Difference Between 1 Butanol and 2 Butanol

Main Difference – 1 Butanol vs 2 Butanol

Butanol is an alcohol. It is an organic compound having the functional group –OH attached to a carbon atom. Butanol has four carbon atoms. The general formula of butanol is C₄H₉OH. This formula has five isomeric structures. Isomers are molecules with the same molecular formula but different chemical structures. 1 Butanol and 2 butanol are two of these isomers. The main difference between 1 Butanol and 2 Butanol is that 1 butanol has the –OH group attached to the terminal carbon of the molecule whereas 2 butanol has the –OH group attached to the second carbon atom.

Key Areas Covered

1. What is 1 Butanol
     – Definition, Chemical Properties, Chemical Structure
2. What is 2 Butanol
     – Definition, Chemical Properties, Chemical Structure
3. What is the Difference Between 1 Butanol and 2 Butanol
     – Comparison of Key Differences

Key Terms: Alcohol, Butanol, Chiral Center, Chirality, Isomers, Racemic Mixture, Stereoisomers

What is 1 Butanol

1 Butanol is an alcohol having the chemical formula C₄H₉OH. The molar mass is 74.12 g/mol. The IUPAC name of this compound is butan-1-ol. At room temperature and pressure, 1 butanol is a colorless liquid. The boiling point of 1 butanol is 117.7 °C and the melting point -89.8 °C.

Figure 1: Chemical Structure of 1 Butanol

When considering the chemical structure of 1 butanol, it has four carbon atoms bonded to each other via single covalent bonds forming a carbon chain. One carbon atom at the terminal of this carbon chain is attached to a –OH group. The rest of the vacant points of the carbon chain are occupied with hydrogen atoms. 1 butanol has a linear structure. It is a primary alcohol since the carbon atom to which –OH group is attached is a primary carbon atom (a carbon atom attached to only one other carbon atom).

What is 2 Butanol

2 Butanol is an alcohol having the chemical formula C₄H₉OH. The molar mass is 74.12 g/mol. The IUPAC name of this compound is butan-2-ol. It is a colorless, flammable liquid at room temperature and pressure. The boiling point of 2 butanol is 99.5 °C, and the melting point is -114.7 °C.

Figure 2: Chemical Structure of 2 Butanol

2 butanol is a secondary alcohol since it is a compound whose hydroxyl group, ‒OH, is attached to a saturated carbon atom which has two other carbon atoms attached to it. 2 butanol is a chiral compound. The carbon atom attached with –OH group is a chiral center. Therefore, this molecule has stereoisomers. 2 Butanol is often found as a racemic mixture of stereoisomers. The stereoisomers of 2 butanol are (R)-2-butanol and (S)-2-butanol.

Difference Between 1 Butanol and 2 Butanol

Definition

1 Butanol: 1 Butanol is an alcohol having the chemical formula C₄H₉OH.

2 Butanol: 2 Butanol is an alcohol having the chemical formula C₄H₉OH.

Category

1 Butanol: 1 Butanol is a primary alcohol.

2 Butanol: 2 Butanol is a secondary alcohol.

Boiling Point

1 Butanol: The boiling point of 1 butanol is 117.7 °C.

2 Butanol: The boiling point of 2 butanol is 99.5 °C.

Melting Point

1 Butanol: The melting point of 1 butanol is -89.8 °C.

2 Butanol: The melting point of 2 butanol is -114.7 °C.

Chirality

1 Butanol: 1 Butanol has no chiral centers.

2 Butanol: 2 Butanol has a chiral center.

Stereoisomers

1 Butanol: 1 Butanol has no stereoisomers.

2 Butanol: 2 butanol has stereoisomers.

IUPAC Name

1 Butanol: The IUPAC name of 1 butanol is butal-1-ol.

2 Butanol: The IUPAC name of 2 butanol is butan-2-ol.

Conclusion

Butanol is a colorless liquid at room temperature and pressure. It is a hydrocarbon compound. It has five major isomeric structures. 1 butanol and 2 butanol are two of them. The main difference between these two molecules is that 1 butanol has the –OH group attached to the terminal carbon of the molecule whereas 2 butanol has the –OH group attached to the second carbon atom.

Reference: 

1. “1-Butanol.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
2. “2-Butanol.” Wikipedia, Wikimedia Foundation, 22 Dec. 2017, Available here.
3. “2-Butanol.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.

Image Courtesy:

1. “Butanol flat structure” By Cacycle – Own work (Public Domain) via Commons Wikimedia
2. “Représentations du butan-2-ol” By Rhadamante assumed -Own work assumed (based on copyright claims)., (CC BY-SA 3.0) via Commons Wikimedia