Propylene glycol

	Email		Print
	Bookmark		Link

Propylene glycol

Propylene glycol, known also by the systematic name propane-1,2-diol, is an organic compound

Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
(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....
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....
), usually a faintly sweet, and colorless clear viscous liquid that is hygroscopic and miscible 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....
, acetone

Acetone

Acetone is the organic compound with the chemical formula OC2. This colorless, mobile, flammable liquid is the simplest example of the ketones....
, and chloroform

Chloroform

Chloroform, also known as trichloromethane and methyl trichloride, is a chemical compound with chemical formula CarbonHydrogenChlorine3....
.

Production
Industrially propylene glycol is produced by propylene oxide

Propylene oxide

Propylene oxide is a highly toxic flammable chemical compound. It is an epoxide having a molecular formula C3H6O. Other names include methyloxirane and 1,2-epoxypropane....
hydration.

Discussion

Ask a question about 'Propylene glycol'

Start a new discussion about 'Propylene glycol'

Answer questions from other users

Full Discussion Forum

Encyclopedia

Propylene glycol, known also by the systematic name propane-1,2-diol, is an organic compound

Organic compound

Diol

Alcohol

Water

Acetone

Acetone is the organic compound with the chemical formula OC2. This colorless, mobile, flammable liquid is the simplest example of the ketones....
, and chloroform

Chloroform

Chloroform, also known as trichloromethane and methyl trichloride, is a chemical compound with chemical formula CarbonHydrogenChlorine3....
.

Chirality

Propylene glycol contains an asymmetrical carbon atom, so it exists in two stereoisomers. The commercial product is a racemic

Racemic

In chemistry, a racemic mixture, or racemate, is one that has equal Amount of substance of left- and right-handed enantiomer of a Chirality molecule....
mixture. Pure optical isomers can be obtained by hydration of optically pure propylene oxide.

Production

Industrially propylene glycol is produced by propylene oxide

Propylene oxide

Propylene oxide is a highly toxic flammable chemical compound. It is an epoxide having a molecular formula C3H6O. Other names include methyloxirane and 1,2-epoxypropane....
hydration. Different manufacturers use non-catalytic high-temperature process at 200-220 °C or catalytic route which proceeds at 150-180 °C in presence of ion exchange resin or small amounts of sulfuric acid or alkali. Final products contain 20% 1,2-propanediol, 1.5% of dipropylene glycol and small amount of other polypropylene glycol. Propylene glycol can also be converted from 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....
, a biodiesel

Biodiesel

Biodiesel refers to a non-petroleum-based diesel fuel consisting of long chain alkyl esters, made by transesterification of vegetable oil or animal fat , which can be used in unmodified diesel-engine vehicles....
byproduct.

Applications

Propylene glycol is used:

As a moisturizer
Moisturizer

Moisturisers or moisturizers are complex mixtures of chemical agents specially designed to make the external layers of the skin softer and more pliable, by increasing its hydration by reducing evaporation....
in medicines
Medication

A pharmaceutical drug, also referred to as medicine or medicament, can be loosely defined as any substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease....
, cosmetics
Cosmetics

Cosmetics are substances used to enhance or protect the appearance or odor of the human body. Cosmetics include skin-care Cream , lotions, Powder , perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, permanent waves, colored contact lenses, hair colors, hair sprays and gels, deodorants, baby products, bath oils, bubb...
, food
Food

Food is any substance, usually composed of carbohydrates, fats, proteins and water, that can be Eating or Drinking by an animal or human for nutrition or pleasure....
, toothpaste
Toothpaste

Toothpaste is a paste or gel dentifrice used to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it can aid in the removal of dental plaque and food from the teeth, aid in the elimination and/or masking of halitosis and deliver active ingredients such as fluoride or xylitol to prevent tooth...
, mouth wash, and tobacco
Tobacco

Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. It can be consumed, used as an organic pesticide, and in the form of nicotine tartrate it is used in some medicines....
products
In electronic cigarettes to deliver vaporized nicotine
As an emulsification agent in Angostura
Angostura bitters

Angostura bitters, often simply referred to as angostura, is a concentrated bitters for food and beverages made of herbs and spices by House of Angostura in the country of Trinidad and Tobago....
and orange bitters
Bitters

A bitters is an alcoholic beverage prepared with herbs and citrus dissolved in alcohol or glycerine and having a Taste#Bitterness or bittersweet flavor....
As a solvent
Solvent

A solvent is a liquid or gas that dissolves a solid, liquid, or gaseous solute, resulting in a solution.The most common solvent in everyday life is water....
for food colors
Food coloring

A food coloring is any substance that is added to food or drink to change its color. Food coloring is used both in commercial food production and in domestic cooking....
and flavorings
As an ingredient, along with wax and gelatin, in the production of paintballs
As a humectant
Humectant

A humectant is a hygroscopic Chemical substance. It is often a molecule with several hydrophilic groups, most often hydroxyl groups, but amines and carboxyl groups, sometimes esterified, can be encountered as well; the affinity to form hydrogen bonds with molecules of water is crucial here....
food additive
Food additive

Food additives are substances added to food to preserve flavour or improve its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , edible salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines....
, labeled as E number
E number

E numbers are number codes for food additives and are usually found on food labels throughout the European Union. The numbering scheme follows that of the International Numbering System as determined by the Codex Alimentarius committee....
E1520
As a cooling agent for beer
Beer

Beer is the world's oldest and most widely consumed alcoholic beverage and the third most popular drink overall after water and tea. It is produced by the brewing and Fermentation of starches, mainly derived from cereal?the most common of which is malted barley, although wheat, maize , and rice are widely used....
and wine
Wine

Wine is an alcoholic beverage often made of fermentation grape juice. The natural chemical balance of grapes is such that they can ferment without the addition of sugars, acids, enzymes or other nutrients....
glycol jacketed fermentation tanks
As a carrier in fragrance oil
Fragrance oil

Fragrance oil, also known as aroma oils, aromatic oils, and flavor oils, are blended Chemical synthesis aroma compounds or natural essential oils that are diluted with a carrier like propylene glycol, vegetable oil, or mineral oil....
s
As a less-toxic
Poison

In the context of biology, poisons are Chemical substance that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
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....
As a solvent
Solvent

A solvent is a liquid or gas that dissolves a solid, liquid, or gaseous solute, resulting in a solution.The most common solvent in everyday life is water....
used in mixing photographic chemicals, such as film developers
In smoke machines to make artificial smoke
Smoke

File:Bling-Bling Skywriting David Shankbone.jpgSmoke is the collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrainment or otherwise mixed into the mass....
for use in firefighter
Firefighter

Firefighters are rescuers extensively trained primarily to put out hazardous fires that threaten civilian populations and property, to rescue people from car accidents, collapsed and burning buildings and other such situations....
s' training and theatrical productions
In hand sanitizers, antibacterial
Antiseptic

Antiseptics are antimicrobials that are applied to living biological tissue/skin to reduce the possibility of infection, sepsis, or putrefaction....
lotions, and saline solutions
In cryonics
Cryonics

Cryonics is the low-temperature Preserve of humans and animals that can no longer be sustained by contemporary medicine until resuscitation may be possible in the future....
As a working fluid in hydraulic presses
As a coolant
Coolant

A coolant is a fluid which flows through a device in order to prevent its overheating, transferring the heat produced by the device to other devices that utilize or dissipate it....
in liquid cooling systems
To regulate humidity in a cigar humidor
Humidor

A humidor is any kind of box or room with constant humidity used to store cigars or smoking pipe tobacco. For private use, small wooden or acrylic glass humidor boxes for a few dozen cigars are used, while cigar shops may have walk-in humidors, sometimes consisting of a whole floor....
As the killing and preserving agent in pitfall traps, usually used to capture ground beetles
To treat livestock ketosis
Ketosis

Ketosis is a state characterised by elevated levels of ketone bodies in the blood, occurring when the liver converts triacylglycerol into fatty acids and ketone bodies ....
As the main ingredient in deodorant
Deodorant

Deodorants are substances applied to the body mainly to reduce body odor which is caused by the bacterial breakdown of perspiration. A subgroup of deodorants are "antiperspirants", which prevent odor and reduce sweat produced by parts of the body....
sticks.
To de-ice aircraft.
UV Blacklite Tattoo Ink

Propylene glycol has properties similar to those of ethylene glycol

Ethylene glycol

Ethylene glycol is an alcohol with two -OH groups , a chemical compound widely used as an automobile antifreeze. In its pure form, it is an odorless, colorless, syrupy, sweet tasting, toxic liquid....
(monoethylene glycol, or MEG). (Note: propylene glycol may also use the acronym MEG, but as an abbreviation of methyl ethyl glycol.) The industrial norm is to replace ethylene glycol by propylene glycol.

Safety

EMERGENCY OVERVIEW http://www.sefsc.noaa.gov/HTMLdocs/PropyleneGlycol.htm

"Hygroscopic.

Potential Health Effects Eye: Causes mild eye irritation. Contact may cause irritation, tearing, and burning pain. Skin: Causes moderate skin irritation. Contact with the skin may cause erythema, dryness, and defatting. Ingestion: May cause gastrointestinal irritation with nausea, vomiting and diarrhea. Low hazard for usual industrial handling. May cause hemoglobinuric nephrosis. May cause changes in surface EEG. Inhalation: Low hazard for usual industrial handling. May cause respiratory tract irritation. Chronic: May cause reproductive and fetal effects. Laboratory experiments have resulted in mutagenic effects. Exposure to large doses may cause central nervous system depression. Chronic ingestion may cause lactic acidosis and possible seizures.

**** SECTION 4 - FIRST AID MEASURES ****

Eyes: Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid. Skin: Get medical aid. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Ingestion: If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid. Inhalation: Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid if cough or other symptoms appear. Notes to Physician: Persons with impaired kidney function may be more susceptible to the effects of this substance. Treat symptomatically and supportively."

Cases of propylene glycol poisoning are related to either inappropriate intravenous use or accidental ingestion by children. The oral toxicity of propylene glycol is very low. In one study, rats were provided with feed containing as much as 5% PG over a period of 104 weeks and they showed no apparent ill effects. Because of its low chronic oral toxicity, propylene glycol is generally recognized as safe

Generally recognized as safe

Generally Recognized as Safe is a United States of America Food and Drug Administration designation that a chemical or substance added to food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act food additive tolerance requirements....
(GRAS) for use as a direct food additive.

Serious toxicity will occur only at extremely high intakes over a relatively short period of time that result in plasma concentrations of over 4 g/L. Such levels of ingestion would not be possible when consuming reasonable amounts of a food product or dietary supplements containing at most 1 g/kg propylene glycol.

The U.S. Food and Drug Administration

Food and Drug Administration

The U.S. Food and Drug Administration is an Government agency of the United States Department of Health and Human Services and is responsible for regulating and supervising the safety of foods, dietary supplements, Medications, vaccines, Biopharmaceutical, blood transfusion, medical devices, Electromagnetic radiation-emitting devices, veteri...
(FDA) has determined propylene glycol to be "generally recognized as safe

Generally recognized as safe

Ethylene glycol

Ethylene glycol is an alcohol with two -OH groups , a chemical compound widely used as an automobile antifreeze. In its pure form, it is an odorless, colorless, syrupy, sweet tasting, toxic liquid....
, propylene glycol affects the body's chemistry by increasing the amount of acid. Propylene glycol is metabolized into pyruvic acid

Pyruvic acid

Pyruvic acid is an organic acid. It is also a ketone. It is the simplest keto acids. The carboxylate ion of pyruvic acid is known as pyruvate....
, which is a normal metabolite in the breakdown of glucose, while ethylene glycol is metabolized into oxalic acid

Oxalic acid

Oxalic acid is the chemical compound with the chemical formula H2C2O4. This dicarboxylic acid is better described with the formula HOOCCOOH....
, which is toxic.

However, propylene glycol is not approved for use in cat food. The U.S. Food and Drug Administration has determined that propylene glycol in or on cat food has not been shown by adequate scientific data to be safe for use. Use of propylene glycol in or on cat food causes the feed to be adulterated and in violation of the Federal Food, Drug, and Cosmetic Act. 21CFR589.1001

Prolonged contact with propylene glycol is essentially non-irritating to the skin. Undiluted propylene glycol is minimally irritating to the eye, and can produce slight transient conjunctivitis (the eye recovers after the exposure is removed). Exposure to mists may cause eye irritation, as well as upper respiratory tract irritation. Inhalation of the propylene glycol vapors appears to present no significant hazard in ordinary applications. However, limited human experience indicates that inhalation of propylene glycol mists could be irritating to some individuals. Therefore inhalation exposure to mists of these materials should be avoided. Some research has suggested that propylene glycol not be used in applications where inhalation exposure or human eye contact with the spray mists of these materials is likely, such as fogs for theatrical productions or antifreeze solutions for emergency eye wash stations.

Propylene glycol does not cause sensitization and it shows no evidence of being a carcinogen or of being genotoxic.

A Clinical Journal of Medicine article states two cases of adult men experiencing psychosis from use of propylene glycol used in phenytoin injection USP. Both patients had to be switched to Cerebyx (Fosphenytoin Sodium) in order to avoid propylene glycol co-solvent.

Allergic reaction

Research has suggested that individuals who cannot tolerate propylene glycol probably experience a special form of irritation, but that they only rarely develop allergic contact dermatitis. Other investigators believe that the incidence of allergic contact dermatitis to propylene glycol may be greater than 2% in patients with eczema.

Patients with vulvodynia

Vulvodynia

Vulvodynia refers to a disorder of vulvar pain, burning, and discomfort that interferes with the quality of life. No discernible physical lesion other than perhaps some redness of the vulval vestibule is present....
and interstitial cystitis

Interstitial cystitis

Interstitial cystitis is a urinary bladder disease of unknown cause characterised by urinary frequency , urgency, pressure and/or pain in the bladder and/or pelvis....
may be especially sensitive to propylene glycol. Women struggling with yeast infections may also notice that some OTC creams can cause intense burning.Post menopausal women who require the use of an estrogen cream may notice that brand name creams made with propylene glycol often create extreme, uncomfortable burning along the vulva and perianal area. In these cases, patients can request that a local compounding pharmacy

Compounding

Compounding pharmacy is the process of mixing drugs by a pharmacist or physician to fit the unique needs of a patient. This may be done for medically necessary reasons, such as to change the form of the medication from a solid pill to a liquid, to avoid a non-essential ingredient that the patient is allergic to, or to obtain the exact Dose...
make a "propylene glycol free" cream.

External links

U.S. Department of Health and Human Services (public domain)
at J.T. Baker's website (via Mallinckrodt Baker's website MSDS listings)

http://www.sefsc.noaa.gov/HTMLdocs/PropyleneGlycol.htm

Propylene glycol

Chirality

Production

Applications

Safety

Allergic reaction

See also

External links