Sodamide mfr. for organic synthesis, e.g. indigo mfr. - in which ammonia is recycled to prevent pollution

摘要

Alkali amides are made by the reaction of molten alkali metals with NH3; and the exhaust gas contg. NH3, from this reaction and/or from any subsequent syntheses in which sodamide is employed, is cleaned, possibly by liquefaction, mixed with further NH3, and recycled for reaction with the alkali metal. The exhaust gas is pref. cleaned via filters before being recycled. The initial raw materials (e.g. sodium) are pref. stored in the absence of air and water to avoid alkali hydroxide impurities, and are melted before being fed into the reactor.