Esters Sentence Examples
These esters are readily hydrolysed and yield the monoand di-alkylimalonic acids which, on heating, are readily decomposed, with evolution of carbon dioxide and the formation of monoand di-alkyl acetic acids.
Of other syntheses of true benzene derivatives, mention may be made of the formation of orcinol or [3 s]-dioxytoluene from dehydracetic acid; and the formation of esters of oxytoluic acid (5-methyl3-oxy-benzoic acid), C6 H3 CH3.
By actual observations it has been shown that ether, alcohol, many esters of the normal alcohols and fatty acids, benzene, and its halogen substitution products, have critical constants agreeing with this originally empirical law, due to Sydney Young and Thomas; acetic acid behaves abnormally, pointing to associated molecules at the critical point.
Recent researches have shown that the law originally proposed by Kopp - " That the specific volume of a liquid compound (molecular volume) at its boiling-point is equal to the sum of the specific volumes of its constituents (atomic volumes), and that every element has a definite atomic value in its compounds " - is by no means exact, for isomers have different specific volumes, and the volume for an increment of CH 2 in different homologous series is by no means constant; for example, the difference among the esters of the fatty acids is about 57, whereas for the aliphatic aldehydes it is 49.
Referring to the esters C9H1802 previously mentioned, it is seen that the highest boilingpoints belong to methyl octoate and octyl formate, the least symmetrical, while the minimum belongs to amyl butyrate, the most symmetrical.Advertisement
The same difference attends the introduction of the methyl group into many classes of compounds, for example, the paraffins, olefines, acetylenes, aromatic hydrocarbons, alcohols, aldehydes, ketones and esters, while a slightly lower value (157.1) is found in the case of the halogen compounds, nitriles, amines, acids, ethers, sulphides and nitro compounds.
It yields both esters and ethers since it is an acid and also a phenol.
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.
When methyl iodide is used, nitromethane is the sole product, but the higher homologues give more or less of the isomeric nitrous esters.
The nitro compounds are colourless, somewhat pleasant smelling liquids, which distil without decomposition and possess boiling points much higher than those of the isomeric nitrous esters.Advertisement
The products of the action of nitric acid on cellulose are not nitro compounds in the sense that picric acid is, but are nitrates or nitric esters.
The organic derivatives of silicon resemble the corresponding carbon compounds except in so far that the silicon atom is not capable of combining with itself to form a complex chain in the same manner as the carbon atom, the limit at present being a chain of three silicon atoms. Many of the earlier-known silicon alkyl compounds were isolated by Friedel and Crafts and by Ladenburg, the method adopted consisting in the interaction of the zinc alkyl compounds with silicon halides or esters of silicic acids.
The normal esters may be prepared by the action of silver carbonate on the alkyl iodides, or by the action of alcohols on the chlorcarbonic esters.
These normal esters are colourless, pleasantsmelling liquids, which are readily soluble in water.
They show all the reactions of esters, being readily hydrolysed by caustic alkalis, and reacting with ammonia to produce carhamic esters and urea.Advertisement
They are neutral to litmus and do not combine with dilute acids or bases; strong bases, such as lime and baryta, yield saccharates, whilst, under certain conditions, acids and acid anhydrides may yield esters.
Ladenburg, Ber., 1886, 19, p. 783); by heating the esters of nitric acid with alcoholic ammonia at 10o C. (0.
Esters, however, are not ionized.
On treatment with zinc and alkyl iodides or with zinc alkyls they are converted into esters of hydroxy-dialkyl acetic acids.
Oxamide, (CONH 2) 2, is best prepared by the action of ammonia on the esters of oxalic acid.Advertisement
This fact explains the so-called "catalytic" action of acids and bases in decomposing such compounds as the esters.
They combine with hypochlorous acid to form chlorhydrins; and are easily soluble in concentrated sulphuric acid, giving rise to sulphuric acid esters; consequently if the solution be boiled with water, the alcohol from which the olefine was in the first place derived is regenerated.
It is also formed by the action of sulphuretted hydrogen on the isocyanic esters, 2CONC 2 H 5 +H 2 S=COS+CO(NHC 2 H 5) 2, by the action of concentrated sulphuric acid on the isothiocyanic esters, Rncs H 2 O = Cos Rnh 2, Or Of Dilute Sulphuric Acid On The Thiocyanates.
The esters of the acid may be obtained by distilling a mixture of the sodium or potassium salts and the corresponding alcohol with hydrochloric or sulphuric acids.
Acid chlorides behave in an analogous manner to esters (Grignard and Tissier, Comptes rendus, 1901, 132, p. 683).Advertisement
Claisen by condensing ethoxymethylene aceto-acetic esters and similar compounds with /3-ketonic esters and with 1.3 diketones.
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).
The hydroxyl group is more reactive than in the phenols, the naphthols being converted into naphthylamines by the action of ammonia, and forming ethers and esters much more readily.
It unites with aldehydes to form esters of ketonic acids, and with aniline yields anilido-acetic acid.
These acid esters retain some of the characteristic properties of the acids, forming, for example, salts, with basic oxides.
The esters of the aliphatic and aromatic acids are colourless neutral liquids, which are generally insoluble in water, but readily dissolve in alcohol and ether.
The fats and waxes are the esters of the higher fatty acids and alcohols.
The esters of the higher fatty acids, when distilled under atmospheric pressure, are decomposed, and yield an olefine and a fatty acid.
Esters of the mineral acids are also known and may be prepared by the ordinary methods as given above.
The neutral esters are as a rule insoluble in water and distil unchanged; on the other hand, the acid esters are generally soluble in water, are non-volatile, and form salts with bases.
They are readily hydrolysed by water, and combine with bases to form alkyl ureas, and with alcohols to form carbamic esters.
Triphenylmethyl also combines with ethers and esters, but the compounds so formed are unsaturated.
At the same time various subsidiary products such as glycerin, succinic acid, small quantities of higher alcohols, volatile acids and compound esters are produced.
It is to these subsidiary matters that the flavour and bouquet in wine are particularly due, at any rate in the first stages of maturation, although some of the substances originally present in the grape, such as ready-formed esters, essential oils, fat and so on, also play a role in this regard.
The bouquet of young wines is due principally to the compound esters which exist in the juice or are formed by the primary fermentation.
It was at one time thought that the quality of the bouquet was dependent upon the absolute quantity of these compound esters present, but the author and others have plainly shown that this is not the case.
Among the characteristic esters present in wine is the well-known " oenanthic ether," which consists principally of ethylic pelargonate.
The conversion of the mixture obtained by extracting coca-leaves into cocaine is effected by saponifying the esters into ecgonine and the respective acids, and then benzoylating and methylating the ecgonine.
Ruhemann prepared y-substituted dioxypyridines by condensing alkyl-dicarboxy-glutaconic esters with ammonia.
Pyrocatechin readily condenses to form heterocyclic compounds; cyclic esters are formed by phosphorus trichloride and oxychloride, carbonyl chloride, sulphuryl chloride, &c.; whilst ortho-phenylenediamine, o-aminophenol, and o-aminothiophenol give phenazine, phenoxazine and thiodiphenylamine.
The formation of esters and ethers are generally facilitated by the presence of this acid.
Alcohols may be readily prepared from the corresponding alkyl haloid by the action of moist silver oxide (which behaves as silver hydroxide); by the saponification of their esters; or b the reduction of of h dric alcohols by P Y Y with hydriodic acid, and the subsequent conversion of the resulting alkyl iodide into the alcohol by moist silver oxide.
Primary alcohols are obtained by decomposing their sulphuric acid esters (from sulphuric acid and the olefines) with boiling water; by the action of nitrous acid on primary amines; or by the reduction of aldehydes, acid chlorides or acid anhydrides.
Secondary alcohols result from the reduction of ketones; and from the reaction of zinc alkyls on aldehydes or formic acid esters.
With strong acids water is split off and esters are formed.
The haloid esters of the paraffin alcohols formed by heating the alcohols with the halogen acids are the monohaloid derivatives of the paraffins, and are more conveniently prepared by the action of the phosphorous haloid on the alcohol.
C 2 H 5 SO 2 C1 (chlorides of sulphonic acids), by heating the salts of esters of sulphuric acid with potassium hydrosulphide, and by heating the alcohols with phosphorus pentasulphide.
Waxes The waxes consist chiefly of the fatty acid esters of the higher monohydric alcohols, with which are frequently associated free alcohols as also free fatty acids.
These acids can be further refined to make fatty alcohols, metallic soaps, fatty amines, fatty acid esters and fatty amides.
Dry hydrogen chloride gas is used in some cases, but these tend to involve aromatic esters (ones containing a benzene ring ).
Lipid compound A substance containing esters or fatty acids, which are important structural materials in living organisms.
Individual phthalate esters were determined in two samples of each of these composite food groups.
Fumaric acid esters (II) differ from Fumaric acid by chemical groups called ' esters ' .
This is now possible with the breakthrough scientific discovery of creatine ethyl esters.
Enhanced MAPK6 activity has been described in fibroblasts and upon treatment with serum or phorbol esters.
The ACNFP was also concerned that products containing phytosterol esters are not appropriate nutritionally for young children and breast feeding women.
H HN CEH?Chch C(Ch3)N.Cs The ketonic esters under like treatment yield oxypyrimidines, whilst if cyanacetic ester be employed then amino-oxypyrimidines are obtained.
Mai, Ber., 1889, 22, p. 2135); from the higher alcohols by converting them into esters which are then distilled (F.
The new blend, based on a mix of sucrose esters, also eliminates the need for lecithin, and partly replaces gelatine.
A number of esters are also produced.
The characteristic flavour and odour of wines and spirits is dependent on the proportion of higher alcohols, aldehydes and esters which may be produced.
Berthelot, and many other chemists, from whose researches it results that glycerin is a trihydric alcohol indicated by the formula C 3 H 5 (OH) 3j the natural fats and oils, and the glycerides generally, being substances of the nature of compound esters formed from glycerin by the replacement of the hydrogen of the OH groups by the radicals of certain acids, called for that reason "fatty acids."
Malonic acid, as well as its esters, is characterized by the large number of condensation products it can form.
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.
It is a most important synthetic reagent; with sodium or sodium ethylate it forms sodio-malonic ester, which reacts readily with alkyl halides, forming alkyl malonic esters, which are again capable of forming sodium derivatives, that by further treatment with alkyl halides yield the di-alkyl malonic esters.