Натрий сульфид нонагидрат

Химические свойства

colourless, white or yellow crystals with an odour of rotten eggs

Использование

Sodium sulfide nonahydrate has been used as a source of H₂S, to study the effect of H₂S on amyloid fibrils associated with neurodegenerative diseases. It has been used in the preparation of sulfide standards for the quantitative analysis of sulfides in raw wastewater (sewage) samples.
It serves as a catalyst during synthesis of thioamides.

Общее описание

Sodium sulfide nonahydrate participates in the conversion of nitroxides to amines, via reduction.

Методы очистки

Some purification of the hydrated salt can be achieved by selecting large crystals and removing the surface layer (contaminated with oxidation products) by washing with distilled water. Other metal ions can be removed from Na2S solutions by passage through a column of Dowex ion-exchange A-1 resin, Na+-form. The hydrated salt can be rendered anhydrous by heating it in a stream of H2 or N2 until water is no longer evolved. (The resulting cake should not be heated to fusion because it is readily oxidised.) Recrystallise it from distilled water [Anderson & Azowlay J Chem Soc, Dalton Trans 469 1986]. Note that sodium sulfide hydrolyses in H2O to form NaHS + H2O, and is therefore alkaline. A 0.1N solution in H2O is 86% hydrolysed at room temperature. Its solubility in H2O is 8% at 0o, 12% at 20o and 30% at 50o. The anhydrous salt is obtained by allowing it to stand in a vacuum over conc H2SO4 or P2O5 at 45o to start with, then at 30-35o when the salt contains 4% of water. The last traces of water are removed by heating to 700o in a glass or porcelain tube in a stream of H2 to give pure H2S. [Fehér in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I pp 358-360 1963.]