9-3-2 Vapor pressure control of liquid NH₃ by NaBH₄

Abstract

Sodium borohydride (NaBH₄) absorbed 2 mol of ammonia (NH₃) /1 mol of NaBH4 and the equilibrium pressure was appeared at 0.09 MPa and 20 °C. The gravimetric NH3 density was 47 wt% and the vapor pressure was about 1/10 lower than that of liquid NH₃. When NaBH₄ absorbed more than 2 mol of NH₃, the NaBH₄-NH₃ system is changed to a solution state, and then the ammonia vapor pressure linearly increases with the NH₃ concentration. In this work, the solution properties are analyzed and discussed from the NH₃ absorption properties obtained by experiments.