Syntin Explained

Syntin is a hydrocarbon with the molecular formula C₁₀H₁₆ used as a rocket fuel. It is a mixture of four stereoisomers (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: Δ_fH°(l)= 133 kJ/mol (980 kJ/kg, the average value for the isomeric mixture),^[1] bringing additional energy into the combustion process. It has advantages over the traditional hydrocarbon fuels, such as RP-1, due to higher density, lower viscosity and higher specific heat of oxidation.

Syntin was used in the Soviet Union and later Russia as fuel for the Soyuz-U2 rocket from 1982 until 1995.^{[2] [3]}

It was first synthesized in the USSR in 1959^[1] and brought to mass production in the 1970s. It was prepared in a multi-step synthetic process from easily obtained acetylcyclopropane (the 3rd molecule):

After dissolution of the USSR, the production of this fuel was halted due to the expense of the synthesis. On September 3, 1995, Soyuz TM-22, the seventy-first and last Soyuz-U2 rocket launched, being the last rocket fueled with Syntin.^[3]

Stereoisomers

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

In practice, syntin is used as a racemic mixture (a mixture where all stereoisomers are present in equal amounts).

See also

• Dicyclopentadiene

References

1. Web site: http://www.mathnet.ru/links/aad75c8a915bf9d604a2a3200dd4cb2c/dan39595.pdf . A.P.. Mesheheryakov. V.G.. Glukhovtsev. A.D.. Petrov. Institute of Organic Chemistry, UdSSR Academy of Sciences.. ru:СИНТЕЗ 1-МЕТИЛ-1,2-ДИЦИКЛОПРОПИЛЦИКЛОПРОПАНА. "Synthesis of 1-Methyl-1,2-Dicyclopropylcyclopropane". ru. 26 September 1959. 779–781. 22 July 2022.
2. Web site: http://www.lpre.de/energomash/RD-107/index.htm . ru:ЖРД РД-107 и РД-108 и их модификации. Liquid Rocket Engines RD-107/108 and their modifications. www.lpre.de. ru. 22 July 2022.
3. Web site: http://www.novosti-kosmonavtiki.ru/nk/forum-pic/Omar_NK2008-02.pdf . ru:Последний бой углеводородов?. The last battle of hydrocarbons?. novosti-kosmonavtiki.ru. Novosti Kosmonavtiki. ru. 2008. Volume 18, No 2.. 44–46. dead. https://web.archive.org/web/20090920132913/http://www.novosti-kosmonavtiki.ru/nk/forum-pic/Omar_NK2008-02.pdf. 20 September 2009.

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.