Of the hygroscopic substances in common use, phosphoric anhydride, concentrated sulphuric acid, and dry potassium hydrate are almost equal in power; sodium hydrate and calcium chloride are not much behind.
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.
When distilled with phosphoric anhydride they yield nitriles.
Dimethyl-meta-aminophenol crystallizes in small prisms which melt at 87° C. It condenses with phthalic anhydride to form rhodamine, and with succinic anhydride to rhodamine S.
Four oxides of sulphur a.re known, namely sulphur dioxide, S02, sulphur trioxide, S03, sulphur sesquioxide, S203, and persulphuric anhydride, S 2 0 7.
Persulphuric anhydride, S207, is a thick viscous liquid obtained by the action of the silent discharge upon a mixture of sulphur trioxide and oxygen.
In the presence of a dehydrating agent (such as acetic anhydride), it combines with aldehydes to form compounds of the type R CH: C(COOH) 2, or their decomposition products (formed by loss of C02) R CH: CH COOH.
A higher temperature decomposes this body into carbon dioxide and itaconic acid, C 5 H 6 0 4, which, again, by the expulsion of a molecule of water, yields citraconic anhydride, C 5 H 4 0 3.
7-dihydroxyxanthone, known as euxanthone, is prepared by heating euxanthic acid with hydrochloric acid or by heating hydroquinone carboxylic acid with 3-resorcylic acid and acetic anhydride (S.
Again, in nitrous oxide we have a compound of 8 parts by weight of oxygen and 14 of nitrogen; in nitric oxide a compound of 16 or 8 X 2 parts of oxygen and 1 4 of nitrogen; in nitrous anhydride a compound of 24 or 8 X 3 parts of oxygen and 14 of nitrogen; in nitric peroxide a compound of 3 2 or 8 X 4 parts of oxygen and 14 of nitrogen; and lastly, in nitric anhydride a compound of 4 o or 8 X 5 parts of oxygen and 14 of nitrogen.
Both phosphoric and phosphorous acids became known, although imperfectly, towards the end of the 18th century; phosphorous acid was first obtained pure by Davy in 1812, while pure phosphorous oxide, the anhydride of phosphorous acid, remained unknown until T.
OH; R.CO Cl; (R.CO)20; R.CO SH; acid; acid-chloride; acid-anhydride; thio-acid; R CO NH 2 i R CO NH NH2.
A notable example is provided by the phthaleins, which result by the condensation of phthalic anhydride with phenols.
Glucoseoxime on warming with acetic anhydride is simultaneously acetylated and dehydrated, yielding an acetylated gluconitrile, which when warmed with ammoniacal silver nitrate loses hydrocyanic acid and is transformed into an acetyl pentose.
It is also formed by heating benzoic anhydride with glycocoll (Th.
Bladin HC -N (Ber., 1892, 25, p. 183) by the action of acetic)NH anhydride on dicyanophenylhydrazine (formed N: CH from cyanogen and phenylhydrazine), the resulting acetyl derivative losing water and yielding phenylmethylcyanotriazole, which, on hydrolysis, gives the free acid.
The osotriazoles are obtained by heating the osazones of orthodiketones with mineral acids; by the action of acetic anhydride on the hydrazoximes of orthodiketones, or by condensing diazo-methane with cyanogen derivatives (A.
The newer glasses, on the other hand, contain a much wider variety of chemical constituents, the most important being the oxides of barium, magnesium, aluminium and zinc, used either with or without the addition of the bases already named in reference to the older glasses, and - among acid bodies - boric anhydride (B20 3) which replaces the silica of the older glasses to a varying extent.
It is decomposed by cold water with the formation of silicoformic anhydride, H2S1203.
Wohl forms the oxime and converts it into an acetylated nitrile by means of acetic anhydride and sodium acetate; ammoniacal silver nitrate solution removes hydrocyanic acid and the resulting acetate is hydrolysed by acting with ammonia to form an amide, which is finally decomposed with sulphuric acid.
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.
It is oxidized by nitric acid to d-saccharic and mucic acids; and acetic anhydride gives an octa-acetate.
Dorp (Ber.,1874,7,P.578) obtained orthobenzoyl benzoic acid by heating phthalic anhydride with benzene in the presence of aluminium chloride.
This compound on heating with phosphoric anhydride loses water and yields anthraquinone, CsH4 O 15 CsH
The hydroxide readily loses its water at a dull red heat and passes into anhydride with vivid incandescence.
Krafft, Ber., 1883, 16, p. 3018): C16H33 CH2 CH2.0H->C161-133CH2 CH2.0 CO R-> C16H33CH: CH 2 -j-R COOH; from tertiary alcohols by the action of acetic anhydride in the presence of a small quantity of sulphuric acid (L.
In making the acid by this process benzaldehyde, acetic anhydride and anhydrous sodium acetate are heated for some hours to about 180 C., the resulting product is made alkaline with sodium carbonate, and any excess of benzaldehyde removed by a current of steam.
Fittig and his pupils (Annalen, 1883, 216, pp. loo, 115; 1885, 227, pp. 55, 119), in which it was shown that the aldehyde forms an addition compound with the sodium salt of the fatty acid, and that the acetic anhydride plays the part of a dehydrating agent.
I propionic anhydride C6H5C(N-O COC2H5 ]-?C 6 H 5 C N O%C.C2H5.
CH2([[Coon)2+Ch3cho-->Ch3 Ch:C(000h)2->Ch3 Ch:Ch 000h]]; or by heating pyruvic acid with an excess of acetic anhydride and sodium acetate to 160-180° C. (B.
Heated with anhydrous sodium acetate and acetic anhydride it gives cinnamic acid; with ethyl bromide and sodium it forms triphenyl-carbinol (C 6 H 5) 3 C OH; with dimethylaniline and anhydrous zinc chloride it forms leuco-malachite green C6H5CH[C6H4N(CH3)2]2; and with dimethylaniline and concentrated hydrochloric acid it gives dimethylaminobenzhydrol, C 6 H 5 CH(OH)C 6 H 4 N(CH 3) 2.
Heated with sulphur it forms benzoic acid and stilbene: 2C 7 H 6 0+S = C6HS000H+C6H5CHS, 2C 6 H 5 CHS =2S +C14H12 Its addition compound with hydrocyanic acid gives mandelic acid C 6 H 5 CH(OH) COOH on hydrolysis; when heated with sodium succinate and acetic anhydride, phenyl-iso-crotonic acid C 6 H 5 CH: CH CH 2 000H is produced, which on boiling is converted into a-naphthol C 10 H 7 0H.
Acid esters yield carbinols, many of which are unstable and readily pass over into unsaturated compounds, especially when warmed with acetic anhydride: R.
They may be prepared by the oxidation of secondary alcohols; by the addition of the elements of water to hydrocarbons of the acetylene type RC CH; by oxidation of primary alcohols of the type RR' CH CH 2 OH:RR' CH CH 2 OH --> R CO R'+H20+H2C02; by distillation of the calcium salts of the fatty acids, C.H2.02; by heating the sodium salts of these acids CnH2n02 with the corresponding acid anhydride to 190 C. (W.
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 free acid is not known; by the addition of the potassium salt to 50% acetic acid at - 20° C., the acid anhydride, benzene diazo oxide, (C6H5N2)20, is obtained as a very unstable, yellow, insoluble compound, exploding spontaneously at o° C. Strong acids convert it into a diazonium salt, and potash converts it into the diazotate.
Bamberger (Ber., 18 94, 27, p. 9 1 4) obtained the diazoic acids, R NH NO 2, substances which he had previously prepared by similarly oxidizing the diazonium salts, by dehydrating the nitrates of primary amines with acetic anhydride, and by the action of nitric anhydride on the primary amines.
Bamberger (Ber., 1895, 28, p. 1682) regards it as the anhydride of iso-diazomethane, CH 3 N: N OH, and has prepared it by a method similar to that used for the preparation of iso-diazobenzene.
Its hydrochloride melts at 163° C., and crystallizes from alcohol in colourless deliquescent prisms. Acetic anhydride converts the base into an acetamino-dimethyl pyrimidine, acetic acid and acetamide being also formed.
It condenses with acetic anhydride to form a methyldiphenyl triazine, acetamide being also formed; with acetyl-acetone to form dimethylphenyl pyrimidine (A.
Acetyl urea, NH 2 CO NH 000H 31 formed by the action of acetic anhydride on urea, crystallizes in needles which melt at 212° C. and, on heating, strongly decomposes into acetamide and cyanuric 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.
Can also be synthesized by heating catechol with phthalic anhydride and sulphuric acid at 150 C. ' 'C 6 H4>Cg>O+C 6 H4(OH)2[1.2] = H 2 0 -}-C6H4C6H2(OH)2.
Anthragallol is synthetically prepared by the condensation of benAoic and gallic acids with sulphuric acid OH i [[Cooh + I 10h - 2h20+ Hooc /Oh]] or from pyrogallol and phthalic anhydride in the presence of sulphuric acid or zinc chloride.
Succinic anhydride, C 2 H 4 (CO) 2 0, is obtained by heating the acid or its sodium salt with acetic anhydride; by the action of acetyl chloride on the barium salt; by distilling a mixture of succinic acid and succinyl chloride, or by heating succinyl chloride with anhydrous oxalic acid.
It forms an anhydride when heated.
It does not yield an anhydride, but when heated loses carbon dioxide and leaves a residue of propionic acid.
Diethyl ketene, (C2H5)2C :CO, is formed on heating diethylmalonic anhydride (Staudinger, ibid.).
It crystallizes from water in large prisms which melt at 168-170° C., and on further heating gives an anhydride and finally chars, emitting a characteristic odour and forming pyroracemic and pyrotartaric acids.
Phosphorous acid, P(OH) 3, discovered by Davy in 1812, may be ' obtained by dissolving its anhydride, P 4 0 61 in cold water; by immersing sticks of phosphorus in a solution of copper sulphate contained in a well-closed flask, filtering from the copper sulphide and precipitating the sulphuric acid simultaneously formed by baryta water, and concentrating the solution in vacuo; or by passing chlorine into melted phosphorus covered with water, the first formed phosphorus trichloride being decomposed by the water into phosphorous and hydrochloric acids.