Volume 1

Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors.

Date:: 1888-1894

Credit: Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

714/796 (page 688)

$slowly added enough HNO:iAq, S.G. 1-525, to completely moisten the whole ; he then digested at 50° to 60°, and then at 60° to 70°, for 25-30 hours ; he poured off the greater part of the acid and dissolved KN03, washed with hot water by decantation, dried in vacuo and then at 100° ; he repeated this treatment 5 or 6 times ; finally he washed the residue with HN03Aq S.G. 1-28, removed the acid by pressing between paper and then by washing with alcohol, washed with ether to remove alcohol, pressed again, and dried on the water-bath in the dark. Gottschalk's analyses lead to the formula 0,,H406 for graphitic acid ; he describes a salt, C33H10K.2O18, obtained by treating with cone. KOHAq and washing with cold water. The action of KC103 and HN03 on graphite has also been investigated by Stingl (B. 6, 391), and by Berthelot (A. Ch. [4] 19, 399). Berthelot calls the compound produced as described graphitic oxide, he says it does not react as an acid; he calls the carbon-like mass left on heating graphitic oxide pyrographitic oxide; the body is completely dissolved by heating with KC103 and HN03. The porous, amorphous, insoluble body obtained by heating 1 part graphitic oxide with 20 parts HIAq— S.G. 2-0 to 280°, Berthelot calls hydrographitic oxide; this body is not explosively decomposed by heating, treated with KC103 and HN03 it yields graphitic oxide. There appear to be differences between the graphitic acids obtained from different kinds of graphite. Berthelot distin- guishes the three allotropic forms of carbon by their reactions with KC103 and cone. HN03; amorphous carbon is oxidised to brown humus- like bodies, which dissolve in water; graphite forms graphitic acid ; diamond is unchanged.— 10. Both graphite and amorphous carbon are said to yield mellitic acid C^CC^H),; by the action of K2Mn208 in KOHAq (Schulze, B. 4, 802).—11. Carbon combines with many metals when strongly heated with them, e.g. with Fe, Ni, Co, &c.; none of these carbides has been isolated as a pure compound (v. Carbides). Carbon, halogen compounds of. Carbon does not combine directly with the halogens. These compounds are represented by the formula CX4, C2X6, and C2X.„ where X = Br or CI; when X = I only CX4 is known: no fluoride of C has been isolated. The chlorides have been gasified and V.D. of each determined; the formula? are therefore molecular. The bromides decompose, partially or wholly, when heated: the formulas are probably molecular. The iodide is easily separated by heat into C and I. The methods of preparation, and reactions, of the chlorides and bromides are very similar. [C,CP] = 21,030 ; [C-'.Cr1] = -1,150 (at const, press. Thomsen). Besides these compounds, several bromochlorides of carbon exist; CBrCl3; two isomeric C2Br2Cl,„ CjBr^Cl;,, C2Br5Cl, C^Cl,, C2Br3Cl. [Tor more details of the halogen compounds of carbon v. the halogen derivatives of Ethane, Ethylene, and Methane.] Carbon bromides. Carbon dibromide C,Br4 (Tetrabromethylene). White crystals; M.P. 53° ; produced by heating C.2BrG, or better, by reducing C2Br6 with Zn and H2SO.Aq; also by reacting with Br on alcohol or ether, adding KOHAq to remove HBr, and distilling ; or by treating C2HBr3.Br2 with alcoholic KOH (Len- nox, C. J. 14, 209). Decomposed by hot Zn, Cu, Fe, ZnO, CuO, &c, giving metallic bromide and C or C02 (Lowig, A. 3,292). Carbon tribromide C2Br0 (Hexabrcmiide. Tetrabromethylene dibromide). Hard, rectan- gular prisms, easily soluble in CS,, insoluble in alcohol or ether ; decomposed to CJBr., and Br2 at 200°. Produced by brominating C,H,Br2, and by heating C2HBi\ with Br and H.,0 to 170°-180° (Keboul, A. 124, 271). Carbon tetrabromide CBr, (Tetra- bromo-methane). White lustrous tables; S.G. 3-42 ; M.P. 91°. B.P. 189-5° (at 760 mm.) with partial decomposition. Insol. in water, very sol. in alcohol, ether, or CHC13. Partially decom- posed with liberation of Br, at 200°; with alco- hol at 100° gives HBr, CHBr3, and CH..CHO; with alcoholic NH3 at 100° gives CHBr3 and a little guanidine. Formed by the reaction between (1) Br, in presence of I or SbBr3, and CHBr3 or CS2 or CBr3(N02) ; (2) Br, in presence of I, and CHCLj. Best prepared by heating 1 part CS2 with U parts I and 7 parts Br to 150°-160° for 48 hours in a closed tube, shaking contents of j tube with NaOHAq, distilling in steam, pressing between paper, and crystallising from alcohol (Bolas a. Groves, C. J. [2] 8, 161 ; 9, 773). Carbon Chlorides. Carbon dichloride C,C14 (Tetrachlor ethylene). Colourless liquid; ethereal odour ; S.G. at 10° 1-62 (B.), 1-612 (G.); S.G. at 0° 1-6595 (B.). B.P. 122° (B.), 116-7° J (G.), 121° (B.). V.D. 5-82. Easily combines 1 with CI in sunlight forming C2C16. Prepared by reducing C2C16; C2C16 is placed in a flask with water and Zn, H2S04Aq is added from time to i time, the flask being kept cold and frequently ! shaken ; the C,C14 is distilled over in steam, dried, and fractionated (Faraday, T. 1821. 47 ; Begnault, A. Ch. 71, 377; Geuther, A. 107, 212 ; Bourgoin, Bl. 23, 344). Carbon trichloride C2C1U (Tetra- chlorethylene dichloride. Carbon hexachloride). Hard, colourless, rhombic prisms ; S.G. 2 0. M.P. 187° and B.P. the same (Stadel a. Hahn, B. 9, 1735). V.D. 8-15. Insol. in H20, sol. in alcohol or ether. Easily reduced, e.g. by Zn and H,SO,Aq. or by alcoholic KHS, to G,C1,; with KOHAq at 200° gives KC1, H?0, and K2C20.,. Prepared by leading CI into boiling C2H4C12 till saturated, cooling by ice, pressing between paper, dissolving in alcohol, ppg. by H.,0, press- ing, and crystallising from alcohol (Faraday, T. 1821. 47; Begnault, A. Ch. 69, 165; 71, 371; Liebig, A. 1, 219; Geuther, A. 60, 247; Ber- thelot, A. 109, 118). Carbon tetrachloride CC14 (Tetra- chlorv-methane). Colourless liquid, with ethereal odour; S.G. g 1-63195; B.P. 76-74° (Thorpe, C. J. 37,199). V.D. 5-24. Prepared by leading- dry CI into boiling CHC13 containing a little SbCl3 or IC1, in a large flask with inverted con- denser, removing excess of CI by shaking with Hg, and fractionating. Also by passing CS2 and CI through a hot porcelain tube (Kolbe, A. 45, 41; 54,146). Unchanged by KOHAq ; with alcoholic KOH slowly gives KC1, K2C03, and H20 ; passed through a hot tube gives C2C14, C,C16, and C; heated with S03 gives COCl2 and SAClj,; with P205 gives POOL, and COCl2$