Tetranitromethane
Encyclopedia
Tetranitromethane or TNM is an organic oxidizer with chemical formula C(NO2)4. Its chemical structure consists of four nitro groups attached to one carbon atom. In 1857 it was first synthesised by the reaction of sodium cyanoacetamide with nitric acid
.
.
of acetic anhydride
with anhydrous nitric acid
(Chattaway's method). This method was attempted on an industrial scale in the 1950s by Nitroform Products Company in Newark, USA, but the entire plant was destroyed by an explosion in 1953.
The first industrial scale production was started in Germany during World War II
in an effort to improve the cetane number of diesel fuel. This process improved the original method, which started with acetic acid
and nitric acid.
. Without regard to yield or cost, approximately 10 tons of TNM were produced in a few weeks. However, this production process has not been used again industrially after the end of the war, because of high associated costs.
For commercial use a cheaper method starting from acetylene
has been used.
First, nitric acid containing mercuric nitrate is reduced by acetylene, resulting in nitroform (trinitromethane) and a mixture of carbon dioxide
and nitrogen oxide
as waste gas. The nitrogen oxides are valuable and normally recovered as nitric acid in an absorption tower. The resulting nitroform is converted to TNM by adding nitric and sulfuric acid at higher temperatures. With this method a yield of 90% (based on nitric acid) before purification can be reached.
as a detonator. However, the ability of TNM to detonate is greatly affected by the presence of impurities, even in small quantities. TNM forms extremely powerful explosive mixtures when fuels are added in stoichiometric proportions. Many of these mixtures show sensitivity to impact even higher than that of nitroglycerine.
TNM reacts with moisture at elevated pH to produce trinitromethane
(nitroform) which reacts easily with metals to form highly unstable and explosive salts.
Tetranitromethane is highly toxic. Absorption of as little as 2.5 mg/kg can cause methemoglobinemia
, lung edema, and damage to liver, kidney, and central nervous system. It is reasonably expected to be a human carcinogen.
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
.
Uses
It has been investigated for use as an oxidizer in bipropellant rockets, however its high freezing temperature makes it unsuitable. Highly purified tetranitromethane cannot be made to explode, but its sensitivity is increased dramatically by oxidizable contaminents, such as anti-freezing additives. This makes it effectively unusable as a propellant. In the laboratory it is used a reagent for the detection of double bonds in organic compounds and as a nitrating reagent. It has also found use as an additive to diesel fuel to increase the cetane numberCetane number
Cetane number or CN is a measurement of the combustion quality of diesel fuel during compression ignition. It is a significant expression of diesel fuel quality among a number of other measurements that determine overall diesel fuel quality.- Definition :...
.
Preparation
TNM is a pale yellow liquid that can be prepared in the laboratory by the nitrationNitration
Nitration is a general chemical process for the introduction of a nitro group into a chemical compound. The dominant application of nitration is for the production of nitrobenzene, the precursor to methylene diphenyl diisocyanate...
of acetic anhydride
Acetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula 2O. Commonly abbreviated Ac2O, it is the simplest isolatable acid anhydride and is a widely used reagent in organic synthesis...
with anhydrous nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
(Chattaway's method). This method was attempted on an industrial scale in the 1950s by Nitroform Products Company in Newark, USA, but the entire plant was destroyed by an explosion in 1953.
The first industrial scale production was started in Germany during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
in an effort to improve the cetane number of diesel fuel. This process improved the original method, which started with acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
and nitric acid.
. Without regard to yield or cost, approximately 10 tons of TNM were produced in a few weeks. However, this production process has not been used again industrially after the end of the war, because of high associated costs.
For commercial use a cheaper method starting from acetylene
Acetylene
Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...
has been used.
First, nitric acid containing mercuric nitrate is reduced by acetylene, resulting in nitroform (trinitromethane) and a mixture of carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
and nitrogen oxide
Nitrogen oxide
Nitrogen oxide can refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:* Nitric oxide, also known as nitrogen monoxide, , nitrogen oxide* Nitrogen dioxide , nitrogen oxide...
as waste gas. The nitrogen oxides are valuable and normally recovered as nitric acid in an absorption tower. The resulting nitroform is converted to TNM by adding nitric and sulfuric acid at higher temperatures. With this method a yield of 90% (based on nitric acid) before purification can be reached.
Safety
Pure TNM is stable and cannot be made to explode, even with the use of 10g of tetrylTetryl
2,4,6-Trinitrophenylmethylnitramine commonly referred to as tetryl is a sensitive explosive compound used to make detonators and explosive booster charges....
as a detonator. However, the ability of TNM to detonate is greatly affected by the presence of impurities, even in small quantities. TNM forms extremely powerful explosive mixtures when fuels are added in stoichiometric proportions. Many of these mixtures show sensitivity to impact even higher than that of nitroglycerine.
TNM reacts with moisture at elevated pH to produce trinitromethane
Trinitromethane
Trinitromethane, also referred to as nitroform, is a nitroalkane and oxidizer with chemical formula HC3. It was first obtained as the ammonium salt by Shiskov in 1857. In 1900, it was discovered that nitroform can be produced by the reaction of acetylene with anhydrous nitric acid. This method...
(nitroform) which reacts easily with metals to form highly unstable and explosive salts.
Tetranitromethane is highly toxic. Absorption of as little as 2.5 mg/kg can cause methemoglobinemia
Methemoglobinemia
Methemoglobinemia is a disorder characterized by the presence of a higher than normal level of methemoglobin in the blood. Methemoglobin is an oxidized form of hemoglobin that has an increased affinity for oxygen, resulting in a reduced ability to release oxygen to tissues. The oxygen–hemoglobin...
, lung edema, and damage to liver, kidney, and central nervous system. It is reasonably expected to be a human carcinogen.