TH-dimer, also called tetrahydromethylcyclopentadiene dimer or RJ-4, is a

liquid rocket propellant The highest specific impulse chemical rockets use liquid propellants (liquid-propellant rockets). They can consist of a single chemical (a monopropellant) or a mix of two chemicals, called bipropellants. Bipropellants can further be divided into ...

used in

missiles In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles are thus also called guided missiles or guided rockets (when a previously unguided rocket i ...

and jet engines. For example, TH-dimer is used in the

turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which achieves mechanic ...

engine of the

Tomahawk cruise missile The Tomahawk () Land Attack Missile (TLAM) is a long-range, all-weather, jet-powered, subsonic cruise missile that is primarily used by the United States Navy and Royal Navy in ship and submarine-based land-attack operations. Under contract fr ...

. It is also a component of the jet fuel JP-9. The fuel is non-volatile so it is safe to use on ships or submarines. It has a high flash point minimum of 60 °C. Chemically, TH-dimer is a mixture of isomeric saturated

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 ...

s derived from

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organ ...

of the dimer of

methylcyclopentadiene Methylcyclopentadiene is any of three isomeric cyclic dialkenes with the formula C5MeH5 (Me = CH3). These isomers are the organic precursor to the methylcyclopentadienyl ligand (C5H4Me, often denoted as Cp′), commonly found in organometallic che ...

References

Aviation fuels Hydrocarbons Tricyclic compounds {{hydrocarbon-stub