Difference Between Butane and Butene

Main Difference – Butane vs Butene

Butane and butene are gaseous compounds that are made out of C and H atoms. They are called hydrocarbons due to the presence of only C and H atoms. Both these molecules are composed of 4 carbon atoms per molecule. The major source of butane and butene is crude oil. Therefore, these gases can be obtained as a byproduct of the petroleum refining processes. But they are present as minor substituents in crude oil. Since these gases are flammable, they can be used as fuel. The complete combustion of butane and butene produces carbon dioxide and water vapor along with heat. But the incomplete combustion will produce carbon monoxide rather than carbon dioxide and a less amount of heat than that of complete combustion. The main difference between butane and butene is that there are no double bonds in butane molecules whereas butene molecules have one double bond.

Key Areas Covered

1. What is Butane
      – Definition, Properties, and Applications
2. What is Butene
      – Definition, Properties, and Applications
3. What are the Similarities Between Butane and Butene
      – Outline of Common Features
4. What is the Difference Between Butane and Butene
      – Comparison of Key Differences

Key Terms: Butane, Butene, Combustion, Crude Oil, Hydrocarbons, Petroleum

What is Butane

Butane is a hydrocarbon that has the chemical formula C₄H₁₀. It is a colorless gas at room temperature and pressure. The molar mass of this compound is about 58.12 g/mol. It has a gasoline like odor. It belongs to the group alkanes since it has no double bonds in its structure. Butane is a nonpolar compound. Therefore, it is not dissolved in polar solvents or water. Butane molecules may exist in two different structural isomers. They are n-butane and isobutane. n-butane is the linear, straight chain form of butane whereas isobutane is a branched structure.

Figure 1: Structural Isomers of Butane

Butane is highly flammable. It is easily liquefied. Since the boiling point of butane is about 1^oC (or less) this butane liquid is quickly vaporized at room temperature. When there is enough oxygen present in the surrounding, butane can undergo complete combustion, forming carbon dioxide and water vapor along with heat energy. But if the oxygen is not enough, then butane will undergo incomplete combustion, producing carbon monoxide and carbon dust.

Butane can be added to gasoline in order to fasten the vaporization of gasoline. This is one of the major uses of butane. It can also be used as a solvent for extractions since butane is highly nonpolar and less reactive. In addition, butane is used as a fuel in small scale applications.

What is Butene

Butene is a hydrocarbon that has the chemical formula C₄H₈. It is a colorless gas at room temperature and pressure. It has a slightly aromatic odor. Butene is an alkene. The major source of butene is crude oil. Butene is present in crude oil as a minor constituent. Butene can be found in several isomers. However, butene has one double bond between two of the carbon atoms. The molar mass of butene is about 56.11 g/mol.

Figure 2: Cis-trans Isomerism of Butene

The isomerism of butene occurs either as structural isomerism or stereoisomerism. The position of the double bond decides the structural isomerism. 1-butene has the double bond at the end of the carbon chain whereas 2-butene has the double bond in the middle of the carbon chain. Moreover, the branched structure isobutylene is another structural isomer of the linear butene molecule. Stereoisomerism occurs according to the differences in the position of alkyl groups at allylic carbon atoms. This is called geometrical isomerism.

Butene is produced in petroleum refining. The production of butene is done through cracking reaction. This is the breakdown of long chain hydrocarbons into small hydrocarbon molecules. Butene is a flammable gas and can be used as a fuel. Butene is an important monomer in the production of polymers. The double bond present in butene allows it to undergo polymerization which will eventually produce a polymer molecule.

Similarities Between Butane and Butene

Butane and butene are hydrocarbons.
These are gases at room temperature and pressure.
Both are colorless gases.
Butane and butene can be obtained from petroleum refining processes.
Both are highly flammable.
Both types show isomerism.

Definition

Butane: Butane is a hydrocarbon that has the chemical formula C₄H₁₀.

Butene: Butene is a hydrocarbon that has the chemical formula C₄H₈.

Chemical Bonding

Butane: Butane has only single bonds.

Butene: Butene has a double bond as well as single bonds.

Classification

Butane: Butane is an alkane.

Butene: Butene is an alkene.

Cis-trans Isomerism

Butane: Butane does not show cis-trans isomerism.

Butene: Butene shows cis-trans isomerism.

Molar Mass

Butane: The molar mass of butane is 58.12 g/mol.

Butene: The molar mass of butene is about 56.11 g/mol.

Conclusion

Butane and butene gases can be used as fuel. These gases produce heat when they are burnt. In addition, butane is used as a solvent for extractions due to its nonpolar properties. Butene is a monomer for the production of different types of polymers. The double bond present in butene allows it to act as a monomer. The main difference between butane and butene is that there are no double bonds in butane molecules whereas butene molecules have one double bond.

References:

1. “Butane.” Encyclopædia Britannica, Encyclopædia Britannica, inc., Available here. Accessed 23 Aug. 2017.
2. “Butene.” Wikipedia, Wikimedia Foundation, 18 Aug. 2017, Available here. Accessed 23 Aug. 2017.

Image Courtesy:

1. “EZalkenes2” By Emmmmmms at English Wikipedia – Own work (Public Domain) via Commons Wikimedia