What is the Difference Between 1 2 Addition and 1 4 Addition

The key difference between 1 2 addition and 1 4 addition is that in 1 2 addition, the functional groups attach to the 1^st and 2^nd carbon atoms of a certain carbon chain, whereas in 1 4 addition process, the functional groups attach to the 1^st and 4^th carbon atoms of the carbon chain.

1 2  addition or 1,2-addition and 1 4 addition or 1,4-addition are two important addition reaction processes that take place in organic compounds. These are very important in obtaining a desired organic chemical product.

CONTENTS

1. Overview and Key Difference
2. What is 1 2 Addition 
3. What is 1 4 Addition
4. 1 2 Addition vs 1 4 Addition in Tabular Form
5. Summary – 1 2 Addition vs 1 4 Addition

What is 1 2 Addition?

1 2 addition or 1,2-addition is a type of organic chemical reaction that involves the addition of functional groups to the 1^st and 2^nd carbon atoms of a carbon chain. In other words, the functional groups in the product of this reaction are attached to the adjacent carbon atoms. Moreover, the 1,2-addition reaction has smaller activation energy compared to the 1 4 addition reaction.

In the above image, the cyclic structure has a double bond between two carbon atoms. The H and Cl atoms of the hydrochloric acid compound (HCl) cleave their bond and attach to the cyclic structure through the double bond breakage. Therefore, the two functional groups, H and Cl, are located on the adjacent carbon atoms.

What is 1 4 Addition?

1 4  addition or 1,4-addition is a type of organic chemical reaction that involves the addition of functional groups to the 1^st and 2^nd carbon atoms of a carbon chain. This means the functional groups in the product of the 1 4 addition reaction are attached to non-adjacent carbon atoms. Moreover, the 1,4-addition reaction has higher activation energy compared to the 1 2  addition reaction.

The above example in the image shows the addition of monomers to form a polymer. The monomers are attached to each other through the 1^st and 4^th carbon atoms of each chain (except the monomers where 1,2-additions have occurred).

What is the Difference Between 1 2 Addition and 1 4 Addition?

1 2  addition or 1,2-addition and 1 4 addition or 1,4-addition are two important addition reaction processes that take place in organic compounds. The key difference between 1 2 addition and 1 4 addition is that in 1 2 addition, the functional groups attach to the 1^st and 2^nd carbon atoms of a certain carbon chain, whereas in 1 4 addition process, the functional groups get attached to the 1^st and 4^th carbon atoms of the carbon chain. Moreover, the 1 4 addition reaction has higher activation energy than the 1 2  addition reaction. In addition, in 1 2 addition, functional groups are attached to adjacent carbon atoms, whereas in 1 4 addition, functional groups are attached to non-adjacent carbon atoms.

The below infographic presents the differences between 1 2 addition and 1 4 addition in tabular form in tabular form for side by side comparison.

Summary – 1 2 Addition vs 1 4 Addition

1 2 addition and 1 4 addition are very important in obtaining a desired organic chemical product. The key difference between 1 2 addition and 1 4 addition is that in the 1 2 addition, the functional groups attach to the 1^st and 2^nd carbon atoms of a certain carbon chain, whereas in 1 4 addition process, the functional groups get attached to the 1^st and 4^th carbon atoms of the carbon chain. Moreover, the 1 4 addition reaction has higher activation energy than the 1 2  addition reaction.

Reference:

1. “16.8 Electrophilic Addition: 1,2- versus 1,4-Addition.” Chemistry LibreTexts, Libretexts, 24 Jan. 2022.

Image Courtesy:

1. “Addition Reaction Example1 V.1” By Jü – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “1,3-Butadiene Polymerization” By Naturwiki – Own work (CC BY-SA 4.0) via Commons Wikimedia