William Edwards Henderson

“ It is insoluble in benzene, chloroform, acetone, ether and ligroin; soluble in glacial acetic acid, from which it separates on cooling in colorless, crystalline condition; insoluble in the cold in water, alcohol and ammonia, but by boiling with these reagents, or by long standing in the cold, it is dissolved with decomposition. It was dissolved in hot water and the solution, which was acid in reaction, was neutralized with potassium carbonate. ”

“ The Action of Glacial Acetic Acid on the Dianil.
When the dianil is boiled with glacial acetic acid for some time, the color of the solution changes to a much lighter shade of yellow, or becomes colorless. On evaporating the solution to small volume, and allowing it to cool, a colorless substance separates. This is infusible anilid. It could not be obtained in crystals from any solvent, but always separated in flakes. It does not melt or undergo change at 340°.
Like the fusible anilid it dissolves in dilute alkali, but on [Pg 80] acidifying the solution it does not immediately reappear. ”

“ 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. ”

“ The heating is continued until a few drops of the mixture, added to cold water, dissolves completely to a clear solution. The time [Pg 7] required for this operation varies much with the conditions. Continued stirring very considerably hastens the reaction, as paranitrotoluene forms a layer on the acid, which presents a small surface to its action. With constant stirring the reaction is complete in a few hours, whereas if no stirring is resorted to, as much as several days may be required, especially when large quantities are employed at one time. ”

“ The oxidation of the potassium salt is effected as follows. 50 grams of the salt are dissolved in 21⁄2 litres of water, and to this is added a solution of 15 grams of potassium hydroxide. The mixture is heated to 100° on a water-bath, and when this temperature is reached, 110 grams of potassium permanganate are added. Heating is continued until the solution is decolorized, care being taken to prevent the evolution of free oxygen. ”

“ By the methods described, the symmetrical chloride of paranitroorthosulphobenzoic acid can be obtained in fine crystalline form, perfectly free from its isomer, with an average yield of forty percent.
2. By treatment of the chloride with benzene and aluminium chloride, only one chlorine atom can be replaced by a phenyl group.
3. The barium salt of paranitroorthobenzoyl benzenesulphonic acid, when perfectly pure, crystallizes constantly with seven molecules of water of crystallization. ”

“ The excess of aniline is [Pg 66] thus removed, and the reaction product obtained as a reddish-brown solid substance. This was treated with dilute sodium hydroxide, all lumps being broken up with a stirring rod. The undissolved substance is largely anil, which was filtered off. The anilid was then regained by acidifying the alkaline solution, in which it was dissolved. It separates immediately as a curdy colorless precipitate, though it is frequently colored pink by impurity. ”

“ As growth proceeded, the crystals became dark in color, and the mother-liquor correspondingly clearer, the crystals evidently absorbing the impurity in their growth. [Pg 28]
When the solution had become quite colorless, rhombic crystals of the salt containing seven molecules of water of crystallization appeared. The larger prismatic crystals were carefully removed, and redissolved in water in order to see if the same phenomena would repeat themselves. This in fact was the case, crystals of both types appearing in the same way as described. ”

“ The method employed in the preparation of paranitroorthosulphobenzoic acid was essentially that described by Hart, [7] Kastle, [8] Gray [9] and Hollis. [10] The details of it are repeated here for the purpose of calling attention to certain facts that came under the author’s notice.
100 grams of paranitrotoluene are added to 400 grams of fuming sulfuric acid, and the mixture heated in a balloon flask at 100° on a water bath. ”

“ Remsen,under whose guidance this work was carried on not only for instruction received in the lecture room, but for his frequent suggestion, and his constant and friendly interest in the work as it progressed. These have at all times been an encouragement and an incentive. ”

“ 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:
For analyses I & II I am indebted to Mr. ”