Ester

In <a href="/facts/Chemistry/SrNqkGVm">chemistry</a>, an ester is a <a href="/facts/Chemical_compound/37FXqqtv">compound</a> derived from an <a href="/facts/Acid/FySU18n1">acid</a> (either organic or inorganic) in which the <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a> atom (H) of at least one <a href="/facts/Acid/FySU18n1">acidic</a> <a href="/facts/Hydroxyl/1Hs2QAEv">hydroxyl</a> group (−OH) of that acid is replaced by an <a href="/facts/Organyl/gqCNaN45">organyl</a> group (R′). These compounds contain a <a href="/facts/Functional_group/GXkSPsjM">distinctive functional group</a>. Analogues derived from <a href="/facts/Oxygen/acyn6o8r">oxygen</a> replaced by other <a href="/facts/Chalcogen/nXLGmnqL">chalcogens</a> belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well (e.g. <a href="/facts/Amides/C6kCzYEA">amides</a>), but not according to the <a href="/facts/IUPAC/2AV6myCK">IUPAC</a>.
<a href="/facts/Glycerides/djXyhPUn">Glycerides</a> are <a href="/facts/Fatty_acid_ester/cGo3Q65m">fatty acid esters</a> of <a href="/facts/Glycerol/sRQ6NBQQ">glycerol</a>; they are important in biology, being one of the main classes of <a href="/facts/Lipid/TdQR87HX">lipids</a> and comprising the bulk of <a href="/facts/Animal_fat/0NVAUT1p">animal fats</a> and <a href="/facts/Vegetable_oil/70v8uQMH">vegetable oils</a>. <a href="/facts/Lactone/UMgRUFtj">Lactones</a> are cyclic carboxylic esters; naturally occurring lactones are mainly 5- and 6-membered ring lactones. Lactones contribute to the aroma of fruits, butter, cheese, <a href="/facts/Vegetables/j3AlDG64">vegetables</a> like <a href="/facts/Celery/r2oRCGJw">celery</a> and other foods.
Esters can be formed from <a href="/facts/Oxoacid/p0bMdwSx">oxoacids</a> (e.g. esters of <a href="/facts/Acetic_acid/uyBKA2Pd">acetic acid</a>, <a href="/facts/Carbonic_acid/fjjVAhwt">carbonic acid</a>, <a href="/facts/Sulfuric_acid/Wom6fymJ">sulfuric acid</a>, <a href="/facts/Phosphoric_acid/l6NbwyCv">phosphoric acid</a>, <a href="/facts/Nitric_acid/UDbwGp6s">nitric acid</a>, <a href="/facts/Xanthic_acid/TVVV7Sna">xanthic acid</a>), but also from acids that do not contain oxygen (e.g. esters of <a href="/facts/Thiocyanic_acid/GXNAYfLP">thiocyanic acid</a> and <a href="/facts/Trithiocarbonate/AByg3lR6">trithiocarbonic acid</a>). An example of an ester formation is the <a href="/facts/Substitution_reaction/zpqsbWAo">substitution reaction</a> between a <a href="/facts/Carboxylic_acid/U4xuMosy">carboxylic acid</a> (R−C(=O)−OH) and an <a href="/facts/Alcohol_(chemistry)/Y0SCTDkh">alcohol</a> (R'−OH), forming an ester (R−C(=O)−O−R'), where R stands for any group (typically hydrogen or organyl) and R′ stands for organyl group.
Organyl esters of carboxylic acids typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in <a href="/facts/Essential_oil/cq8V5ocP">essential oils</a> and <a href="/facts/Pheromone/ymEDICw3">pheromones</a>. They perform as high-grade <a href="/facts/Solvent/LoMPMz8S">solvents</a> for a broad array of <a href="/facts/Plastics/Kla5QItn">plastics</a>, <a href="/facts/Plasticizer/RjzuplRY">plasticizers</a>, <a href="/facts/Resin/r1uVThQ8">resins</a>, and <a href="/facts/Lacquer/83C6H1IW">lacquers</a>, and are one of the largest classes of synthetic <a href="/facts/Lubricants/9PXISDwU">lubricants</a> on the commercial market. <a href="/facts/Polyester/Ivp9CHpl">Polyesters</a> are important plastics, with <a href="/facts/Monomer/Gw3CltMb">monomers</a> linked by ester <a href="/facts/Moiety_(chemistry)/WxKqcJe1">moieties</a>. <a href="/facts/Phosphoester/fCjTAnxa">Esters of phosphoric acid</a> form the backbone of <a href="/facts/DNA/nB89Iauz">DNA</a> molecules. <a href="/facts/Nitrate_ester/4mSHBqaw">Esters of nitric acid</a>, such as <a href="/facts/Nitroglycerin/GUzdegnK">nitroglycerin</a>, are known for their explosive properties.
There are compounds in which an acidic hydrogen of acids mentioned in this article are not replaced by an organyl, but by some other group. According to some authors, those compounds are esters as well, especially when the first carbon atom of the organyl group replacing acidic hydrogen, is replaced by another atom from the <a href="/facts/Group_14_elements/PkWCV3Vx">group 14 elements</a> (<a href="/facts/Silicon/cgWx0hdr">Si</a>, <a href="/facts/Germanium/wtoALHGs">Ge</a>, <a href="/facts/Tin/vxbbBgNz">Sn</a>, <a href="/facts/Lead/EYljasJN">Pb</a>); for example, according to them, trimethylstannyl acetate (or trimethyltin acetate) CH3COOSn(CH3)3 is a <a href="/facts/Organotin/B4aDa9Lq">trimethylstannyl</a> ester of <a href="/facts/Acetic_acid/uyBKA2Pd">acetic acid</a>, and <a href="/facts/Dibutyltin_dilaurate/Xr6NamUH">dibutyltin dilaurate</a> (CH3(CH2)10COO)2Sn((CH2)3CH3)2 is a <a href="/facts/Organotin/B4aDa9Lq">dibutylstannylene</a> ester of <a href="/facts/Lauric_acid/ejIJQaMc">lauric acid</a>, and the <a href="/facts/Phillips_catalyst/Yjala8Ts">Phillips catalyst</a> CrO2(OSi(OCH3)3)2 is a trimethoxysilyl ester of <a href="/facts/Chromic_acid/jukMaHzR">chromic acid</a> (H2CrO4).

Ester open-in-new

Ester