Ethylene glycol

	Email		Print
	Bookmark		Link

Ethylene glycol

Ethylene glycol (monoethylene glycol (MEG), 1,2-ethanediol, IUPAC name

IUPAC nomenclature

IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. It is developed and kept up to date under the auspices of the International Union of Pure and Applied Chemistry ....
: ethane-1,2-diol) is an alcohol

Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
with two -OH groups (a diol

Diol

A diol or glycol is a chemical compound containing two hydroxyl groups Vicinal diols have hydroxyl groups attached to adjacent atoms. Examples of vicinal diol compounds are ethylene glycol and propylene glycol....
), a chemical compound

Chemical compound

A chemical compound is a Chemical substance consisting of two or more different chemical element Chemical bond together in a fixed mass ratio that can be split into simpler substances....
widely used as an automotive

Automobile

An automobile or motor car is a wheeled motor vehicle for transportation passengers, which also carries its own car engine or motor. Most definitions of the term specify that automobiles are designed to run primarily on roads, to have seating for one to eight people, to typically have four wheels, and to be constructed principally f...
antifreeze

Antifreeze

Antifreeze is a cryoprotectant used in internal combustion engines, and for many other heat transfer applications, such as HVAC chillers and solar water heaters....
. In its pure form, it is an odorless, colorless, syrupy, sweet tasting, toxic liquid.

lene glycol is produced from ethylene

Ethylene

Ethylene is the chemical compound with the formula C2H4. It is the simplest alkene. Because it contains a carbon-carbon double bond, ethylene is called an unsaturated hydrocarbon or an olefin....
, via the intermediate ethylene oxide

Ethylene oxide

Ethylene oxide is the organic compound with the chemical formula C2H4O. This colorless flammable gas with a faintly sweet odor is the simplest epoxide, a three-membered ring consisting of two carbon and one oxygen atom....
. Ethylene oxide reacts with water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
to produce ethylene glycol according to the chemical equation

Chemical equation

A chemical equation may be described as a chemical reaction or a means of writing out and describing such a phenomenon. The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric coefficient....

C₂H₄O

Ethylene oxide

Water (molecule)

File:Blue-water-pool.jpgWater is the most abundant molecule on Earth's surface, constituting about 70% of the Earth's surface in liquid, solid, and gaseous states....
? HOCH₂CH₂OH

This reaction

Chemical reaction

A chemical reaction is a process that always results in the interconversion of chemical substances. The substance or substances initially involved in a chemical reaction are called reactants....
can be catalyzed by either acid

Acid

An acid is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion Activity greater than in pure water, i.e....
s or base

Base (chemistry)

In chemistry, a base is most commonly thought of as an aqueous substance that can accept protons. A base is also often referred to as an alkali if OH- ions are involved....
s, or can occur at neutral pH

Discussion

Ask a question about 'Ethylene glycol'

Start a new discussion about 'Ethylene glycol'

Answer questions from other users

Full Discussion Forum

Production

Ethylene glycol is produced from ethylene

Ethylene

Ethylene oxide

Water

Chemical equation

C₂H₄O

Ethylene oxide

Water (molecule)

File:Blue-water-pool.jpgWater is the most abundant molecule on Earth's surface, constituting about 70% of the Earth's surface in liquid, solid, and gaseous states....
? HOCH₂CH₂OH

This reaction

Chemical reaction

Acid

An acid is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion Activity greater than in pure water, i.e....
s or base

Base (chemistry)

pH is a measure of the Acid or Base of a solution. It is defined as the cologarithm of the Activity of dissolved hydrogen ions . Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations....
under elevated temperatures. The highest yields of ethylene glycol occur at acidic or neutral pH with a large excess of water. Under these conditions, ethylene glycol yields of 90% can be achieved. The major byproducts are the ethylene glycol oligomer

Oligomer

In chemistry, an oligomer consists of a limited number of monomer units , in contrast to a polymer which, at least in principle, consists of an unbounded number of monomers....
s diethylene glycol

Diethylene glycol

Diethylene glycol is an organic compound described by the structural chemical formula HO-CH2-CH2-O-CH2-CH2-OH....
, triethylene glycol

Triethylene glycol

Triethylene glycol, TEG, or triglycol is a colourless odourless viscous liquid with molecular formula HO3H. It is used as a plasticizer for vinyl....
, and tetraethylene glycol.

This molecule has been observed in space.

Uses

Coolant

The major use of ethylene glycol is as a medium for convective heat transfer

Convective heat transfer

Convective heat transfer is a mechanism of heat transfer occurring because of bulk motion of fluids . This can be contrasted with Heat conduction heat transfer, which is the transfer of energy by vibrations at a molecular level through a solid or fluid, and radiation heat transfer, the transfer of energy through electromagnetic waves....
in, for example, automobiles and personal computers. Due to its low freezing point it is used as a deicing

Deicing

De-icing is the process of removing frozen contaminant, snow, ice, slush,from a surface.Anti-icing is the process of protecting against the formation of frozen contaminant, snow, ice, slush on a surface....
fluid for windshield

Windshield

The windshield or windscreen of an aircraft, automobile, bus, motorcycle, or tram is the front window. Modern windshields are generally made of Laminated glass, a type of treated glass, which consists of two curved sheets of glass with a plastic layer laminated between them for safety, and are Polyurethaned into the window frame....
s and aircraft. Ethylene glycol is also commonly used in chilled water air conditioning

Air conditioning

An air conditioner is an appliance, system, or Mechanism designed to extract heat from an area via a refrigeration cycle. In construction, a complete system of heating, Ventilation , and air conditioning is referred to as "HVAC." Its purpose, in a building or an automobile, is to provide comfort during either hot or cold...
systems that place either the chiller or air handlers outside, or systems that must cool below the freezing temperature of water.

Hydrate inhibition

Ethylene glycol is widely used to inhibit the formation of natural gas clathrates

Methane clathrate

Methane clathrate, also called methane hydrate or methane ice, is a solid form of water that contains a large amount of methane within its crystal structure ....
in long multiphase pipelines that convey natural gas from remote gas fields to an onshore processing facility. Ethylene glycol can be recovered from the natural gas and reused as an inhibitor after purification treatment that removes water and inorganic salts.

Manufacturing

Ethylene glycol has become increasingly important in the plastic

Plastic

Plastic is the general common term for a wide range of synthetic or semisynthetic organic chemistry solid materials suitable for the manufacture of industrial products....
s industry for the manufacture of polyester

Polyester

Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate ....
fibers and resin

Resin

Resin is a hydrocarbon secretion of many plants, particularly Pinophyta. It is valued for its chemical constituents and uses, such as varnishes and adhesives, as an important source of raw materials for organic synthesis, or for incense and perfume....
s, including polyethylene terephthalate

Polyethylene terephthalate

Polyethylene tephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P), is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid Packaging; thermoforming applications; and engineering resins often in combination with glass fiber....
, which is used to make plastic bottles for soft drink

Soft drink

A soft drink is a beverage that does not contain alcohol. Carbonated soft drinks are commonly known as soda, soda pop, pop, coke or tonic in various parts of the United States, pop in Canada, fizzy drinks in the United Kingdom and Australia and sometimes minerals in Ireland....
s. The antifreeze capabilities of ethylene glycol have made it an important component of vitrification

Vitrification

Vitrification is a process of converting a material into a glass-like amorphous solid that is free from any crystalline structure, either by the quick removal or addition of heat, or by mixing with an additive....
mixtures for low-temperature preservation of biological tissues and organs.

Minor uses of ethylene glycol include the manufacture of capacitor

Capacitor

A capacitor or condenser is a Passive component electronic component consisting of a pair of electrical conductor separated by a dielectric....
s, as a chemical intermediate in the manufacture of 1,4-dioxane

1,4-Dioxane

1,4-Dioxane, often just called dioxane, is a clear, colorless heterocyclic organic compound which is a liquid at room temperature and pressure....
and as an additive to prevent corrosion

Corrosion

Corrosion means the breaking down of essential properties in a material due to chemical reactions with its surroundings. In the most common use of the word, this means a loss of electrons of metals reacting with water and oxygen....
in liquid cooling systems for personal computer

Personal computer

A personal computer is any general-purpose computer whose original sales price, size, and capabilities make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator....
s. penis

Chemistry

Ethylene glycol may also be used as a protecting group

Protecting group

A protecting group or protective group is introduced into a molecule by chemical modification of a functional group in order to obtain chemoselectivity in a subsequent chemical reaction....
for carbonyl groups in organic synthesis

Organic synthesis

Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic_chemistry molecules can often contain a higher level of complexity compared to purely Inorganic_chemistry compounds, so the synthesis of organic compounds has developed into one of the most im...
. Reacting a ketone or aldehyde with ethylene glycol will, with acid catalyst (e.g. p-toluenesulfonic acid

P-Toluenesulfonic acid

p-Toluenesulfonic acid is an organic compound with the formula methyl groupbenzeneSulfonic acid. TsOH, as it is abbreviated, is a white solid that is soluble in water, alcohols, and other Chemical polarity organic solvents....
; BF₃·Et₂O

Boron trifluoride

Boron trifluoride is the chemical compound with the chemical formula BF3. This pungent colourless toxic gas forms white fumes in moist air....
), give a cyclic acetal

Acetal

An acetal is a molecule with two single bonded oxygens attached to the same carbon atom.Traditional usages distinguish ketal from acetal . Current accepted terminology classifies ketals as a subset of acetals....
— a 1,3-dioxolane, which is resistant to bases and other nucleophiles. The 1,3-dioxolane protecting group can thereafter be removed, e.g. by further acid hydrolysis

Hydrolysis

Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
. In this example, isophorone

Isophorone

Isophorone is an Carbonyl#.CE.B1.2C.CE.B2-Unsaturated_carbonyl_compounds, a colorless to yellowish liquid with characteristic smell, that is used as a solvent and as an intermediate in organic synthesis....
was protected using ethylene glycol with p-toluenesulfonic acid in moderate yield. Water was removed by azeotropic distillation

Azeotropic distillation

In chemistry, azeotropic distillation is any of a range of techniques used to break an azeotrope in distillation. In chemical engineering, azeotropic distillation usually refers to the specific technique of adding another component to generate a new lower-boiling azeotrope that is heterogeneous, such as the example below with the additio...
to shift the equilibrium to the right.

Geothermal Systems

Ethylene glycol is commonly used in geothermal heating

Geothermal heating

Geothermal heating is best defined as the use of the Earth's thermal energy for space and water heating. It has been used since the time of the Roman Empire as a way of HVAC buildings and spas by utilizing sources of hot water and steam that exist near the Earth's surface....
/cooling systems. The ethylene glycol is the fluid

Fluid

A fluid is defined as a substance that continually deforms under an applied shear stress. All liquids and all gases are fluids. Fluids are a subset of the Phase and include liquids, gas, Plasma physics and, to some extent, plasticity ....
that is passed through the loops of hoses in geothermal systems to transport heat through the use of a geothermal heat pump. The ethylene glycol either gains energy from the source (lake, ocean, water well

Water well

A water well is an excavation or structure created in the ground ??by digging, driving, boring or drilling to access water in underground aquifers....
) or dissipates heat to the source depending if the system is being used for heating or cooling.

Laboratory use

Ethylene glycol is commonly used as a preservative for specimens in schools, frequently during dissection. It is said to be safer than formaldehyde

Formaldehyde

Formaldehyde is a chemical compound with the chemical formula H2CO. It is the simplest aldehyde. Formaldehyde exists in several forms aside from H2CO: the cyclic trimer trioxane and the polymer Polyoxymethylene....
, but the safety is questionable.

Other applications

Ethylene glycol's high boiling point and affinity for water makes it an ideal desiccant

Desiccant

A desiccant is a hygroscopic substance that induces or sustains a state of dryness in its local vicinity in a moderately-well sealed container.Commonly encountered pre-packaged desiccants are solids, and work through absorption or adsorption of water, or a combination of the two....
for natural gas

Natural gas

Natural gas is a gas consisting primarily of methane. It is found associated with fossil fuels, in coal beds, as methane clathrates, and is created by methanogenic organisms in marshes, bogs, and landfills....
production. In the field, excess water vapor is usually removed by glycol dehydration. Ethylene glycol flows down from the top of a tower and meets a rising mixture of water vapor and hydrocarbon

Hydrocarbon

In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. With relation to chemical terminology, aromatic hydrocarbons or arenes, alkanes, alkenes and alkyne-based compounds composed entirely of carbon or hydrogen are referred to as "pure" hydrocarbons, whereas other hydrocarbons with bonded com...
gases from the bottom. The glycol chemically removes the water vapor, allowing dry gas to exit from the top of the tower. The glycol and water are separated, and the glycol cycles back through the tower.

Instead of removing water ethylene glycol can also be used to depress the temperature at which hydrates are formed. The purity of glycol used for hydrate suppression (mono-ethylene glycol) is typically around 80%, whereas the purity of glycol used for dehydration (tri-ethylene glycol) is typically 95-99+%. Moreover, the injection rate for hydrate suppression is much lower than the circulation rate in a glycol dehydration tower.

Ethylene glycol is also used in the manufacture of some vaccine

Vaccine

A vaccine is a biological preparation that establishes or improves immunity to a particular disease.Vaccines can be prophylaxis , or Medication ....
s, but it is not itself present in these injections. It is used as a minor (1–2%) ingredient in shoe polish

Shoe polish

Shoe polish , usually a waxy paste or a cream , is a consumer product used to polishing, waterproofing, and restore the appearance of leather shoes or boots, thereby extending the footwear's life....
and also in some inks and dyes. Ethylene glycol has seen some use as a rot and fungal treatment for wood, both as a preventative and a treatment after the fact. It has been used in a few cases to treat partially rotted wooden objects to be displayed in museums. It is one of only a few treatments that are successful in dealing with rot in wooden boats, and is relatively cheap. Ethylene glycol may also be one of the minor ingredients in screen cleaning solutions, along with the main ingredient isopropyl alcohol

Isopropyl alcohol

Isopropyl alcohol is a common name for isopropanol, a colorless, flammable chemical compound with a strong odor. It has the molecular formula C3H7OH and is the simplest example of a Alcohol#Primary.2C secondary.2C and tertiary alcohols, where the alcohol carbon is attached to two other carbons....
.

Toxicity

The major danger from ethylene glycol is ingestion. Due to its sweet taste, children and animals will sometimes consume large quantities of it if given access to antifreeze. Upon ingestion, ethylene glycol is chemically broken down in the body into toxic compounds. It and its toxic byproducts first affect the central nervous system

Central nervous system

The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms....
, then the heart, and finally the kidneys. Ingestion of sufficient amounts can be fatal.

Industrial hazards

Ethylene glycol can begin to breakdown at 230° – 250°F (110° – 121°C). Note that breakdown can occur when the system bulk (average) temperature is below these limits because surface temperatures in heat exchangers and boilers can be locally well above these temperatures.

The electrolysis

Electrolysis

In chemistry and manufacturing, electrolysis is a method of separating Chemical bond chemical compound by passing an electric current through them....
of ethylene glycol solutions with a silver

Silver

Silver is a chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal....
anode

Anode

An anode is an electrode through which electric charge flows into a polarized electrical device. Mnemonic: ACID . Electrons flow in the opposite direction to the positive electric current....
results in an exothermic reaction

Exothermic reaction

An exothermic reaction is a chemical reaction that releases energy in the form of heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation:...
. In the Apollo 1

Apollo 1

Apollo 1 is the official name that was later given to the never-flown Apollo/Saturn 204 mission. Its command module was destroyed by fire during a test and training exercise on January 27 1967 at Pad 34 atop a Saturn IB rocket....
fire catastrophe a coolant consisting of ethylene glycol and water was implicated as a possible cause via this reaction. An ethylene glycol–water mixture can be ignited and burns in an atmosphere of pure low pressure oxygen.

History

Ethylene glycol was first prepared in 1859 by the French

France

France , officially the French Republic , is a country whose Metropolitan France is located in Western Europe and that also comprises various Overseas departments and territories of France....
chemist Charles-Adolphe Wurtz

Charles-Adolphe Wurtz

Adolphe Wurtz was a French chemist of German extraction. He is perhaps best remembered by chemists for the Wurtz reaction, to form carbon-carbon bonds by reacting alkyl halides with sodium, and for his discoveries of ethylamine and ethylene glycol....
from ethylene glycol diacetate via saponification

Saponification

Saponification is the hydrolysis of an ester under base conditions to form an alcohol and the salt of a carboxylic acid . Saponification is commonly used to refer to the reaction of a metallic alkali with a fat or oil to form soap....
with potassium hydroxide

Potassium hydroxide

Potassium hydroxide is the inorganic compound with the formula potassiumhydroxide. Along with sodium hydroxide, this colourless solid is a prototypical "strong base"....
and, in 1860, from the hydration

Hydration

Hydration may refer to:* Hydration reaction, a chemical addition reaction* Mineral hydration, an inorganic chemical reaction where water is added to the crystal structure of a mineral...
of ethylene oxide

Ethylene oxide

World War I

World War I, or the First World War , was a global military conflict which involved the Great powers, organized into two opposing military alliances: the Allies of World War I and the Central Powers....
, when it was synthesized from ethylene dichloride in Germany and used as a substitute for glycerol

Glycerol

Glycerol is a chemical compound also commonly called glycerin or glycerine. It is a colorless, odorless, Viscosity liquid that is widely used in pharmaceutical formulations....
in the explosives industry.

In the United States, semicommercial production of ethylene glycol via ethylene chlorohydrin was started in 1917. The first large-scale commercial glycol plant was erected in 1925 at South Charleston, West Virginia,, by Carbide and Carbon Chemicals Co. (now Union Carbide Corp.). By 1929, ethylene glycol was being used by almost all dynamite

Dynamite

Dynamite is an Explosive material based on the explosive potential of nitroglycerin, initially using diatomaceous earth or another absorbent substance such as sawdust as an adsorbent....
manufacturers.

In 1937, Carbide started up the first plant based on Lefort's process for vapor-phase oxidation of ethylene to ethylene oxide. Carbide maintained a monopoly on the direct oxidation process until 1953 when the Scientific Design process was commercialized and offered for licenes.

External links

U.S. Department of Health and Human Services (public domain)