Difference between SN1 Reactions and SN2 Reactions
Main difference
Organic chemistry is the compact field, filled with simple to complex reactions that form different organic compounds. Based on nucleophilic substitution reactions, S N 1 and S N 2 are two different types of reactions in the field of organic chemistry. S N 1 represents unimolecular reactions, it is also known as first order reaction, where the reaction rate can be expressed as K [R-LG], on the other hand, S N 2 represents bimolecular reactions, where the reaction rate it can be expressed as K ‘[R-LG] [Nu – ]. The other difference between these two types of nucleophilic substitution reactions is that S N1 is a complex reaction as it is a multi-step process, while S El N 2 is a simple reaction and it is a one-step process. In the S N 1 reaction , the substrate affects the reaction rate, while in the S N 2 reaction , both the substrate and the nucleophile appreciate the reaction rate.
Comparative chart
| SN1 reaction | SN2 reaction | |
| Type | S N 1 represents the unimolecular reaction. | S N 2 represents bimolecular reactions. |
| Steps | S N 1 is a complex reaction and it is a multi-step process. | S N 2 is a simple reaction since it is a one-step process. |
| Factors | In the S N 1 reaction , the substrate affects the reaction rate. | In the S N 2 reaction , both the substrate and the nucleophile appreciate the reaction rate. |
| Expression of reaction rate | In S N 1, the reaction rate can be expressed as K [R-LG]. | The reaction rate of S N 2 can be expressed as K ‘[R-LG] [Nu – ]. |
What is the SN1 reaction?
It is the type of nucleophilic substitution reaction that is a complex reaction process as it is a multi-step process. This type of reaction can be expressed as K [R-LG], it means that the substrate directly affects the efficiency of this type of reaction. S N 1 represents unimolecular reactions, and with this two-step process a carbocation is initially formed. It is worth mentioning that in S N 1 Reaction; carbocation stability is the key factor. As mentioned above, S N 1 is the two-step process that forms intermediate and transition states as the reaction progresses. The intermediate state is more stable than the other transition stages, since the stable carbocation is initially formed in it. The SN 1 reaction product can lead to the formation of a racemic mixture.
What is the SN2 reaction?
It is the type of nucleophilic substitution reaction that is a one-time reaction, as it is a one-step process. This type of reaction rate can be expressed as K ‘[R-LG] [Nu – ]. In the S N 2 reaction , both the substrate and the nucleophile affect the reaction rate. S N 2 represents the bimolecular reaction and is a one-step process. Since the reaction S N 1 is the first-order reaction, S N2 reaction is called a second-order reaction. Apart from SN2 and second-order reaction, this type of reaction is also called “associative substitution” or “exchange mechanism.” in the field of organic chemistry. Two molecular species are involved in the rate determination step, resulting in the bimolecular nucleophilic substitution reaction, or SN2. In the SN2 type of reaction, two molecules are involved in the transition state.
SN1 vs SN2 reactions
- S N 1 represents unimolecular reactions, while S N 2 represents bimolecular reactions.
- S N 1 is a complex reaction since it is a multi-step process, while S N 2 is a simple reaction since it is a one-step process.
- In the S N 1 reaction , the substrate affects the reaction rate, while in the S N 2 reaction , both the substrate and the nucleophile affect the reaction rate.
- In S N 1, the reaction rate can be expressed as K [R-LG], on the other hand, the reaction rate S N 2 can be expressed as K ‘[R-LG] [Nu – ].
