The key difference between methylacetylene and acetylene is that methylacetylene contains a methyl group attached to an acetylene molecule, whereas acetylene is an organic compound having a triple bonded carbon atom pair.
Methylacetylene and acetylene are organic compounds having triple bonded carbon atoms. These are the simplest alkene compounds in the alkyne series.
CONTENTS
1. Overview and Key Difference
2. What is Methylacetylene
3. What is Acetylene
4. Side by Side Comparison – Methylacetylene vs Acetylene in Tabular Form
5. Summary
What is Methylacetylene?
Methylacetylene or propyne is an organic compound having the chemical formula CH3C≡CH. It is the second simplest alkene of the alkyne series. We can find this chemical compound in the gaseous phase when it is a component of MAPD gas (along with propadiene – the isomer of propyne). Methylacetylene is a colorless gas having a sweet odor.
Figure 01: Chemical Structure of Methylacetylene Molecule
Methylacetylene gas usually exists in equilibrium with propadiene, the isomer of methylacetylene. This mixture is called the MAPD gas. In the laboratory, we can produce methylacetylene via reducing 1-propanol, allyl alcohol or acetone vapors over magnesium catalyst.
This gaseous compound is an important building block for organic synthesis reactions. For example, deprotonation of Methylacetylene with n-butyllithium gives propynyllithium. Purified methylacetylene is expensive, but we can generate this gas cheaply in large amounts using MAPP gas. Methylacetylene gas can act as a nucleophilic reagent and get added to carbonyl groups, resulting in alcohols and esters. Further, methylacetylene can be made into relatively a high performing liquid rocket fuel.
What is Acetylene?
Acetylene is the simplest alkyne having the chemical formula C2H2. The systemic IUPAC name of acetylene is ethyne. This gas occurs as a colorless gas at room temperature and pressure conditions. We can categorize it as a hydrocarbon because it contains only carbon and hydrogen atoms with bonds between carbon atoms. The acetylene gas is widely useful as a fuel and a building block for the synthesis of different chemical compounds.
Figure 02: The Chemical Structure of Acetylene Molecule
The acetylene molecule, as shown in the above image, has a triple bond between the two carbon atoms, which leads to its categorization as an alkyne. Furthermore, the valency of each carbon atom in this molecule is 4. In other words, each carbon atom in this molecule binds to a hydrogen atom via a single bond, other than forming a triple bond between the other carbon atoms. Therefore, the acetylene molecule has a linear geometry, and it has a planar structure. Each carbon atom in this molecule is sp hybridized.
What is the Difference Between Methylacetylene and Acetylene?
Methylacetylene and acetylene are the simplest alkene compounds in the alkene series. The key difference between methylacetylene and acetylene is that mthylacetylene contains a methyl group attached to an acetylene molecule, whereas acetylene is an organic compound having a triple bonded carbon atom pair. Moreover, methylacetylene has a sweet odor whereas acetylene has a garlic-like odor.
Furthermore, concerning the production, methylacetylene is made via reducing 1-propanol, allyl alcohol or acetone vapors over magnesium catalyst whereas acetylene made through the reaction of water with calcium carbide, by the passage of a hydrocarbon through an electric arc, and by partial combustion of methane with air or oxygen.
Below infographic tabulates side-by-side the differences between methylacetylene and acetylene.
Summary – Methylacetylene vs Acetylene
Methylacetylene and acetylene are the simplest alkene compounds in the alkene series. The key difference between methylacetylene and acetylene is that methyacetylene contains a methyl group attached to an acetylene molecule, whereas acetylene is an organic compound having a triple bonded carbon atom pair. Moreover, unlike acetylene gas, methylacetylene can be condensed safely.
Reference:
1. “Acetylene.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.
2. “Propyne.” Wikipedia, Wikimedia Foundation, 2 Nov. 2020, Available here.
Image Courtesy:
1. “Propyne” By Edgar181 – Own work (Public Domain) via Commons Wikimedia
2. “Acetylene-CRC-IR-dimensions-2D” By Ben Mills – Own work (Public Domain) via Commons Wikimedia