メチルメルカプタンの水に対する溶解度

Abstract

In the course of our field-work investigating the behaviour of methyl mer-captan found in the atmosphere near a kraft mill, it was observed that the concentration of mercaptan kept in both a plastic bag and a glass bottle decreases with the lapse of time, with the conclusion that the humidity in air has an indisputable influence on the preservation of mercaptan after its sampling. In order to inquire into the property of mercaptan in moist air, it is indispensable to have knowledge of its soubility in water. There are some data presented in literature, though they are practically useless on accunt of discrepancies among them so that we have measured the solubility at 20℃ or thereabouts. Methyl mercaptan, diluted with nitrogen, was introduced into a glass bulb containing water at its bottom and was allowed to stand, with frequent agitation, at the scheduled tempeature. When the equilibrium was attained, portions were drawn from gaseous and liquid phases into glass syringes and were analyzed by gas-chromatography. The results obtained are summarized as follows : The solubility, expressed as Bunen's absorption coefficient, is (10.5)_0 (15℃), (9.1)_9 (20℃) and (7.3)_7 (25℃). Using these figures, the differential heat of solution was calculated to be 5.7kcal/mol at ordinary temperature.