Ester Group are a functional group that we usually encounter in organic chemistry. They are characterized by carbon attached to three other atoms, a single bond to a carbon, a double bond to an oxygen, and a single bond to an oxygen. Unique oxygen is limited to another carbon.
The term “ester” was coined in 1848 by the German chemist Leopold Gmelin. It was probably the German word for contraction, “essigäther”, which means “ether steak”. Esters are generally represented by RCOOR or RCO2R. Esters are usually fragrant, and those whose molecular weight is sufficiently unstable are commonly used as fragrances and are found in essential oils and pheromones. Polymerized esters or polyesters are also very important plastics.
Ester Group contain a carbonyl center that creates a 120-degree C-C-O and O-C-O bond angle due to sp2 hybridization. Unlike amides, esters are structurally flexible because rotation in the case of C-O-C blocks less energy. Their flexibility and low polarity affect their macroscopic physical properties. They tend to be firmer and lead to a lower and more unstable melting point and lead to a lower boiling point than the corresponding amides.
Ethyl acetate (ethyl acetate) is ester. Other examples of esters include ethylpropanoate, propyl methanate, propyl ethanoate, and methyl butanoate. Glycerides are also glycerol fat esters. Fats and oils are examples of esters. The difference between them is the melting point of their esters. If the melting point is below room temperature, ester is considered an oil (such as vegetable oil). On the other hand, if the ester is at room temperature, it is considered fat (such as butter or beef).
The source of this article is the Persian section of the site, which you can read if you are fluent in Persian: گروه استری