Editing Ester (section)

== Nomenclature ==

=== Etymology ===
The word ''ester'' was coined in 1848 by a German chemist [[Leopold Gmelin]],<ref>Leopold Gmelin, ''Handbuch der Chemie'', vol. 4: ''Handbuch der organischen Chemie'' (vol. 1) (Heidelberg, Baden (Germany): Karl Winter, 1848), [https://books.google.com/books?id=4ooMAQAAIAAJ&pg=PA182 page 182].<br />
Original text:<blockquote>{{lang|de|b. Ester oder sauerstoffsäure Aetherarten.<br />Ethers du troisième genre.<br /><br />Viele mineralische und organische Sauerstoffsäuren treten mit einer Alkohol-Art unter Ausscheidung von Wasser zu neutralen flüchtigen ätherischen Verbindungen zusammen, welche man als gepaarte Verbindungen von Alkohol und Säuren-Wasser oder, nach der Radicaltheorie, als Salze betrachten kann, in welchen eine Säure mit einem Aether verbunden ist.}}</blockquote>Translation:<blockquote>b. Ester or oxy-acid ethers.<br />Ethers of the third type.<br /><br />Many mineral and organic acids containing oxygen combine with an alcohol upon elimination of water to [form] neutral, volatile ether compounds, which one can view as coupled compounds of alcohol and acid-water, or, according to the theory of radicals, as salts in which an acid is bonded with an ether. </blockquote></ref> probably as a contraction of the German {{lang|de|Essigäther}}, "[[Ethyl acetate|acetic ether]]".

=== IUPAC nomenclature ===
{{Main|IUPAC nomenclature of organic chemistry#Esters}}
The names of esters that are formed from an alcohol and an acid, are derived from the parent alcohol and the parent acid, where the latter may be organic or inorganic. Esters derived from the simplest [[carboxylic acid]]s are commonly named according to the more traditional, so-called "[[trivial names]]" e.g. as formate, acetate, propionate, and butyrate, as opposed to the IUPAC nomenclature methanoate, ethanoate, propanoate, and butanoate. Esters derived from more complex carboxylic acids are, on the other hand, more frequently named using the systematic IUPAC name, based on the name for the acid followed by the suffix ''-oate''. For example, the ester hexyl octanoate, also known under the trivial name hexyl [[Caprylic acid|caprylate]], has the formula {{chem2|CH3(CH2)6CO2(CH2)5CH3}}.

[[Image:Butyl acetate ester example.png|thumb|[[Butyl acetate]], an ester derived from a residue of [[butanol]] ({{chem2|CH3CH2CH2CH2OH}}) (the butanol residue is [[butyl group]] {{chem2|\sCH2CH2CH2CH3}}) (right side of the picture, blue) and [[acetic acid]] {{chem2|CH3CO2H}} (left side of the picture, orange). The [[acid]]ic [[hydrogen]] atom ({{chem2|\sH}}) from acetic acid [[molecule]] is replaced by the butyl group.]]

The chemical formulas of organic esters formed from carboxylic acids and alcohols usually take the form {{chem2|RCO2R'}} or RCOOR', where R and R' are the [[organyl]] parts of the carboxylic acid and the alcohol, respectively, and R can be a [[hydrogen]] in the case of esters of [[formic acid]]. For example, [[butyl acetate]] (systematically butyl ethanoate), derived from [[n-Butanol|butanol]] and [[acetic acid]] (systematically ethanoic acid) would be written {{chem2|CH3CO2(CH2)3CH3}}. Alternative presentations are common including BuOAc and {{chem2|CH3COO(CH2)3CH3}}.

Cyclic esters are called [[lactone]]s, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is [[gamma-valerolactone|γ-valerolactone]].

=== Orthoesters ===
An uncommon class of esters are the [[orthoester]]s. One of them are the esters of orthocarboxylic acids. Those esters have the formula {{chem2|RC(OR′)3}}, where R stands for any group (organic or inorganic) and R{{prime}} stands for [[organyl]] group. For example, [[triethyl orthoformate]] ({{chem2|HC(OCH2CH3)3}}) is derived, in terms of its name (but not its synthesis) from [[esterification]] of [[orthoformic acid]] ({{chem2|HC(OH)3}}) with [[ethanol]].

===Esters of inorganic acids===
[[Image:Phosphate Group.svg|130px|thumb|A phosphoric acid ester, where R stands for an [[organyl]] group.]]
Esters can also be derived from inorganic acids.
*[[Perchloric acid]] forms [[perchlorate]] esters, e.g., [[methyl perchlorate]] ({{chem2|CH3\sO\sCl(\dO)3}})
*[[Sulfuric acid]] forms [[organosulfate|sulfate ester]]s, e.g., [[dimethyl sulfate]] ({{chem2|(CH3\sO\s)2S(\dO)2}}) and [[methyl bisulfate]] ({{chem2|CH3\sO\sS(\dO)2\sOH}})
*[[Nitric acid]] forms [[organic nitrate|nitrate esters]], e.g. [[methyl nitrate]] ({{chem2|CH3\sO\sNO2}}) and [[nitroglycerin]] ({{chem2|CH(\sO\sNO2)(\sCH2\sO\sNO2)2}})
*[[Phosphoric acid]] forms [[phosphate ester]]s, e.g. [[triphenyl phosphate]] ({{chem2|O\dP(\sO\sC6H5)3}}) and [[methyl dihydrogen phosphate]] ({{chem2|O\dP(\sO\sCH3)(\sOH)2}})
**[[Pyrophosphoric acid|Pyrophosphoric (diphosphoric) acid]] forms [[pyrophosphate]] esters, e.g. [[tetraethyl pyrophosphate]], [[Adenosine diphosphate|ADP]], [[dADP]], [[ADPR]], [[cADPR]], [[Cytidine diphosphate|CDP]], [[dCDP]], [[Guanosine diphosphate|GDP]], [[Deoxyguanosine diphosphate|dGDP]], [[Uridine diphosphate|UDP]], [[dTDP]], [[MEcPP]], [[HMBPP]], [[DMAPP]], [[Isopentenyl pyrophosphate|IPP]], [[Geranyl pyrophosphate|GPP]], [[Farnesyl pyrophosphate|FPP]], [[Geranylgeranyl pyrophosphate|GGPP]], [[ThDP]], [[FAD]], [[Nicotinamide adenine dinucleotide|NAD]], [[NADP]].
**[[Triphosphoric acid]] forms [[triphosphate]] esters, e.g. [[Adenosine triphosphate|ATP]], [[dATP]], [[Cytidine triphosphate|CTP]], [[dCTP]], [[Guanosine triphosphate|GTP]], [[dGTP]], [[Uridine triphosphate|UTP]], [[dTTP]], [[Inosine triphosphate|ITP]], [[Xanthosine triphosphate|XTP]], [[ThTP]], [[AThTP]].
**[[Tetraphosphoric acid]] forms tetraphosphate esters, e.g. [[hexaethyl tetraphosphate]], [[adenosine tetraphosphate]] (ATPP, Ap4), [[Ap4A]].
*[[Carbonic acid]] forms [[carbonate ester]]s, e.g. [[dimethyl carbonate]] ({{chem2|(CH3\sO\s)2C\dO}}) and 5-membered [[cyclic compound|cyclic]] [[ethylene carbonate]] ({{chem2|(\sCH2\sO\s)2C\dO}}) (if one classifies carbonic acid as an inorganic compound)
*[[Thiocarbonic acid|Trithiocarbonic acid]] forms [[thiocarbonate|trithiocarbonate ester]]s, e.g. [[dimethyl trithiocarbonate]] ({{chem2|(CH3\sS\s)2C\dS}}) (if one classifies trithiocarbonic acid as an inorganic compound)
*[[Chloroformic acid]] forms [[chloroformate]] esters, e.g. [[methyl chloroformate]] ({{chem2|Cl\sC(\dO)\sO\sCH3}}) (if one classifies chloroformic acid as an inorganic compound)
*[[Boric acid]] forms [[Borate#Borate esters|borate esters]], e.g. [[trimethyl borate]] ({{chem2|B(\sO\sCH3)3}})
*[[Chromic acid]] forms [[di-tert-butyl chromate|di-''tert''-butyl chromate]] ({{chem2|((CH3)3C\sO\s)2Cr(\dO)2}})

Inorganic acids that exist as [[tautomers]] form two or more types of esters.
*[[Thiosulfuric acid]] forms two types of [[thiosulfate]] esters, e.g. ''O'',''O''-dimethyl thiosulfate ({{chem2|(CH3\sO\s)2S(\dO)(\dS)}}) and ''O'',''S''-dimethyl thiosulfate ({{chem2|(CH3\sO\s)(CH3\sS\s)S(\dO)2}})
*[[Thiocyanic acid]] forms [[thiocyanate]] esters, e.g. [[methyl thiocyanate]] ({{chem2|CH3\sS\sC\tN}}) (if one classifies thiocyanic acid as an inorganic compound), but forms [[isothiocyanate]] "esters" as well, e.g. [[methyl isothiocyanate]] ({{chem2|CH3\sN\dC\dS}}), although [[organyl]] isothiocyanates are not classified as esters by the [[IUPAC]]
*[[Phosphorous acid]] forms two types of esters: [[phosphite ester]]s, e.g. [[triethyl phosphite]] ({{chem2|P(\sO\sCH2CH3)3}}), and [[Phosphonate|phosphonate esters]], e.g. [[diethyl phosphite|diethyl phosphonate]] ({{chem2|H\sP(\dO)(\sO\sCH2CH3)2}})

Some inorganic acids that are unstable or elusive form stable esters.
*[[Sulfurous acid]], which is unstable, forms stable [[dimethyl sulfite]] ({{chem2|(CH3\sO\s)2S\dO}})
*[[Dicarbonic acid]], which is unstable, forms stable [[dimethyl dicarbonate]] ({{chem2|CH3\sO\sC(\dO)\sO\sC(\dO)\sO\sCH3}})

In principle, a part of metal and metalloid [[alkoxide]]s, of which many hundreds are known, could be classified as esters of the corresponding acids (e.g., [[aluminium triethoxide]] ({{chem2|Al(OCH2CH3)3}}) could be classified as an ester of aluminic acid which is [[aluminium hydroxide]], [[tetraethyl orthosilicate]] ({{chem2|Si(OCH2CH3)4}}) could be classified as an ester of [[orthosilicic acid]], and [[titanium ethoxide]] ({{chem2|Ti(OCH2CH3)4}}) could be classified as an ester of [[Titanic acid|orthotitanic acid]]).