CO 2 R C02R It may also be prepared by heating the anhydride of y-methyloxyglutaric acid with concentrated sulphuric acid, and by oxidation of methyl heptenone and of geraniol.
It can be obtained by the oxidation of uric acid by means of lead dioxide, manganese dioxide, ozone or potassium permanganate: C 5 H 4 N 4 O 3 + H 2 O + O = C 4 H 6 N 4 O 3 + C02.
On oxidation with potassium permanganate it is converted into acetyl urea, together with other products.
Claus, Ber., 1873, 6, p. 723); by passing aniline vapour over lead oxide, or by the oxidation of dihydrophenazine, which is prepared by heating pyrocatechin with orthophenylene diamine (C. Ris, Ber., 1886, 19, p. 2206).
Hinsberg, Ann., 1887, 2 37, p. 340); by the oxidation of an ortho-diamine in the presence of a-naphthol (0.
On oxidation with chromic or nitric acids, or potassium permanganate, it yields nicotinic acid or (3-pyridine carboxylic acid, C 5 H 4 N CO 2 H; alkaline potassium ferricyanide gives nicotyrine, C10H10N2, and hydrogen peroxide oxynicotine, C10H14N20.
Ethylene dibromide) with silver acetate or with potassium acetate and alcohol, the esters so produced being then hydrolysed with caustic alkalis, thus: C 2 H 4 Br 2 + C2H302 Ag-*C2H4(O C2H30)2->C2H4(OH)2+2K C2H302 by the direct union of water with the alkylen oxides; by oxidation of the olefines with cold potassium permanganate solution (G.
The other constructive processes, which arc dependent partly upon the oxidation of the carbohydrates so formed and therefore upon an expenditure of part of such energy, also mar]~ the storage of energy in the potential form.
Phys., 1888 (6) 14, p. 435); by heating phenol carboxylic acids with baryta; and, in small quantities by the oxidation of benzene with hydrogen peroxide or nascent ozone (A.
The urine becomes dark green in colour owing to the formation of various oxidation products such as pyrocatechin.
It should be noted that the oxidation of sulphur itself by atmospheric influence may give rise to sulphuric acid, which in the presence of limestone will form gypsum: thus the sulphur-deposits of Sicily suffer alteration of this kind, and have their outcrop marked by a pale earthy gypseous rock called briscale.
Rhombic sulphur may be obtained artificially by slowly crystallizing a solution of sulphur in carbon bisulphide, or, better, by exposing pyridine saturated with sulphuretted hydrogen to atmospheric oxidation (Ahrens, Ber., 1890, 23, p. 2708).
In this latter reaction the deep yellow solution obtained is exposed to air when the calcium polysulphide formed is gradually converted into thiosulphate by oxidation, and the calcium salt thus formed is converted into the sodium salt by sodium carbonate or sulphate.
It is obtained by the oxidation of xanthene (methylene diphenylene oxide) with chromic acid; by the action of phosphorus oxychloride on disodium salicylate; by heating 2 2'-dioxybenzophenone with concentrated sulphuric acid; by distilling fluoran with lime; by the oxidation of xanthydrol (R.
The phlogistic theory, which pervaded the chemical doctrine of this period, gave rise to continued study of the products of calcination and combustion; it thus happened that the knowledge of oxides and oxidation products was considerably developed.
Oxidation of thio-ethers results in the formation of sulphoxides, R2: S: 0, and sulphones, R2: S02; oxidation of mercaptans yields sulphonic acids, R S0 3 H, and of sodium mercaptides sulphinic acids, R S0(OH).
Compounds containing an oxy in addition to an aldehydic or ketonic group) undergo both condensation and oxidation when treated with phenylhydrazine, forming compounds known as osozones; these are of great importance in characterizing the sugars (q.v.).
C. Graebe (Ann., 1869, 149, p. 22) orientated the ortho-compound or phthalic acid from its formation from naphthalene on oxidation; the meta-compound or isophthalic acid is orientated by its production from mesitylene, shown by A.
If we accept Kekule's formula for the benzene nucleus, then we may expect the double linkages to be opened up partially, either by oxidation or reduction, with the formation of di-, tetra-, or hexa-hydro derivatives, or entirely, with the production of open chain compounds.
Strong oxidation breaks the benzene complex into such compounds, as carbon dioxide, oxalic acid, formic acid, &c.; such decompositions are of little interest.
Zincke; and his researches have led to the discovery of many chlorinated oxidation products which admit of decomposition into cyclic compounds containing fewer carbon atoms than characterize the benzene ring, and in turn yielding openchain or aliphatic compounds.
For succinosuccinic ester, formed by the action of sodium on two molecules of succinic ester, has either of the formulae (I) or (II); oxidation of the free acid gives dioxyterephthalic acid in which the para-positions must remain substituted as in (I) and (II).
The transformation is not one of the oxidation of a hexamethylene compound to a benzenoid compound, for only two hydrogen atoms are removed.
This is obviously unsymmetrical, consisting of an aliphatic and an aromatic nucleus; Claus explained the formation of the same phthalic acid from the oxidation of either nucleus by supposing that if the aromatic group be oxidized, the aliphatic residue assumes the character of a benzene nucleus.
During recent years an immense number of ringed or cyclic compounds have been discovered, which exhibit individual characters more closely resembling benzene, naphthalene, &c. than purely aliphatic substances, inasmuch as in general they contain double linkages, yet withstand oxidation, and behave as nuclei, forming derivatives in much the same way as benzene.
Thus ortho-phenylene diamine yields the following products: N H N ./`N; Xn NZ In some cases oxidation of condensed benzenoid-heterocyclic nuclei results in the rupture of the heterocyclic ring with the formation of a benzene dicarboxylic acid; but if the aromatic nucleus be weakened by the introduction of an amino group, then it is the benzenoid nucleus which is destroyed and a dicarboxylic acid of the heterocyclic ring system obtained.
The precipitate formed by sulphuretted hydrogen may contain the black mercuric, lead, and copper sulphides, dark-brown bismuth sulphide, yellow cadmium and arsenious sulphides, orange-red antimony sulphide, brown stannous sulphide, dull-yellow stannic sulphide, and whitish sulphur, the last resulting from the oxidation of sulphuretted hydrogen by ferric salts, chromates, &c. Warming with ammonium sulphide dissolves out the arsenic, antimony and tin salts, which are reprecipitated by the addition of hydrochloric acid to the ammonium sulphide solution.
Methods depending upon oxidation in the presence of a contact substance have come into favour during recent years.
The oxidation with nitric acid in sealed tubes at a temperature of 150° to 200° for aliphatic compounds, and 250° to 260° for aromatic compounds, is in common use, for both the sulphur and phosphorus can be estimated, the former being oxidized to sulphuric acid and the latter to phosphoric acid.
Sulphur and phosphorus can sometimes be estimated by Messinger's method, in which the oxidation is effected by potassium permanganate and caustic alkali, or by potassium bichromate and hydrochloric acid.
38, p. 1 434) has devised a method in which the oxidation is effected by sodium peroxide; the halogens,phosphorus and sulphur can be determined by one operation.
There is thus a minimum circulation in the greater depths causing there uniformity of temperature, an absence of the circulation of oxygen by other means than diffusion, and a protection of the sulphuretted hydrogen from the oxidation which takes place in homologous situations in the open ocean.
Arndt, Ber., 1899, 32, p. 2136); by the oxidation of hydroxylamine (ibid., 1900, 33, p. 30); and by the electrolysis of hydrazine and its salts (E.
Hofmann, Ber., 1880, 13, p. 1224); by heating the acid anilides with sulphur or by the oxidation of thio-anilides.
On reduction glucose appears to yield the hexahydric alcohol d-sorbite, and on oxidation d-gluconic and d-saccharic acids.
In practice this oxidation process is continued until the whole of the oxygen is as nearly as possible equal in weight to the sulphur present as sulphide or as sulphate, i.e.
The furnace has, in addition to the usual tuyeres near the bottom, a second set near the throat in order to effect a complete oxidation of all combustible matter.
When kept fused in the presence of air lead readily takes up oxygen, with the formation at first of a dark-coloured scum, and then of monoxide PbO, the rate of oxidation increasing with the temperature.
The suboxide, Pb 2 0, is the first product of the oxidation of lead, and is also obtained as a black powder by heating lead oxalate to 300° out of contact with air.
As in Hopkinson's experiments, ring magnets were employed; these were wound with primary and secondary coils of insulated platinum wire, which would bear a much higher temperature than copper without oxidation or fusion.
The whole was wrapped in several coverings of asbestos and placed in a glass vessel from which the air was partially exhausted, additional precautions being taken to guard against oxidation of the iron.
The name is derived from alcohol dehydrogenatum in allusion to the fact that they may be prepared by the oxidation of alcohols.
The aldehydes may be prepared by the careful oxidation of primary alcohols with a mixture of potassium dichromate and sulphuric acid,-3Rï¿½CH OH+K Cr 07+4H SO = K2S04+ Cr (SO) +7H O+3Rï¿½CHO; by distilling the calcium salts of the fatty acids with calcium formate; and by hydrolysis of the acetals.
The simplest member of the series is acrolein, C 3 H 4 0 or CH 2: CHï¿½CHO, which can be prepared by the oxidation of allyl alcohol, or by the abstraction of the elements of water from glycerin by heating it with anhydrous potassium bisulphate.
It is found in the volatile oils of Spiraea, and can be obtained by the oxidation of the glucoside salicin, (C13H1807), which is found in willow bark.
Tertiary nitro compounds may also be obtained by the oxidation of the corresponding amino-, hydroxyl amino-, and nitroso-hydrocarbons with monopersulphuric acid (E.
On oxidation with chromic acid they yield dinitrohydrocarbons, and on reduction with hydroxylamine (in alkaline solution) or with potassium sulphydrate give ketoximes, RR': C: NOH (R.
Nitrosohydrocarbons have been prepared in the aliphatic series by the oxidation of the corresponding hydroxylamino compounds.
Its universal disintegration and waste by oxidation; and its concomitant reintegration by the intussusception of new matter.
0 - / CH2/ O - - CH :CH CH:CH 000H (I) - 01 1 - CH - CH:CH CH:CH CO N(CH 2) 5 (2) O Oxidation with potassium permanganate converts piperic acid into piperonal, C 8 H 6 0 3, and piperonylic acid, C 8 H 6 0 4.