Nitroglycerin (NG), (alternative spelling of nitroglycerine) also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily,
explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...
liquid most commonly produced by
nitrating glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
with
white fuming nitric acid under conditions appropriate to the formation of the nitric acid
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...
. Chemically, the substance is an
organic nitrate compound rather than a
nitro compound, but the traditional name is retained. Invented in 1847 by
Ascanio Sobrero
Ascanio Sobrero (12 October 1812 – 26 May 1888) was an Italian chemist, born in Casale Monferrato. He was studying under Théophile-Jules Pelouze at the University of Turin, who had worked with the explosive material guncotton.
He studied med ...
, nitroglycerin has been used ever since as an active ingredient in the manufacture of
explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...
s, namely
dynamite, and as such it is employed in the
construction
Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and ...
,
demolition, and
mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econom ...
industries. Since the 1880s, it has been used by militaries as an active ingredient and gelatinizer for
nitrocellulose
Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...
in some solid
propellants such as
cordite and
ballistite
Ballistite is a smokeless propellant made from two high explosives, nitrocellulose and nitroglycerine. It was developed and patented by Alfred Nobel in the late 19th century.
Military adoption
Alfred Nobel patented https://www.nobelprize.org/alfr ...
. It is a major component in double-based
smokeless propellants used by
reloaders. Combined with
nitrocellulose
Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...
, hundreds of powder combinations are used by rifle, pistol, and shotgun reloaders.
Nitroglycerin has been used for over 130 years
in medicine as a potent
vasodilator (dilation of the vascular system) to treat
heart
The heart is a muscular Organ (biology), organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as ca ...
conditions, such as
angina pectoris and
chronic heart failure. Though it was previously known that these beneficial effects are due to nitroglycerin being converted to
nitric oxide
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its ...
, a potent venodilator, the enzyme for this conversion was only discovered to be mitochondrial
aldehyde dehydrogenase (
ALDH2) in 2002.
Nitroglycerin is available in
sublingual tablets, sprays, ointments, and patches.
History
Nitroglycerin was the first practical explosive produced that was stronger than
black powder
Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). T ...
. It was first synthesized by the Italian
chemist
A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...
Ascanio Sobrero
Ascanio Sobrero (12 October 1812 – 26 May 1888) was an Italian chemist, born in Casale Monferrato. He was studying under Théophile-Jules Pelouze at the University of Turin, who had worked with the explosive material guncotton.
He studied med ...
in 1847, working under
Théophile-Jules Pelouze at the
University of Turin
The University of Turin (Italian language, Italian: ''Università degli Studi di Torino'', UNITO) is a public university, public research university in the city of Turin, in the Piedmont (Italy), Piedmont region of Italy. It is one of the List ...
. Sobrero initially called his discovery ''pyroglycerine'' and warned vigorously against its use as an explosive.
Nitroglycerin was later adopted as a commercially useful explosive by
Alfred Nobel, who experimented with safer ways to handle the dangerous compound after his younger brother,
Emil Oskar Nobel, and several factory workers were killed in an explosion at the Nobels' armaments factory in 1864 in
Heleneborg, Sweden.
One year later, Nobel founded
Alfred Nobel and Company in Germany and built an isolated factory in the Krümmel hills of
Geesthacht near
Hamburg
Hamburg (, ; nds, label=Hamburg German, Low Saxon, Hamborg ), officially the Free and Hanseatic City of Hamburg (german: Freie und Hansestadt Hamburg; nds, label=Low Saxon, Friee un Hansestadt Hamborg),. is the List of cities in Germany by popul ...
. This business exported a liquid combination of nitroglycerin and
gunpowder
Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). T ...
called "Blasting Oil", but this was extremely unstable and difficult to handle, as evidenced in numerous catastrophes. The buildings of the Krümmel factory were destroyed twice.
In April 1866, three crates of nitroglycerin were shipped to
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
for the
Central Pacific Railroad
The Central Pacific Railroad (CPRR) was a rail company chartered by U.S. Congress in 1862 to build a railroad eastwards from Sacramento, California, to complete the western part of the " First transcontinental railroad" in North America. Incor ...
, which planned to experiment with it as a blasting explosive to expedite the construction of the
Summit Tunnel through the
Sierra Nevada Mountains. One of the crates exploded, destroying a
Wells Fargo
Wells Fargo & Company is an American multinational financial services company with corporate headquarters in San Francisco, California; operational headquarters in Manhattan; and managerial offices throughout the United States and intern ...
company office in
San Francisco
San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17t ...
and killing 15 people. This led to a complete ban on the transportation of liquid nitroglycerin in California. The on-site manufacture of nitroglycerin was thus required for the remaining hard-rock
drilling and blasting required for the completion of the
First transcontinental railroad in
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...
.
In June 1869, two one-ton wagons loaded with nitroglycerin, then known locally as Powder-Oil, exploded in the road at the North Wales village of
Cwm-y-glo
Cwm-y-glo is a small village in Wales, east of Caernarfon, between Llanberis and Llanrug. It is in the Arfon Parliamentary constituency, the community of Llanrug, and the Gwynedd Council electoral ward. Cwm-y-glo ward includes Ceunant and ...
. The explosion led to the loss of six lives, many injuries and much damage to the village. Little trace was found of the two horses. The UK Government was so alarmed at the damage caused and what could have happened in a city location (these two tons were part of a larger load coming from Germany via Liverpool) that they soon passed The Nitro-Glycerine Act of 1869. Liquid nitroglycerin was widely banned elsewhere, as well, and these legal restrictions led to Alfred Nobel and his company's developing
dynamite in 1867. This was made by mixing nitroglycerin with
diatomaceous earth
Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to l ...
("''Kieselguhr''" in German) found in the Krümmel hills. Similar mixtures, such as "dualine" (1867), "lithofracteur" (1869), and "
gelignite
Gelignite (), also known as blasting gelatin or simply "jelly", is an explosive material consisting of collodion- cotton (a type of nitrocellulose or guncotton) dissolved in either nitroglycerine or nitroglycol and mixed with wood pulp and saltp ...
" (1875), were formed by mixing nitroglycerin with other inert absorbents, and many combinations were tried by other companies in attempts to get around Nobel's tightly held patents for dynamite.
Dynamite mixtures containing
nitrocellulose
Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...
, which increases the viscosity of the mix, are commonly known as "gelatins".
Following the discovery that
amyl nitrite helped alleviate chest pain, the physician
William Murrell experimented with the use of nitroglycerin to alleviate angina pectoris and to reduce the
blood pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure ...
. He began treating his patients with small diluted doses of nitroglycerin in 1878, and this treatment was soon adopted into widespread use after Murrell published his results in the journal ''
The Lancet
''The Lancet'' is a weekly peer-reviewed general medical journal and one of the oldest of its kind. It is also the world's highest-impact academic journal. It was founded in England in 1823.
The journal publishes original research articles ...
'' in 1879.
A few months before his death in 1896, Alfred Nobel was prescribed nitroglycerin for this heart condition, writing to a friend: "Isn't it the irony of fate that I have been prescribed nitro-glycerin, to be taken internally! They call it Trinitrin, so as not to scare the chemist and the public." The medical establishment also used the name "glyceryl trinitrate" for the same reason.
Wartime production rates
Large quantities of nitroglycerin were manufactured during
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...
and
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
for use as military propellants and in
military engineering work. During World War I,
HM Factory, Gretna, the largest propellant factory in the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...
, produced about 800
tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
s of cordite RDB per week. This amount required at least 336 tonnes of nitroglycerin per week (assuming no losses in production). The
Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against Fr ...
had its own factory at the
Royal Navy Cordite Factory, Holton Heath
The Royal Naval Cordite Factory, Holton Heath (RNCF) was set up at Holton Heath, Dorset, England, in World War I to manufacture cordite for the Royal Navy. It was reactivated in World War II to manufacture gun propellants for the Admiralty and ...
, in
Dorset
Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset. Covering an area of , ...
, England. A large cordite factory was also built in Canada during World War I. The
Canadian Explosives Limited cordite factory at
Nobel, Ontario, was designed to produce of cordite per month, requiring about 286 tonnes of nitroglycerin per month.
Instability and desensitization
In its undiluted form, nitroglycerin is a
contact explosive, with physical shock causing it to explode. If it has not been adequately purified during manufacture it can degrade over time to even more unstable forms. This makes nitroglycerin highly dangerous to transport or use. In its undiluted form, it is one of the world's most powerful explosives, comparable to the more recently developed
RDX and
PETN.
Early in its history, liquid nitroglycerin was found to be "
desensitized" by freezing it at a temperature below depending on its purity.
Its sensitivity to shock while frozen is somewhat unpredictable: "It is more insensitive to the shock from a
fulminate cap or a rifle ball when in that condition but on the other hand it appears to be more liable to explode on breaking, crushing, tamping, etc."
Frozen nitroglycerine is much less energetic than liquid, and so must be thawed before use.
Thawing it out can be extremely sensitizing, especially if impurities are present or the warming is too rapid.
Ethylene glycol dinitrate
Ethylene glycol dinitrate, abbreviated EGDN and NGC, also known as Nitroglycol, is a colorless, oily, explosive liquid obtained by nitrating ethylene glycol. It is similar to nitroglycerine in both manufacture and properties, though it is more vo ...
or another polynitrate may be added to lower the melting point and thereby avoid the necessity of thawing frozen explosive.
Chemically "desensitizing" nitroglycerin is possible to a point where it can be considered about as "safe" as modern
high explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ...
s, such as by the addition of
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
,
acetone
Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour.
Acetone is miscibl ...
, or
dinitrotoluene Dinitrotoluenes could refer to one of the following compounds:
* 2,3-Dinitrotoluene
* 2,4-Dinitrotoluene
2,4-Dinitrotoluene (DNT) or dinitro is an organic compound with the formula C7H6N2O4. This pale yellow crystalline solid is well known as a ...
.
The nitroglycerin may have to be extracted from the desensitizer chemical to restore its effectiveness before use, for example by adding water to draw off ethanol used as a desensitizer.
Detonation
Nitroglycerin and any diluents can
deflagrate
Deflagration (Lat: ''de + flagrare'', "to burn down") is subsonic combustion in which a pre-mixed flame propagates through a mixture of fuel and oxidizer. Deflagrations can only occur in pre-mixed fuels. Most fires found in daily life are diff ...
(burn). The explosive power of nitroglycerin derives from
detonation: energy from the initial decomposition causes a strong pressure wave that detonates the surrounding fuel. This is a self-sustained
shock wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...
that propagates through the explosive medium at 30 times the speed of sound as a near-instantaneous pressure-induced decomposition of the fuel into a white-hot gas. Detonation of nitroglycerin generates gases that would occupy more than 1,200 times the original volume at ordinary room temperature and pressure. The heat liberated raises the temperature to about .
This is entirely different from
deflagration, which depends solely upon available fuel regardless of pressure or shock. The decomposition results in a much higher ratio of energy to gas moles released compared to other explosives, making it one of the hottest detonating
high explosives.
Manufacturing
Nitroglycerin can be produced by acid-catalyzed nitration of
glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
(glycerin).
The industrial manufacturing process often reacts
glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
with a nearly 1:1 mixture of concentrated
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...
and concentrated
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
. This can be produced by mixing
white fuming nitric acid—a quite expensive pure
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
in which the oxides of nitrogen have been removed, as opposed to
red fuming nitric acid, which contains
nitrogen oxides—and concentrated
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...
. More often, this mixture is attained by the cheaper method of mixing fuming
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...
, also known as
oleum
Oleum (Latin ''oleum'', meaning oil), or fuming sulfuric acid, is a term referring to solutions of various compositions of sulfur trioxide in sulfuric acid, or sometimes more specifically to disulfuric acid (also known as pyrosulfuric acid). Ol ...
—
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...
containing excess
sulfur trioxide
Sulfur trioxide (alternative spelling sulphur trioxide, also known as ''nisso sulfan'') is the chemical compound with the formula SO3. It has been described as "unquestionably the most important economically" sulfur oxide. It is prepared on an ind ...
—and
azeotropic nitric acid (consisting of about 70%
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
, with the rest being water).
The
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...
produces
protonated nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
species, which are attacked by
glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
's
nucleophilic oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...
atoms. The
nitro
Nitro may refer to:
Chemistry
*Nitrogen, a chemical element and a gas except at very low temperatures, with which many compounds are formed:
**Nitro compound, an organic compound containing one or more nitro functional groups, -NO2
**Nitroalkene, ...
group is thus added as an ester C−O−NO
2 and water is produced. This is different from an electrophilic aromatic substitution reaction in which
nitronium ions are the
electrophile.
The addition of
glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
results in an
exothermic reaction (i.e., heat is produced), as usual for mixed-acid nitrations. If the mixture becomes too hot, it results in a runaway reaction, a state of accelerated nitration accompanied by the destructive
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or ...
of organic materials by the hot
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
and the release of poisonous
nitrogen dioxide gas at high risk of an explosion. Thus, the
glycerin mixture is added slowly to the reaction vessel containing the mixed acid (not acid to glycerin). The nitrator is cooled with cold water or some other coolant mixture and maintained throughout the
glycerin addition at about , hot enough for esterification to occur at a fast rate but cold enough to avoid runaway reaction. The nitrator vessel, often constructed of
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...
or
lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...
and generally stirred with
compressed air, has an emergency trap door at its base, which hangs over a large pool of very cold water and into which the whole reaction mixture (called the charge) can be dumped to prevent an explosion, a process referred to as drowning. If the temperature of the charge exceeds about (actual value varying by country) or brown fumes are seen in the nitrator's vent, then it is immediately drowned.
Use as an explosive and a propellant
The main use of nitroglycerin, by tonnage, is in explosives such as dynamite and in propellants.
Nitroglycerin is an oily liquid that may explode when subjected to heat, shock, or flame.
Alfred Nobel developed the use of nitroglycerin as a blasting explosive by mixing nitroglycerin with inert
absorbents, particularly "''Kieselgur''", or
diatomaceous earth
Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to l ...
. He named this explosive
dynamite and
patented it in 1867. It was supplied ready for use in the form of sticks, individually wrapped in greased waterproof paper. Dynamite and similar explosives were widely adopted for
civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewa ...
tasks, such as in drilling
highway
A highway is any public or private road or other public way on land. It is used for major roads, but also includes other public roads and public tracks. In some areas of the United States, it is used as an equivalent term to controlled-access ...
and
railroad
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a prep ...
tunnels, for
mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econom ...
, for clearing farmland of stumps, in
quarrying, and in
demolition work. Likewise,
military engineers have used dynamite for construction and demolition work.
Nitroglycerin was also used as an ingredient in military propellants for use in
firearms
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions).
The first firearms originated in 10th-century China, when bamboo tubes ...
.
Nitroglycerin has been used in conjunction with
hydraulic fracturing, a process used to recover
oil and
gas from
shale formations. The technique involves displacing and detonating nitroglycerin in natural or hydraulically induced fracture systems, or displacing and detonating nitroglycerin in hydraulically induced fractures followed by wellbore shots using pelletized
TNT.
Nitroglycerin has an advantage over some other high explosives that on detonation it produces practically no visible smoke. Therefore, it is useful as an ingredient in the formulation of various kinds of
smokeless powder
Finnish smokeless powderSmokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to gunpowder ("black powder"). The combustion products are mainly gaseous, compared t ...
.
Its sensitivity has limited the usefulness of nitroglycerin as a military explosive, and less sensitive explosives such as
TNT,
RDX, and
HMX
HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the compound's name is the subject of much speculation, having been variously listed as High Melting Explosive, Her ...
have largely replaced it in munitions. It remains important in military engineering, and
combat engineers still use dynamite.
Alfred Nobel then developed
ballistite
Ballistite is a smokeless propellant made from two high explosives, nitrocellulose and nitroglycerine. It was developed and patented by Alfred Nobel in the late 19th century.
Military adoption
Alfred Nobel patented https://www.nobelprize.org/alfr ...
, by combining nitroglycerin and
guncotton. He patented it in 1887. Ballistite was adopted by a number of European governments, as a military propellant. Italy was the first to adopt it. The British government and the Commonwealth governments adopted
cordite instead, which had been developed by Sir
Frederick Abel and Sir
James Dewar
Sir James Dewar (20 September 1842 – 27 March 1923) was a British chemist and physicist. He is best known for his invention of the vacuum flask, which he used in conjunction with research into the liquefaction of gases. He also studied a ...
of the United Kingdom in 1889. The original Cordite Mk I consisted of 58% nitroglycerin, 37% guncotton, and 5.0%
petroleum jelly. Ballistite and cordite were both manufactured in the form of "cords".
Smokeless powders were originally developed using nitrocellulose as the sole explosive ingredient. Therefore, they were known as single-base propellants. A range of smokeless powders that contains both nitrocellulose and nitroglycerin, known as double-base propellants, were also developed. Smokeless powders were originally supplied only for military use, but they were also soon developed for civilian use and were quickly adopted for sports. Some are known as sporting powders. Triple-base propellants contain nitrocellulose, nitroglycerin, and
nitroguanidine
Nitroguanidine - sometimes abbreviated NGu - is a colorless, crystalline solid that melts at 257 °C and decomposes at 254 °C. Nitroguanidine is an extremely insensitive but powerful high explosive. Wetting it with > 20 wt.-% water effe ...
, but are reserved mainly for extremely high-caliber ammunition rounds such as those used in tank cannons and
naval artillery. Blasting gelatin, also known as
gelignite
Gelignite (), also known as blasting gelatin or simply "jelly", is an explosive material consisting of collodion- cotton (a type of nitrocellulose or guncotton) dissolved in either nitroglycerine or nitroglycol and mixed with wood pulp and saltp ...
, was invented by Nobel in 1875, using nitroglycerin,
wood pulp
Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemical or plant-based additives, pulp is the major raw ...
, and
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
or
potassium nitrate
Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and ...
. This was an early, low-cost, flexible explosive.
Medical use
Nitroglycerin belongs to a group of drugs called nitrates, which includes many other nitrates like
isosorbide dinitrate (Isordil) and
isosorbide mononitrate (Imdur, Ismo, Monoket).
These agents all exert their effect by being converted to
nitric oxide
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its ...
in the body by mitochondrial
aldehyde dehydrogenase (
ALDH2),
and nitric oxide is a potent natural vasodilator.
In
medicine
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...
, nitroglycerin is probably most commonly prescribed for
angina pectoris, a painful symptom of
ischemic heart disease
Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pl ...
caused by inadequate flow of blood and oxygen to the heart and as a potent antihypertensive agent. Nitroglycerin corrects the imbalance between the flow of oxygen and blood to the heart and the heart’s energy demand.
There are plenty of formulations on the market at different doses. At low doses, nitroglycerin dilates veins more than arteries, thereby reducing
preload (volume of blood in the heart after filling); this is thought to be its primary mechanism of action. By decreasing preload, the heart has less blood to pump, which decreases oxygen requirement since the heart does not have to work as hard. Additionally, having a smaller preload reduces the ventricular transmural pressure (pressure exerted on the walls of the heart), which decreases the compression of heart arteries to allow more blood to flow through the heart. At higher doses, it also dilates arteries, thereby reducing
afterload
Afterload is the pressure that the heart must work against to eject blood during systole (ventricular contraction). Afterload is proportional to the average arterial pressure. As aortic and pulmonary pressures increase, the afterload increases on ...
(decreasing the pressure against which the heart must pump).
An improved ratio of myocardial oxygen demand to supply leads to the following therapeutic effects during episodes of angina pectoris: subsiding of chest pain, decrease of
blood pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure ...
, increase of heart rate, and
orthostatic hypotension
Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when standing up or sitting down. Primary orthostatic hypertension is also often referred to as neurogenic orthostatic hyp ...
. Patients experiencing angina when doing certain physical activities can often prevent symptoms by taking nitroglycerin 5 to 10 minutes before the activity. Overdoses may generate
methemoglobinemia
Methemoglobinemia, or methaemoglobinaemia, is a condition of elevated methemoglobin in the blood. Symptoms may include headache, dizziness, shortness of breath, nausea, poor muscle coordination, and blue-colored skin (cyanosis). Complications ...
.
Nitroglycerin is available in tablets, ointment, solution for
intravenous use,
transdermal patches, or sprays administered
sublingual
Sublingual (abbreviated SL), from the Latin for "under the tongue", refers to the pharmacological route of administration by which substances diffuse into the blood through tissues under the tongue.
The sublingual glands receive their primary ...
ly. Some forms of nitroglycerin last much longer in the body than others. Nitroglycerin as well as the onset and duration of action of each form is different. The sublingual or tablet spray of nitroglycerin has a two minute onset and twenty five minute duration of action. The oral formulation of nitroglycerin has a thirty five minute onset and a duration of action of 4-8 hours. The transdermal patch has an onset of thirty minutes and a duration of action of ten to twelve hours. Continuous exposure to nitrates has been shown to cause the body to stop responding normally to this medicine. Experts recommend that the patches be removed at night, allowing the body a few hours to restore its responsiveness to nitrates. Shorter-acting preparations of nitroglycerin can be used several times a day with less risk of developing tolerance. Nitroglycerin was first used by
William Murrell to treat angina attacks in 1878, with the discovery published that same year.
Industrial exposure
Infrequent exposure to high doses of nitroglycerin can cause severe
headaches known as "NG head" or "bang head". These headaches can be severe enough to incapacitate some people; however, humans develop a
tolerance
Tolerance or toleration is the state of tolerating, or putting up with, conditionally.
Economics, business, and politics
* Toleration Party, a historic political party active in Connecticut
* Tolerant Systems, the former name of Veritas Software ...
to and dependence on nitroglycerin after long-term exposure. Although rare, withdrawal can be fatal.
Withdrawal symptoms include chest pain and other heart problems. These symptoms may be relieved with re-exposure to nitroglycerin or other suitable organic nitrates.
For workers in nitroglycerin (NTG) manufacturing facilities, the effects of withdrawal sometimes include "Sunday heart attacks" in those experiencing regular nitroglycerin exposure in the workplace, leading to the development of tolerance for the venodilating effects. Over the weekend, the workers lose the tolerance, and when they are re-exposed on Monday, the drastic
vasodilation produces a
fast heart rate
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (s ...
, dizziness, and a headache. This is referred to as "Monday disease."
People can be exposed to nitroglycerin in the workplace by breathing it in, skin absorption, swallowing it, or eye contact. The
Occupational Safety and Health Administration
The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agen ...
has set the legal limit (
permissible exposure limit
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupationa ...
) for nitroglycerin exposure in the workplace as 0.2 ppm (2 mg/m
3) skin exposure over an 8-hour workday. The
National Institute for Occupational Safety and Health has set a
recommended exposure limit of 0.1 mg/m
3 skin exposure over an 8-hour workday. At levels of 75 mg/m
3, nitroglycerin is
immediately dangerous to life and health.
See also
*
Erythritol tetranitrate
Erythritol tetranitrate (ETN) is an explosive compound chemically similar to PETN, though it is thought to be slightly more sensitive to friction and impact.
Like many nitrate esters, ETN acts as a vasodilator, and was the active ingredient in th ...
*
Ethylene glycol dinitrate
Ethylene glycol dinitrate, abbreviated EGDN and NGC, also known as Nitroglycol, is a colorless, oily, explosive liquid obtained by nitrating ethylene glycol. It is similar to nitroglycerine in both manufacture and properties, though it is more vo ...
*
Mannitol hexanitrate
*
Methyl nitrate
*
Tetranitratoxycarbon
Tetranitratoxycarbon, systematic name tetra(nitrato-''O'',''O'',''O''-methyl)methane (often shortened to tetrakis(nitratoxycarbon)methane),
is a hypothetical molecule that was proposed by Clara Lazen, a fifth-grader in Kansas City, Missouri, who ...
*
Xylitol pentanitrate
*
RE factor
TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The is a unit of energy defined by that convention to be , which is the approximate energy released in the detonation of a ...
References
External links
* – 1866 Newspaper article
WebBook page for C3H5N3O9Detailed and horrific stories of the historical use of nitroglycerin-filled
torpedoes to restart petroleum wells.
Dynamite and TNTat ''
The Periodic Table of Videos'' (University of Nottingham)
{{Use dmy dates, date=April 2017
Disulfiram-like drugs
Nitrate esters
Explosive chemicals
Liquid explosives
Sugar alcohol explosives
Italian inventions
Glycerol esters