Esters are organic chemical compounds whose structure has the general form:general molecular structure of an ester (class of organic compounds)where the symbols "R1" and "R2" represent organic radicals, usually carbon chains.[Symbols such as "R","R' ", "R1", "R2", "R1" and "R2" and similar are often used to represent organic radicals in general, which are frequently (linear or branched) carbon chains that may or may not have additional functional groups attached, or can alternatively be hydrogen atoms or halogen atoms, e.g. flourine (F), chlorine (Cl), bromine (Br).]In the case of esters, "R1" and "R2" are often carbon chains that may be either linear or branched and may also have other functional groups attached."R2" is not a hydrogen atom because if it were, the molecule would be a carboxylic acid rather than an ester.The simplest esters to describe are those where both R1 and R2 are "an alkane less the hydrogen atom at the end of the chain", and hence where the hydrogen atom at the end of the corresponding alkane is replaced by the carbon or oxygen atom to which that "R" (so, R1 or R2 in the diagram above) is attached.R1 and R2 are not necessarily the same (hence the "1" and "2" to distinguish them in the general definition of an ester). However, they may be the same.Names of Esters in GeneralEsters are named according to the standard system of naming organic compunds. As true for other types of organic compounds, there are also some non-standard names for esters in common usage. Some of the alternative names used for the simple esters shown in the tables of examples on this page are listed in the column under the header "synonyms".The standard system for naming esters uses the suffix -oate to indicate that a molecule is an ester.The two organic radicals (which are often carbon chains) labelled "R1" and "R2" in the diagram at the top of this page are also identified in the name of the compound, or molecule drawn-out to represent the compound.This may be explained using a diagram of the simple example of ethyl propanoate:Names and Structures of simple Linear Esters in which R2 = CH3, which is known as a "-methyl group"The homologous series of linear esters that include a -methyl group attached (via a single covalent bond) to the oxygen atom in the chain of the ester molecule. This description is easier to follow in conjunction with viewing the molecular structures in the table:methyl formate (C2H4O2)Simple Structure:molecular structure of methyl formate*Examples of other / previous names:methyl formatemethyl methanoateformic acid, methyl estermethyl ethanoate (C3H6O2)Simple Structure:molecular structure of methyl ethanoate*Examples of other / previous names:methyl acetatemethylacetatemethyl acetic esteracetic acid, methyl esterdevotonteretonmethyl propanoate (C4H8O2)Simple Structure:molecular structure of methyl propanoate*Examples of other / previous names:methyl propanoatemethyl propionatemethyl propylatepropanoic acid, methyl esterpropionic acid, methyl estermethyl butanoate (C5H10O2)Simple Structure:molecular structure of methyl butanoate*Examples of other / previous names:methyl butanoatemethyl n-butanoatemethyl butyratebutanoic acid, methyl esterbutyric acid, methyl estermethyl n-butyratemethyl-n-butyratemethyl n-butanoate2-methyl butyric acidmethyl pentanoate (C6H12O2)Simple Structure:molecular structure of methyl pentanoate*Examples of other / previous names:methyl pentanoatemethyl valeratevaleric acid, methyl esterpentanoic acid, methyl estermethyl n-valeratemethyl valerianatemethyl hexanoate (C7H14O2)Simple Structure:molecular structure of methyl hexanoate*Examples of other / previous names:methyl hexanoatemethyl caproatehexanoic acid, methyl estermethyl hexoatemethyl capronatemethyl n-hexanoatemethyl hexylatecaproic acid methyl esterhexanoic acid methyl esterNames and Structures of simple Linear Esters in which R2 = CH2CH3, which is known as an "-ethyl group"The homologous series of linear esters that include an -ethyl group attached (via a single covalent bond) to the oxygen atom in the chain of the ester molecule. This description is easier to follow in conjunction with viewing the molecular structures in the table:ethyl formate (C3H6O2)Simple Structure:molecular structure of ethyl formate*Examples of other / previous names:ethyl formateethyl methanoateethyl formic esterformic acid, ethyl esterformic etherformic acid ethyl estercarboxylic acid oxaethaneareginalethyl ethanoate (C4H8O2)Simple Structure:molecular structure of ethyl ethanoate*Examples of other / previous names:ethyl acetateethylacetateacetoxyethaneacetic acid, ethyl esterethyl acetic estervinegar naphthaethylacetateacetidinacetic acid ethyl esteracetic esterethyl propanoate (C5H10O2)Simple Structure:molecular structure of ethyl propanoate*Examples of other / previous names:ethyl propanoateethyl propionatepropanoic acid, ethyl esterpropionic esterethyl butanoate (C6H12O2)Simple Structure:molecular structure of ethyl butanoate*Examples of other / previous names:ethyl butanoateethyl butyrateethyl n-butyratebutanoic acid, ethyl esterbutyric acid, ethyl esterbutyric esterbutyric acid ethyl esterbutanoic acid ethyl esterethyl pentanoate (C7146O2)Simple Structure:molecular structure of ethyl pentanoate*Examples of other / previous names:ethyl pentanoateethyl valeratevaleric acid, ethyl esterethyl n-valeratepentanoic acid, ethyl esterethyl valerianateethyl hexanoate (C8H16O2)Simple Structure:molecular structure of ethyl hexanoate*Examples of other / previous names:ethyl hexanoateethyl caproateethyl hexoateethyl butyl acetatehexanoic acid, ethyl estercaproic acid ethyl estercapronic ether absolutecaproic acid ethylesterNames and Structures of simple Linear Esters in which R2 = CH2CH2CH3, which is known as an "-propyl group"The homologous series of linear esters that include an -propyl group attached (via a single covalent bond) to the oxygen atom in the chain of the ester molecule. This description is easier to follow in conjunction with viewing the molecular structures in the table:propyl formate (C4H8O2)Simple Structure:molecular structure of propyl formate*Examples of other / previous names:propyl formatepropyl methanoaten-propyl methanoaten-propyl formateformic acid, propyl esterpropyl ethanoate (C5H10O2)Simple Structure:molecular structure of propyl ethanoate*Examples of other / previous names:propyl acetaten-propylacetateacetic acid, propyl ester1-acetoxypropane1-propyl acetaten-propyl ethanoateacetic acid propyl esteracetic acid n-propyl esterpropyl propanoate (C6H12O2)Simple Structure:molecular structure of propyl propanoate*Examples of other / previous names:propyl propanoatepropyl propionaten-propyl propionatepropanoic acid, propyl esterpropionic acid, propyl esterpropyl propanoaten-ropyl propanoatepropyl butanoate (C7H14O2)Simple Structure:molecular structure of propyl butanoate*Examples of other / previous names:propyl butanoatepropyl butyratebutyric acid, propyl esterbutanoic acid, propyl esterpropyl butanoatepropyl n-butyrate1-propyl butyraten-propyl-n-butanoatepropyl pentanoate (C8H16O2)Simple Structure:molecular structure of propyl *Examples of other / previous names:propyl pentanoaten-propyl n-valeratepropyl valeratevaleric acid, propyl esterpentanoic acid, propyl esterpropyl hexanoate (C9H18O2)Simple Structure:molecular structure of propyl hexanoate*Examples of other / previous names:propyl hexanoaten-propyl hexanoatepropyl caproatehexanoic acid, propyl estercaproic acid propyl esterWhy stop at six carbon atoms (before the -O- )? It doesn't. There are more similar linear esters.

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