Syntin (original) (raw)

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Syntin
Names
Preferred IUPAC name 21-Methyl-11,21:22,31-tercyclopropane
Other names1-Methyl-1,2-dicyclopropylcyclopropane; Sintin; Synthin; Tsycklin; Tsiklin
Identifiers
CAS Number 93223-46-2 checkY
3D model (JSmol) Interactive image
ChemSpider 452765 checkY
PubChem CID 519050
CompTox Dashboard (EPA) DTXSID90333879 Edit this at Wikidata
InChI InChI=1S/C10H16/c1-10(8-4-5-8)6-9(10)7-2-3-7/h7-9H,2-6H2,1H3 ☒NKey: GTKAAVZEFUFXDD-UHFFFAOYSA-N ☒NInChI=1/C10H16/c1-10(8-4-5-8)6-9(10)7-2-3-7/h7-9H,2-6H2,1H3Key: GTKAAVZEFUFXDD-UHFFFAOYAR
SMILES CC1(C2CC2)C(C3CC3)C1
Properties
Chemical formula C10H16
Molar mass 136.238 g·mol−1
Density 0.851 g/mL
Boiling point 158 °C (316 °F; 431 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). ☒N verify (what is checkY☒N ?) Infobox references

Chemical compound

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: Δf_H_°(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):

Syntin synthesis 01

Syntin synthesis 01

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]

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

Four Syntin Stereoisomers

Four Syntin Stereoisomers

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

  1. ^ a b A.P., Mesheheryakov; V.G., Glukhovtsev; A.D., Petrov (26 September 1959). СИНТЕЗ 1-МЕТИЛ-1,2-ДИЦИКЛОПРОПИЛЦИКЛОПРОПАНА ["Synthesis of 1-Methyl-1,2-Dicyclopropylcyclopropane"] (PDF) (in Russian). Institute of Organic Chemistry, UdSSR Academy of Sciences. pp. 779–781. Retrieved 22 July 2022.
  2. ^ ЖРД РД-107 и РД-108 и их модификации [Liquid Rocket Engines RD-107/108 and their modifications]. www.lpre.de (in Russian). Retrieved 22 July 2022.
  3. ^ a b Последний бой углеводородов? [The last battle of hydrocarbons?] (PDF). novosti-kosmonavtiki.ru. Volume 18, No 2. (in Russian). Novosti Kosmonavtiki. 2008. pp. 44–46. Archived from the original (PDF) on 20 September 2009.