Tetra-ethyl lead
Encyclopedia
Tetraethyllead abbreviated TEL, is an organolead compound
with the formula (CH3CH2
)4Pb
. An inexpensive additive, its addition to gasoline
(petrol) from the 1920's allowed octane ratings and thus engine compression to be boosted significantly, increasing power and fuel economy. TEL was phased out because of the toxicity of lead
and its deleterious effect on catalytic converters. It is still used as an additive in aviation fuel
for piston engine
-powered aircraft.
, wherein it served as an effective antiknock agent
and prevented exhaust valve and seat wear.
. Once the valves would reopen, the microwelds would pull apart and leave the valves with a rough surface that would abrade the seats, leading to valve recession. When lead began to be phased out of motor fuel, the automotive industry began specifying hardened valve seats
and upgraded exhaust valve materials to prevent valve recession without lead.
to prevent uncontrolled combustion known as engine knocking
("knock" or "ping"). Antiknock agents allow the use of higher compression ratio
s for greater efficiency
and peak power
. Adding varying amounts of TEL to gasoline allowed easy, inexpensive control of octane ratings - aviation spirits used in WWII reached 150 octane to enable supercharged engines such as the Rolls-Royce Merlin
and Griffon
to produce 1500 HP at altitude. In military aviation, TEL manipulation allowed a range of different fuels to be tailored for particular flight conditions, and ease and safety of handling.
The use of TEL in gasoline started in the US, while in Europe
, alcohol
was initially used. The advantages of leaded gasoline from its higher energy content and storage quality eventually led to a universal switch to leaded fuel. One of the greatest advantages of TEL over other antiknock agents or the use of high octane blend stocks is the very low concentrations needed. Typical formulations called for 1 part of prepared TEL to 1260 parts untreated gasoline. Competing antiknock agents must be used in greater amounts, often reducing the energy content of the gasoline.
When used as an antiknock agent, alcohol
will cause fuel to absorb moisture from the air. Over time fuel humidity can rise, leading to corrosion in fuel lines. Whereas TEL is highly soluble in gasoline, ethanol is poorly soluble and that solubility decreases as fuel humidity increases. Over time, droplets and pools of water can form in the fuel system creating a risk of fuel line icing. High fuel humidity can also enable biological contamination, as certain bacteria can grow on the surface of the water/gasoline interface, forming bacterial mats in the fuel system. TEL's biocidal properties helped prevent fuel contamination and degradation from bacterial growth.
neurotoxicity of lead
. Leaded fuel also spoils catalytic converter
s, which were introduced in the 1970s to meet tightening emissions regulations. The need for TEL was lessened by several advances in automotive engineering and petroleum chemistry. Other antiknock additives of varying toxicity, such as MMT
, MTBE, and ETBE
, and safer methods for making higher octane blending stocks such as reformate and iso-octane reduced the need for TEL.
As of June 2011, unleaded automotive gasoline is available almost universally throughout the world and the only countries in which leaded gasoline is the only type available are Burma and Afghanistan
; Leaded gasoline also remains available in Algeria
, Iraq
, North Korea
, and Yemen
. Lead-replacement additives were scientifically tested and some were approved by the Federation of British Historic Vehicle Clubs at the UK's Motor Industry Research Association
in 1999. In Europe, Professor Derek Bryce-Smith
was among the first to highlight the potential dangers of TEL and became a leading campaigner for removal of lead additives from petrol. However, leaded motor fuel re-entered the UK
market in small quantities from 2000 in response to fervent lobbying from classic-car organisations who contended their vehicles would be rendered useless without leaded fuel. The lead content is up to 0.15 grams per litre and Bayford & Co are the only wholesale supplier.
Vehicles designed and built to run on leaded fuel may require modification to run on unleaded gasoline. These modifications fall into two categories: those required for physical compatibility with unleaded fuel, and those performed to compensate for the relatively low octane of early unleaded fuels. Physical compatibility requires the installation of hardened
exhaust valves and seats. Compatibility with reduced octane was addressed by reducing compression, generally by installing thicker cylinder head gaskets and/or rebuilding the engine with compression-reducing pistons. The availability of high-octane unleaded gasolines has reduced or eliminated the need to alter engines' compression ratios.
Leaded-fuel bans for road vehicles came into effect as follows:
Europe
Africa
Leaded petrol was supposed to be completely phased out continent-wide on 1 January 2006, following a ban initiated from the 2002 Earth Summit. However, leaded fuel remains available in Algeria
.
North America
South America
Asia
Oceania
switched to unleaded fuel in 2008 after years of research, spurred when blood tests of NASCAR teams revealed elevated blood lead levels. An initial test in 2005 with usually dependable motors had led to five cars retiring with engine troubles in a single race.
avgas
for piston-engine aircraft. The United States Environmental Protection Agency and others are working on an economically feasible replacement for leaded avgas. The current formulation of 100LL (low lead) aviation gasoline contains 2.12 grams of lead per gallon, half the amount of the previous 100 octane avgas (at 4.24 grams per gallon), but far more than the 0.1 gram per gallon permitted in automotive leaded gasoline or the 0.001 grams per gallon in automotive unleaded gasoline sold in the United States.
(MMT or methylcymantrene), was used for a time as an antiknock agent, though its safety is controversial and it has been the subject of bans and lawsuits. Ferrocene
, an organometallic compound of iron
, has also been reported as an effective antiknock agent.
High-percentage additives are organic compounds that do not contain metals, but they require much higher blending ratios, such as 20–30% for benzene
and ethanol. It had also been established by 1921 that ethanol
was an effective antiknock agent, but TEL was introduced instead mainly for commercial reasons. Oxygenate
s such as TAME derived from natural gas, MTBE made from methanol, and ethanol-derived ETBE
, have largely supplanted TEL. MTBE has environmental risks of its own and there are also bans on its use. ETBE, on the other hand, requires more expensive ethanol
as a starting material.
Improvements of the gasoline itself decrease the need for added antiknock agents. Synthetic iso-octane and alkylate are examples of such blending stocks. Benzene and other high-octane aromatics
can be also blended to raise the octane number, but they are disfavored today because of toxicity and carcinogenity.
with a sodium
–lead
alloy
.
Despite decades of research, no reactions were found to improve upon this rather difficult process that involves metallic sodium. The product, TEL, is a viscous
colorless liquid
. Because TEL is charge neutral and contains an exterior of alkyl groups, it is highly lipophilic and soluble in petrol (gasoline).
A process with lithium
was developed, but never put into practice. A related compound, tetramethyllead, was commercially produced by a different electrolytic reaction.
s decomposes completely into lead and lead oxides and combustible, short-lived ethyl radical
s. Lead and lead oxide scavenge radical intermediates
in combustion
reactions. This prevents ignition of unburnt fuel during the engine's exhaust stroke. Lead itself is the reactive antiknock agent, and TEL serves as a gasoline-soluble lead carrier. When (CH3CH2)4Pb burns, it produces not only carbon dioxide and water, but also lead:
This lead can oxidize further to give species such as lead(II) oxide
:
The Pb and PbO would quickly over-accumulate and destroy an engine. For this reason, the lead scavengers 1,2-dibromoethane
and 1,2-dichloroethane
are used in conjunction with TEL—these agents form volatile lead(II) bromide
and lead(II) chloride
, respectively, which are flushed from the engine and into the air.
and 1,2-dichloroethane
. Ethyl fluid also contained a reddish dye to distinguish treated from untreated gasoline and discourage the use of leaded gasoline for other purposes such as cleaning.
Ethyl fluid was added to gasoline at rate of 1:1260, usually at the refinery. Because of the widespread use and toxic nature of ethyl fluid, the Ethyl Corporation
developed an expertise in its safe handling. In the 1920s, before safety procedures were yet developed, some 17 workers for the Ethyl Corporation and Standard Oil died from the effects of exposure to lead.
The formula for ethyl fluid is:
Dibromoethane and dichloroethane act in a synergistic manner, where a particular mixing ratio provides the best lead scavenging ability.
.
Lead pollution from engine exhaust is dispersed into the air and into the vicinity of roads and easily inhaled. Lead is a toxic metal
that accumulates and has subtle and insidious neurotoxic effects especially at low exposure levels, such as low IQ and antisocial behavior. It has particularly harmful effects on children. These concerns eventually led to the ban on TEL in automobile gasoline in many countries. Some neurologists have speculated that the lead phaseout may have caused average IQ levels to rise by several points in the US (by reducing cumulative brain damage throughout the population, especially in the young). For the entire US population, during and after the TEL phaseout, the mean blood lead level dropped from 16 μg/dL in 1976 to only 3 μg/dL in 1991. The US Centers for Disease Control considered blood lead levels "elevated" when they were above 10 μg/dL. Lead exposure affects the intelligence quotient
(IQ) such that a blood lead level of 30 μg/dL is associated with a 6.9-point reduction of IQ, with most reduction (3.9 points) occurring below 10 μg/dL.
A statistically-significant correlation has been found between the usage rate of leaded gasoline and violent crime: taking into account a 22-year time lag, the violent crime curve virtually tracks the lead exposure curve. After the ban on TEL, blood lead levels in US children dramatically decreased.
Although leaded gasoline is largely gone in North America, it has left high concentrations of lead in the soil adjacent to roads that were constructed prior to its phaseout. Children are particularly at risk if they consume this.
, working under Charles Kettering
at General Motors Corporation Research. General Motors patent
ed the use of TEL as a knocking agent and called it "Ethyl" in its marketing materials, thereby avoiding the negative connotation of the word "lead". By 1923, leaded gasoline was being sold. In 1924, Standard Oil of New Jersey (ESSO/EXXON) and General Motors created the Ethyl Gasoline Corporation
to produce and market TEL.
The toxicity of concentrated TEL was recognized early on, as lead had been recognized since the 19th century as a dangerous substance which could cause lead poisoning
. In 1924, a public controversy arose over the "loony gas" which the production created after several workers died and others went insane in a refinery in New Jersey and a DuPont facility in Ohio. However, for two years prior to this controversy several public health experts including Alice Hamilton
engaged Midgley and Kettering with letters warning of the dangers to public health of the proposed plan. After the death of the workers, dozens of newspapers reported on the issue. In 1925, the sales of TEL were suspended for one year to conduct a hazard assessment.
The U.S. Public Health Service conducted a conference in 1925. The conference was initially expected to last for several days, but reportedly the conference decided that evaluating presentations on alternative anti-knock agents was not "its province" so it lasted a single day. Kettering and Midgley stated that no alternatives for anti-knocking were available, although private memos showed discussion of such agents. One commonly discussed agent was ethanol, although it was not as cheap. The Public Health Service created a committee which reviewed a government-sponsored study of workers and an Ethyl lab test, and concluded that while leaded gasoline should not be banned, it should continue to be investigated. The low concentrations present in gasoline and exhaust were not perceived as immediately dangerous. A U.S. Surgeon General committee issued a report in 1926 that concluded there was no real evidence that the sale of TEL was hazardous to human health but urged further study. In the years that followed, research was heavily funded by the lead industry; in 1943, Randolph Byers found children with lead poisoning had behavior problems, but he was threatened with a lawsuit and the research ended.
In the late 1920s, Dr. Robert Kehoe of the University of Cincinnati was the Ethyl Corporation's chief medical consultant. In 1928, Dr. Kehoe expressed the opinion that there was no basis for concluding that leaded fuels posed any health threat. He convinced the Surgeon General that the dose–response relationship of lead was "no effect" below a certain threshold. As the head of Kettering Laboratories for many years, Kehoe would become a chief promoter of the safety of TEL, an influence that did not begin to wane until about the early 1960s. But by the 1970s, the general opinion of the safety of TEL would change, and by 1976 the U.S. government would begin to require the phaseout of this product.
As early as the late 1940s and early 1950s, Clair Patterson
accidentally discovered the pollution caused by TEL in the environment while determining the age of the earth. As he attempted to measure lead content of very old rocks, and the time it took uranium to decay into lead, the readings were made inaccurate by lead in the environment that contaminated his samples. He was then forced to work in a clean room to keep his samples uncontaminated by environmental pollution of lead. After coming up with a fairly accurate estimate of the age of the earth, he turned to investigating the lead contamination problem by examining ice cores from countries such as Greenland
. He realized that the lead contamination in the environment dated from about the time that TEL became widely used as a fuel additive in gasoline. Being aware of the health dangers posed by lead and suspicious of the pollution caused by TEL, he became one of the earliest and most effective opponents of its use.
In the 1960s the first clinical works were published proving the toxicity of this compound in humans, e.g. by Mirosław Jan Stasik
.
In the 1970s Herbert Needleman
found that higher blood levels in children were correlated with decreased school performance. Needleman was repeatedly accused of scientific misconduct by individuals within the lead industry, but he was eventually cleared by a scientific advisory council.
In the U.S. in 1972, the EPA
launched an initiative to phase out leaded gasoline based on a regulation under the authority of the Clean Air Act Extension of 1970
. Ethyl Corp's response was to sue the EPA. Although the EPA's regulation was initially dismissed, the EPA won the case on appeal, so the TEL phaseout began in 1976 and was completed by 1986. A 1994 study indicated that the concentration of lead in the blood of the U.S. population had dropped 78% from 1976 to 1991.
By 2000, the TEL industry had moved the major portion of their sales to developing countries whose governments they lobbied against phasing out leaded gasoline. Leaded gasoline was withdrawn entirely from the European Union market on 1 January 2000, although it had been banned much earlier in most member states. It was phased out in China
beginning around 2001. In the United Kingdom
a small amount of leaded gasoline ("four-star petrol") is still permitted to be manufactured and sold for use in classic cars, albeit with a higher rate of fuel duty. In Australia, owners of old cars built to run on leaded petrol can buy lead additives and mix them with octane 98 fuel (premium unleaded).
by Ellery Queen
.
Organolead compound
Organolead compounds are chemical compounds containing a chemical bond between carbon and lead. Organolead chemistry is the corresponding science. The first organolead was hexaethyldilead synthesised in 1858. Sharing the same group with carbon, lead is tetravalent.Going down the carbon group the...
with the formula (CH3CH2
Ethyl group
In chemistry, an ethyl group is an alkyl substituent derived from ethane . It has the formula -C2H5 and is very often abbreviated -Et.Ethylation is the formation of a compound by introduction of the ethyl functional group, C2H5....
)4Pb
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
. An inexpensive additive, its addition to gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
(petrol) from the 1920's allowed octane ratings and thus engine compression to be boosted significantly, increasing power and fuel economy. TEL was phased out because of the toxicity of lead
Lead poisoning
Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
and its deleterious effect on catalytic converters. It is still used as an additive in aviation fuel
Avgas
Avgas is an aviation fuel used to power piston-engine aircraft. Avgas is distinguished from mogas , which is the everyday gasoline used in cars and some non-commercial light aircraft...
for piston engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
-powered aircraft.
In motor fuel
Tetraethyl lead was extensively used as an additive to gasolineGasoline 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...
, wherein it served as an effective antiknock agent
Antiknock agent
An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating.The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early causing a damaging "engine knocking" noise...
and prevented exhaust valve and seat wear.
As valve wear preventive
Tetraethyl lead works a buffer against microwelds forming between the hot exhaust valves and their seatsValve seat
The valve seat in an internal combustion gasoline or diesel engine is the surface against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed...
. Once the valves would reopen, the microwelds would pull apart and leave the valves with a rough surface that would abrade the seats, leading to valve recession. When lead began to be phased out of motor fuel, the automotive industry began specifying hardened valve seats
Valve job
A valve job is an operation which is performed on any four stroke cycle, internal combustion engine, the purpose of which is to clean up the mating surfaces of the poppet valves that control the intake and exhaust of the air/fuel mixture that powers the motion of the pistons.In the earliest...
and upgraded exhaust valve materials to prevent valve recession without lead.
As antiknock agent
An engine requires fuel of sufficient octane ratingOctane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...
to prevent uncontrolled combustion known as engine knocking
Engine knocking
Knocking in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.The...
("knock" or "ping"). Antiknock agents allow the use of higher compression ratio
Compression ratio
The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...
s for greater efficiency
Fuel efficiency
Fuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...
and peak power
Power (physics)
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
. Adding varying amounts of TEL to gasoline allowed easy, inexpensive control of octane ratings - aviation spirits used in WWII reached 150 octane to enable supercharged engines such as the Rolls-Royce Merlin
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...
and Griffon
Rolls-Royce Griffon
The Rolls-Royce Griffon is a British 37-litre capacity, 60-degree V-12, liquid-cooled aero engine designed and built by Rolls-Royce Limited...
to produce 1500 HP at altitude. In military aviation, TEL manipulation allowed a range of different fuels to be tailored for particular flight conditions, and ease and safety of handling.
The use of TEL in gasoline started in the US, while in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, 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....
was initially used. The advantages of leaded gasoline from its higher energy content and storage quality eventually led to a universal switch to leaded fuel. One of the greatest advantages of TEL over other antiknock agents or the use of high octane blend stocks is the very low concentrations needed. Typical formulations called for 1 part of prepared TEL to 1260 parts untreated gasoline. Competing antiknock agents must be used in greater amounts, often reducing the energy content of the gasoline.
When used as an antiknock agent, 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....
will cause fuel to absorb moisture from the air. Over time fuel humidity can rise, leading to corrosion in fuel lines. Whereas TEL is highly soluble in gasoline, ethanol is poorly soluble and that solubility decreases as fuel humidity increases. Over time, droplets and pools of water can form in the fuel system creating a risk of fuel line icing. High fuel humidity can also enable biological contamination, as certain bacteria can grow on the surface of the water/gasoline interface, forming bacterial mats in the fuel system. TEL's biocidal properties helped prevent fuel contamination and degradation from bacterial growth.
Phaseout and ban
In most industrialised countries, TEL was phased out of motor fuels in the late 1990s to early 2000s because of concerns over air and soil pollution (e.g., the areas around roads) and the accumulativeBioaccumulation
Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost...
neurotoxicity of lead
Lead poisoning
Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
. Leaded fuel also spoils catalytic converter
Catalytic converter
A catalytic converter is a device used to convert toxic exhaust emissions from an internal combustion engine into non-toxic substances. Inside a catalytic converter, a catalyst stimulates a chemical reaction in which noxious byproducts of combustion are converted to less toxic substances by dint...
s, which were introduced in the 1970s to meet tightening emissions regulations. The need for TEL was lessened by several advances in automotive engineering and petroleum chemistry. Other antiknock additives of varying toxicity, such as MMT
Methylcyclopentadienyl manganese tricarbonyl
Methylcyclopentadienyl manganese tricarbonyl is an organomanganese compound with the formula Mn3. Marketed initially in 1958 as a supplement to the gasoline additive tetraethyl lead to increase the fuel's octane rating, MMT was later used in unleaded gasoline...
, MTBE, and ETBE
ETBE
Ethyl 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...
, and safer methods for making higher octane blending stocks such as reformate and iso-octane reduced the need for TEL.
As of June 2011, unleaded automotive gasoline is available almost universally throughout the world and the only countries in which leaded gasoline is the only type available are Burma and Afghanistan
Afghanistan
Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...
; Leaded gasoline also remains available in Algeria
Algeria
Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...
, Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
, North Korea
North Korea
The Democratic People’s Republic of Korea , , is a country in East Asia, occupying the northern half of the Korean Peninsula. Its capital and largest city is Pyongyang. The Korean Demilitarized Zone serves as the buffer zone between North Korea and South Korea...
, and Yemen
Yemen
The Republic of Yemen , commonly known as Yemen , is a country located in the Middle East, occupying the southwestern to southern end of the Arabian Peninsula. It is bordered by Saudi Arabia to the north, the Red Sea to the west, and Oman to the east....
. Lead-replacement additives were scientifically tested and some were approved by the Federation of British Historic Vehicle Clubs at the UK's Motor Industry Research Association
MIRA
MIRA may refer to:* Margin Infused Relaxed Algorithm* Movement for Islamic Reform in Arabia* Monterey Institute for Research in Astronomy* Movimiento Independiente de Renovación Absoluta* Motor Industry Research Association...
in 1999. In Europe, Professor Derek Bryce-Smith
Derek Bryce-Smith
Derek Bryce-Smith was a chemist at the University of Reading. His work included organometallic chemistry, radical chemistry and photochemistry. He was among the first to describe the dangers of tetraethyl lead, which was used for several decades as an anti-knock additive in petrol. Initially, his...
was among the first to highlight the potential dangers of TEL and became a leading campaigner for removal of lead additives from petrol. However, leaded motor fuel re-entered the UK
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
market in small quantities from 2000 in response to fervent lobbying from classic-car organisations who contended their vehicles would be rendered useless without leaded fuel. The lead content is up to 0.15 grams per litre and Bayford & Co are the only wholesale supplier.
Vehicles designed and built to run on leaded fuel may require modification to run on unleaded gasoline. These modifications fall into two categories: those required for physical compatibility with unleaded fuel, and those performed to compensate for the relatively low octane of early unleaded fuels. Physical compatibility requires the installation of hardened
Hardening (metallurgy)
Hardening is a metallurgical and metalworking process used to increase the hardness of a metal. The hardness of a metal is directly proportional to the uniaxial yield stress at the location of the imposed strain...
exhaust valves and seats. Compatibility with reduced octane was addressed by reducing compression, generally by installing thicker cylinder head gaskets and/or rebuilding the engine with compression-reducing pistons. The availability of high-octane unleaded gasolines has reduced or eliminated the need to alter engines' compression ratios.
Leaded-fuel bans for road vehicles came into effect as follows:
Europe
- Austria: 1989
- Serbia: 2010
- Bosnia and Herzegovina: 2009
- E.U.European UnionThe European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
: 1 January 2000 - Iceland:
- Monaco: 2000
- Norway:
- Switzerland: 2000
- Poland: 2005
Africa
Leaded petrol was supposed to be completely phased out continent-wide on 1 January 2006, following a ban initiated from the 2002 Earth Summit. However, leaded fuel remains available in Algeria
Algeria
Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...
.
North America
- Canada: 1993
- California: 1992
- USA: 1995
- Bahamas:
- Belize:
- Bermuda:
- Costa Rica:
- Dominican Republic:
- El Salvador:
- Guatemala:
- Haiti:
- Honduras:
- Mexico:
- Nicaragua:
- Puerto Rico:
- Trinidad and Tobago: 2000
South America
- Argentina:
- Bolivia:
- Brazil: 1989
- Chile:
- Colombia:
Asia
- Japan: 1986
- Hong Kong: 1999
- Malaysia:
- Singapore: 1998
- South Korea: 1993
- Sri Lanka: 1999
- Thailand:
- Bangladesh:
- Taiwan: 2000
- China: 2000
- Philippines: 2000
- India: 2000
- Nepal: 2000
- Indonesia: 2006
Oceania
- Australia: 2002
- New Zealand: 1996
- Guam:
In race vehicles
Until recently, leaded fuel was used in professional auto racing. NASCARNASCAR
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...
switched to unleaded fuel in 2008 after years of research, spurred when blood tests of NASCAR teams revealed elevated blood lead levels. An initial test in 2005 with usually dependable motors had led to five cars retiring with engine troubles in a single race.
In aviation fuel
TEL remains an ingredient of 100 octaneOctane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...
avgas
Avgas
Avgas is an aviation fuel used to power piston-engine aircraft. Avgas is distinguished from mogas , which is the everyday gasoline used in cars and some non-commercial light aircraft...
for piston-engine aircraft. The United States Environmental Protection Agency and others are working on an economically feasible replacement for leaded avgas. The current formulation of 100LL (low lead) aviation gasoline contains 2.12 grams of lead per gallon, half the amount of the previous 100 octane avgas (at 4.24 grams per gallon), but far more than the 0.1 gram per gallon permitted in automotive leaded gasoline or the 0.001 grams per gallon in automotive unleaded gasoline sold in the United States.
Alternative antiknock agents
Antiknock agents are classed as "high-percentage" additives, such as alcohol, and "low-percentage" additives based on heavy elements. Since the main problem with TEL is its lead content, many alternative additives that contain less poisonous metals have been examined. A manganese-carrying additive, methylcyclopentadienyl manganese tricarbonylMethylcyclopentadienyl manganese tricarbonyl
Methylcyclopentadienyl manganese tricarbonyl is an organomanganese compound with the formula Mn3. Marketed initially in 1958 as a supplement to the gasoline additive tetraethyl lead to increase the fuel's octane rating, MMT was later used in unleaded gasoline...
(MMT or methylcymantrene), was used for a time as an antiknock agent, though its safety is controversial and it has been the subject of bans and lawsuits. Ferrocene
Ferrocene
Ferrocene is an organometallic compound with the formula Fe2. It is the prototypical metallocene, a type of organometallic chemical compound consisting of two cyclopentadienyl rings bound on opposite sides of a central metal atom. Such organometallic compounds are also known as sandwich compounds...
, an organometallic compound of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, has also been reported as an effective antiknock agent.
High-percentage additives are organic compounds that do not contain metals, but they require much higher blending ratios, such as 20–30% for benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
and ethanol. It had also been established by 1921 that 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...
was an effective antiknock agent, but TEL was introduced instead mainly for commercial reasons. Oxygenate
Oxygenate
Oxygenated chemical compounds contain oxygen as a part of their chemical structure. The term usually refers to oxygenated fuels. Oxygenates are usually employed as gasoline additives to reduce carbon monoxide that is created during the burning of the fuel....
s such as TAME derived from natural gas, MTBE made from methanol, and ethanol-derived ETBE
ETBE
Ethyl 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...
, have largely supplanted TEL. MTBE has environmental risks of its own and there are also bans on its use. ETBE, on the other hand, requires more expensive 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...
as a starting material.
Improvements of the gasoline itself decrease the need for added antiknock agents. Synthetic iso-octane and alkylate are examples of such blending stocks. Benzene and other high-octane aromatics
Aromatic hydrocarbon
An aromatic hydrocarbon or arene is a hydrocarbon with alternating double and single bonds between carbon atoms. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent...
can be also blended to raise the octane number, but they are disfavored today because of toxicity and carcinogenity.
Synthesis and properties
TEL is produced by reacting chloroethaneChloroethane
Chloroethane or monochloroethane, commonly known by its old name ethyl chloride, is a chemical compound with chemical formula , once widely used in producing tetraethyllead, a gasoline additive...
with a sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
–lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
.
- 4 NaPb + 4 CH3CH2Cl → (CH3CH2)4Pb + 4 NaCl + 3 Pb
Despite decades of research, no reactions were found to improve upon this rather difficult process that involves metallic sodium. The product, TEL, is a viscous
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
colorless liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
. Because TEL is charge neutral and contains an exterior of alkyl groups, it is highly lipophilic and soluble in petrol (gasoline).
A process with lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
was developed, but never put into practice. A related compound, tetramethyllead, was commercially produced by a different electrolytic reaction.
Reactions
A noteworthy feature of TEL is the weakness of its four C–Pb bonds. At the temperatures found in internal combustion engineInternal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
s decomposes completely into lead and lead oxides and combustible, short-lived ethyl radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
s. Lead and lead oxide scavenge radical intermediates
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
in combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
reactions. This prevents ignition of unburnt fuel during the engine's exhaust stroke. Lead itself is the reactive antiknock agent, and TEL serves as a gasoline-soluble lead carrier. When (CH3CH2)4Pb burns, it produces not only carbon dioxide and water, but also lead:
- (CH3CH2)4Pb + 13 O2 → 8 CO2 + 10 H2O + Pb
This lead can oxidize further to give species such as lead(II) oxide
Lead(II) oxide
Lead oxide is the inorganic compound with the formula PbO. Lead oxide occurs in two polymorphs, red, having a tetragonal crystal structure and yellow, having an orthorhombic crystal structure...
:
- 2 Pb + O2 → 2 PbO
The Pb and PbO would quickly over-accumulate and destroy an engine. For this reason, the lead scavengers 1,2-dibromoethane
1,2-Dibromoethane
1,2-Dibromoethane, also known as ethylene dibromide , is the chemical compound with the formula BrCH2CH2Br. Although trace amounts occur naturally in the ocean, where it is formed probably by algae and kelp, it is mainly a synthetic...
and 1,2-dichloroethane
1,2-Dichloroethane
The chemical compound 1,2-dichloroethane, commonly known by its old name of ethylene dichloride , is a chlorinated hydrocarbon, mainly used to produce vinyl chloride monomer , the major precursor for PVC production. It is a colourless liquid with a chloroform-like odour...
are used in conjunction with TEL—these agents form volatile lead(II) bromide
Lead(II) bromide
Lead bromide is the stable salt of lead and hydrobromic acid. It is typically formed by precipitation from lead nitrate by the addition of a water-soluble bromide. As a chemical compound containing lead, it is categorized as probably carcinogenic to humans , by the International Agency for Research...
and lead(II) chloride
Lead(II) chloride
Lead chloride is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead chloride is one of the most important lead-based reagents...
, respectively, which are flushed from the engine and into the air.
Formulation of ethyl fluid
TEL was supplied for mixing with raw gasoline in the form of ethyl fluid, which was TEL blended together with the lead scavengers 1,2-dibromoethane1,2-Dibromoethane
1,2-Dibromoethane, also known as ethylene dibromide , is the chemical compound with the formula BrCH2CH2Br. Although trace amounts occur naturally in the ocean, where it is formed probably by algae and kelp, it is mainly a synthetic...
and 1,2-dichloroethane
1,2-Dichloroethane
The chemical compound 1,2-dichloroethane, commonly known by its old name of ethylene dichloride , is a chlorinated hydrocarbon, mainly used to produce vinyl chloride monomer , the major precursor for PVC production. It is a colourless liquid with a chloroform-like odour...
. Ethyl fluid also contained a reddish dye to distinguish treated from untreated gasoline and discourage the use of leaded gasoline for other purposes such as cleaning.
Ethyl fluid was added to gasoline at rate of 1:1260, usually at the refinery. Because of the widespread use and toxic nature of ethyl fluid, the Ethyl Corporation
Ethyl Corporation
Ethyl Corporation is a fuel additive company headquartered in Richmond, Virginia. The company is a manufacturer, blender and distributor of fuel additives...
developed an expertise in its safe handling. In the 1920s, before safety procedures were yet developed, some 17 workers for the Ethyl Corporation and Standard Oil died from the effects of exposure to lead.
The formula for ethyl fluid is:
- Tetraethyllead 61.45%
- 1,2-Dibromoethane1,2-Dibromoethane1,2-Dibromoethane, also known as ethylene dibromide , is the chemical compound with the formula BrCH2CH2Br. Although trace amounts occur naturally in the ocean, where it is formed probably by algae and kelp, it is mainly a synthetic...
17.85% - 1,2-Dichloroethane1,2-DichloroethaneThe chemical compound 1,2-dichloroethane, commonly known by its old name of ethylene dichloride , is a chlorinated hydrocarbon, mainly used to produce vinyl chloride monomer , the major precursor for PVC production. It is a colourless liquid with a chloroform-like odour...
18.80% - Inerts & dye 1.90%
Dibromoethane and dichloroethane act in a synergistic manner, where a particular mixing ratio provides the best lead scavenging ability.
Toxicity
Contact with concentrated TEL leads to the familiar symptoms of acute lead poisoningLead poisoning
Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
.
Lead pollution from engine exhaust is dispersed into the air and into the vicinity of roads and easily inhaled. Lead is a toxic metal
Toxic metal
Toxic metals are metals that form poisonous soluble compounds and have no biological role, i.e. are not essential minerals, or are in the wrong form. Often heavy metals are thought as synonymous, but lighter metals also have toxicity, such as beryllium, and not all heavy metals are particularly...
that accumulates and has subtle and insidious neurotoxic effects especially at low exposure levels, such as low IQ and antisocial behavior. It has particularly harmful effects on children. These concerns eventually led to the ban on TEL in automobile gasoline in many countries. Some neurologists have speculated that the lead phaseout may have caused average IQ levels to rise by several points in the US (by reducing cumulative brain damage throughout the population, especially in the young). For the entire US population, during and after the TEL phaseout, the mean blood lead level dropped from 16 μg/dL in 1976 to only 3 μg/dL in 1991. The US Centers for Disease Control considered blood lead levels "elevated" when they were above 10 μg/dL. Lead exposure affects the intelligence quotient
Intelligence quotient
An intelligence quotient, or IQ, is a score derived from one of several different standardized tests designed to assess intelligence. When modern IQ tests are constructed, the mean score within an age group is set to 100 and the standard deviation to 15...
(IQ) such that a blood lead level of 30 μg/dL is associated with a 6.9-point reduction of IQ, with most reduction (3.9 points) occurring below 10 μg/dL.
A statistically-significant correlation has been found between the usage rate of leaded gasoline and violent crime: taking into account a 22-year time lag, the violent crime curve virtually tracks the lead exposure curve. After the ban on TEL, blood lead levels in US children dramatically decreased.
Although leaded gasoline is largely gone in North America, it has left high concentrations of lead in the soil adjacent to roads that were constructed prior to its phaseout. Children are particularly at risk if they consume this.
History
Tetraethyllead was first discovered by a German chemist in 1854, but remained commercially unused for many years. In 1921, TEL was found to be an effective antiknock agent by Thomas MidgleyThomas Midgley, Jr.
Thomas Midgley, Jr. was an American mechanical engineer and chemist. Midgley was a key figure in a team of chemists, led by Charles F. Kettering, that developed the tetraethyllead additive to gasoline as well as some of the first chlorofluorocarbons . Over the course of his career, Midgley was...
, working under Charles Kettering
Charles Kettering
Charles Franklin Kettering was an American inventor, engineer, businessman, and the holder of 186 patents. He was a founder of Delco, and was head of research for General Motors for 27 years from 1920 to 1947. Among his most widely used automotive inventions were the electrical starting motor and...
at General Motors Corporation Research. General Motors patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
ed the use of TEL as a knocking agent and called it "Ethyl" in its marketing materials, thereby avoiding the negative connotation of the word "lead". By 1923, leaded gasoline was being sold. In 1924, Standard Oil of New Jersey (ESSO/EXXON) and General Motors created the Ethyl Gasoline Corporation
Ethyl Corporation
Ethyl Corporation is a fuel additive company headquartered in Richmond, Virginia. The company is a manufacturer, blender and distributor of fuel additives...
to produce and market TEL.
The toxicity of concentrated TEL was recognized early on, as lead had been recognized since the 19th century as a dangerous substance which could cause lead poisoning
Lead poisoning
Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
. In 1924, a public controversy arose over the "loony gas" which the production created after several workers died and others went insane in a refinery in New Jersey and a DuPont facility in Ohio. However, for two years prior to this controversy several public health experts including Alice Hamilton
Alice Hamilton
Alice Hamilton was the first woman appointed to the faculty of Harvard University and was a leading expert in the field of occupational health...
engaged Midgley and Kettering with letters warning of the dangers to public health of the proposed plan. After the death of the workers, dozens of newspapers reported on the issue. In 1925, the sales of TEL were suspended for one year to conduct a hazard assessment.
The U.S. Public Health Service conducted a conference in 1925. The conference was initially expected to last for several days, but reportedly the conference decided that evaluating presentations on alternative anti-knock agents was not "its province" so it lasted a single day. Kettering and Midgley stated that no alternatives for anti-knocking were available, although private memos showed discussion of such agents. One commonly discussed agent was ethanol, although it was not as cheap. The Public Health Service created a committee which reviewed a government-sponsored study of workers and an Ethyl lab test, and concluded that while leaded gasoline should not be banned, it should continue to be investigated. The low concentrations present in gasoline and exhaust were not perceived as immediately dangerous. A U.S. Surgeon General committee issued a report in 1926 that concluded there was no real evidence that the sale of TEL was hazardous to human health but urged further study. In the years that followed, research was heavily funded by the lead industry; in 1943, Randolph Byers found children with lead poisoning had behavior problems, but he was threatened with a lawsuit and the research ended.
In the late 1920s, Dr. Robert Kehoe of the University of Cincinnati was the Ethyl Corporation's chief medical consultant. In 1928, Dr. Kehoe expressed the opinion that there was no basis for concluding that leaded fuels posed any health threat. He convinced the Surgeon General that the dose–response relationship of lead was "no effect" below a certain threshold. As the head of Kettering Laboratories for many years, Kehoe would become a chief promoter of the safety of TEL, an influence that did not begin to wane until about the early 1960s. But by the 1970s, the general opinion of the safety of TEL would change, and by 1976 the U.S. government would begin to require the phaseout of this product.
As early as the late 1940s and early 1950s, Clair Patterson
Clair Cameron Patterson
Clair Cameron Patterson was a geochemist born in Mitchellville, Iowa, United States. He graduated from Grinnell College in Grinnell, Iowa, received his Ph.D...
accidentally discovered the pollution caused by TEL in the environment while determining the age of the earth. As he attempted to measure lead content of very old rocks, and the time it took uranium to decay into lead, the readings were made inaccurate by lead in the environment that contaminated his samples. He was then forced to work in a clean room to keep his samples uncontaminated by environmental pollution of lead. After coming up with a fairly accurate estimate of the age of the earth, he turned to investigating the lead contamination problem by examining ice cores from countries such as Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
. He realized that the lead contamination in the environment dated from about the time that TEL became widely used as a fuel additive in gasoline. Being aware of the health dangers posed by lead and suspicious of the pollution caused by TEL, he became one of the earliest and most effective opponents of its use.
In the 1960s the first clinical works were published proving the toxicity of this compound in humans, e.g. by Mirosław Jan Stasik
Mirosław Jan Stasik
Mirosław Jan Stasik - Polish medical doctor and toxicologist.- Education and early career :Stasik graduated from Łódź School of Medicine and later studied toxicology at the University of Surrey, United Kingdom. He obtained his Dr Med...
.
In the 1970s Herbert Needleman
Herbert Needleman
Herbert Needleman, MD, known for research studies on the neurodevelopmental damage caused by lead poisoning, is a pediatrician, child psychiatrist, researcher and professor at the University of Pittsburgh Medical Center, an elected member of the Institute of Medicine, and the founder of the...
found that higher blood levels in children were correlated with decreased school performance. Needleman was repeatedly accused of scientific misconduct by individuals within the lead industry, but he was eventually cleared by a scientific advisory council.
In the U.S. in 1972, the EPA
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...
launched an initiative to phase out leaded gasoline based on a regulation under the authority of the Clean Air Act Extension of 1970
Clean Air Act (United States)
The Clean Air Act is a United States federal law enacted by Congress, and signed by President Richard Nixon on December 31, 1970 to control air pollution on a national level. It requires the Environmental Protection Agency to develop and enforce regulations to protect the general public from...
. Ethyl Corp's response was to sue the EPA. Although the EPA's regulation was initially dismissed, the EPA won the case on appeal, so the TEL phaseout began in 1976 and was completed by 1986. A 1994 study indicated that the concentration of lead in the blood of the U.S. population had dropped 78% from 1976 to 1991.
By 2000, the TEL industry had moved the major portion of their sales to developing countries whose governments they lobbied against phasing out leaded gasoline. Leaded gasoline was withdrawn entirely from the European Union market on 1 January 2000, although it had been banned much earlier in most member states. It was phased out in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
beginning around 2001. In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
a small amount of leaded gasoline ("four-star petrol") is still permitted to be manufactured and sold for use in classic cars, albeit with a higher rate of fuel duty. In Australia, owners of old cars built to run on leaded petrol can buy lead additives and mix them with octane 98 fuel (premium unleaded).
In literature
The effects of tetraethyllead are described in The Roman Hat MysteryThe Roman Hat Mystery
The Roman Hat Mystery is a novel that was written in 1929 by Ellery Queen. It is the first of the Ellery Queen mysteries.-Plot summary:The novel deals with the poisoning of a disreputable lawyer named Monte Field in the Roman Theater in New York City during a performance of a play called "Gunplay!"...
by Ellery Queen
Ellery Queen
Ellery Queen is both a fictional character and a pseudonym used by two American cousins from Brooklyn, New York: Daniel Nathan, alias Frederic Dannay and Manford Lepofsky, alias Manfred Bennington Lee , to write, edit, and anthologize detective fiction.The fictional Ellery Queen created by...
.
See also
- LeadLeadLead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
- Lead poisoningLead poisoningLead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
- Elmer Keiser Bolton
- Ethyl CorporationEthyl CorporationEthyl Corporation is a fuel additive company headquartered in Richmond, Virginia. The company is a manufacturer, blender and distributor of fuel additives...
- Organolead chemistry
External links
- U.S. Gov't, Agency for Toxic Substances and Disease Registry. Case Studies in Environmental Medicine (CSEM): Lead Toxicity
- U.S. Gov't, Agency for Toxic Substances and Disease Registry. ToxFAQs: Lead
- Australian Government, National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
- Kovarik, Bill (1999). Charles F. Kettering and the 1921 Discovery of Tetraethyl Lead
- True unleaded alternative for 100LL needed for general aviation