Volume 1
A treatise on chemistry / by H.E. Roscoe and C. Schorlemmer.
- Henry Enfield Roscoe
- Date:
- 1877-1892
Licence: Public Domain Mark
Credit: A treatise on chemistry / by H.E. Roscoe and C. Schorlemmer. Source: Wellcome Collection.
669/792 page 653
![CARBON YLD1URE A. G53 6,493 parts of water at 15°, whilst at 106°, the boiling point of a saturated solution, 222 parts only are needed.1 When a few drops of cupric sulphate and then an excess of caustic soda are added to a solution of biuret in water, the liquid assumes a colour varying from red to violet, according to the quantity of copper salt added. By means of this reaction it is easy to show the passage of urea into biuret; it is only neces- sary to heat a small quantity of urea in a test-tube until ammonia begins to be evolved, the melted mass being poured into hot water and treated as described. Carbonyldiurea, C3HgX403. 407 When urea is heated to 100° with carbonyl chloride in a sealed tube, this substance is formed ; thus:— 2 CO + COCl2 = CO + 2I1C1. It is a white powder which separates from boiling water in crystals. On heating biuret with carbonyl chloride a substance very similar to the one now described is obtained, to which the name of CarbonylcU-biuret has been given,2 and which has the follow- ing constitution :— /Nil—CO—XII—CO—NIL,. CO \NII—CO—NH—CO—NH2. OXYTIIIOCARBAMIC ACID, CO (NH ( SH Bertlielot first obtained the ammonium salt of the above acid. This salt separates out in crystals, when dry carbonyl sulphide is brought in contact with ammonia. The acid itself is not known. When heated in a closed tube the ammonium salt is con- verted into urea:3 1 2 3 C0 { SNH4 “ H2S + CO ^ ^ ^2- co i nh2. Hofmann, Bcr. Deutsch. Chcm. Qes. iv. 262. E. Schmidt, Journ. Bract. Chcm. [2], v. 35. Kretzschmar, Journ. Pract. Chcm. [2], vii. 4 74.](https://iiif.wellcomecollection.org/image/b28122409_0001_0671.jp2/full/800%2C/0/default.jpg)
