ester, any one of a group of organic compounds with general formula RCO₂R′ (where R and R′ are alkyl groups or aryl groups) that are formed by the reaction between an alcohol and an acid. For example, when ethanol and acetic acid react, ethyl acetate (an ester) and water are formed; the reaction is called esterification. Ethyl acetate acetate , one of the most important forms of artificial cellulose-based fibers; the ester of acetic acid. The first patents for the production of fibers from cellulose acetate appeared at the beginning of the 20th cent.
..... Click the link for more information. is used as a solvent. Methyl acetate, formed by the reaction between methanol and acetic acid, is a sweet-smelling liquid used in making perfumes, extracts, and lacquers. Esters react with water (hydrolysis hydrolysis , chemical reaction of a compound with water, usually resulting in the formation of one or more new compounds. The most common hydrolysis occurs when a salt of a weak acid or weak base (or both) is dissolved in water.
..... Click the link for more information. ) under basic conditions to form an alcohol and an acid. When heated with a hydroxide certain esters decompose to yield soap and glycerin; the process is called saponification. Common fats and oils fats and oils, group of organic substances that form an important part of the diet and also are useful in many industries. The fats are usually solid, the oils generally liquid at ordinary room temperatures.
..... Click the link for more information. are mixtures of various esters, such as stearin stearin , fat that is the triglyceride of stearic acid, CH₃(CH₂)₁₆CO₂H, i.e., the tristearate ester of glycerol. It is a white crystalline solid at ordinary temperatures and is insoluble in water and very slightly soluble
..... Click the link for more information. , palmitin palmitin , fat that is the triglyceride of palmitic acid, CH₃(CH₂)₁₄CO₂H, i.e., the tripalmitate ester of glycerol.
..... Click the link for more information. , and linolein, formed from the alcohol glycerol glycerol, glycerin, glycerine, or 1,2,3-propanetriol , CH₂OHCHOHCH₂OH, colorless, odorless, sweet-tasting, syrupy liquid. Glycerol is a trihydric alcohol. It melts at 17.
..... Click the link for more information. and fatty acids fatty acid, any of the organic carboxylic acids present in fats and oils as esters of glycerol. Molecular weights of fatty acids vary over a wide range. The carbon skeleton of any fatty acid is unbranched. Some fatty acids are saturated, i.e.
..... Click the link for more information. . Naturally occurring esters of organic acids in fruits and flowers give them their distinctive odors. Esters perform important functions in the animal body; e.g., the ester acetylcholine is a chemical transmitter of nerve stimuli.

ester

Any of a class of organic compounds that can react with water (see hydrolysis) to produce an alcohol and an organic or inorganic acid. They are formed by the reverse process, esterification, in which acid reacts with alcohol to form an ester and water. Esters of carboxylic acids, the most common esters, contain the acid's carbonyl group (−C=O; see functional group); the carbon's fourth bond is with the alcohol's oxygen atom. Hydrolysis of esters in the presence of an alkali (saponification) is used to make soaps from fats and oils. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours; they give flavour and fragrance to fruits and flowers and are used as synthetic flavours and fragrances. Others, such as ethyl acetate and butyl acetate, are used as solvents for lacquers, paints, and varnishes. Certain polymers are esters, including Lucite (polymethyl methacrylate) and Dacron (polyethylene terephthalate). Esters of alcohols and inorganic acids include nitrate esters (e.g., nitroglycerin), which are explosive; phosphate esters, including such biologically important compounds as nucleic acids; and others that are used as flame retardants, solvents, plasticizers, gasoline and oil additives, and insecticides.

ester

Chem any of a class of compounds produced by reaction between acids and alcohols with the elimination of water. Esters with low molecular weights, such as ethyl acetate, are usually volatile fragrant liquids; fats are solid esters

ester [′es·tər]

(organic chemistry)

The compound formed by the elimination of water and the bonding of an alcohol and an organic acid.

Ester

any of a number of organic compounds, such as C₂H₅OCOCH₃ or C₅H₁₁ONO, that are derived from acids by replacing the hydroxyl group (OH) with an alcohol, enol, or phenol radical (OR).

Esters are structural analogues of the salts of oxygen acids, but where a metal atom would be attached to the salt, a hydrocarbon group (R) is attached to the ester. The nomenclature for the salts and esters is similar; for example, NaOCOCH₃ is called sodium acetate, and C₂H₅OCOCH₃ is known as ethyl acetate. Like salts, esters form products of incomplete and complete replacement with dibasic and multibasic acids; thus, there are acid esters, such as monomethylsulfate (HOSO₂OCH₃), and complete (neutral) esters, such as dimethylsulfate (CH₃OSO₂OCH₃).

Esters differ greatly from salts in their properties, however. Typical organic compounds, esters are usually volatile liquids. In some instances, they have a fruity or flowery fragrance. Virtually insoluble in water, they are readily soluble in organic solvents. Esters are hydrolyzed by the action of water to form the corresponding alcohol and acid, in accordance with the general formula

RCOOR′ + H₂O ⇆ RCOOH + HOR′

The reaction is catalyzed by acids and even more so by bases. When alkaline catalysts are used, salts of acids are formed instead of free acids; the reaction is irreversible. Of the other reactions in which esters display acylating properties, the most common are transesterification, alcoholysis, and double exchange reactions. Some esters—for example, those formed by the lower aliphatic alcohols and such acids as sulfuric, trifluoroacetic, phosphoric, and phthalic acids—also have alkylating properties (seeDIMETHYL SULFATE and ).

Esters are usually obtained by esterification (see). They may also be formed by the acylation of alcohols by various acid derivatives (including acid halides and anhydrides), by the action of acid salts on alkyl halides, as in the reaction

C₂H₅I + AgONO → C₂H₅ONO + AgI

or by the action of acids on olefins, as in the reaction

HOSO₂OH + CH₂=CH₂ → HOSO₂OCH₂CH₃

Esters of glycerin and the higher carboxylic acids are the principal components of fats, and esters of the higher monohydric aliphatic alcohols and carboxylic acids are the main components of waxes. Other esters—mainly those of the terpene alcohols—are components of essential oils. Esters are used in technology as plastic monomers (acrylates and vinyl acetates), plasticizers for plastics (dioctyl and dibutyl phthalates), detergents (alkyl sulfates), solvents (amyl, butyl, and ethyl acetates), extraction agents and pesticides (esters of phosphoric acid), explosives (esters of nitric acid and polyhydric alcohols, such as nitroglycerin), pharmaceuticals (validol and aspirin), and fragrances (benzyl acetate and terpenyl acetate). Many esters of high molecular weight (including polyethylene terephthalate and cellulose acetates) are used in industry as plastics, lacquers, and synthetic fibers (seeALKYD RESINS and POLYESTER FIBER).

REFERENCES

Nesmeianov, A. N., and N. A. Nesmeianov. Nachala organicheskoi khimii, books 1–2. Moscow, 1969–70.
Chichibabin, A. E. Osnovnye nachala organicheskoi khimii, 7th ed., vol. 1. Moscow, 1963.

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No references found			Weekly sampling and analysis of OA-group toxins including fatty acid esters ('DTX-3') as well as PTX in individual shellfish and plankton samples were performed. Differential retention of okadaic acid (OA) group toxins and ... by Lindegarth, Susanne; Torgersen, Trine; Lundve, Bengt; Sandvik, Morten / Journal of Shellfish Research Focus is placed on specialty esters derived from fatty acid and methylester fractions. Chemrez Technologies, Inc by Household & Personal Products Industry The first ever arginine, citrulline and creatine esters combined with the anabolic salts of orotic acid and a normal acetate ester of clean twenty-beta-hydroxy-ecdysone extort. Fizogen Supplements ? Can Be Very Effective by Ricky Hussey / Health, general community			estate law Estate Monarchy estate tax Estates General Estates-General Este Este family Esteban Jose Antonio Echeverria Esteban José Antonio Echeverría Estella Estelle Estelle Sylvia Pankhurst Ester ester gum ester hydrolysis Esterase Esterel Esterházy Esterházy family Esterhazy, Ferdinand Walsin Esterification Estero Bay Preserve State Park Estero Bay State Beach Estero Llano Grande State Park esterolysis Esters estersil Estes, Richard Estes, William K Estevan esthacyte Esther Esther, Queen esthesia Esthesiometer esthesioneuroblastoma esthesioneuroepithelioma esthetics esthiomene Estienne Estienne, Henri II Estill County Estimate Estimated Cost of Construction in the USSR estimated design load estimated exposure concentration estimated maximum load estimated position Estimated Prices estimated time estimated time of arrival			esterified e's esterified e's esterified estrogen esterified estrogens esterified estrogens esterified estrogens esterifies esterifies esterifies esterify esterify esterify esterifying esterifying esterifying Esterman grid Esterman grid Esterman grid Esterman grid Esterman grid Esterman Visual Field Test Estero Bay Nutrient Management Partnership Estero Bay Preserve State Park Estero Bay Preserve State Park Estero Bay State Beach Estero Bay State Buffer Preserve Estero Llano Grande State Park esterolysis esterolysis esterophilic site Esters estersil Estes Estes Estes Estes Area Lodging Association Estes Kefauver Estes Land Stewardship Association Estes Park Estes Park Area Historical Museum Estes Park Area Weavers Guild Estes Park Board of Realtors Estes Park Center Estes Park Chamber of Commerce Estes Park Chamber Resort Association Estes Park Conference Center Estes Park Convention and Visitors Bureau Estes Park Film Festival Estes Park Freight Line Estes Park High School Estes Park History Project Estes Park History Rescue Project Estes Park Housing Authority Estes Park Improvement Contribution Estes Park Indoor Climbing Estes Park Intermediate School Estes Park Internet Computer Users Group, Inc.

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ester

REFERENCES

Ester
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