Chemical Glossary

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.

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 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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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-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.

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 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.

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 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.

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

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).

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

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 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.