On some salts and products of decomposition of pyromeconic acid / by James F. Brown.

Date:
[1852?]
Catalogue details

Licence: Public Domain Mark

Credit: On some salts and products of decomposition of pyromeconic acid / by James F. Brown. 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.

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    It loses nothing at 213°, even after, being kept for three or four hours at that temperature. The following is the result of analysis, the lead being deter- mined as sulphate by ignition of the salt with a few drops of strong sulphuric acid. 5- 48 grains substance gave 5*65 carbonic acid and 0'815 water. 5*29 grains substance gave 374 sulphate of lead. Calculation. Experiment. , 1 Carbon . . . 28-12 27-94 C^o 60 Hydrogen . . 1-65 1-39 3 Oxygen . . . 18-21 18-77 0^ 40 Oxide of lead . 52-02 51-90 PbO 111-56 100-00 100-00 214-56 The formula is therefore represented by PbO, 0^. Pyromeconate of Copper.—The ammonio-sulphate of copper mixed wdth a warm aqueous solution of pyromeconic acid causes an immediate precipitate of this salt in bright green crystalline needles, which are extremely brittle and easily pulverized. This salt has also been examined by Stenhouse*, who prepared it by boiling the acid with hydrated oxide of copper, and allowing the filtered solution to cool. The crystals require a considerable amount of hot water for their solution, and are very slightly soluble in cold water or alcohol. The copper was determined as oxide by heating the salt to redness, and then igniting the residue with nitric acid. It loses nothing at 212°. 6- 00 grains substance gave 1-66 oxide of copper, which calcu- lated per-centage gives 27-66 of oxide of copper, the number 27-79 being that corresponding with the formula CuO, C^o W 0\ Fxjromeconate of Iron.—Dr. Stenhouse has observed in the paper before mentioned, that when pyromeconic acid is boiled with hydrated peroxide of iron, and also with the persulphate, it combines with the oxide and forms a brownish-red powder, ■which when neutral is very little soluble in cold water. It may also be obtained, and perhaps more conveniently, by adding perchloride of iron to a hot concentrated solution of the acid in water, when the cinnabar-red crystals begin to make their ap- pearance, adhering firmly to the sides and bottom of the vessel. Its pro]ierties have been so fully described by Stenhouse, that further remark is unnecessary. The crystals were well washed with cold water, until the fluid * Mem. and Proc. Clicm. Soc. vol. ii. [riiil. Mag. S. 3. vol. xxiv. p. 128.]