IX. The Action of Phosphorus Oxychloride upon the Fusible Anilid.
Reading edition
Hunter[26] found that when either of the anilids of orthosulphobenzoic acid were treated with phosphorus oxychloride, or similar dehydrating agents, a molecule of water was abstracted with the formation of a new substance. A careful study of the compound led to the belief that it was a dianil, and that its formation and structure could be represented by the equation
C=N.C₆H₅ /\ CO.NH.C₆H₅/\ //.N.C₆H₅ C₆H₄= C₆H₄/+ H₂O. \\/ SO₂NH.C₆H₅SO₂
A corresponding study of the fusible anilid of paranitroorthosulphobenzoic acid was undertaken.
The method employed in this study was as follows. A tubulated retort of convenient size was fused onto the inner tube of a small condenser. This was done to avoid connections, which are nearly always attacked by the oxychloride. Another satisfactory plan is to have the neck of the retort of the same size as the inner tube of the condenser. The ends are placed in contact, and the tubes bound in position by wrapping with asbestos paper. Over the joint so made, a tight rubber tube is drawn.
A convenient amount of phosphorus oxychloride (50 c.c.) was placed in the retort and the anilid (5 gr.) added through the tubulus. On boiling, with the condenser inverted, the anilid soon dissolved, with evolution of hydrochloric acid gas, and the solution became bright yellow in color, sometimes inclining to orange. The boiling was continued as long as hydrochloric acid was given off. The oxychloride was then distilled off under diminished pressure, care being taken to shake the retort constantly during the distillation as violent bumping is almost sure to occur especially towards the end of the operation. The product remaining, spattered over the walls of the retort, was a greenish yellow solid.
Water was then added, and the whole allowed to stand for an hour or so to thoroughly dissolve the phosphoric acid formed in the reaction.
In case the anilid is not perfectly dry, a much more energetic reaction occurs, and on distilling off the oxychloride, the product remains as a dark, gummy mass. This should be spread out on the sides of the retort while still liquid. On cooling and adding water, this gum gradually disappears, and in its place is found the yellow solid product just described. The gum appears to be a solution of this substance in phosphoric acid.
After the substance is filtered off and dried, it can be crystallized from acetone, benzene, glacial acetic acid or alcohol. From these solvents it crystallizes in small yellow needles resembling quinone in appearance.
The crystals obtained form acetone are rather larger than those from the other solvents, and are more nearly orange in color, apparently because of their greater compactness. When glacial acetic acid is used, care must be taken to avoid any unnecessary heating, as continued heating produces a change that will presently be described. The substance melts at 208°.
Analysis of the substance resulted as follows:
I. 0.3822 gram gave 0.8334 gram CO₂ and 0.1272 gram H₂O.
II. 0.2645 gram gave 0.5812 gram CO₂ and 0.0910 gram H₂O.
III. 0.2023 gram gave 0.1283 gram BaSO₄.
IV. 0.2061 gram gave 0.1280 gram BaSO₄.
V. 0.1853 gram gave 16.73 C.C.N (Standard).
C=N.C₆H₅ /\ /.N.C₆H₅ // Cal. for C₆H₃—SO₂ \ NO₂ Found.
I II III IV V
C = 60.11 59.47 59.93 —— —— ——
H = 3.44 3.69 3.82 —— —— ——
S = 8.45 —— —— 8.70 8.52 ——
N = 11.08 —— —— —— —— 11.35
For analyses I & II I am indebted to Mr. Nakaseko, who kindly made them for me.