RbBrCsBr-CH3OHC2H5OH-H 2O三元体系的溶解度

采用自制的相平衡研究装置, 测定了RbBr-CH3OH/C2H5OH-H2O和CsBr-CH3OH/C2H5OH-H2O四个三元体系在25、35、45 ℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据. 实验结果表明,在所有的体系中, 随着甲醇或乙醇质量分数的增加, RbBr和CsBr 在

May[Article]

ActaPhys.鄄Chim.Sin.,2007,23(5)：695-700

物理化学学报(WuliHuaxueXuebao)

695

RbBr/CsBr鄄CH3OH/C2H5OH鄄H2O三元体系的溶解度

赵文霞

胡满成鄢

李淑妮

蒋育澄

张晓蕾

710062)

胡蕾陈怀军

(陕西师范大学化学与材料科学学院,西安

摘要：采用自制的相平衡研究装置,测定了RbBr鄄CH3OH/C2H5OH鄄H2O和CsBr鄄CH3OH/C2H5OH鄄H2O四个三元体系在25、35、45益三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据.实验结果表明,在所有的体系中,随着甲醇或乙醇质量分数的增加,RbBr和CsBr在水中的溶解度逐渐降低;并且折光率也逐渐减小.用经验关联方程对溶解度进行了拟合,同时给出了CH3OH和C2H5OH分别对RbBr和CsBr的盐析率曲线.关键词：溴化铷;中图分类号：O642

溴化铯;

甲醇;

乙醇;溶解度;折光率

TheSolubilityofTernarySystemRbBr/CsBr鄄CH3OH/C2H5OH鄄H2OatDifferentTemperatures

ZHAOWen鄄XiaHUMan鄄Cheng鄢LIShu鄄NiJIANGYu鄄Cheng

ZHANGXiao鄄LeiHULeiCHENHuai鄄Jun

(SchoolofChemistryandMaterialsScience,ShaanxiNormalUniversity,Xi忆an710062,P.R.China)

Abstract：Thesolubilitiesofrubidiumbromideandcesiumbromideinwater,waterplusmethanol,andwaterplus

ethanolweremeasuredbyusingaccurateanalyticalmethodatdifferenttemperatures.Andrefractiveindicesweredeterminedforthetwoternarysystemsinsaturatedsolutionwithvariedsaltconcentrationsaswell.Inallcases,thepresenceofeithermethanolorethanolsignificantlyreducedthesolubilitiesofrubidiumbromideandcesiumbromideinaqueoussolution,buttherefractiveindicesreducedwiththeincreasingmassfractionofeithermethanolorethanol.Thesolubilitiesofthesaturatedsolutionswerefittedviapolynomialequationsasafunctionofthemassfractionofmethanolorethanol,andthesalting鄄outratiosofRbBrandCsBrbymethanolandethanolwerealsoobtained.KeyWords：Rubidiumbromide;

Cesiumbromide;Methanol;

Ethanol;

Solubility;

Refractiveindex

铷和铯是典型的稀贵活泼碱金属,并且是典型的分散元素,很少形成独立的矿物,而是存在于其他矿物中,给铷和铯金属及其化合物的分离和提纯带来很多困难.有机溶剂例如醇的存在明显降低了无机盐在水中的溶解度.这种体系通常用在无机盐的结晶提纯中,与传统的蒸发冷却相比,这种方法将为在室温下得到高纯度晶体提供一种先进且简易的操作方法[1].最近几年,一些研究小组已经研究过这类

体系[2-7].本实验比较系统地研究了RbBr和CsBr在CH3OH鄄H2O和C2H5OH鄄H2O中不同温度下的溶解度,旨在探讨利用价廉且无毒性的简单脂肪醇作为盐析剂分离纯化铷盐和铯盐的可行性,为进一步的应用开发研究积累必备的基本参考数据.

1实验部分

1.1试剂和仪器

Received:October24,2006;Revised:December7,2006;PublishedonWeb:April18,2007.

鄢

Correspondingauthor.Email:hmch@.

鬁EditorialofficeofActaPhysico鄄ChimicaSinica

国家自然科学基金(20471035)及陕西省自然科学基金(2004B17)资助项目

采用自制的相平衡研究装置, 测定了RbBr-CH3OH/C2H5OH-H2O和CsBr-CH3OH/C2H5OH-H2O四个三元体系在25、35、45 ℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据. 实验结果表明,在所有的体系中, 随着甲醇或乙醇质量分数的增加, RbBr和CsBr 在

696

ActaPhys.鄄Chim.Sin.,2007

Vol.23

甲醇、无水乙醇(99.5%,分析纯,西安化学试剂

溴化铯(99.5%,分析纯,上海中理实业厂);溴化铷、

有限公司);实验用水均为二次蒸馏水.

微型平衡溶解度测定装置[8];电子天平(FA1104,上海精科天平厂);原子吸收光谱仪(TAS鄄986,北京普析通用仪器公司);美国PE鄄A型热重分析仪;阿贝折光率仪(2WA鄄J,上海光学仪器五厂,精度为1伊10-4).1.2实验步骤

在平衡管中依次加入预算量的CH3OH鄄H2O或C2H5OH鄄H2O,再加入适当过量的RbBr或CsBr盐,将样品夹置于半微量相平衡的转动盘上,恒温水浴控温精度为依0.1益.达到预定温度后,恒温转动

48h,不断观察,确保每个平衡管中均有适量晶体存在,否则需要补充盐,重新进行上述过程,再恒温静置约24h.从平衡管中取出液相和固相进行分析.样品取出后应立即测量折光率;溶液中盐的含量通过在150益的高温下蒸发干燥后确定,这种方法质量分数的误差为依0.5%;对于那些甲醇或乙醇的质量分数大于80%的样品,盐的含量通过原子吸收法确定,这种方法的盐的质量分数的误差在依0.2%;饱和溶液的折光率是用折光率仪平行测定三次后取其平均值得到的.

2结果与讨论

RbBr/CsBr鄄CH3OH/C2H5OH鄄H2O在25、35和45

表1RbBr(1)鄄CH3OH(2)鄄H2O(3)三元体系在25、35和45益的溶解度和折光率数据

Table1Solubility(S)andrefractiveindex(nD)forRbBr(1)鄄CH3OH(2)鄄H2O(3)ternarysystemat25,35and45益

20.0005.3295.6876.32419.4623.6724.3627.3829.650.0004.4856.1038.69510.3811.6812.4718.6123.7626.7631.910.0006.8878.4169.37810.6012.4915.3421.6531.1336.53

230.0000.11310.12080.13440.43590.54700.56560.64940.71800.0000.1000.13680.19460.23590.26740.28510.44170.58390.67100.83810.0000.16160.19950.22250.25250.30170.37510.54860.85481.055

D

1.41091.40291.40211.40121.38651.38321.38221.38031.3782

35益

1.41351.40691.40411.40051.39891.39701.39601.38931.38411.38131.3771

45益

1.41551.40401.40301.40101.39921.39751.39411.38711.37801.3735

232.4036.7739.3141.7246.6350.1355.9261.34

230.80210.95701.0481.1431.3641.5381.8962.316

D1.37651.37401.37191.37001.36691.36451.36141.35841.34581.37351.37301.36751.36401.36151.35751.35721.34581.34031.3350

112.790.7589.4887.2955.9849.3948.3043.8240.94124.7102.897.1187.3483.8580.6977.9664.6455.1650.0542.89135.0102.097.6294.0990.2485.5277.8363.6448.0440.56

37.3833.0130.1527.8523.7320.9017.0813.870.640036.9935.9728.5423.7120.5816.7816.506.8374.2830.9300

puremethanol36.4237.2944.4849.9954.0559.6859.9980.3289.65

0.99601.0281.3351.6211.8722.3002.3226.04714.35

puremethanol

37.5342.7947.5853.9057.6958.8468.1580.8187.12

1.0921.3261.5681.9552.2442.3503.3576.51914.17

39.1133.2328.3222.7519.9119.2113.067.2837.2131.600

1.37201.36831.36411.35981.35701.35691.35011.34211.33821.3320

puremethanol

2332

采用自制的相平衡研究装置, 测定了RbBr-CH3OH/C2H5OH-H2O和CsBr-CH3OH/C2H5OH-H2O四个三元体系在25、35、45 ℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据. 实验结果表明,在所有的体系中, 随着甲醇或乙醇质量分数的增加, RbBr和CsBr 在

No.5赵文霞等：RbBr/CsBr鄄CH3OH/C2H5OH鄄H2O三元体系的溶解度697

益的溶解度及折光率数据分别列于表1至表4中.从这几个表中可以看出,在同一温度下随着甲醇或乙醇质量分数的增加,RbBr和CsBr在混合溶剂中的溶解度逐渐减小,体系的折光率也逐渐降低,这种现象与文献报道的其他体系中的现象一致[9-12].

在所研究体系中溶解度均用下列方程进行拟合[13]:

3

lnS=A+Bw2+Cw22+Dw2

图1为RbBr鄄CH3OH鄄H2O三元体系在25、35和45益的溶解度随甲醇质量分数变化趋势图.由图1可以看出,在不同温度下RbBr的溶解度随温度的升高而增大;在同一温度下RbBr的溶解度随甲醇质量分数的增加而减小.图中也观察到三个温度下CsBr的溶解度随甲醇质量分数变化的现象.图2为CsBr鄄C2H5OH鄄H2O三元体系25益的三元相图,所研究的其他体系的三元相图与该三元相图类似.

图3为RbBr鄄CH3OH鄄H2O和RbBr鄄C2H5OH鄄H2O两个三元体系在25、35和45益的溶解度随醇质量分数变化趋势图.由图3可以看出,在相同的温度下RbBr溶解度随CH3OH质量分数变化趋势与RbBr溶解度随C2H5OH质量分数变化趋势具有一致性.CsBr鄄CH3OH/C2H5OH鄄H2O体系中CsBr溶解度随醇

(1)

其中S为盐的溶解度(每100g溶剂中溶解的盐的质量);w2代表甲醇或乙醇的质量分数.A、B、C、D均为拟合参数,所研究体系的拟合参数值及相对标准偏差(啄)列于表5,整个实验的相对标准偏差均小于1.0%.由热重分析确定,所研究的体系中的平衡固相均为无水溴化铷和无水溴化铯.

表2RbBr(1)鄄C2H5OH(2)鄄H2O(3)三元体系在25、35和45益的溶解度和折光率数据

Table2Solubility(S)andrefractiveindex(nD)forRbBr(1)鄄C2H5OH(2)鄄H2O(3)ternarysystemat25,35and45益

20.0004.0994.8025.11520.0623.8426.8531.850.0006.8589.38112.2316.3518.3024.4624.7729.2031.200.0007.52510.1313.0217.2717.4323.1827.5330.9138.10

230.0000.085740.10030.10660.43780.53350.61290.75180.0000.15130.20690.27070.37100.41250.57350.59260.70710.78250.0000.17420.23540.30640.41410.41880.57560.70660.81491.071

112.792.6589.7688.4151.7745.9241.5334.73124.791.6682.7774.1765.4859.6349.0150.2041.8440.72135.097.1988.1180.1769.5169.3157.6150.4045.2735.71

D

1.41091.40551.40481.40451.39321.39191.39101.3880

35益1.41351.40551.40321.40051.39751.39531.39171.39221.38891.3882

45益1.41551.40621.40391.40101.39801.39781.39321.39101.38901.3845

232.9339.8740.8148.1451.6956.4963.50

pureethanol38.6042.7246.4349.7456.5260.9164.4284.7791.24

pureethanol39.5044.2948.1754.6259.1863.1883.6291.56

pureethanol

230.79271.0141.0521.3711.5331.8162.314

34.2826.2625.6320.1117.1114.169.9620.5700

D1.38801.38501.38451.38251.38101.37951.37791.36951.38491.38301.38201.38071.37751.37601.37521.37001.36821.36501.38411.38151.37911.37491.37401.37301.36631.36391.3612

1.0281.1951.3451.5171.8692.1832.5106.54211.78

31.3427.4423.5321.1615.2612.6011.012.3261.0240.9100

1.1241.3281.5121.8712.1812.4946.24012.86

33.9828.8124.9519.3215.8512.973.0701.3341.505

22532

采用自制的相平衡研究装置, 测定了RbBr-CH3OH/C2H5OH-H2O和CsBr-CH3OH/C2H5OH-H2O四个三元体系在25、35、45 ℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据. 实验结果表明,在所有的体系中, 随着甲醇或乙醇质量分数的增加, RbBr和CsBr 在

698

ActaPhys.鄄Chim.Sin.,2007

表3CsBr(1)鄄CH3OH(2)鄄H2O(3)三元体系在25、35和45益的溶解度和折光率数据

Vol.23

Table3Solubility(S)andrefractiveindex(nD)forCsBr(1)鄄CH3OH(2)鄄H2O(3)ternarysystemat25,35and45益

20.000

8.45611.1212.3519.4022.4728.310.0007.11110.8112.6415.6521.5328.550.0006.5018.0519.87414.0720.0023.06

230.0000.18910.24950.27870.44900.52950.69250.0000.16990.25970.30670.38240.53970.74690.0000.16800.20830.25640.37110.54360.6378

D1.40411.38981.38601.38491.37721.37491.36981.41711.40501.39911.39681.39311.38681.38001.42031.40901.40651.40301.39681.39031.3869

122.688.0979.5576.4759.7154.0344.55142.3104.290.6785.6476.6862.8349.78159.8121.2114.1106.792.3476.0768.89

223D1.36301.35701.34781.34331.33811.33481.32911.37331.36671.35601.34921.34501.34001.33551.37601.36611.35181.34851.34121.33711.3325

35益

37.681.00646.751.38263.022.47471.233.47081.325.99087.419.869puremethanol35.631.00043.761.33560.792.40471.093.67679.665.73888.1811.64puremethanol34.941.04644.221.46763.952.93370.013.74981.827.18888.8013.91puremethanol

33.1024.0913.008.9985.3773.8742.41840.3330.6316.1710.596.9094.4332.79046.2834.4816.6012.767.2945.0593.650

45益

23表4CsBr(1)鄄C2H5OH(2)鄄H2O(3)三元体系在25、35和45益的溶解度和折光率数据

Table4Solubility(S)andrefractiveindex(nD)forCsBr(1)鄄C2H5OH(2)鄄H2O(3)ternarysystemat25,35and45益

20.000

7.30810.2514.2118.6924.7731.080.0008.3238.77211.8317.6224.2330.710.0007.1988.65611.9516.0920.1127.40

230.0000.15950.22410.31230.41690.56980.74980.0000.19520.20640.27870.42160.59710.79210.0000.18120.21800.30290.41190.52350.7400

D1.41321.40451.40051.39751.39471.39151.38851.41701.40581.40501.40181.39701.39221.3883

122.688.2778.6467.4557.4746.5537.87142.396.1995.0084.2768.3554.3043.95159.8113.1106.894.5281.3270.8655.23

2

41.1748.7263.9177.8983.6791.05

pureethanol39.6851.1759.2873.1685.4688.45

pureethanol

231.0991.4112.3014.2585.92311.34

D1.38451.38201.37751.37451.37331.37151.36901.38411.37981.37681.37221.36911.36891.36501.38861.37961.37401.36901.36511.36411.3621

35益

27.2020.129.0643.9742.2520.93050.390032.2820.8414.636.5802.1661.5840.640045.0426.6214.895.8403.0871.2850.8921

1.1051.6212.1213.5416.8798.848

1.421133.530.94671.410548.141.5611.408261.352.3881.404876.114.1431.400883.926.4121.397092.2014.111.3921pureethanol2345益

采用自制的相平衡研究装置, 测定了RbBr-CH3OH/C2H5OH-H2O和CsBr-CH3OH/C2H5OH-H2O四个三元体系在25、35、45 ℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据. 实验结果表明,在所有的体系中, 随着甲醇或乙醇质量分数的增加, RbBr和CsBr 在

No.5赵文霞等：RbBr/CsBr鄄CH3OH/C2H5OH鄄H2O三元体系的溶解度表5溶解度数据用方程(1)拟合后所得参数值及其标准偏差Table5ValuesofparametersofEq.(1)andstandarddeviations(啄

)

253545253545253545253545

4.7014.8114.8764.7194.8244.9024.8094.9555.0704.8094.9575.071

-3.812-3.996-3.689-4.804-4.807-4.589-4.132-4.483-4.317-4.859-5.069-5.053

2.4963.2802.1665.8555.8715.3542.8123.9843.5375.5286.1686.261

-2.976-3.628-2.438-6.900-6.809-6.321-2.989-3.922-3.527-6.539-6.926-7.075

0.22270.55310.52490.44420.53700.40570.17910.44840.57300.20720.28510.4822

32699

RbBr(1)鄄C2H5OH(2)鄄H2O(3)

CsBr(1)鄄CH3OH(2)鄄H2O(3)

CsBr(1)鄄C2H5OH(2)鄄H2O(3)

质量分数变化图中也观察到同样的现象.

图4为RbBr鄄C2H5OH鄄H2O体系不同温度折光率随乙醇质量分数的变化.由图4可以看到,在RbBr鄄C2H5OH鄄H2O体系中,45益的折光率随乙醇质量分数的增加下降较35益的快,25益的折光率随乙醇质量分数的增加下降较35益的慢.三条线相交于乙醇质量分数约0.3处.在所研究的其他几个三元体系中也存在这种现象.此现象可以解释为饱和溶液体系的折光率主要受三个因素影响,一是混合溶剂

图1RbBr鄄CH3OH鄄H2O体系在不同温度下

的溶解度随甲醇质量分数的变化

Fig.1Solubility(S)fortheRbBr鄄CH3OH鄄H2O

ternarysystematdifferenttemperatureasafunctionofthemethanolmassfraction

荫25益,银35益,姻45

益

的组成,二是盐的浓度,三是温度.折光率随着盐的质量分数和有机溶剂含量的增加而增加,但是盐的

图3RbBr鄄CH3OH鄄H2O和RbBr鄄C2H5OH鄄H2O体系在

不同温度下的溶解度随醇质量分数的变化

Fig.3Solubility(S)fortheRbBr鄄CH3OH鄄H2OandRbBr鄄C2H5OH鄄H2Oternarysystemsatdifferenttemperaturesasafunctionofthemethanolorethanol

massfraction

荫25益(methanol),银35益(methanol),姻45益(methanol),

茵25益(ethanol),吟35益(ethanol),阴45益(ethanol)

图2CsBr鄄C2H5OH鄄H2O体系25益的相图Fig.2ThephasediagramofCsBr鄄C2H5OH鄄H2O

ternarysystemat25益

采用自制的相平衡研究装置, 测定了RbBr-CH3OH/C2H5OH-H2O和CsBr-CH3OH/C2H5OH-H2O四个三元体系在25、35、45 ℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据. 实验结果表明,在所有的体系中, 随着甲醇或乙醇质量分数的增加, RbBr和CsBr 在

700

ActaPhys.鄄Chim.Sin.,2007

Vol.23

图4RbBr鄄C2H5OH鄄H2O体系在不同温度折光

率随乙醇质量分数的变化

Fig.4Therefractiveindex(nD)ofRbBr鄄C2H5OH鄄H2O

systematdifferenttemperaturesasafunctionoftheethanolmassfraction

荫25益,银35益,姻45益

图545益时甲醇和乙醇分别对RbBr的盐析率曲线

forFig.5themethandThecurvesoftherateofsalt鄄outbromide姻methanol,separatelyethanolversus银ethanol

at45rubidium

益

溶解度随着有机溶剂含量的增加而减小,所以这两个因素是相反的;另一方面,折光率随着温度的升高而降低,但是盐的溶解度随着温度的升高而增大,所以这两个因素也是相反的;因此在交点之前,溶液的组成是主要因素,而在交点之后,温度是主要因素.

由图5可以看出,在同一个温度下,乙醇对RbBr的盐析作用比甲醇对RbBr的盐析作用强.在所研究的CsBr的两个三元体系中也观察到同样的现象.

3结论

本文比较系统地研究了RbBr鄄CH3OH鄄H2O,RbBr鄄C2H5OH鄄H2O,CsBr鄄CH3OH鄄H2O和CsBr鄄C2H5OH鄄H2O

四个三元体系多温度下的相平衡情况,给出了不同温度下RbBr及CsBr在CH3OH鄄H2O和C2H5OH鄄H2O中的溶解度及折光率数据,并对溶解度进行了拟合,得到了比较好的结果.同时比较了在相同温度下甲醇和乙醇分别对溴化铷及溴化铯的盐析效果,由分析得知,在相同温度下,乙醇对溴化铷和溴化铯的盐析效果比甲醇强.这些数据对在水溶液中分离和提纯溴化铷和溴化铯有很大的帮助.

References

1Mullin,J.W.Crystallization.3rded.London:ButterworthHeinemann,1993

2Hu,M.C.;Zhai,Q.G.;Liu,Z.H.;Xia,S.P.J.Chem.Eng.Data,2003,48(6):1561[胡满成,翟全国,刘志宏,夏树屏.化学工程

数据,2003,48(6):1561]

3Zhai,Q.G.;Hu,M.C.;Liu,Z.H.;Xia,S.P.ChineseJournalofChemistry,2004,22(1):14

4

Hu,M.C.;Meng,M.;Gao,S.Y.;Liu,Z.H.;Xia,S.P.Chem.J.Chin.Univ.,2002,23(7):1219[胡满成,孟

梅,高世

扬,刘志宏,夏树屏.高等学校化学学报,2002,23(7):1219]5

Hu,M.C.;Liu,Z.H.;Gao,S.Y.;Xia,S.P.;Hao,L.X.;Yue,X.L.Chem.J.Chin.Univ.,2000,21(11):1717[胡满成,刘志宏,

高世扬,夏树屏,郝丽霞,岳先丽.高等学校化学学报,2000,21

(11):1717]6H佴ctor,R.G.;Mar侏a,E.T.;Te佼filoA.G.J.Chem.Eng.Data,2003,48:405

7

Zhang,F.X.;Zhao,P.;Yang,Q.;Shi,Q.Z.Chem.J.Chin.Univ.,1999,20(10):1499[张逢星,赵

霈,杨

琴,史启祯.高等学

校化学学报,1999,20(10):1499]

8

Zhai,Q.G.;Hu,M.C.;Liu,Z.H.;Xia,S.P.;Gao,S.Y.ActaPhys.鄄Chim.Sin.,2003,19(11):1089[翟全国,胡满成,刘志宏,夏树

屏,高世扬.物理化学学报,2003,19(11):1089]

9

Zhang,F.X.;Wei,X.L.;Zhou,X.Chem.J.Chin.Univ.,1997,18(4):605[张逢星,魏小兰,周

霞.高等学校化学学报,1997,

18(4):605]

10Li,S.N.;Hu,M.C.;Jin,L.H.;Zhang,X.L.;Jiang,Y.C.ChineseJournalofChemistry,2005,23(10):1348

11

Zhang,J.;Gao,S.Y.;Xia,S.P.ChineseJournalofInorganicChemistry,2002,18(12):1241[张军,高世扬,夏树屏.无机

化学学报,2002,18(12):1241]12

Li,M.H.;Gao,S.Y.;Xia,S.P.Yue,T.ChineseJournalofRareMetals,2003,27(2):238[李明华,高世扬,夏树屏,岳

涛.稀

有金属,2003,27(2):238]13

Xia,S.P.;Zhang,X.J.;Wang,G.F.;Gao,S.Y.ChineseJournalofAppliedChemistry,1989,6(5):63[夏树屏,张晓军,王桂芬,

高世扬.应用化学,1989,6(5):

63]

本文来源：https://www.bwwdw.com/article/o154.html