298.15K时浓磷酸水溶液的体积性质  

Volumetric Properties of Concentrated Aqueous Phosphoric Acid Solution at 298.15K

作　　者：江成发[1] 

机构地区：[1]四川联合大学化学工程系

出　　处：《高校化学工程学报》1997年第3期249-254,共6页Journal of Chemical Engineering of Chinese Universities

摘　　要：在２９８．１５Ｋ的浓磷酸水溶液中，认为存在Ｈ３ＰＯ４Ｈ＋＋Ｈ２ＰＯ－４和Ｈ２ＰＯ－４＋Ｈ３ＰＯ４Ｈ５Ｐ２Ｏ－８两个化学平衡。用修正的Ｐｉｔｚｅｒ离子相互作用模型表达磷酸水溶液的过剩Ｇｉｂｂｓ自由能，推导出能精确描述浓度高达１８．０ｍｏｌ·ｋｇ－１的磷酸水溶液体积性质的数学模型。用磷酸水溶液密度的文献值关联该模型，得到磷酸的标准偏摩尔体积Ｖ０＝４５．４４±０．０７ｃｍ３·ｍｏｌ－１，以及一组有关浓磷酸水溶液的体积Ｐｉｔｚｅｒ相互作用参数。应用本文得到的浓磷酸水溶液体积性质的数学模型和体积Ｐｉｔｚｅｒ相互作用参数，计算了磷酸水溶液的密度和磷酸的表观摩尔体积。结果表明，磷酸水溶液体积性质的模型计算值能很好地吻合实测值，表明Ｐｉｔｚｅｒ离子相互作用模型可以用来精确预测浓磷酸水溶液的体积性质。Two chemical equilibria H 3PO 4H ++H 2PO - 4 and H 2PO - 4+H 3PO 4H 5P 2O - 8, and one modified Pitzer′s ion interaction expression for excess Gibbs energy of concentrated aqueous phosphoric acid solution are used to develop a model that provides an accurate representation of the volumetric properties, such as the solution density and the apparent molar volume of phosphoric acid, of aqueous phosphoric acid solution from 0 to 18.0 mol·kg -1 at 298.15K. Literature densities of aqueous phosphoric acid solution are analyzed with the developed model, yielding the standard partial molar volume of phosphoric acid, 0=45.44±0.07 cm 3·mol -1 , and a set of volumetric Pitzer interaction parameters of aqueous phosphoric acid solution to high concentration of 18.0 mol·kg -1 at 298.15K. From this information, densities of aqueous phosphoric acid solution as well as apparent molar volumes of phosphoric acid are predicted with good accuracy, as showen by the comparision of calculated and experimental data.

关 键 词：体积性质 磷酸 浓磷酸水溶液 电解质水溶液 

分 类 号：O613.62[理学—无机化学] O646.16[理学—化学]