Oxygenate
Encyclopedia
Oxygenated chemical compounds contain oxygen
as a part of their chemical structure. The term usually refers to oxygenated fuel
s. Oxygenates are usually employed as gasoline additive
s to reduce carbon monoxide
that is created during the burning of the fuel.
The oxygenate MTBE has been found to have contaminated groundwater, mostly through leaks in underground gasoline storage tanks. In 2004, California
and New York
banned MTBE, generally replacing it with ethanol
. Several other states started switching soon afterward.
The oxygenates commonly used are either alcohol
s or ether
s:
In the United States
, preferential regulatory and tax treatment of ethanol (and methanol) automotive fuels introduces complexities beyond the energy balance inherent in and the engineering merits of the fuels themselves. North American automakers have in 2006 and 2007 enthusiastically promoted a blend of 85% ethanol and 15% gasoline, marketed as E85
, and their flex-fuel vehicles, e.g. GM
's " Live Green, Go Yellow" campaign. The apparent motivation for this is the nature of U.S. Corporate Average Fuel Economy (CAFE)
standards, which give an effective 54% fuel efficiency bonus to vehicles capable of running on 85% alcohol blends over vehicles not adapted to run on 85% alcohol blends,. This regulatory artificiality is quite valuable to the North American auto manufacturers in avoiding fines for failing to meet CAFE fuel economy standards imposed upon each manufacturer's car and light truck fleets. In addition to this auto manufacturer-driven impetus for 85% alcohol blends, the United States Environmental Protection Agency
had authority to mandate that minimum proportions of oxygenates be added to automotive gasoline on regional and seasonal basis from 1992 until 2006 in an attempt to reduce air pollution, in particular ground-level ozone and smog
. As a consequence, much gasoline sold in the United States is blended with up to 10% of an unspecified oxygenating agent. This product is known formally as oxygenated fuel and often (but not entirely correctly, as there are Federally-mandated reformulated gasolines without oxygenate) as reformulated gasoline. Groundwater contamination scares and the State of California
's ban of the substance as a gasoline additive has allowed ethanol to displace methyl tert(iary)-butyl ether (MTBE) as the most popular fuel oxygenate in the United States.
Many motorists in the U.S. did not welcome oxygenated gasoline because of its reduced energy density resulting in increased fuel consumption and because of fears of damage to cars, particularly to older cars. Alcohol (particularly methanol) fuel blends were expected to cause chemical damage to fuel system materials not designed to withstand exposure to alcohols, to increase water contamination due to alcohols' co-solvent properties, and via alcohols' solvent action loosening fixed fuel system deposits thus causing free-moving particulate contamination and clogging of various components. Experience with oxygenated fuels has shown little widespread deleterious mechanical effects, but oxygenated fuels have resulted in increased fuel consumption and often higher fuel prices. Although market conditions vary widely, ethanol is generally more expensive on a volumetric basis (and unquestionably more expensive on an energy content basis) than the gasoline with which it is blended. Refining and distribution complexities associated with regionally-specific oxygenated 'boutique gas' blends also has significantly raised gasoline prices in parts of the United States, particularly in California. Air pollution benefits from oxygenated fuels have thus far been difficult to quantify and to attribute to oxygenated fuel, but undoubtedly small.
The promotion of, Federal subsidy for, and high import tariffs protecting domestic production of ethanol motor fuel and the Federal mandate for oxygenated gasoline are essentially political phenomena. The principal driver in promoting E85 is the North American auto industry's need to avoid CAFE fines; in the fuel alcohol industry as a whole lobbying by American corn producers and agribusiness, in particular Archer Daniels Midland
, the biggest ethanol producer in the United States, has done much to get the fuel alcohol industry its present subsidized and protected status. Advocates for wheat, corn and sugar growers have succeeded in their attempts to lobby for regulatory intervention encouraging adoption of ethanol, stimulating debate over who the major beneficiaries of increased use of ethanol would be. Some researchers have warned that ethanol produced from agricultural feedstocks will cause a global food shortage, contributing to starvation in the third world.
Most forms of automobile racing that require the use of gasoline as fuel (as opposed to higher-energy blended fuels or straight alcohols) prohibit the use of oxygenate compounds in fuels, as they can allow higher fuel burn than the engine intake
restrictions are designed to permit. Prior to the 2007 Daytona 500
, for example, NASCAR
driver Michael Waltrip
and his team were heavily penalized when evidence of an unspecified oxygenate compound was found in the car's intake manifold during inspections.
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
as a part of their chemical structure. The term usually refers to oxygenated fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
s. Oxygenates are usually employed as gasoline additive
Gasoline additive
Gasoline additives increase gasoline's octane rating or act as corrosion inhibitors or lubricants, thus allowing the use of higher compression ratios for greater efficiency and power, however some carry heavy environmental risks...
s to reduce carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
that is created during the burning of the fuel.
The oxygenate MTBE has been found to have contaminated groundwater, mostly through leaks in underground gasoline storage tanks. In 2004, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
banned MTBE, generally replacing it with ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
. Several other states started switching soon afterward.
The oxygenates commonly used are either alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
s or ether
Ether
Ethers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...
s:
- Alcohols:
- MethanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
(MeOH) - EthanolEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
(EtOH) - Isopropyl alcoholIsopropyl alcoholIsopropyl alcohol is a common name for a chemical compound with the molecular formula C3H8O. It is a colorless, flammable chemical compound with a strong odor...
(IPA) - n-butanolN-Butanoln-Butanol or n-butyl alcohol or normal butanol is a primary alcohol with a 4-carbon structure and the molecular formula C4H9OH. Its isomers include isobutanol, 2-butanol, and tert-butanol...
(BuOH) - Gasoline grade t-butanolTert-Butanoltert-Butanol, or 2-methyl-2-propanol, is the simplest tertiary alcohol. It is one of the four isomers of butanol. tert-Butanol is a clear liquid with a camphor-like odor. It is very soluble in water and miscible with ethanol and diethyl ether...
(GTBA)
- Methanol
- Ethers:
- Methyl tert-butyl etherMethyl tert-butyl etherMethyl tert-butyl ether, also known as methyl tertiary butyl ether and MTBE, is an organic compound with molecular formula 3COCH3. MTBE is a volatile, flammable, and colorless liquid that is immiscible with water. It has a minty odor vaguely reminiscent of diethyl ether, leading to unpleasant taste...
(MTBE) - Tertiary amyl methyl etherTertiary amyl methyl ethertert-Amyl methyl ether is an ether used as a fuel oxygenate. It has an ethereous odor. Unlike most ethers, does not form peroxides on storage.-Uses:...
(TAME) - Tertiary hexyl methyl ether (THEME)
- Ethyl tertiary butyl etherETBEEthyl tert-butyl ether is commonly used as an oxygenate gasoline additive in the production of gasoline from crude oil. ETBE offers equal or greater air quality benefits than ethanol, while being technically and logistically less challenging...
(ETBE) - Tertiary amyl ethyl ether (TAEE)
- Diisopropyl etherDiisopropyl etherDiisopropyl ether is secondary ether that is used as a solvent. It is a colorless liquid that is slightly soluble in water, but miscible with most organic solvents...
(DIPE)
- Methyl tert-butyl ether
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, preferential regulatory and tax treatment of ethanol (and methanol) automotive fuels introduces complexities beyond the energy balance inherent in and the engineering merits of the fuels themselves. North American automakers have in 2006 and 2007 enthusiastically promoted a blend of 85% ethanol and 15% gasoline, marketed as E85
E85
E85 is an abbreviation for an ethanol fuel blend of up to 85% denatured ethanol fuel and gasoline or other hydrocarbon by volume. E85 is commonly used by flex-fuel vehicles in the US, Canada, and Europe. Some of the benefits of E85 over conventional gasoline powered vehicles include the potential...
, and their flex-fuel vehicles, e.g. GM
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...
's " Live Green, Go Yellow" campaign. The apparent motivation for this is the nature of U.S. Corporate Average Fuel Economy (CAFE)
Café
A café , also spelled cafe, in most countries refers to an establishment which focuses on serving coffee, like an American coffeehouse. In the United States, it may refer to an informal restaurant, offering a range of hot meals and made-to-order sandwiches...
standards, which give an effective 54% fuel efficiency bonus to vehicles capable of running on 85% alcohol blends over vehicles not adapted to run on 85% alcohol blends,. This regulatory artificiality is quite valuable to the North American auto manufacturers in avoiding fines for failing to meet CAFE fuel economy standards imposed upon each manufacturer's car and light truck fleets. In addition to this auto manufacturer-driven impetus for 85% alcohol blends, the United States Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
had authority to mandate that minimum proportions of oxygenates be added to automotive gasoline on regional and seasonal basis from 1992 until 2006 in an attempt to reduce air pollution, in particular ground-level ozone and smog
Smog
Smog is a type of air pollution; the word "smog" is a portmanteau of smoke and fog. Modern smog is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine...
. As a consequence, much gasoline sold in the United States is blended with up to 10% of an unspecified oxygenating agent. This product is known formally as oxygenated fuel and often (but not entirely correctly, as there are Federally-mandated reformulated gasolines without oxygenate) as reformulated gasoline. Groundwater contamination scares and the State of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
's ban of the substance as a gasoline additive has allowed ethanol to displace methyl tert(iary)-butyl ether (MTBE) as the most popular fuel oxygenate in the United States.
Many motorists in the U.S. did not welcome oxygenated gasoline because of its reduced energy density resulting in increased fuel consumption and because of fears of damage to cars, particularly to older cars. Alcohol (particularly methanol) fuel blends were expected to cause chemical damage to fuel system materials not designed to withstand exposure to alcohols, to increase water contamination due to alcohols' co-solvent properties, and via alcohols' solvent action loosening fixed fuel system deposits thus causing free-moving particulate contamination and clogging of various components. Experience with oxygenated fuels has shown little widespread deleterious mechanical effects, but oxygenated fuels have resulted in increased fuel consumption and often higher fuel prices. Although market conditions vary widely, ethanol is generally more expensive on a volumetric basis (and unquestionably more expensive on an energy content basis) than the gasoline with which it is blended. Refining and distribution complexities associated with regionally-specific oxygenated 'boutique gas' blends also has significantly raised gasoline prices in parts of the United States, particularly in California. Air pollution benefits from oxygenated fuels have thus far been difficult to quantify and to attribute to oxygenated fuel, but undoubtedly small.
The promotion of, Federal subsidy for, and high import tariffs protecting domestic production of ethanol motor fuel and the Federal mandate for oxygenated gasoline are essentially political phenomena. The principal driver in promoting E85 is the North American auto industry's need to avoid CAFE fines; in the fuel alcohol industry as a whole lobbying by American corn producers and agribusiness, in particular Archer Daniels Midland
Archer Daniels Midland
The Archer Daniels Midland Company is a conglomerate headquartered in Decatur, Illinois. ADM operates more than 270 plants worldwide, where cereal grains and oilseeds are processed into products used in food, beverage, nutraceutical, industrial and animal feed markets worldwide.ADM was named the...
, the biggest ethanol producer in the United States, has done much to get the fuel alcohol industry its present subsidized and protected status. Advocates for wheat, corn and sugar growers have succeeded in their attempts to lobby for regulatory intervention encouraging adoption of ethanol, stimulating debate over who the major beneficiaries of increased use of ethanol would be. Some researchers have warned that ethanol produced from agricultural feedstocks will cause a global food shortage, contributing to starvation in the third world.
Most forms of automobile racing that require the use of gasoline as fuel (as opposed to higher-energy blended fuels or straight alcohols) prohibit the use of oxygenate compounds in fuels, as they can allow higher fuel burn than the engine intake
Intake
An intake , or especially for aircraft inlet, is an air intake for an engine. Because the modern internal combustion engine is in essence a powerful air pump, like the exhaust system on an engine, the intake must be carefully engineered and tuned to provide the greatest efficiency and power...
restrictions are designed to permit. Prior to the 2007 Daytona 500
2007 Daytona 500
The 2007 Daytona 500 was the first race of the 2007 NASCAR NEXTEL Cup Series season, taking place on February 18, 2007 at Daytona International Speedway in Daytona Beach, Florida. Kevin Harvick won the race by .02 second over Mark Martin in the closest finish since the first race at Daytona...
, for example, NASCAR
NASCAR
The National Association for Stock Car Auto Racing is a family-owned and -operated business venture that sanctions and governs multiple auto racing sports events. It was founded by Bill France Sr. in 1947–48. As of 2009, the CEO for the company is Brian France, grandson of the late Bill France Sr...
driver Michael Waltrip
Michael Waltrip
Michael Curtis Waltrip is a semi-former professional race car driver, co-owner of Michael Waltrip Racing, and a published author. He is the younger brother of three-time NASCAR champion and racing commentator Darrell Waltrip. Waltrip is a two-time winner of the Daytona 500; having won the race in...
and his team were heavily penalized when evidence of an unspecified oxygenate compound was found in the car's intake manifold during inspections.