五水合五硼酸钠溶解热测定及其热力学性质  

Dissolution Enthalpy and Thermodynamic Properties of NaB_(5)O_(8)·5H_(2)O

作　　者：肖举 袁菲 李珑 郭亚飞 王士强 邓天龙 XIAO Ju;YUAN Fei;LI Long;GUO Ya-fei;WANG Shi-qiang;DENG Tian-long(Key Laboratory of Marine Resource Chemistry and Food Technology(TUST),Ministry of Education,Tianjin,300457,China;Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization,Tianjin,300457,China;College of Chemical Engineering and Materials Science at Tianjin University of Science and Technology,Tianjin,300457,China)

机构地区：[1]海洋资源化学与食品技术教育部重点实验室,天津300457 [2]天津市卤水化工与资源生态化利用重点实验室,天津300457 [3]天津科技大学化工与材料学院,天津300457

出　　处：《盐湖研究》2022年第1期1-6,100,共7页Journal of Salt Lake Research

基　　金：National Nature Science Foundation of China(U21A20299 and 22103056);Yangtze Scholars and Innovative Research Team in Chinese University(IRT_17R81)。

摘　　要：不同形态硼酸盐焓、熵、吉布斯自由能等热力学参数极为缺乏,其准确测定对丰富和发展盐湖硼酸盐化学理论至关重要。采用微量热计测定了五水合五硼酸钠(NaB_(5)O_(8)·5H_(2)O)溶解热。根据设计的热化学循环和热力学基本公式,获得了NaB_(5)O_(8)·5H_(2)O在298.15 K下标准生成焓(△H^(θ)_(f),NaB_(5)O_(8)·5H_(2)O,-5189.4820kJ·ml^(-1))、标准生成熵(△S^(θ)_(f),NaB_(5)O_(8)·5H_(2)O,701.2728J·mol^(-1)·K^(-1))、标准生成吉布斯自由能(△G^(θ)_(f),NaB_(5)O_(8)·5H_(2)O,-5398.566.kJ·mol^(-1))等等热力学参数。这些基础热力学参数的获得对丰富无机盐热力学数据和促进盐湖资源综合利用具有重要意义。Thermodynamic parameters of different borates,such as the dissolution enthalpy(△H_(s)),the standard enthalpy of formation(△H^(θ)_(f),the standard entropy of formation(△H^(θ)_(f)and the standard Gibbs free energy(△H^(θ)_(f)are essential to enrich and develop the boron chemistry theory of salt lakesIn the present work,the dissolution enthalpy(△H_(s))of sodium pentaborate pentahydrate(NaB_(5)O_(8)·5H_(2)O)at 298.15 K and 101.325 kPa was measured using microcalorimeterBased on the designed thermochemical cycles and the basic formulae of thermodynamics,the standard enthalpy of formation(△H^(θ)_(f),the standard entropy of forma1tion(△S^(θ)_(f)and the standard Gibbs free energy(△H^(θ)_(f)of NaB_(5)O_(8)·5H_(2)O were obtained for the first time,and the results are in order with-5189.4820 kJ·mol^(-1),701.2728 J·mol^(-1)·K^(-1),-5398.5665 kJ·mol^(-1),respectively.These basic thermodynamic parameters obtained in this work are of great significance in enriching the thermodynamic data of inorganic salts and promoting the comprehensive utilization of salt lake resources.

关 键 词：溶解焓 硼酸钠 标准生成焓 标准生成熵 标准吉布斯自由能 

分 类 号：O642.3[理学—物理化学]