Syntin is 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 ex ...

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 in ...

(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 Cyclopropane is the cycloalkane with the molecular formula (CH2)3, consisting of three methylene groups (CH2) linked to each other to form a ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane itself ...

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 ...

: Δ_f''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 st ...

, 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 transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

and later

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

as fuel for the

Soyuz-U2 The Soyuz-U2 (GRAU index 11A511U2) was a Soviet Union, Soviet, later Russian, carrier rocket. It was derived from the Soyuz-U, and a member of the R-7 (rocket family), R-7 family of rockets. It featured increased performance compared with the b ...

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 In organic chemistry, acetyl is a functional group with the chemical formula and the structure . It is sometimes represented by the symbol Ac (not to be confused with the element actinium). In IUPAC nomenclature, acetyl is called ethanoyl, ...

(the 3rd molecule): : Syntin synthesis 01

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

rocket launched, being the last rocket fueled with Syntin.

Stereoisomers

Syntin has two stereocenters at the central cyclopropane ring. Thus, four stereoisomers exist: : Syntin Stereoisomers Formulae V

{{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).

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

Stereoisomers

See also

References

Literature