As soon as the phenol melts, some slight action occurs, as is indicated by the fact that the mixture assumes a bright red color. No appreciable amount of hydrochloric acid gas is evolved however, until the liquid mixture has reached a temperature of about 115°. At this point the gas is freely evolved, and the action is complete at a temperature of 125°. The temperature observations were made by means of a thermometer used as a stirring rod in the mixture. During the heating, the color of the liquid becomes a much more intense red, growing darker in shade, and the liquid itself becomes somewhat viscous but does not solidify while hot.
When cool, the melt was repeatedly extracted with boiling water, the aqueous solution being very deep purple in color. The colored matter was removed very slowly in this manner, and so the process was continued with dilute alkali. A solid insoluble residue was thus obtained, of a light-brownish color. This was dissolved in alcohol, boiled with boneblack and filtered. On cooling, needles of a straw yellow color were deposited from the alcoholic solution.
This proved to be the normal diphenyl etherial salt of paranitroorthosulphobenzoic acid, the formation of this substance being expressed by the equation:
COClCOOC₆H₅
//
C₆H₃—SO₂Cl + 2C₆H₅OH = C₆H₃—SO₂OC₆H₅ + 2HCl.
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NO₂NO₂
Analysis of the substance gave the following results:
| I. 0.1627 gram gave 0.3398 gram CO₂ and 0.0510 gram H₂O. | |||
| II. 0.1999 gram gave 0.4180 gram CO₂ and 0.0600 gram H₂O. | |||
| III. 0.2649 gram gave 0.1561 gram BaSO₄. | |||
| Cal. for | COOC₆H₅ / C₆H₃—SO₂OC₆H₅ \ NO₂ | Found. | |
| I | II | III | |
| C =57.14 | 56.97 | 57.03 | —— |
| H = 3.26 | 3.47 | 3.33 | —— |
| S = 8.02 | —— | —— | 8.09 |
This substance melts at 119° (uncorr).
It possesses properties similar to those of the diphenyl etherial salt of orthosulphobenzoic acid described by Saunders. It is insoluble in water, and is unaffected by hydrochloric acid or aqueous alkali. On heating for a short time with alcoholic potash, the needles were transformed into a voluminous precipitate. This was filtered off, dissolved in water, and hydrochloric acid was added. On cooling, characteristic crystals of the acid potassium salt of paranitroorthosulphobenzoic separated.
Analysis.
| 0.1392 gram lost 0.009 gram at 150° and gave 0.0385 gram K₂SO₄. | |
| COOH / Cal. for C₆H₃—SO₂OK + H₂O \ NO₂ | Found. |
| H₂O = 5.95 | H₂O = 6.51 |
| K = 13.65 | K = 13.35 |