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Syntin is a 
After dissolution of the USSR, the production of this fuel was halted due to the expense of the synthesis. On September 3rd 1995,
{{clear left
In practice, syntin is used as a
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
with the molecular formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...
C10H16 used as a rocket fuel. It is a mixture of four stereoisomers
In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms ...
(see below). It has a density of 0.851 g/mL, and a boiling point of 158 °C. Due to the presence of three strained cyclopropane rings, the molecule has a highly positive enthalpy of formation
Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant p ...
: Δf''H''°(l)= 133 kJ/mol (980 kJ/kg, the average value for the isomeric mixture), bringing additional energy into the combustion process. It has advantages over the traditional hydrocarbon fuels, such as RP-1
RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (LH2), but is cheaper, is s ...
, due to higher density, lower viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
and higher specific heat of oxidation.
Syntin was used in the Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
and later Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
as fuel for the Soyuz-U2
The Soyuz-U2 ( GRAU index 11A511U2) was a Soviet, later Russian, carrier rocket. It was derived from the Soyuz-U, and a member of the R-7 family of rockets. It featured increased performance compared with the baseline Soyuz-U, due to the use ...
rocket from 1982 until 1995.
It was first synthesized in the USSR in 1959 and brought to mass production in the 1970s. It was prepared in a multi-step synthetic process from easily obtained acetyl cyclopropane (the 3rd molecule):
:
After dissolution of the USSR, the production of this fuel was halted due to the expense of the synthesis. On September 3rd 1995, Soyuz TM-22
Soyuz TM-22 was a Soyuz spaceflight to the Soviet space station Mir.The mission report is available here: http://www.spacefacts.de/mission/english/soyuz-tm22.htm It launched from Baikonur Cosmodrome Launch Pad 1 on September 3, 1995. After two d ...
, the seventy-first and last Soyuz-U2
The Soyuz-U2 ( GRAU index 11A511U2) was a Soviet, later Russian, carrier rocket. It was derived from the Soyuz-U, and a member of the R-7 family of rockets. It featured increased performance compared with the baseline Soyuz-U, due to the use ...
rocket launched, being the last rocket fueled with Syntin.
Stereoisomers
Syntin has two stereocenters at the central cyclopropane ring. Thus, four stereoisomers exist: :{{clear left
In practice, syntin is used as a racemic
In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...
mixture (a mixture where all stereoisomers are present in equal amounts).
See also
*Dicyclopentadiene
Dicyclopentadiene, abbreviated DCPD, is a chemical compound with formula C10H12. At room temperature, it is a white brittle wax, although lower purity samples can be straw coloured liquids. The pure material smells somewhat of soy wax or camphor ...
References
Literature
* A. P. Mesheheryakov, V. G. Glukhovtsev, A. D. Petrov, “Synthesis of 1-methyl-1,2-dicyclopropylcyclopropane”, ''Doklady Akademii Nauk SSSR'', 1960, ''130'', 779-81. * Yu. P. Semenov, B. A. Sokolov, S. P. Chernykh, A. A. Grigor'ev, O. M. Nefedov, N. N. Istomin, G. M. Shirshov, “Multiple strained-ring alkane as high-performance liquid rocket fuel”, RU 2233385, C2 20040727. * T. Edwards, “Liquid Fuels and Propellants for Aerospace Propulsion: 1903-2003”, ''Journal of Propulsion and Power'', 2003, ''19(6)'', 1089-1107. * V. Azov, D. Vorontsov, "The last battle of hydrocarbons?", ''Novosti Kosmonavtiki'', 2008, ''18'', No. 2 (301), 44-46. Hydrocarbons Rocket fuels Cyclopropanes Substances discovered in the 1960s Soviet inventions