Otto fuel II

Last updated
MK-46 torpedo, which uses Otto fuel II Search and rescue swimmer Quartermaster 2nd Class Justin Peel, from Polson, Mont., secures an MK-46 exercise torpedo to be hoisted aboard the guided missile cruiser USS Vincennes (CG 49).jpg
MK-46 torpedo, which uses Otto fuel II

Otto fuel II is a monopropellant mixture of chiefly propylene glycol dinitrate (an ester of nitric acid and propylene glycol, and structurally similar to nitroglycerin) that is used to drive torpedoes and other weapon systems. It was invented by Otto Reitlinger in 1963 (although tests with the substance had taken place before, for example in 1960 [1] ). Otto fuel II, sometimes known simply as Otto fuel, is not related to the Otto cycle; it is named after Reitlinger and for being the second iteration of the fuel. It was developed by the US Navy and the first torpedo to use it was the Mark 48 torpedo in the 1960s. [2] [3]

Contents

Properties

Otto fuel II is a distinct-smelling (described by submariners as being similar in smell to wintergreen oil; i.e. sweet, fruity and minty),[ citation needed ] reddish-orange, oily liquid that is a mixture of three synthetic substances: propylene glycol dinitrate (the major component), 2-nitrodiphenylamine, and dibutyl sebacate. [4] It does not need exposure to any oxidant to ignite and release energy, as its three components will react among themselves whenever vaporised and heated. Needing no oxidants and being a stable substance makes Otto fuel II ideal for use in the constrained environment of a submarine. Although the fuel can be made to explode, this requires such extreme conditions that it can be regarded as practically stable. The vapour pressure of the fuel is low (i.e., it is not volatile), minimizing toxic hazards. Finally, the fuel's energy density far surpasses the capacity of the electric battery used in other torpedoes, maximizing range.

Major ingredients

Named after its inventor, Otto Reitlinger, [5] Otto fuel II consists of the nitrated ester explosive propellant propylene glycol dinitrate (PGDN), to which a desensitizer (dibutyl sebacate) and a stabilizer (2-nitrodiphenylamine) have been added. The chief component, propylene glycol dinitrate, accounts for approximately 76% of the mixture, while dibutyl sebacate and 2-nitrodiphenylamine account for approximately 22.5% and 1.5% (by weight), respectively. [6]

The principal current use of propylene glycol dinitrate is as a propellant in Otto fuel II. Nitrates of polyhydric alcohols such as this have been used in medicine for the treatment of angina pectoris, and as explosives since the mid-nineteenth century.

In addition to its use by the United States Navy as a stabilizer in the manufacture of Otto fuel II, 2-nitrodiphenylamine is employed for similar purposes by the United States Army in the manufacture of double base solid propellants. It also has civilian applications as a solvent dye.

Dibutyl sebacate is a desensitizer in Otto fuel II. However, its major use is as a plasticizer in production of plastics, namely cellulose acetate butyrate, cellulose acetate propionate, polyvinyl butyral, polystyrene, and many synthetic rubbers. It can be used for plastics in use in the food packaging industry. It is also used as a lubricating ingredient in shaving lotions, and a flavoring additive in non-alcoholic beverages, ice cream, ices, candy, and baked goods.

Toxicity

Otto fuel II is a toxic substance found in EPA National Priorities List. Ingestion of contaminated food or direct exposure at worksites can cause headaches, poor eye–hand coordination, eye irritation, congested noses, nausea, dizziness, and difficulty breathing. [4] An MSA Demand Mask is mandatory for cleanup/mitigation efforts.

Used in

Related Research Articles

<span class="mw-page-title-main">RDX</span> Explosive chemical compound

RDX (abbreviation of "Research Department eXplosive" or Royal Demolition eXplosive) or hexogen, among other names, is an organic compound with the formula (CH2N2O2)3. It is white, odorless and tasteless, widely used as an explosive. Chemically, it is classified as a nitroamine alongside HMX, which is a more energetic explosive than TNT. It was used widely in World War II and remains common in military applications.

<span class="mw-page-title-main">Nitroglycerin</span> Chemical compound

Nitroglycerin (NG), also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive liquid most commonly produced by nitrating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. Chemically, the substance is an organic nitrate compound rather than a nitro compound, but the traditional name is retained. Discovered in 1847 by Ascanio Sobrero, nitroglycerin has been used as an active ingredient in the manufacture of explosives, namely dynamite, and as such it is employed in the construction, demolition, and mining industries. It is combined with nitrocellulose to form double-based smokeless powder, which has been used as a propellant in artillery and firearms since the 1880s.

<span class="mw-page-title-main">Nitrocellulose</span> Highly flammable compound

Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and sulfuric acid. One of its first major uses was as guncotton, a replacement for gunpowder as propellant in firearms. It was also used to replace gunpowder as a low-order explosive in mining and other applications. In the form of collodion it was also a critical component in an early photographic emulsion, the use of which revolutionized photography in the 1860s.

<span class="mw-page-title-main">Petrochemical</span> Chemical product derived from petroleum

Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.

Celluloids are a class of materials produced by mixing nitrocellulose and camphor, often with added dyes and other agents. Once much more common for its use as photographic film before the advent of safer methods, celluloid's common present-day uses are for manufacturing table tennis balls, musical instruments, combs, office equipment, fountain pen bodies, and guitar picks.

Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with bipropellants that release energy through the chemical reaction between an oxidizer and a fuel. While stable under defined storage conditions, monopropellants decompose very rapidly under certain other conditions to produce a large volume of its own energetic (hot) gases for the performance of mechanical work. Although solid deflagrants such as nitrocellulose, the most commonly used propellant in firearms, could be thought of as monopropellants, the term is usually reserved for liquids in engineering literature.

<span class="mw-page-title-main">Propylene glycol</span> Chemical compound

Propylene glycol (IUPAC name: propane-1,2-diol) is a viscous, colorless liquid, which is nearly odorless but possesses a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH. As it contains two alcohol groups, it is classed as a diol. It is miscible with a broad range of solvents, including water, acetone, and chloroform. In general, glycols are non-irritating and have very low volatility.

An antifreeze is an additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression for cold environments. Common antifreezes also increase the boiling point of the liquid, allowing higher coolant temperature. However, all common antifreeze additives also have lower heat capacities than water, and do reduce water's ability to act as a coolant when added to it.

<span class="mw-page-title-main">Plasticizer</span> Substance added to a material to make it softer and more flexible

A plasticizer is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture.

<span class="mw-page-title-main">Smokeless powder</span> Type of propellant

Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to black powder. Because of their similar use, both the original black powder formulation and the smokeless propellant which replaced it are commonly described as gunpowder. The combustion products of smokeless powder are mainly gaseous, compared to around 55% solid products for black powder. In addition, smokeless powder does not leave the thick, heavy fouling of hygroscopic material associated with black powder that causes rusting of the barrel.

Glycol ethers are a class of chemical compounds consisting of alkyl ethers that are based on glycols such as ethylene glycol or propylene glycol. They are commonly used as solvents in paints and cleaners. They have good solvent properties while having higher boiling points than the lower-molecular-weight ethers and alcohols.

Dibutyl sebacate (DBS) is an organic chemical, a dibutyl ester of sebacic acid. Its main use is as a plasticizer in production of plastics, namely cellulose acetate butyrate, cellulose acetate propionate, ethyl cellulose, polyvinyl butyral, polyvinyl chloride, polystyrene, and many synthetic rubbers and other plastics. It can be used for plastics in use in the food packaging industry, in plastics used for medical devices, and for pharmaceutical applications, e.g. as a plasticizer for film coating of tablets, beads, and granules. It is also used as a lubricant in shaving lotions, and a flavoring additive in non-alcoholic beverages, ice cream, ices, candy, and baked goods. It provides excellent compatibility with a range of plastic materials, superior properties at low temperatures, and good oil resistivity. Its other names include Morflex, Kodaflex, polycizer, Proviplast 1944 and PX 404. Dibutyl sebacate is also used as a desensitizer in Otto fuel II, a torpedo monopropellant.

<span class="mw-page-title-main">Propylene glycol dinitrate</span> Chemical compound

Propylene glycol dinitrate (PGDN, 1,2-propylene glycol dinitrate, or 1,2-propanediol dinitrate) is an organic chemical, an ester of nitric acid and propylene glycol. It is structurally similar to nitroglycerin, except that it has one fewer nitrate group. It is a characteristically and unpleasantly smelling colorless liquid, which decomposes at 121 °C, below its boiling point. It is flammable and explosive. It is shock-sensitive and burns with a clean flame producing water vapor, carbon monoxide, and nitrogen gas.

<span class="mw-page-title-main">2-Nitrodiphenylamine</span> Chemical compound

2-Nitrodiphenylamine is an organic chemical with the formula C6H5NHC6H4NO2. It is a nitrated derivative of diphenylamine. It is a red solid, usually found in form of flakes or powder. It is polar but hydrophobic.

A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions. Pyrotechnic substances do not rely on oxygen from external sources to sustain the reaction.

<span class="mw-page-title-main">Diethylene glycol dinitrate</span> Chemical compound

Diethylene glycol dinitrate (DEGDN) is an explosive nitrated alcohol ester with the formula C4H8N2O7. While chemically similar to numerous other high explosives, pure diethylene glycol dinitrate is difficult to ignite or detonate. Ignition typically requires localized heating to the decomposition point unless the DEGDN is first atomized.

<span class="mw-page-title-main">Trimethylolethane trinitrate</span> Chemical compound

Trimethylolethane trinitrate (TMETN), also known as metriol trinitrate or nitropentaglycerin, is a nitrate ester. It is a high explosive similar to nitroglycerin. It is a transparent oily liquid, colorless to light brown. It is odorless. It is used in some solid propellants and smokeless powders as a plasticizer. Its chemical formula is CH3−C(CH2−O−NO2)3.

Bulk loaded liquid propellants are an artillery technology that was pursued at the U.S. Army Research Laboratory and U.S. Naval Weapons Center from the 1950s through the 1990s. The advantages would be simpler guns and a wider range of tactical and logistic options. Better accuracy and tactical flexibility would theoretically come from standard shells with varying propellant loads, and logistic simplification by eliminating varying powder loads.

2-Ethoxyethyl acetate is an organic compound with the formula CH3CH2OCH2CH2O2CCH3. It is the ester of ethoxyethanol and acetic acid. A colorless liquid, it is partially soluble in water.

References

  1. U.S. Naval Propellant Plant (c. 1964). Otto Fuel II (Technical Film Report). Indian Head, Maryland: Bureau of Naval Weapons. Retrieved 2022-12-10.
  2. "OTTOFUELII CAS#: 106602-80-6".
  3. "Otto fuel II - Everything2.com".
  4. 1 2 "ToxFAQs for Otto fuel II and Its Components". Toxic Substances Portal. Agency for Toxic Substances and Disease Registry. Retrieved 10 April 2021.
  5. "Otto Reitlinger Inventions, Patents and Patent Applications - Justia Patents Search".
  6. Powell, S.; Franzmann, P. D.; Cord-Ruwisch, R.; Toze, S. (1998). "Degradation of 2-nitrodiphenylamine, a component of Otto fuel II, by Clostridium spp". Anaerobe. 4 (2): 95–102. doi:10.1006/anae.1997.0141. PMID   16887628.