Shenstone, two classes are to be recognized: (I) Nataloins, which yield picric and oxalic acids with nitric acid, and do not give a red coloration with nitric acid; and (2) Barbaloins, which yield aloetic acid, C7H2N205, chrysammic acid, C 7 H 2 N 2 0 6, picric and oxalic acids with nitric acid, being reddened by this reagent.
It is somewhat readily oxidized; nitric acid gives carbonic and oxalic acids, and chromic acid, carbonic and acetic acids.
The alkaloid is obtained from an aqueous extract of tobacco by distillation with slaked lime, the distillate being acidified with oxalic acid, concentrated to a syrup and decomposed by potash.
Chromium oxychloride reacts violently on phenol, producing hydroquinone ether, O(C 6 H 4 OH)2; chromic acid gives phenoquinone, and potassium permanganate gives paradiphenol, oxalic acid, and some salicylic acid (R.
When distilled over lead oxide, it forms diphenylene oxide, (C 6 H 4) 2 O: and when heated with oxalic acid and concentrated sulphuric acid, it forms aurin, C19H1403.
Carbolic acid is distinguished from all other acids so-called - except oxalic acid and hydrocyanic acid - in that it is a neurotic poison, having a marked action directly upon the nervous system.
A solution of the free acid may be prepared by adding oxalic acid to the solution of the sodium salt.
Lavoisier, to whom chemistry was primarily the chemistry of oxygen compounds, having developed the radical theory initiated by Guyton de Morveau, formulated the hypothesis that vegetable and animal substances were oxides of radicals composed of carbon and hydrogen; moreover, since simple radicals (the elements) can form more than one oxide, he attributed the same character to his hydrocarbon radicals: he considered, for instance, sugar to be a neutral oxide and oxalic acid a higher oxide of a certain radical, for, when oxidized by nitric acid, sugar yields oxalic acid.
Strong oxidation breaks the benzene complex into such compounds, as carbon dioxide, oxalic acid, formic acid, &c.; such decompositions are of little interest.
Bromine water oxidizes this substance to oxalic acid and tetrabromdichloracetone (5).
Determinations have been made with calcium oxalate, CaC 2 04+H 2 0, which is easily decomposed by acids, oxalic acid and a soluble calcium salt being formed.
The affinities of acids relative to that of oxalic acid are thus found, so that the acids can be compared among themselves (column II.).
It oxidizes readily: exposure to air giving acrylic acid, nitric acid giving oxalic acid, bichromate of potash and sulphuric acid giving carbon dioxide and formic acid.
One method for this purpose is to convert it into a solution of the nitrate U02(N03)2, and from it to precipitate the metal as oxalate by oxalic acid (Peligot).
Some glycerin may be re-formed, but with very strong alkaline solutions little of the glycerin molecule escapes destruction, oxalic acid and several other products resulting.
Silico-oxalic acid, (SiO.
When heated to about 200° it yields a brown amorphous substance, named caramel, used in colouring liquors, &c. Concentrated sulphuric acid gives a black carbonaceous mass; boiling nitric acid oxidizes it to d-saccharic, tartaric and oxalic acids; and when heated to 160° with acetic anhydride an octa-acetyl ester is produced.
Potassium bichromate oxidizes it to malonic acid; nitric acid oxidizes it to oxalic acid; and hydriodic acid reduces it to succinic acid.
OXALIC ACID, H2 C204 2H20, one of the oldest known organic acids.
It loses its water of crystallization at loo C., and begins to sublime at about 150160° C., whilst on heating to a still higher temperature it partially decomposes into carbon dioxide and formic acid, or into carbon dioxide, carbon monoxide and water; the latter decomposition being also brought about by heating oxalic acid with concentrated sulphuric acid.
Oxalic acid is very poisonous, and by reason of its great similarity in appearance to Epsom salts, it has been very frequently mistaken for this substance with, in many cases, fatal results.
The antidotes for oxalic acid poisoning are milk of lime, chalk, whiting, or even wall-plaster, followed by evacuation brought about by an enema or castor oil.
Ethyl oxalate, (C0.0C2H5)2, prepared by boiling anhydrous oxalic acid with absolute alcohol, is a colourless liquid which boils at 186° C. Methyl oxalate (CO.
Mente, Ber., 1886, 19, p. 3229), crystallizes in prisms, and when boiled with water is rapidly hydrolysed to oxamide and oxalic acid.
Oxamide, (CONH 2) 2, is best prepared by the action of ammonia on the esters of oxalic acid.
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.
The olefines may be synthetically prepared by eliminating water from the alcohols of the general formula CnH2n+1 OH, using sulphuric acid or zinc chloride generally as the dehydrating agent, although phosphorus pentoxide, syrupy phosphoric acid and anhydrous oxalic acid may frequently be substituted.
It may also be prepared by heating formic and oxalic acids (or their salts) with concentrated sulphuric acid (in the case of oxalic acid, an equal volume of carbon dioxide is produced); and by heating potassium ferrocyanide with a large excess of concentrated sulphuric acid, K 4 Fe(CN) 6 -i-6H2S04+6H20=2K2S04+FeS04+3(NH4)2S04+6C0.
Hot concentrated nitric acid oxidizes it to picric acid and oxalic acid, whilst on treatment with hydrochloric acid and potassium chlorate it yields chloranil (tetrachloroquinone).
In the last years of his life he returned to the vegetable acids, and investigated citric, malic, oxalic and gallic acids.
And is readily soluble in water, but the solution is unstable and decomposes on standing, giving amorphous insoluble substances, and ammonium formate, oxalic acid, &c. An aqueous solution of hydrogen peroxide converts it into oxamide, (CONH 2) 2, and reduction by zinc and hydrochloric acid gives methylamine.
It may be prepared artificially by the oxidation of methyl alcohol and of formaldehyde; by the rapid heating of oxalic acid (J.
Phys., 1831  46, p. 218), but best by heating oxalic acid with glycerin, at a temperature of iooI to° C. (M.
A concentrated acid may be obtained from the diluted acid either by neutralization with soda, the sodium salt thus obtained being then dried and heated with the equivalent quantity of anhydrous oxalic acid (Lorin, Bull.
The free acid, when heated with concentrated sulphuric acid, is decomposed into water and pure carbon monoxide; when heated with nitric acid, it is oxidized first to oxalic acid and finally to carbon dioxide.
The liquid which exudes from the glandular hairs clothing the leaves and stems of the plant, more especially during the cold season when the seeds ripen, contains a notable proportion of oxalic acid.
He mentioned as an important exception the case of ferric ferrocyanide, which, when dissolved in oxalic acid, transmits the rays in great abundance, though the same rays be absorbed both by ferrocyanides and by ferric salts.
Potash fusion converts it into acetic acid; nitric acid oxidizes it to acetic and oxalic acids; chromic acid mixture to acetaldehyde and acetic acid, and potassium permanganate to a0-dioxybutyric acid.
The oxide and carbonate of magnesium are also invaluable as antidotes, since they form insoluble compounds with oxalic acid and salts of mercury, arsenic, and copper.
Dilute nitric acid oxidizes it to acetic and oxalic acids, while potassium permanganate oxidizes it to acetone, carbon dioxide and oxalic acid.
The residue is then dissolved in water, decolorized by animal charcoal and saturated at 50 C. with oxalic acid.
Urea may be recognized by its crystalline oxalate and nitrate, which are produced on adding oxalic and nitric acids to concentrated solutions of the base; by the white precipitate formed on adding mercuric nitrate to the neutral aqueous solutions of urea; and by the so-called "biuret" reaction.
Parabanic acid (oxalyl urea), C0[NH C0] 21 is formed by oxidizing uric acid; or by condensing oxalic acid and urea in the presence of phosphorus oxychloride.
Hydrochloric acid at 200° C. decomposes into oxalic acid, carbon dioxide and methylamine, whilst an alcoholic solution of a caustic alkali gives dimethyl urea and oxalic acid.
Benzoic anhydride, (C 6 H 5 C0) 2 0, is prepared by the action of benzoyl chloride on sodium benzoate, or by heating benzoyl chloride with anhydrous oxalic acid (R.
The crude oxide of the metal is obtained from cerite, by evaporating the mineral with strong sulphuric acid, removing excess of acid and dissolving the residue in ice-cold water; sulphuretted hydrogen is passed through the solution, which is then filtered, acidified with hydrochloric acid, and precipitated as oxalate by oxalic acid; the oxalate is then converted into oxide by ignition.
His services to industry included his improvements in the processes for the manufacture of sulphuric acid (1818) and oxalic acid (1829); methods of estimating the amount of real alkali in potash and soda by the volume of standard acid required for neutralization, and for estimating the available chlorine in bleaching powder by a solution of arsenious acid; directions for the use of the centesimal alcoholometer published in 1824 and specially commended by the Institute; and the elaboration of a method of assaying silver by a standard solution of common salt, a volume on which was published in 1833.
A mixture of chlorine peroxide and chlorine is obtained by the action of hydrochloric acid on potassium chlorate, and similarly, on warming a mixture of potassium chlorate and oxalic acid to 70° C. on the water bath, a mixture of chlorine peroxide and carbon dioxide is obtained.
A small crystal of oxalic acid added to concentrated sulphuric acid containing about 1 per cent.
In chloroform solution it combines with anhydrous oxalic acid to form a compound, Sb2C18(C204), which is to be considered as COOSbC14 tetra-chlorstibonium oxalate I (R.
Pure Oxalic Acid May Also Be Used, Which, In The Presence Of Sulphuric Acid, Is Oxidized By The Standard Solution According To The Reaction: 5(H2C2042H20) 3H 2 So 4 2Kmn04 =10002 2Mns04 K2S04 18H20 The Reaction In Case Of Ferrous Sulphate Is: 10Fes04 2Kmn04 8H2S04 = 5Fe2(S04)3 K2S04 2Mns04 8H20; That Is, The Same Amount Of Potassium Permanganate Is Required To Oxidize 5 Molecules Of Oxalic Acid That Is Necessary To Oxidize I O Molecules Of Iron In The Form Of Ferrous Sulphate To Ferric Sulphate, Or 63 Parts By Weight Of Oxalic Acid Equal 56 Parts By Weight Of Metallic Iron.
Chromic acid oxidizes it to acetic acid and carbon dioxide; potassium permanganate oxidizes it to pyruvic acid; nitric acid to oxalic acid, and a mixture of manganese dioxide and sulphuric acid to acetaldehyde and carbon dioxide.
Nitric acid and chromic acid have little action on quinoline, but alkaline potassium permanganate oxidizes it to carbon dioxide, ammonia, oxalic, and quinolinic acids (S.
18 99, 3 2, p. 333 2): Cn112n_10Na - >C,,H2n_10 CS.SNa(R) -->Cn,H 2 n_2+COS- FR SH; or simply by dehydrating with anhydrous oxalic acid (N.
Wislicenus, Ann., 18 93, 2 75, p. 312), is also obtained by the action of sodium on the esters of pimelic acid; by the distillation of calcium succinate; and by hydrolysis of the cyclopentanone carboxylic acid, obtained by condensing adipic and oxalic esters in the presence of sodium ethylate.
The 1.3 compound boils at 81-82° C. and on oxidation yields succinic and oxalic acids.
Oxalic Acid >>
Iodide by the action of moist silver oxide; by the reduction of acrolein; or by heating glycerin with oxalic acid and a little ammonium chloride to 260° C. In this last reaction glycerol monoformin is produced as an intermediate product, but is decomposed as the temperature rises: C3H5(OH)3+H2C204 = C3H5(OH),.0.CHO+C02+H20 glycerol monoformin C 3 H 5 (OH) 2.0.
The trioxide, V 2 0 3, is formed when the pentoxide is reduced at a red heat in a current of hydrogen, or by the action of oxalic acid on ammonium metavanadate.
The tetroxide, V204, results when the pentoxide is heated with dry oxalic acid and the resulting mixture of the triand pentoxide is warmed in the absence of air, or when the pentoxide is reduced by sulphur dioxide.
Its impurities are lead, oxalic acid, lime and potassium tartrate.