Vapor pressure above concentrated aqueous solution of lithium bromide at subzero temperatures

• The vapor pressures above water solutions of LiBr are measured at subzero temperatures.
• An empirical formula with a mean deviation of 2.81% is proposed for data correlation.
• The benefit of using low temperature LiBr solution as hygroscopic solution is demonstrated.

The property of vapor pressure above aqueous solution of lithium bromide has been extensively studied, but the experimental data are mostly limited to temperature range above 0°C. During recent years novel applications of hygroscopic solutions at subzero temperatures were proposed; thus more accurate data of vapor pressure are anticipated. In this paper the equilibrium vapor pressure above aqueous LiBr solution was measured with static method in the temperature range from 217K to 273K. The molality of LiBr varied from 8.62 to 11.51 mol kg−1. The measured data were compared with the calculated values of an existing formulation (Pátek and Klomfar in 2006), and a mean deviation of 35.85% was found. If the data were correlated with a modified Antoine equation, a mean deviation of 2.81% could be obtained. In order to estimate the hygroscopic potential of low temperature aqueous LiBr solution as compared to cold surface, the temperature differences between the solution and the ice at the same vapor pressures were estimated.