syntin

{{Chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 424850837

| ImageFile = Syntin.svg

| ImageSize = 200px

| ImageAlt =

| PIN = 2¹-Methyl-1¹,2¹:2²,3¹-tercyclopropane

| OtherNames = 1-Methyl-1,2-dicyclopropylcyclopropane; Sintin; Synthin; Tsycklin; Tsiklin

|Section1={{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|??}}

| CASNo = 93223-46-2

| PubChem = 519050

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 452765

| InChI = 1/C10H16/c1-10(8-4-5-8)6-9(10)7-2-3-7/h7-9H,2-6H2,1H3

| InChIKey = GTKAAVZEFUFXDD-UHFFFAOYAR

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C10H16/c1-10(8-4-5-8)6-9(10)7-2-3-7/h7-9H,2-6H2,1H3

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = GTKAAVZEFUFXDD-UHFFFAOYSA-N

| SMILES = CC1(C2CC2)C(C3CC3)C1}}

|Section2={{Chembox Properties

| C=10 | H=16

| Appearance =

| Density = 0.851 g/mL

| MeltingPt =

| BoilingPtC = 158

| Solubility = }}

|Section3={{Chembox Hazards

| MainHazards =

| FlashPt =

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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),{{cite web

|url=http://www.mathnet.ru/links/aad75c8a915bf9d604a2a3200dd4cb2c/dan39595.pdf

|last1=A.P.

|first1=Mesheheryakov

|last2=V.G.

|first2=Glukhovtsev

|last3=A.D.

|first3=Petrov

|publisher=Institute of Organic Chemistry, UdSSR Academy of Sciences.

|script-title=ru:СИНТЕЗ 1-МЕТИЛ-1,2-ДИЦИКЛОПРОПИЛЦИКЛОПРОПАНА

|trans-title="Synthesis of 1-Methyl-1,2-Dicyclopropylcyclopropane"

|language=ru

|date=26 September 1959

|pages=779–781

|access-date=22 July 2022}} 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.{{cite web

|url=http://www.lpre.de/energomash/RD-107/index.htm

|script-title=ru:ЖРД РД-107 и РД-108 и их модификации

|trans-title=Liquid Rocket Engines RD-107/108 and their modifications

|website=www.lpre.de

|language=ru

|access-date=22 July 2022}}{{cite web

|url=http://www.novosti-kosmonavtiki.ru/nk/forum-pic/Omar_NK2008-02.pdf

|script-title=ru:Последний бой углеводородов?

|trans-title=The last battle of hydrocarbons?

|website=novosti-kosmonavtiki.ru

|publisher=Novosti Kosmonavtiki

|language=ru

|date=2008

|series=Volume 18, No 2.

|pages=44–46

|url-status=dead

|archive-url=https://web.archive.org/web/20090920132913/http://www.novosti-kosmonavtiki.ru/nk/forum-pic/Omar_NK2008-02.pdf

|archive-date=20 September 2009}}

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 acetylcyclopropane (the 3rd molecule):

:File:Syntin synthesis 01.svg{{clear left}}

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.

== Stereoisomers ==

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

:File:Syntin Stereoisomers Formulae V.1.svg{{clear left}}

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