Process for preparing crystals of anhydrous sodium sulfide
AssigneeSankyo Kasei Kabushiki Kaisha
InventorsKannosuke Maeda, Yoshio Aoyama
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Abstract
Disclosed is a process for preparing crystals of anhydrous sodium sulfide, the process being characterized in that the process comprises the steps of heating crystals of polyhydrate of sodium sulfide under a pressure of about 500 torr or less at a temperature varying not more than .+-.about 10.degree. C. from the phase transition point between polyhydrate crystals and monohydrate crystals of sodium sulfide for about 2 hours or longer and further heating the monohydrate under atmospheric or reduced pressure at about 90.degree. to about 200.degree. C. for about 2 hours or longer.
Claims5
A process for preparing crystals of anhydrous sodium sulfide, comprising the steps of heating crystals of polyhydrate of sodium sulfide in a solid state under a pressure of about 500 torr or less at a temperature varying not more than .+-. about 10.degree. C. from the phase transition point between polyhydrate crystals and monohydrate crystals of sodium sulfide for about 2 hours or longer and further heating the monohydrate under atmospheric or reduced pressure at about 90.degree. to about 200.degree. C. for about 2 hours or longer.
Dependencies are inferred from the claim text.