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.
Esters with ammonia.
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.
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.
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.
CH :CH (OH), formed by acting on formic ester with acetone in the presence of sodium ethylate, readily yields [1.3.51-triacetylbenzene, C 6 H 3 (CO CH 3) 3; oxymethylene acetic ester or formyl acetic ester or ß-oxyacrylic ester, (HO)CH :CH CO 2 C 2 H 51 formed by condensing acetic ester with formic ester, and also its dimolecular condensation product, coumalic acid, readily yields esters of [1.3.
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.
As a useful preliminary it is convenient to divide heterocyclic ring systems into two leading groups: (I) systems resulting from simple internal dehydration (or similar condensations) of saturated aliphatic compounds - such compounds are: the internal anhydrides or cyclic ethers of the glycols and thioglycols (ethylene oxide, &c.); the cyclic alkyleneimides resulting from the splitting off of ammonia between the amino groups of diaminoparaffins (pyrrolidine, piperazine, &c.); the cyclic esters of oxycarboxylic acids (lactones, lactides); the internal anhydrides of aminocarboxylic acids (lactams, betaines); cyclic derivatives of dicarboxylic acids (anhydrides, imides, alkylen-esters, alkylenamides, &c.).
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.
In general, isomers boil at about the same temperature, as is shown by the isomeric esters CH1802: Methyl octoate..
Thus in the normal fatty alcohols, acids, esters, nitriles and ketones, the increment per CH 2 is 19°-21°; in the aldehydes it is 26°-27°.
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.
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.
These esters on hydrolysis yield the free acids, which readily decompose, with loss of carbon dioxide and formation of an aldehyde, R /Crri /Crri Oc< +ï¿½Cl ï¿½ CH ï¿½ [[Cooc H - O I ?Ch Cooc H 0c Chï¿½Cooh - Co +Chrr I Cho]].
Busch, Ber., 1899, 32, p. 2960): N C(SH):N C 6 H 5 /N C:NC6H5 C. 2 S 7Hs " H s d-H N NH C,H 7 C7 "N N C,H7 C. Harries (Ber., 1895, 28, p. 1223) has also shown that as-phenylhydrazino-acetic esters, when heated with formamide and substituted formamides under pressure, yield dihydrotriazines: CO 2 R CO-NR'-CH H2 N(C6H5)NH2 +R'NH CHO --> CH 2 N(C 6 H 5) IV The phen-a-triazines are yellow-coloured crystalline compounds of a somewhat basic character.
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.
(2) The organic carbonates are the esters of carbonic acid, H 2 CO 3, and of the unknown ortho-carbonic acid, C(OH) 4.
The acid esters of carbonic acid of the type HO CO.
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.
Ladenburg, Ber., 1886, 19, p. 783); by heating the esters of nitric acid with alcoholic ammonia at 10o C. (0.
The salts of the metals, the organic salts (or esters) being termed nitriles.
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.
With 0-ketonic esters, HO(CH 3)C: CH.
ESTERS, in organic chemistry, compounds formed by the condensation of an alcohol and an acid, with elimination of water; they may also be considered as derivatives of alcohols, in which the hydroxylic hydrogen has been replaced by an acid radical, or as acids in which the hydrogen of the carboxyl group has been replaced by an alkyl or aryl group. In the case of the polybasic acids, all the hydrogen atoms can be replaced in this way, and the compounds formed are known as "neutral esters."
If, however, some of the hydrogen of the acid remain undisplaced, then "acid esters" result.
These acid esters retain some of the characteristic properties of the acids, forming, for example, salts, with basic oxides.
Esters may be prepared by heating the silver salt of an acid with an alkyl iodide; by heating the alcohols or alcoholates with an acid chloride; by distilling the anhydrous sodium salt of an acid with a mixture of the alcohol and concentrated sulphuric acid; or by heating for some hours on the water bath, a mixture of an acid and an alcohol, with a small quantity of hydrochloric or sulphuric acids (E.
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.
The esters of the aliphatic amino acids may be diazotized in a manner similar to the primary aromatic amines, a fact discovered by T.