J. Chem. Eng. Data 1988, 33,418-423
418
Density, Refractive Index, and Specific Refraction of Aqueous Lithium Iodate Solutions J. Szewczyk Institute of Physics, Technical University of G d i , W6lczafiska 2 19, 93-005 G d Z Poland
K. Sangwal" Institute of Chemistry, Peahgogical University of Czqstochowa, AI. Za wadzkiego 13/ 15, 42-200 Czqstochowa, Poland
Dendtles and refractlve Indexes of aqueous llthlum iodate solutions (0.01-3.0 M) have been determlned over the temperature range 18 to 60 OC. From these experlmental data, the relative density d/dHp, relative refractive Index n/nHtO,specHic refraction R , and relatlve speclflc refraction R/RHSohave been calculated. I t was found that in the lnvestlgated range of Concentration the values of R and R / R H p are practically Independent of temperature but that in the whole range of temperatures both decrease wlth an Increase In solutlon concentration. The temperature and concentratlon dependence of all these quantltes may be represented by quadratic or linear functions. Introduction
Solid lithium iodate is an interesting material for scientific investigations. In contrast with a large majority of substances for which data on physical properties of solutions are available in the literature, lithium iodate has a negative temperature coefficient of solubility and its physical properties have been little investigated. In particular, a survey of the existing Iierature showed that, apart from the data on the density of saturated solutions ( 7 ) , data for undersaturated solutions are either very old (2, 3)or sparse (4). When present in the crystalline form, LiIO, exhibffs nonlinear electrooptic behavior (5).For the investigation of the nonlinear properties and for the use of the material in device fabrication, it is grown as single crystals with the lowest possible density of defects. Since 1971 several papers have been devoted to the investigation of its growth in the form of single crystals of good quality under a variety of experimental conditions (5-8). The quality of a crystal grown from solution depends on a number of factors such as temperature, solution concentration, and the presence of impurities. These factors also determine the structure and the macroscopic and microscopic properties of solutions. This means that the q u a l i of a crystal grown from solution depends on the chemical constitution and structure of the solution. I n fact, on the basis of a study of the osmotic pressure and density of saturated aqueous solutions, it was concluded that the best lithium iodate crystals are produced from those solutions in which the ions of the solid are least associated ( 1 ) . As a part of our general research program on the structure of growth media, it was thought worthwhile to study the density and refractive index of aqueous lithium iodate solutions as a function of temperature and solute concentration. Experlmentai Sectlon
LiIO, compound for experimental purposes was synthesized by neutralizing a solution of 1 M HiO, to pH 7 by adding ana* To whom all correspondence should be
addressed
lytical grade Li,C03 or LiOH. Solid LiIO, was obtained by drying this neutral solution to constant weight. By dissolution of a known mass of s o l i LiIO, (weighed with an analytical balance g accuracy) in double distilled water, 1 L of up to 1 X solution of the desired concentration was prepared at 20 'C. Density and refractive index measurements were made on 0.6 L of solution contained in a 20 cm long cylindrical glass vessel of 0.75-L capacity. The vessel was placed in a thermostated water jacket whose temperature was regulated by a contact thermometer and measured with a mercury thermometer with an accuracy of 0.05 O C . The temperature variations in the vessel solution were estimated to be less than 0.01 OC. Density measurements of a solution were carried out by using a hydrostatic balance (accuracy 5 X lo4 g) and a 1 0 c m 3 float immersed in the solution. The correct values of density d , considering capillary action and air density, were calculated from the measured density d , by using the relation: d = d , 0.0002dm 0.0012,verified for water in the temperature range 15-65 O C . Density measurements for solution of a given concentration were made at least twice at a particular temperature. The density values were reproducible to 1 X lo4 g/cm3. Refractive index data were obtained by using a Carl Zeiss immersion refractometer supplied with three thermoprisms TI, T, and T, of refractive index intervals 1.3254-1.3664, 1.3642-1.3999, and 1.3989-1.4360,respectively. T, and T, were calibrated in the whole temperature interval with water and acetic acid, respectively, while the third was calibrated in such a way that the refractive index values obtained by the second prism corresponded to those by T., The correction in the refractive index value was 1 X 10't. Reproducibility of the data was within 1 X and the error in the calibration due whence the instrumental error to temperature was 1 X was 2 X Initially only density measurements were planned and carried out for LiIO, solutions in the concentration range 0.2-3.0M. Later, however, refractive index measurements were also planned and the concentration range was extended down to 0.01 M. Consequently, in the 0.2-3.0M concentration range density measurements were made for one set of solutions, while refractive index data were obtained for another set of solutions prepared again. However, in the 0.01-0.1 M concentration range both density and refractive data were obtained from the same set of solutions.
+
+
Results
Experimental density, d (g/cm3), and refractive index, n , data for aqueous LiIO, solutions at different temperatures are given in Tables 1-111. I t may be noted from the tables that density and refractive index values decrease as solution temperature increases but increase as solution concentration increases. Plots of the densities and refractive indenes of the solutions as a function of temperature revealed that the curves for both become increasingly linear as solute concentration increases.
0021-9568/88/1733-0418$01.50/00 1988 American Chemical Society
Journal of Chemical and Engineering Data, Vol. 33, No. 4, 1988 419
+ b,c + b,C2 d = do@)+ a3t + a4t2 n = no@) + b3f + b4t2
n = no(t)
Table I. Experimental Density Data (g/cma) for Aqueous LiIOl Solutions in the Concentration Range 0.01-0.1 M at Various Temperatures concentration, M t, O C 0.01 0.02 0.04 0.06 0.08 0.10 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
1.0001 0.9997 0.9992 0.9987 0.9982 0.9977 0.9971 0.9965 0.9959 0.9952 0.9944 0.9937 0.9929 0.9921 0.9913 0.9905 0.9896 0.9887 0.9877 0.9867 0.9857 0.9847
1.0015 1.0011 1.0007 1.0002 0.9997 0.9992 0.9987 0.9982 0.9975 0.9967 0.9960 0.9952 0.9944 0.9936 0.9928 0.9920 0.9911 0.9902 0.9893 0.9883 0.9873 0.9863
1.0047 1.0042 1.0038 1.0033 1.0028 1.0023 1.0017 1.0011 1.0004 0.9997 0.9990 0.9982 0.9974 0.9967 0.9959 0.9950 0.9941 0.9932 0.9922 0.9912 0.9903 0.9893
1.0078 1.0074 1.0069 1.0064 1.0059 1.0055 1.0049 1.0043 1.0036 1.0029 1.0022 1.0015 1.0007 0.9999 0.9990 0.9981 0.9972 0.9963 0.9954 0.9944 0.9934 0.9924
1.0109 1.0105 1.0099 1.0094 1.0089 1.0083 1.0078 1.0071 1.0065 1.0058 1.0050 1.0043 1.0035 1.0027 1.0019 1.0011 1.0003 0.9994 0.9984 0.9974 0.9964 0.9954
1.0141 1.0137 1.0132 1.0126 1.0120 1.0114 1.0109 1.0103 1.0097 1.0090 1.0083 1.0074 1.0066 1.0058 1.0050 1.0041 1.0032 1.0023 1.0013 1.0003 0.9993 0.9983
This behavior is presented in Figure 1 for the temperature dependence of the refractive index of solutions. The experimental data on the densities and refractive indexes of the solutions may be represented by the quadratic equations
+
d = d o ( t ) a 1c
+ a2c2
(1)
t , "C 17.8 19.8 21.8 23.7 26.2 28.4 30.0 32.1 34.2 35.9 37.6 40.1 42.0 44.0 46.9 50.2 53.5 56.8 60.0
1.0294 1.0284 1.0276 1.0262 1.0248 1.0238 1.0224 1.0211 1.0200 1.0190 1.0175 1.0160 1.0146 1.0130 1.0116 1.50 M 1.2284 1.2275 1.2266 1.2256 1.2244 1.2233 1.2226 1.2214 1.2205 1.2196 1.2186 1.2170 1.2160 1.2150 1.2131 1.2110 1.2092 1.2071 1.2050
18.0 21.3 24.5 27.8 30.7 33.2 35.8 38.3 40.4 42.8 45.6 48.7 50.6 53.4 56.0 59.3
1.0611 1.0601 1.0592 1.0580 1.0571 1.0562 1.0552 1.0540 1.0531 1.0521 1.0508 1.0491 1.0482 1.0467 1.0454 1.0437 t , "C 18.0 20.0 22.0 23.8 25.9 27.8 29.8 32.2 34.4 36.0 37.8 40.0 42.2 44.0 46.5 48.1 50.3 52.3 54.1 56.0 60.0
18.0 19.7 22.1 25.5 28.9 32.2 35.9 38.4 41.2 44.3 47.6 49.7 52.1 54.5 58.6 61.0 2.00 M 1.3026 1.3019 1.3007 1.3000 1.2990 1.2980 1.2965 1.2949 1.2936 1.2926 1.2916 1.2902 1.2888 1.2877 1.2862 1.2852 1.2836 1.2825 1.2811 1.2799 1.2773
(3) (4)
Here eq 1 and 2 describe the density and refractive index data as a function of concentration, and do(t),a 1, a2,no(t),b 1, and b 2 are temperature-dependent constants. Similarly, eq 3 and 4 represent them as a function of solution temperature, and do@),a3, a 4 , no@),b 3 , and b 4 are concentrationdependent constants. The experimental data were fitted by the leastsquares method, and values of the various coefficient and the standard deviations were determined. These are given in Tables IV-VII. One notes from Tables I V and V that the values of both do(t) and a and of no(t)and b decrease with an increase in temperature, but the value of a increases with temperature while that of b 2 remains constant. Tables V I and VII, on the other hand, show that as solution concentration increases, the values of do(c),no@), a4, and b 4 Increase, while those of a 3 and b 3 decrease. Recently, a new equation was proposed to describe the temperature dependence of the density of saturated solutions (9).The data on both the temperature dependence of density and refractive index were analyzed according to this new equation, written, respectively, in the form
d = do' exp[p'( T - T i ) ' ] n = no' exp[p"(T
-
(5)
T,,")2]
(6)
where the coefficients d,,', p', and T,,' of eq 5, and n,,', p", and
Table 11. Experimental Density Data (g/cms) for Aqueous LiIOa Solutions in the Concentration Range 0.2-3.0 TemDeratures t, o c 0.20 M t, O C 0.40 M tOC 0.60 M tOC 0.80 M tOC 18.0 21.1 24.4 28.3 32.2 35.6 39.2 42.5 44.6 47.2 49.8 52.8 55.4 57.8 60.2
(2)
1.0914 1.0910 1.0902 1.0891 1.0879 1.0865 1.0844 1.0838 1.0826 1.0809 1.0792 1.0781 1.0768 1.0756 1.0735 1.0720
t , "C 17.9 20.9 24.7 29.0 33.8 38.1 41.7 45.6 49.8 53.3 55.9 58.6 60.3
18.0 21.5 23.0 25.9 29.1 32.2 35.4 38.4 42.3 46.5 49.4 52.9 56.4 60.0
2.50 M 1.3770 1.3751 1.3730 1.3705 1.3674 1.3645 1.3621 1.3596 1.3569 1.3546 1.3529 1.3512 1.3501
1.1217 1.1205 1.1200 1.1190 1.1177 1.1164 1.1151 1.1135 1.1116 1.1094 1.1080 1.1061 1.1042 1.1021
18.0 20.8 23.8 27.2 31.4 35.2 38.8 42.4 46.5 49.2 52.4 56.0 59.2 60.6
t, o c 17.5 20.5 22.7 26.8 29.5 32.8 36.6 40.3 44.1 48.5 52.4 56.3 59.8 61.2
M at Various 1.00 M 1.1524 1.1514 1.1502 1.1489 1.1472 1.1452 1.1434 1.1417 1.1393 1.1378 1.1361 1.1338 1.1319 1.1312
3.00 M 1.4508 1.4488 1.4474 1.4448 1.4431 1.4409 1.4384 1.4357 1.4332 1.4302 1.4277 1.4251 1.4228 1.4219
420 Journal of Chemical and Engineering Data, Vol. 33, No. 4, 1988
Table 111, Experimental Refractive Index Data for Aqueous LiIOs Solutions in the Concentration Range 0.01-3.00 M at Various Temperatures concentration, M t, "C 0.01 0.02 0.04 0.06 0.08 0.10 0.20 0.40 1.33571 1.338 21 1.34305 1.33474 1.335 23 1.334 22 1.33342 1.33365 18 ~~
1.334 55 1.334 34 1.334 13 1.333 92 1.33370 1.33342 1.333 16 1.332 87 1.332 60 1.332 30 1.332 00 1.331 72 1.33138 1.33105 1.33074 1.330 39 1.33006 1.32971 1.32938 1.32899 1.32863
1.33403 1.33383 1.33361 1.33340 1.333 18 1.33294 1.33266 1.332 38 1.332 10 1.33180 1.33152 1.331 23 1.33092 1.33056 1.33025 1.329 93 1.32959 1.32925 1.32892 1.32855 1.32818
1.33348 1.33327 1.33309 1.33289 1.33266 1.33240 1.332 13 1.331 86 1.33159 1.33130 1.33102 1.330 74 1.33044 1.330 12 1.32978 1.32944 1.329 12 1.328 76 1.32843 1.32805 1.32768
1.33326 1.33307 1.33289 1.332 66 1.332 44 1.332 18 1.33190 1.33164 1.33136 1.33106 1.330 78 1.33049 1.330 19 1.32986 1.329 53 1.329 20 1.32887 1.32852 1.328 19 1.327 80 1.327 44
20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Table IV. Coefficients and Standard Deviations of Eq 1 at Different Temperaturesa ddt), a19 -a2 x io3, t , O C g/cm3 (g L)/(cm3mol) ( g L2)/(cm3mol2) SDb X lo6 20 30 40 50 60
0.99811 0.99562 0.99223 0.98813 0.98326
" d = do@)+ a l c
0.155 30 0.153 48 0.151 82 0.150 37 0.14894
1.666 1.517 1.333 1.135 0.846
6.1 5.8 7.6 8.4 10.4
+ a2c2. bSD = standard deviation.
Table V. Coefficients and Standard Deviations of Eq 2 at Different Temperaturesa t. O C nJt) b,, Limo1 -b, X 10' L/mo12 SD X lo6 20 30 40 50 60
1.333095 1.331990 1.330593 1.329000 1.327266
" n = no(t)+ blc
0.024 365 0.024042 0.023626 0.023388 0.023 250
3.236 3.367 2.894 2.920 3.047
2.5 1.8 1.5 1.3 2.1
+ b2c2. f
1.04
1398 1396
139 L 1360 1350 1338 1336
'330 '328 '327
20
30 40 50 - e m p e r o t u r e t:'C)
60
Figure 1. Temperature dependenceof refractiveindex of lithium iodate solutions at selected concentrations. The plot for water is based on the data from CRC Handbook ( 12).
TO" of eq 6 are functions of concentration. These constants and standard deviations are summarized in Tables VI11 and IX.
1.33552 1.33530 1.335 14 1.334 88 1.334 64 1.334 38 1.334 10 1.33382 1.333 54 1.333 26 1.332 95 1.332 68 1.332 32 1.332 00 1.33166 1.33134 1.33100 1.33064 1.330 32 1.32995 1.32960
1.33504 1.33483 1.33462 1.33440 1.334 18 1.33390 1.33358 1.33336 1.33305 1.332 78 1.332 48 1.332 18 1.33184 1.33152 1.331 18 1.33086 1.33054 1.330 17 1.32984 1.32947 1.32910
1.34285 1.342 41 1.34264
1.33805 1.33784 1.33761 1.33737 1.33711 1.33685 1.33656 1.33627 1.33598 1.33568 1.335 39 1.33509 1.334 78 1.33444 1.33409 1.33373 1.33339 1.33304 1.33268 1.332 33 1.33198
1.342 16 1.34190 1.34161 1.341 32 1.34100 1.34069 1.340 36 1.34000 1.33968 1.33933 1.33899 1.33866 1.338 31 1.337 96 1.33763 1.33730 1.33695 1.33661
Tah-4 VI. Coefficients and Standard DevAions of Eq 3 at Different Solute Concentrations' -a3 x iob, -a, x los, g/(cm3 "C2) SD X lo5 concn, M do(c), g/cm3 g/(cm3 "C) 3.835 0.7 1.001 16 7.008 0.00 0.01 0.02 0.04 0.06 0.08 0.10 0.20 0.40 0.60 0.80 1.00 1.50 2.00 2.50 3.00
1.00259 1.00386 1.007 27 1.010 13 1.01379 1.016 88 1.031 89 1.064 85 1.096 15 1.12690 1.15803 1.23562 1.31201 1.38764 1.46221
6.874 5.668 7.407 5.633 9.804 8.744 6.979 14.178 19.543 22.835 25.109 36.050 46.719 57.655 64.514
3.832 3.953 3.778 4.009 3.469 3.716 4.405 3.670 3.314 3.105 3.208 2.508 1.896 0.793 0.243
0.9 1.7 1.1 1.2 1.0 1.2 3.7 2.3 3.1 2.6 2.9 2.2 4.1 3.4 2.6
' d = do(c)+ a3t + a4t2.
Table VII. Coefficients and Standard Deviations Eq 4 at Different Solute Concentrations' -b3 X lo6, - b d X lo', no(c) ("C)-' (°C)-2 SD x lo6 concn, M 1.334645 1.334866 1.335032 1.335719 1.336265 1.336818 1.337310 1.339912 1.345126 1.350167 1.354914 1.360208 1.371706 1.383796 1.395802 1.407658
0.00 0.01 0.02 0.04 0.06 0.08 0.10 0.20 0.40 0.60 0.80 1.00 1.50 2.00 2.50 3.00
+
a n = no(c) b3t
5.940 5.697 5.422 6.227 6.345 6.749 6.797 7.288 9.527 10.806 10.544 13.219 13.182 15.381 19.215 20.989
1.088 1.119 1.143 1.062 1.070 1.025 1.020 1.001 0.800 0.717 0.833 0.573 0.643 0.631 0.223 0.203
5.9 5.3 4.4 4.8 4.8 5.4 5.8 5.4 11.4 7.3 8.0 10.3 9.2 9.4 5.3 7.3
+ b,t2.
These tables show that the values of do', n,', p, and @" increase whereas those of T,' and TO'' decrease with an increase in solute concentration. However, relatively poor values of standard deviation obtained for eq 5 and 6 suggest that eq
Journal of Chemical and Engineering Data, Vol. 33, No. 4, 1988 421
concentration, M 0.60
0.80
1.00
1.50
2.00
2.50
3.00
1.34793 1.34768 1.347 44 1.347 18 1.346 92 1.346 62 1.346 33 1.34600 1.34570 1.34536 1.34500 1.344 68 1.344 35 1.34399 1.34366 1.34330 1.342 93 1.342 59 1.342 25 1.34185 1.34151 1.34116
1.35266 1.35244 1.352 20 1.35194 1.35166 1.35138 1.35105 1.35071 1.350 37 1.35001 1.349 68 1.34934 1.34900 1.34864 1.34828 1.34750 1.347 54 1.347 15 1.346 80 1.34642 1.34603 1.34560
1.35756 1.357 29 1.35700 1.35674 1.35648 1.356 10 1.35580 1.35544 1.35506 1.354 69 1.354 32 1.35400 1.35366 1.35325 1.35289 1.35250 1.352 12 1.35174 1.351 37 1.35102 1.35066 1.350 28
1.36904 1.36878 1.36850 1.368 18 1.36788 1.36757 1.36723 1.366 89 1.36652 1.366 14 1.365 76 1.36538 1.36499 1.36460 1.36423 1.36386 1.36350 1.36309 1.362 70 1.36231 1.36192 1.36154
1.380 75 1.38043 1.380 10 1.375 76 1.37940 1.37907 1.37868 1.37829 1.37783 1.37746 1.37702 1.37663 1.376 20 1.375 78 1.37536 1.37488 1.37449 1.37406 1.37366 1.37325 1.372 76 1.37235
1.392 29 1.39188 1.39144 1.39104 1.39064 1.390 24 1.38986 1.38941 1.38900 1.38867 1.38820 1.38774 1.387 32 1.386 94 1.38648 1.38606 1.38561 1.38518 1.38478 1.384 36 1.38391 1.38348
1.40383 1.40340 1.40292 1.40248 1.402 04 1.401 62 1.401 20 1.40071 1.400 28 1.39988 1.399 40 1.39896 1.398 51 1.39803 1.39752 1.397 12 1.39659 1.396 20 1.39582 1.395 22 1.394 80 1.39434
Table VIII. Coefficients and Standard Deviations of Eq 5 at Different Solute Concentrations" concn, M d,, a/cm3 -a' X lo6, K-2 tn', K SD X lo5 1.001 32 3.962 265 3.0 0.00 0.01 0.02 0.04 0.06 0.08 0.10 0.20 0.40 0.60 0.80 1.00 1.50 2.00 2.50 3.00
1.002 77 1.004 24 1.007 53 1.01071 1.01380 1.01730 1.03302 1.066 23 1.09882 1.13060 1.16284 1.247 31 1.33789 1.47590 1.762 38
3.938 3.906 3.851 3.845 3.745 3.748 3.976 3.505 3.130 2.897 2.851 2.176 1.589 0.695 0.262
265 265 264 264 263 262 261 254 245 239 235 207 162 -25 -572
4.0 8.0 4.8 6.4 5.9 5.7 15.9 8.5 11.2 8.5 9.3 7.8 14.3 8.9 6.5
" d = do exp[@'(T - T()*].
Table IX. Coefficients and Standard Deviations of Eq 6 at Different Solute Concentrations" concn, M n0 -yx 106, K-2 TC,K SD x 105 0.834 247 2.1 0.00 1.335373 0.01 0.02 0.04 0.06 0.08 0.10 0.20 0.40 0.60 0.80 1.00 1.50 2.00 2.50 3.00
1.335567 1.335253 1.336619 1.337 169 1.337 945 1.338430 1.341 221 1.347 864 1.354079 1.358255 1.367603 1.378205 1.392664 1.431813 1.457697
0.847 0.971 0.802 0.811 0.769 0.769 0.754 0.607 0.544 0.619 0.433 0.483 0.477 0.183 0.159
248 256 244 244 240 240 237 215 200 210 161 174 157 -100 -196
2.1 3.4 1.7 1.7 1.8 2.2 1.9 4.0 2.7 2.7 3.4 3.1 3.1 1.6 2.5
" n = no e x p [ v ( T 3 and 4 better describe the temperature dependence of the density and refractive index of aqueous LiIO, solutions. A careful inspection of the values for parameters a and a (Table VI), and b 3 and b 4 (Table V I I ) reveals that at certain concentratins (e.g., 0.02, 0.2, and 1.O M for density, and 0.02, 0.8, and 1.5 M for refractive index) a sudden increase is ob-
,
__
Table X. Coefficients and Standard Deviations of Eq 7 at Different Temperatures" -a2
t , "C 20 30 40 50 60
q ,L/mol
0.99991 0.99957 1.00002 1.00009 1.00005
ad/dH,o = a.
0.15558 0.15415 0.15301 0.15219 0.15148
x
lo3, (L/moU2 SD X lo5 1.669 1.524 1.343 1.149 0.861
6.1 5.8 7.6 8.4 10.4
+ ale + a2c2.
Table XI. Coefficients and Standard Deviations of Eq 8 at Different Temperatures" x 102, -p2 x 104, t , "C PO L/mol (L/mol)2 SD X lo5 20 30 40 50 60
1.000080 1.000055 1.000061 1.000045 1.000065
1.8278 1.8048 1.7755 1.7601 1.7517
2.429 2.519 2.164 2.206 2.295
1.8 1.4 1.1 0.9 1.6
served. These jumps may be associated with the properties of the water ( 70, 7 I), used as solvent here, as well as with the measurement errors. In order to eliminate the possible influence of the properties of the solvent water, the data were f i e d according to the equations
(7)
(9)
where the quanti ~ l l d , ,is~ relative density, n InHflais relative refractive index, and a,and P, are constants. Equations 7 and 8 describe relative density and relative refractive index of the solutions as a function of solute concentration, while eq 9 and 10 express them as a function of temperature. For the calculation of these quantities, the values of dH,Oand nH2, were taken from the CRC Handbook (72).The values of the coef-
422 Journal of Chemical and Engineering Data, Vol. 33, No. 4, 1988
Table XII. Coefficients and Standard Deviations of Eq 9 at Different Solute Concentrations" -0(4 x 104, as x 106, concn, M a3 (T)-1 SD x los 0.20 0.40 0.60 0.80 1.00 1.50 2.00 2.50 3.00
"d/dHZ0= (
-0.033 0.679 1.095 1.498 1.701 2.786 3.645 4.833 5.461
1.03071 1.06362 1.09476 1.12564 1.15672 1.23428 1.31031 1.38611 1.46062
4.488 0.412 0.723 1.176 1.178 2.237 2.937 4.515 5.302
4.1 1.9 2.2 2.2 2.4 2.2 3.8 2.9 2.0
+ a4t + a,tZ.
~ 3
Table XIII. Coefficients and Standard Deviations of Eq 10 at Different Solute Concentrations" -p4 x 106 ps x 107, concn, M p3 (OC)-l (°C)-2 SD x lo6 0.06 0.08 0.10 0.20 0.40 0.60 0.80 1.00 1.50 2.00 2.50 3.00
1.001206 1.001635 1,001997 1.003948 1.007860 1.011 634 1.015 189 1.019 159 1.027714 1.036830 1.045827 1.054 698
'66
0.245 0.634 0.625 1.014 2.686 3.613 3.392 5.404 5.315 6.926 9.770 10.987
0.063 0.528 0.509 0.708 2.244 2.876 2.027 4.040 3.542 3.702 6.835 6.954
2.5 3.0 3.2 3.3 6.1 3.5 2.1 4.6 4.8 4.4 6.7 7.8
Table XIV. Coefficients and Standard Deviations of Eq 13 at Different Temperaturesn -A3 X lo2, A, X los, t , " C A,, cm3/g (cm3 L)/(g mol) (cm3L2)/(g mol2) SD X lo5 20 30 40 50 60
0.20602 0.20591 0.20584 0.20579 0.20581
" R = A,
1.729 1.715 1.712 1.700 1.696
1.614 1.576 1.568 1.525 1.503
3.4 3.0 3.8 3.8 3.5
+ A3c + A,c2.
Table XV. Coefficients and Standard Deviations of Eq 15 at Different TemDeratures" -B3 X lo2, B, X lo3, t , "C B2 L/mol (L/mol)2 SD X lo4 20 30 40 50 60
0.99985 0.99966 0.99974 0.99962 0.99973
"R/RH,o = Bt
8.388 8.344 8.324 8.270 8.258
7.823 7.714 7.652 7.448 7.365
1.5 1.4 1.7 1.8 1.6
+ B ~ +c B ~ C ' ,
,-
133
0 20
-
s 0 019 (r
,
0 18
0 17
Concentration c
I
M
'
Flgure 3. Concentration dependences of specific refraction R and rektive specific refraction /?/Rw of lithium iodate solutions at 20 OC. For the sake of clarity, several actual data points are omitted at lower
concentrations. Dl LE6 104M i02M 100
d at temperatures at which only n has been measured experimentally, the specific refraction
--D--o
R = (n2- l ) / ( n 2
~
23
30
TeTperotu
LO
50
6C
e tl'Ci
Figure 2. Curves of the temperature dependence of relative refractive index n ln,,, of aqueous l i i u m iodate solutions at selected concentrations. For the sake of clarity all data points are not indicated on
the curves. ficients a and p are given in Tables X - X I I I . Tables X and X I show that with an increase in temperature the values of constants a,,and a? increase, those of al and p1decrease, while those of Po and p2 are practically invariant. Tables X I 1 and X I I I , however, show that with an increase in concentration the values of a3,a5,P3, and p5 increase while those of a4and p4decrease Vegularly. The values of parameters a3,cy4, a5,p3, p4,and pS are not included for solutions having concentrations lower than 0.6 M because of relatively small changes in the values of density and refractive index at these concentrations. I t should be noted that the values of parameters a5 and p5 are negligible in comparison with the contribution of the linear terms in eq 9 and 10. Therefore, the dependence of n / n H,o on temperature is practically linear as shown in Figure 2 . A similar trend was observed for the dependence of dldH20on temperature. From the experimentaldensity and refractive index data given in Tables 1-111 and also using eq 1 to estimate the values of
+ 2)d
(11)
and the relative specific refraction
R / R ~ 2
( n 2 - I) = ~ (n2 2)d
+
/
(nHzO
2
-
+ 2)dH,o
(12)
(nHz02
were calculated. I n the calculations of RHzothe data on dHzO and nHzOreported in CRC Handbook (12) were used. These values of R and RHlOwere subsequently f i e d to the equations
+ A ,t R = A , + A3c + A 4 c 2 R = A,
R / R H P 0= B 2
+ B3c + b,C2
(13) (14)
(16)
where A, and B, are constants. I t was found that in view of small changes in R with temperature, the temperature dependence of R and R / R w cannot be represented satisfactorily by eq 13 and 15. However, the concentration dependence may be represented by eq 14 and 16. The values of the constants for these equations, along with the calculated standard deviations, are listed in Tables X I V and XV. A plot of specific refraction (R) and relative specific
J. Chem. Eng. Data 1988,33,423-426
refraction ( R l R H Z Oas ) a function of solution concentration is shown in Figure 3. Obviously, with an increase in solution concentration both R and RlR,,, decrease. One also notes from Tables XIV and XV that with an increase in temperature the values of A , A 4 , B,, and B 4 decrease while those of A and B , increase. One also finds that at a constant temperature t , A2 = RH20, 8 2 = A2/RH20, B , = A ~ / R H ~and ? , B4 = A41 RH,O because the molar refraction of solid LiI03 is practically constant in the investigated range of temperature.
no(t) nH20 R RH,O T To’, TO’’ t a09
temperature-dependent constant in eq 2 refractive index of water specific refraction of solution, cm3/g specific refraction of water, cm3/g temperature, K constants in eq 5 and 6, K temperature, ‘ C constants in eq 7 and 9
a1-a5
constants in eq 8 and 10
PO?
Acknowledgment
423
P d 5
We express our sincere thanks to L. A. Romankiw for making valuable suggestions and corrections in the first version of the manuscript.
PI,
p”
concentration-dependent constants in eq 5 and 6, K-2
Reglslry No. LIIO,,
13765-03-2.
Literature Cited (1) Nalbandyan, A. G.; Alaverdyan, A. V. Izv. Akad. NaukSSSR: Neorg. Mater. 1085, 27, 1011-1013. (2) Washburn, E. W., Ed. International Critical Tables of Numerical Data, Physics, Chemistry, and Technology; McGraw-Hiik New York, 1928; Vol. 111. (3) Sohnei, 0.; Novotny, P. Densities of Aqueous Soiutlons of Inorgsnic Substances ; Akademia: Praha, Czechoslovakia, 1985. (4) Ricci, J. E.; Amron, J. J . Am. Chem. SOC. 1951, 73, 3613-3618. (5) Bogdanov, S.V., Ed. Lithium Iodate: Growth of Crystals, their Properties and Application ; Nauka: Novosibksk, 1980. (6) Deslgnes, J. M.; Remoissenet, M. Mater. Res. Bull. 1971, 6,
constants in eq 13 and 14 constants in eq 1 and 3 constants in eq 15 and 16 constants in eq 2 and 4 solution concentration, M corrected density of solution, g/cm3 measured density of solution, glcm3 concentrationdependent constants in eq 3 and 5, g/cm3 temperaturedependent constants in eq 1, g/cm3 density of water, glcm3 refractive index of solution concentrationdependent constants in eq 4 and 6
705-7 IO. (7) Robertson, D. S.;Roslington, J. M. J. Phys. D: Appl. Phys. 1071, 4, 1582-1585. (8) Szewczyk, J.; Sangwai, K. I n European Meerting on Crystal Growth 82: Materkls for Electronics, Prague, August 7982; Poster C-55, pp
233-234. (9) Sangwal, K. Cryst. Res. Techno/. 1087, 22, 789-792. (10) Benson, S.W. J. Am. Chem. Soc. 1078, 100, 5640-4. (11) Wojciechowski, B. I n Industrial Crystallkation 78; de Jong, E. J., Jancie, S., Eds.; North-Holland: Amsterdam, 1979;p 533-4. (12)Hodgman, C. D.; Weast, R. C.; Seiby, S. M., Eds. Handbook of Chemistry and Physics, 40th ed.; CRC Press: Cleveland, OH, 1958. Received for review April 13, 1987. Revised April 7, 1988. Accepted June
16,1988.
Thermodynamics of Binary Mixtures Containing Organic Carbonates. 1. Excess Enthalpies of Dimethyl Carbonate Hydrocarbons or Tetrachloromethane+
+
+
Isaias Garda, Jose C. Cobos, Juan A. GonrGlez, and Carlos Casanova* Departamento de l%ca
Apiicada 11, Facultad de Ciencias, 4707 I- Vaiiadoiid, Spain
Maria J. Cocero Departamento de Ingenieria Odmica, Facultad de Ciencias, 4707 1- Vaiiadoiid, Spain
Molar excess enthalpy HEdata at 298.15 K are reported for the binary llquld systems dimethyl carbonate hexane, heptane, octane, decane, cyclohexane, methylcyciohexane, benzene, toluene, or tetrachloromethane.
+
+
+
+
+
+
+
++
Introductlon
Esters Of carbonic
dialkyl carbonates CH3(CH2)i?-10-
This paper is a contribution to the TOM Project ( 7 2 ) .
CO-O(CH,),-,CH3 and polymethylene carbonates O-CO-O1
(CH,),,, are used in the syntesis of pharmaceuticals, agricultural chemicals, and dyestuffs. They are also used as solvents for many synthetic and natural resins and polymers, and some of them are used in photoengraving as assist agents for silicon circuitry. In spite of the potential applications of carbonic acid esters there are only a few experimental thermodynamics studies on this class of substances; mainly on cyclic derivatives (3-5).In to our knowledge, no data exist on the properties of binary mixtures of dialkyl carbonates (CH,(CH,), - 1 0 ) 2 C 0with normal alkanes. Accordingly, no interaction parameters are yet
0021-9568/88/1733-0423$01.50/0 0 1988 American Chemical Society
