Methylacetylene

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Methylacetylene

Methylacetylene (propyne) is an alkyne

Alkyne

Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms, with the formula CnH2n-2. The alkynes are traditionally known as acetylenes or the acetylene series, although the name acetylene is also used to refer specifically to the simplest member of the series, known as e...
with the chemical formula

Chemical formula

A chemical formula is a way of expressing information about the atoms that constitute a particular chemical compound, and how the relationship between those atoms changes in chemical reactions....
H

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the chemical symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly combustion and explosive Diatomic molecule gas with the molecular formula H2....
₃C=CH. It is a component of MAPP gas

MAPP gas

MAPP gas is liquefied petroleum gas mixed with methylacetylene-allene. In Australia, it is known as RazorGas and is a trademark of ELGAS....
along with its isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulae. Isomers do not necessarily share similar properties unless they also have the same functional groups....
1,2-propadiene (allene), which is commonly used in gas welding. Unlike acetylene

Acetylene

Acetylene is the chemical compound with the symbol carbonhydrogen. It is the simplest alkyne.As an alkyne, acetylene is Saturation because its two carbon atoms are Chemical bond together in a triple bond....
, methylacetylene can be safely condensed.

ylacetylene exists in equilibrium with allene, the mixture of methylacetylene and propadiene being called MAPD:

H₃CC≡CH H₂C=C=CH₂

K_eq = 0.22 (270 °C), 0.1 K (5 °C) MAPD is produced as a side product, often an undesirable one, by cracking

Cracking

Cracking may refer to:* Cracking, the formation of a fracture or partial fracture in a solid material* Fluid catalytic cracking, a catalytic process widely used in oil refineries for cracking large hydrocarbon molecules into smaller molecules...
propane to produce propene, an important feedstock in the chemical industry.

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Encyclopedia

Methylacetylene (propyne) is an alkyne

Alkyne

Chemical formula

Hydrogen

MAPP gas

MAPP gas is liquefied petroleum gas mixed with methylacetylene-allene. In Australia, it is known as RazorGas and is a trademark of ELGAS....
along with its isomer

Isomer

Acetylene

Production and equilibrium with allene

Methylacetylene exists in equilibrium with allene, the mixture of methylacetylene and propadiene being called MAPD:

H₃CC≡CH H₂C=C=CH₂

K_eq = 0.22 (270 °C), 0.1 K (5 °C) MAPD is produced as a side product, often an undesirable one, by cracking

Cracking

Ziegler-Natta catalyst

A Ziegler-Natta catalyst is a reagent or a mixture of reagents used in the production of polymers of 1-alkenes . Ziegler-Natta catalysts are typically based on titanium compounds and organometallic chemistry aluminium compounds, for example triethylaluminium, 3Al....
polymerization of propene.

Use as a rocket fuel

Research by European space concerns into using light hydrocarbons with liquid

Liquid

Liquid is one of the principal states of matter. A liquid is a fluid that has the particles loose and can freely form a distinct surface at the boundaries of its bulk material....
oxygen

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
as a relatively high performing propellant

Propellant

A propellant is a material that is used to move an object. This will often involve a chemical reaction. It may be a gas, liquid, Plasma , or, before the chemical reaction, a solid....
combination which would also be less toxic than the commonly used MMH

MMH

MMH may refer to:* Monomethylhydrazine, a chemical with the formula CH3N2H3.* The IATA location identifier for Mammoth Yosemite Airport....
/NTO (monomethylhydrazine

Monomethylhydrazine

Monomethylhydrazine is a Volatility hydrazine with the chemical formula CarbonHydrogen3Nitrogen2Hydrogen3. It is used as a rocket fuel in bipropellant rocket engines....
/nitrogen tetroxide) systems, showed that propyne would be highly advantageous as a rocket fuel for craft intended for low Earth

Earth

Earth is the third planet from the Sun. Earth is the largest of the terrestrial planets in the Solar System in diameter, mass and density. It is also referred to as the World and Wiktionary:Terra.Note that by International Astronomical Union convention, the term "Terra" is used for naming extensive land masses, rather...
orbital

Orbital spaceflight

An orbital spaceflight is a spaceflight in which a spacecraft is placed on a trajectory where it could remain in outer space for at least one orbit....
operations. This conclusion was reached based upon a specific impulse

Specific impulse

Specific impulse is a way to describe the efficiency of rocket engine and jet engine engines. It represents the impulse per unit of propellant....
expected to reach 370 s

Second

The second , sometimes abbreviated sec., is the name of a units of measurement of time, and is the International System of Units SI base unit of time....
if oxygen is used as oxidizer, a high density

Density

The density of a material is defined as its mass per unit volume. The symbol of density is ....
, and energy

Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
/volume

Volume

The volume of any solid, liquid, plasma, vacuum or theoretical object is how much three-dimensional space it occupies, often quantified numerically....
ratio, and the moderate boiling point

Boiling point

The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
, which causes the chemical to present fewer problems in storage than for example a fuel

Fuel

Fuel is any material that is burned or altered in order to obtain energy and to heat or to move an object. Fuel releases its energy either through a chemical reaction means, such as combustion, or nuclear means, such as nuclear fission or nuclear fusion....
that needs to be kept at extremely low temperatures. (See cryogenics

Cryogenics

In physics, cryogenics is the study of the production of very low temperature and the behavior of materials at those temperatures. Rather than the familiar temperature scales of Fahrenheit and Celsius, cryogenicists use the Kelvin scales....
.)

Organic chemistry

Propyne is a convenient three-carbon building block for organic synthesis

Organic synthesis

Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic_chemistry molecules can often contain a higher level of complexity compared to purely Inorganic_chemistry compounds, so the synthesis of organic compounds has developed into one of the most im...
. Deprotonation with n-butyllithium

N-Butyllithium

n-Butyllithium is the most prominent organolithium reagent. It enjoys wide use as a polymerisation initiator in the production of elastomers such as polybutadiene or Styrene-butadiene....
gives propynyllithium. This nucleophilic reagent adds to carbonyl

Carbonyl

In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double bond to an oxygen atom : C=O.The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex ; in this situation, carbon is triple-bonded to oxygen : C=O....
groups, producing alcohol

Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
s and ester

Ester

An ester is an often Aroma compound organic chemistry or partially organic compound formed by the reaction between an acid and an alcohol or aromatic alcohol with the elimination of water....
s. Whereas purified propyne is expensive, MAPP gas can be used to cheaply generate large amounts of the reagent.