The key difference between Fischer esterification and Steglich esterification is that Fischer esterification involves the reaction between a carboxylic acid and an alcohol in the presence of a strong acid as the catalyst whereas Steglich esterification involves the reaction between a carboxylic acid and an alcohol in the presence of dimethylaminopyridine (DMAP) as a catalyst.
Esterification is an important organic synthesis reaction in chemistry where we can produce an ester compound using a carboxylic acid and an alcohol. This reaction, however, requires a catalyst to boost the reaction. The Fischer esterification and Steglich esterification are two types of esterification reactions where we can use two different types of catalysts that are specific to each reaction.
CONTENTS
1. Overview and Key Difference
2. What is Fischer Esterification
3. What is Steglich Esterification
4. Side by Side Comparison – Fischer Esterification vs Steglich Esterification in Tabular Form
5. Summary
What is Fischer Esterification?
Fischer esterification is a type of organic chemical reaction in which we can produce an ester through the reaction between a carboxylic acid and an alcohol in the presence of a strong acid as the catalyst. It is a special type of esterification reaction in which the refluxing of the carboxylic acid and alcohol occurs to give the final product. This method was developed by Emil Fischer in 1895. Almost all carboxylic acid compounds are suitable for this reaction, but only primary and secondary alcohols can be used. When tertiary alcohols are used, it can cause an elimination reaction rather than esterification. The commonly used catalyst for this reaction is sulfuric acid; however, there are some other catalysts as well, such as p-toluenesulfonic acid and Lewis acids.
Figure 01: An Apparatus Used for Fisher Esterification
The Fischer esterification is suitable for less valuable and less sensitive substrates. When considering the esterification reaction that is involved in this method, we often use a medium where there is no solvent, mostly when a large excess amount of alcohol is used. Or else, the method is carried out using a nonpolar solvent such as toluene. This type of solvents facilitates the Dean-Stark method (an important technique that helps in collecting the water that is produced as a byproduct of the esterification).
What is Steglich Esterification?
Steglich esterification is a type of organic chemical reaction in which we can produce an ester through the reaction between a carboxylic acid and an alcohol in the presence of dimethylaminopyridine (DMAP) as a catalyst and dicyclohexylcarbodimide (DCC) as a coupling agent. This reaction method was developed by the scientist Wolfgang Steglich in 1978.
Figure 02: General Formula for Stiglich Esterification
Generally, this reaction occurs at room temperature. The most suitable solvent for this route is dichloromethane. This reaction is very mild so, we can obtain esters that are inaccessible through other methods. As a characteristic feature, we can observe (the water produced in this method) uptake by DCC. This water uptake forms a urea compound, dicyclohexylurea (DCU).
What is the Difference Between Fischer Esterification and Steglich Esterification?
Esterification is an organic chemical reaction that is useful in producing an ester. The key difference between Fischer esterification and Steglich esterification is that Fischer esterification involves the reaction between a carboxylic acid and an alcohol in the presence of a strong acid as the catalyst whereas Steglich esterification involves the reaction between a carboxylic acid and an alcohol in the presence of dimethylaminopyridine (DMAP) as a catalyst.
Below infographic tabulates more differences between Fischer esterification and Steglich esterification.
Summary – Fischer Esterification vs Steglich Esterification
Fischer esterification and Steglich esterification are two types of esterification reactions that are different from each other according to the catalyst used in the reaction. The key difference between Fischer esterification and Steglich esterification is that Fischer esterification involves the reaction between a carboxylic acid and an alcohol in the presence of a strong acid as the catalyst whereas Steglich esterification involves the reaction between a carboxylic acid and an alcohol in the presence of dimethylaminopyridine (DMAP) as a catalyst.
Reference:
1. “Fischer Esterification.” Chemistry LibreTexts, Libretexts, 13 Sept. 2020, Available here.
Image Courtesy:
1. “Fischer Esterification by Sam Tet Students” By Gan Kin Boon – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “SteglichVeresterung Uebersicht” By MaChe (talk) – Own work (Public Domain) via Commons Wikimedia