Ester vs Ether
Ester and ether are organic molecules with oxygen atoms. Both have the ether linkage which is –O-. Esters have the group –COO. One oxygen atom is bonded to carbon with a double bond, and the other oxygen is bonded with a single bond. Since only three atoms are connected to the carbon atom, it has a trigonal planar geometry around it. Further, the carbon atom is sp2 hybridized. Carboxyl group is a widely occurring functional group in chemistry and bio chemistry. This group is the parent of related family of compounds known as acyl compounds. Acyl compounds are also known as carboxylic acid derivatives. Ester is a carboxylic acid derivative like that.
Esters have a general formula of RCOOR’. Esters are made by the reaction between a carboxylic acid with an alcohol. Esters are named by writing the names of the alcohol derived part first. Then the name derived from the acid part is written with the ending –ate or –oate. For example, ethyl acetate is the name of the following ester.
Esters are polar compounds, but they don’t have the capability to form strong hydrogen bonds to each other due to the lack of hydrogen bounded to oxygen. As a result, esters have lower boiling points compared to acids or alcohols with similar molecular weights. Often esters have a pleasant smell which is responsible for producing the characteristic smells of fruits, flowers, etc.
This is a type of organic molecule where two alkyl groups, aryl groups, or an alkyl and an aryl group are connected to both side of an oxygen atom. Depending on the R groups, ethers can be symmetrical or unsymmetrical. If both R groups are similar, then the ether is symmetrical and, if both are different, it is unsymmetrical. For example, dimethylether is the simplest ether with the following formula.
Oxygen has a sp3 hybridization and the two lone pairs are in two hybridized orbitals while two are participating in bonding with R groups. R-O-R bond angle is about 104.5° which is similar to water. Boiling points of ethers are roughly comparable with those of hydrocarbons with the same molecular weight, but the boiling points of ethers are less than the value of alcohols. Though ethers cannot make hydrogen bonds within them, they are able to form hydrogen bonds with other compounds such as water. Therefore, ethers are soluble in water, but the solubility may decrease depending on the length of the hydrocarbon chains attached.
Ethers can be produces by intermolecular dehydration of alcohols. This usually takes place at a lower temperature than dehydration to the alkene. Williamson synthesis is another method to produce unsymmetrical ethers. This synthesis takes place between a sodium alkoxide and an alkyl halide, alkyl sulfonate or alkyl sulfate. Dilakyl ethers react with very few reagents other than acids. The reactive sites are the C-H bonds of the alkyl groups and the –o- group of the ether linkage.
What is the difference between Ester and Ether?
• Esters are carboxylic acid derivatives and have the group –COO. Ethers have the –O- functional group.
• Ester has a carbonyl group adjacent to the –O- oxygen, but ether doesn’t have such.
• Esters have so many characteristic smells.
• Esters are easily hydrolyzed to produce an alcohol and a carboxylic acid in contrast to ethers.