced by a refinery. These products differ from petrochemical products in that they generally consist of a mixture of chemicals, whose value is based on their combined physical properties rather than their chemistry. Refined products are used as energy sources across all areas of economic activity, with the petrochemical industry accounting for only a small percentage of total demand.

Refinery Propylene

Refinery propylene refers to a mixture of propylene and propane (typically 75 percent propylene) that is produced by refineries for sale to petrochemical producers or for use as a feedstock to make gasoline components. Refinery propylene can be upgraded to propylene by distillation in a propylene splitter. Refinery propylene can also be used directly as a feedstock for production of cumene.


Reformate is the term given to the side stream produced by refinery reformers. These units are designed to produce higher value gasoline components from highly aromatic naphtha streams. Reformate is produced from naphtha in continuous catalytic reformers and semi-regenerative reformers and is a mixture of aromatic and aliphatic hydrocarbons. Its composition can be controlled within limits by the aromatics producer. It is the major source of aromatics in most of the world.

Sour Crude

Sour Crude is the term used for crudes with a higher sulphur content. Tightening emissions legislation has meant that refiners need to add considerable desulphurisation capacity in order to process Sour Crude.


Styrene (also known as vinyl benzene, ethenylbenzene) is a colourless liquid in the Aromatics family. Styrene is a chemical intermediate made from the dehydration of ethyl benzene and a vinyl group on styrene molecule can readily undergo polymerization. Styrene is a monomer used in the production of variety of polymer and rubbers including: polystyrene, ABS, SBR, SBL, and unsaturated polyesters.

Styrenics family

The Styrenics chain includes the chemical products and polymers that can be produced from the styrene monomer. Ethylbenzene, the immediate precursor used in the production of styrene is also included in this grouping.

Sweet Crude

Sweet Crude is the term used for crudes with a low sulphur content. Continued tightening of emissions legislation has increased the value of low sulphur crude in recent years.


Toluene is one of the "aromatic" compounds along with benzene and xylenes. There is limited chemical consumption of toluene but it may be converted to benzene by hydrodealkylation (THDA) or to benzene and xylenes by disproportionation (TDP) or transalkylation. Chemical applications include solvents and toluene diisocyanate (TDI).

Toluene diisocyanate (TDI)

Toluene diisocyanate (TDI) is an aromatic derivative produced by the nitration of toluene followed by phosgenation. TDI-based polyurethanes are used in flexible foams, coating resins, adhesives, sealants and elastomers.

Toluene Disproportionation (TDP)

Incremental mixed xylenes can be produced from available toluene through disproportionation. Technologies are available that will permit co-processing C9 aromatics with toluene into mixed xylenes. The analysis presented here gives the costs for a typical TDP unit processing toluene only, valuing the feedstock at its gasoline blending value. Xylenes production from gasoline value toluene, in general, has a lower cash cost of production than xylenes from reformate. This result is sensitive to co-product credits from benzene and other gasoline based co-products, and the position can be reversed if toluene is valued throughout at its market price.


Urea is an organic compound that occurs naturally as a product of excretion in living organisms, and is produced industrially by reacting ammonia with carbon dioxide. Urea's main use is as a fertilizer in the form of granules, prills or in aqueous solution. Urea is also an important ingredient for the manufacture of melamine, and for urea-formaldehyde resins, which are used as adhesives for wood products, paper and textiles.

Vinyl Acetate Monomer (VAM)

Vinyl acetate monomer (VAM) is a highly versatile intermediate used in the production of a variety of polymers, such as polyvinyl acetate (PVAc), polyvinyl alcohol (PVOH), polyvinyl butyral (PVB), polyvinyl formal (PVF) and ethylene vinyl acetate (EVA). The main process used to produce VAM is vapor-phase acetoxylation (reaction of ethylene with acetic acid), except in China where the acetylene process dominates.

Vinyl Chloride Monomer (VCM)

Vinyl chloride monomer (VCM) is an intermediate chemical of the vinyls chain, mainly produced by thermal cracking of EDC. Almost all VCM produced is used to manufacture PVC, with other applications consuming very little VCM. VCM is a toxic gas at room temperature, and thus transporting VCM is costly and hazardous. As such, trade in VCM is usually minimised, in favour of shipping EDC (the precursor to VCM) or PVC.

Vinyls family

The Vinyls family contains those chemicals used in the production of PVC resin, namely chlorine, EDC, VCM, and PVC. Although not specifically used for PVC production, caustic soda is often associated with the vinyls chain, as it is a major by-product of chlorine production.

WTI Crude Oil

West Texas Intermediate Crude Oil is a light sweet crude that is particularly suited for the production of gasoline. WTI production is widely utilised as a refinery feed in the United States Mid West and to a lesser extent on the Gulf Coast. WTI crude usually trades at a premium to the other two benchmark crudes owing to its higher gasoline yield.