The solubility of sodium nitrite (NaNO₂) in water is important to many industries, including those of heat pumps, oil extraction, and the management of alkaline nuclear waste. This study reviews solubility data for NaNO₂ in water between the freezing point (−19 °C) and boiling point (128 °C) of a saturated solution. The temperature of the transition between the hemihydrate and anhydrous NaNO₂ solid phases occurs at ca. −5 °C. There is excellent agreement between most studies above 0 °C, with the average solubility at 25 °C reported being 12.4 mol·kg^–1 water. The electrical conductivity, viscosity, and density of saturated solutions were also reviewed, with mean values from several studies reported at 25 °C. The intrinsic volume of dissolved NaNO₂ determined in this study (36.5 cm³·mol^–1) is only 6% different from the value determined by extrapolating the density of molten salt to ambient temperatures. The flow in concentrated NaNO₂ solutions behaves more like a molten salt than a soft colloidal behavior that more hydrated electrolytes resemble. Indeed, given that there is only ∼0.87 mol of water per mole of dissolved ion at 128 °C, the extremely high solubility of NaNO₂ in water resembles a hydrated molten salt. A thermodynamic-based solubility model was developed.

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亚硝酸钠在水中的溶解度和饱和溶液的物理性质综述

亚硝酸钠 (NaNO ₂ ) 在水中的溶解度对许多行业都很重要，包括热泵、石油开采和碱性核废料的管理。本研究回顾了 NaNO ₂在饱和溶液的凝固点 (-19 °C) 和沸点 (128 °C) 之间的水中溶解度数据。半水合物和无水 NaNO ₂固相之间的转变温度发生在大约 -5℃。大多数研究在 0 °C 以上有很好的一致性，据报道在 25 °C 下的平均溶解度为 12.4 mol·kg ^–1水。还审查了饱和溶液的电导率、粘度和密度，在 25 °C 时报告了几项研究的平均值。本研究中确定的溶解 NaNO ₂的固有体积(36.5 cm ³ ·mol ^–1 ) 与通过将熔盐密度外推到环境温度而确定的值仅相差 6%。浓 NaNO ₂溶液中的流动更像熔盐，而不是更像水合电解质的软胶体行为。事实上，考虑到在 128 °C 下每摩尔溶解离子只有约 0.87 摩尔水，NaNO ₂的极高溶解度在水中类似于水合熔盐。开发了基于热力学的溶解度模型。