noun
definition
A compound most often formed by the condensation of an alcohol and an acid, with elimination of water, which contains the functional group carbon-oxygen double bond joined via carbon to another oxygen atom.
Examples of ester in a Sentence
It is the methyl ester of a neutral body colchicein, which may be obtained in white acicular crystals.
We may here mention the synthesis of oxyuvitic ester (5-methyl-4-oxy-I-3-benzene dicarboxylic ester) by the condensation of two molecules of sodium acetoacetic ester with one of chloroform (Ann., 1883, 222, p. 249).
Many esters of malonic acid have been prepared, the most important being the diethyl ester (malonic ester), CH 2 (000C 2 H 5) 2, which is obtained by dissolving monochloracetic acid in water, neutralizing the solution with potassium carbonate, and then adding potassium cyanide and warming the mixture until the reaction begins.
The half nitrile of malonic acid is cyanacetic acid, CN CH 2 COOH, which, in the form of its ester, may be obtained by the action of a solution of potassium cyanide on monochloracetic acid.
Held synthesized the acid from ethyl chlor-acetoacetate (from chlorine and acetoacetic ester) by heating with potassium cyanide and saponifying the resulting nitrile.
Perkin, junr., in 1883, that ethylene and trimethylene bromides are capable of acting in such a way on sodium acetoacetic ester as to form triand tetramethylene rings.
Amino derivatives similarly result from thio-ureas and a-haloid ketones; the oxy derivatives from a-sulphocyanoketones by the action of caustic alkali; and the carboxylic acids from chloro-aceto-acetic ester, &c. and thioamides.
Darzens (Comptes Rendus, 1904, 139, p. 1214) prepares esters of disubstituted glycidic acids, by condensing the corresponding ketone with monochloracetic ester, in the presence of sodium ethylate.
Its ethyl ester reacts with hydrazine to form hippuryl hydrazine, C,H 5 CO NH CH 2 CO NH NH 2, which was used by Curtius for the preparation of azoimide.
The latter reacts with chlorine to give silicon nonyl-chloride Si(C2H5)3 C2H4C1, which condenses with potassium acetate to give the acetic ester of silicon nonyl alcohol from which the alcohol (a camphor-smelling liquid) may be obtained by hydrolysis.
Triethyl silicol, (C2H5),Si OH, is a true alcohol, obtained by condensing zinc ethyl with silicic ester, the resulting substance of composition, (C2H5)3 SiOC2H51 with acetyl chloride yielding a chloro-compound (C2H5)3SiC1, which with aqueous ammonia yields the alcohol.
By heating with phosphorus pentachloride an alkyl group is eliminated and a chlorcarbonic ester formed.
Sodium amalgam converts it into formic acid; whilst with alcohol it yields the normal carbonic ester.
Rhamnose or isodulcite, a component of certain glucosides, fucose, found combined in seaweeds and chinovose, present as its ethyl ester, chinovite, in varieties of quina-bark, are methyl pentoses.
Propylene is liberated during the reaction, and the phosphoric acid ester of meta-cresol which is formed is then fused with potash.
Of foremost importance are the reactions termed the malonic acid and the aceto-acetic ester syntheses; these are discussed under their own headings.
It is manufactured by distilling wood in iron retorts at about 50o C., when an aqueous distillate, containing methyl alcohol, acetone, acetic acid and methyl acetic ester, is obtained.
To obtain it perfectly pure the crude alcohol is combined with oxalic, benzoic or acetic acid, and the resulting ester separated, purified, and finally decomposed with potash.
After his removal to the Piombi at Venice in February 1821, he composed several Cantiche and the tragedies Ester d'Engaddi and Iginia d'Asti.
After his release in 1830 he commenced the publication of his prison compositions, of which the Ester was played at Turin in 1831, but immediately suppressed.
Chemically it is the methyl ester of arecaidine.
It is detected by heating with ordinary alcohol and sulphuric acid, which gives rise to acetic ester or ethyl acetate, recognized by its" fragrant odour; or by heating with arsenious oxide, which forms the pungent and poisonous cacodyl oxide.
In this reaction a glycerol ester is formed as an intermediate product, and undergoes decomposition by the water which is also produced at the same time.
Duppa (Annalen, 1865, 136, p. 12) by acting with phosphorus pentachloride on oxyisobutyric ester (CH 3) 2 C(OH) 000C 2 H 5.
It combines with acetoacetic ester to form the aromatic compound meta-oxyuvitic acid, C 6 11 2 CH 3 OH (Cooh) 2.
The ethoxymethylene aceto-acetic esters are prepared by condensing aceto-acetic ester with ortho-formic ester in the presence of acetic anhydride (German patents 77354, 79087, 79863).
It forms an addition product with acrylic ester, which on heating loses nitrogen and leaves trimethylene dicarboxylic ester.
Diazosuccinic ester, N2 C(C02C2H5)2, is similarly prepared by the action of nitrous acid on the hydrochloride of aspartic ester.
It is decomposed by boiling water and yields fumaric ester.
Meyer (Ber., 18 94, 2 7, p. 510 et seq.) showed that in benzenoid compounds ortho-substituents exert a great hindering effect on the esterification of alcohols by acids in the presence of hydrochloric acid, this hindering being particularly marked when two substituents are present in the ortho positions to the carboxyl group. In such a case the ester is best prepared by the action of an alkyl halide on the silver salt of the acid, and when once prepared, can only be hydrolysed with great difficulty.
The ester is separated from the solution by means of its barium salt, and the salt decomposed by the addition of the calculated amount of sulphuric acid.
Normal butyric acid or fermentation butyric acid is found in butter, as an hexyl ester in the oil of Heracleum giganteum and as an octyl ester in parsnip (Pastinaca sativa); it has also been noticed in the fluids of the flesh and in perspiration.
Isobutyric acid is found in the free state in carobs (Ceratonia siliqua) and in the root of Arnica dulcis, and as an ethyl ester in croton oil.
Ethylidene succinic acid or isosuccinic acid, CH3 CH(C02H)2, is produced by the hydrolysis of a-cyanpropionic acid and by the action of methyl iodide on sodio-malonic ester.
Wanklyn have shown that pure ethyl acetate free from alcohol will not react with sodium to produce aceto-acetic ester.
Acetoacetic ester is a most important synthetic reagent, having been used in the production of pyridines, quinolines, pyrazolones, furfurane, pyrrols, uric acid, and many complex acids and ketones.
Silver picrate and methyl iodide yield the methyl ester, which gives with ammonia picramide.
The cetyl ester is spermaceti, and the myricyl ester is largely present in beeswax.
In this reaction the proportions of aldehyde and acetoacetic ester may be interchanged and ay disubstituted pyridines are then obtained.
Of the insoluble salts we may notice the tannate, the propionic acid ester (euquinine) and carbonic acid ester (aristoquin), the salicylic acid ester.
The valerianic;ester of guaiacol is known as geosote, the benzoic as benzosol,' the salicylic as guaiacolsalol, while the glycerin ether appears as guaiamar.
Canine is a secondary base, forming a nitroso derivative with nitrous acid, a urethane with chlorcarbonic ester and a tertiary base (methyl conine) with methyl iodide; reactions which point to the presence of the = NH group in the molecule.
The '1.1' dicarboxylic acid is prepared from ethylene dibromide and sodio-malonic ester.
The cis 1.2-cyclo-propane dicarboxylic acid is formed by eliminating carbon dioxide from cyclo-propane tricarboxylic acid -1.2.3 (from 43-dibrompropionic ester and sodio-malonic ester).
The trans-acid is produced on heating pyrazolin-4.5-dicarboxylic ester, or by the action of alcoholic potash on a-bromglutaric ester.
When sodio-malonic ester is condensed with trimethylene bromide the chief product is ethyl pentane tetracarboxylate, tetramethylene dicarboxylic ester being also formed, and from this the free acid may be obtained on hydrolysis.
C 6 H 7 0, is obtained by condensing sodium aceto-acetate with methylene iodide, the ester so formed being then hydrolysed.
Hexahydrobenzoic acid, C 6 H 11 CO 2 I-I, is obtained by the reduction of benzoic acid, or by the condensation of 1.5 dibrompentane with disodio-malonic ester.
It may be synthesized from toluene; more interesting is its production when acetone dicarboxylic ester is condensed with the aid of sodium.
As an illustration of the extent to which this part of the industry suffers from the climate, it may be stated that oil from lavender plants grown in England never produces more than 7 to 10% linalool acetate, which gives the characteristic scent to lavender oil, whilst oil from lavender grown in the south of France frequently yields as much as 35% of the ester.