J. Chem. Eng. Data 2001, 46, 1627-1631
1627
Solubilities of Substituted Ferrocenes in Organic Solvents Marek Da¸ browski,† Bogusław Misterkiewicz,‡ and Andrzej Sporzyn ´ ski*,† Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland, and Department of Chemistry, Technical University of Radom, Chrobrego 27, 26-600 Radom, Poland
The solubilities of some ferrocenes (ferrocene, ferrocenylmethanol, and 1-ferrocenylethanol) in hexane, benzene, toluene, ethanol, 3-pentanone, and butyl methyl ether have been determined experimentally by a dynamic method at temperatures from (280 to 350) K. The results have been correlated by the Wilson and UNIQUAC equations. The average root-mean-square deviations of the solubility temperatures for all of the measured data vary from (0.4 to 4.5) K and depend on the particular system and equation.
Introduction
Table 1. Characteristics of Ferrocenes
Ferrocenes have wide application in many fields: they are used in supramolecular chemistry, as magnetic materials and liquid crystals, in asymmetric catalysis,1 and as oil additives.2 Ferrocenyl compounds function as enzyme inhibitors and can act as cancer therapeutic agents.3,4 The ferrocene molecule is a lipophilic one and can easily cross cellular membranes.3 Recently, there has been a large increase in the number of papers dealing with solid-liquid equilibria (SLE) in new organic and organometallic systems. For substituted ferrocenes few SLE data have been reported. The aim of the present work was to study the solubility of three selected ferrocenes (I) in a series of organic solvents to investigate the influence of the introduction of an organic group to ferrocene on solubility and to attempt a correlation of the experimental results with established theories of solutions.
compound
V°m a/(cm3‚mol-1)
Tm,1/K
∆fusH/kJ‚mol-1
Fc FcCH2OH FcCH(CH3)OH
128.9 156.1 161.9
447.60 351.38 351.60
17.49 23.82 26.65
a
Vmo is the molar volume at 298.15 K.
melting temperature and 1% for enthalpy of fusion. The properties of the investigated ferrocenes are listed in Table 1. Solubilities were determined according to a dynamic (synthetic) method, described by Doman´ska et al.7 The reproducibility of the measurements was 0.1 K, which corresponded to a standard error in mole fraction δx1 of 0.0005. All of the experimental data are shown in Tables 2-4. Results and Discussion
Experimental Section Materials. Ferrocene was obtained from Aldrich and used without purification. Monosubstituted ferrocenes [ferrocenylmethanol (FcCH2OH) and 1-ferrocenylethanol (FcCH(CH3)OH)] were synthesized and purified as described by Misterkiewicz.5,6 The solvents were dried over 4A molecular sieves and were fractionally distilled using a 10-plate laboratory column. Molar volumes of ferrocenes were calculated from density measurements according to a pycnometric method. Melting temperatures and enthalpies of fusion were determined by DSC (Perkin-Elmer Pyris 1). Uncertainties for these measurements were 0.1 K for * Author to whom correspondence should be addressed (e-mail
[email protected]). † Warsaw University of Technology. ‡ Technical University of Radom.
The solubilities of each ferrocene in the solvents were lower than expected from ideal solution behavior, and the solution showed positive deviations from ideality (γ1 > 1). All experimental activity coefficients are listed in Tables 2-4, and the SLE data are shown in comparison with the ideal solubility in Figures 1-3. The introduction of the hydroxyalkyl group to ferrocene strongly influences the solubility, causing a decrease in the solubility in hexane, an increase in the solubility in aromatic solvents, and a large increase in the solubility in alcohol, ether, and ketone. Solubilities are similar for linear and branched alcohol groups (with the exception of hexane). The solubility of a solid nonelectrolyte 1 in a liquid solvent can be approximated by
- ln x1 )
(
)
∆fusH 1 1 + ln γ1 R T Tm1
(1)
where x1 is the mole fraction, γ1 the activity coefficient, ∆fusH the enthalpy of fusion, Tm1 the melting temperature, and T the equilibrium temperature of the solute. Equation 1 is the simplified version of the solubility equation, missing the term containing ∆Cp because sufficiently accurate thermodynamic data are not available for fer-
10.1021/je010197q CCC: $20.00 © 2001 American Chemical Society Published on Web 10/24/2001
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Journal of Chemical and Engineering Data, Vol. 46, No. 6, 2001
Table 2. Experimental Mole Fraction Solubilities and Activity Coefficients of Ferrocene x1
T1/K
x1
γ1
0.0720 0.0764 0.0806 0.0850 0.0898 0.0951
290.75 293.05 295.65 298.45 301.95 304.85
Benzene 1.100 0.1005 1.097 0.1063 1.109 0.1130 1.124 0.1214 1.154 0.1311 1.164
0.0179 0.0224 0.0250 0.0277 0.0296 0.0337
288.45 296.05 300.15 302.95 307.05 311.45
4.178 4.023 3.972 3.824 3.934 3.807
0.0045 0.0051 0.0056 0.0063 0.0070 0.0078 0.0088 0.0096
291.05 295.15 299.05 303.65 307.45 311.35 315.55 318.05
17.583 17.477 17.203 17.157 16.792 16.353 15.990 15.295
0.0211 0.0259 0.0315 0.0349 0.0362 0.0408 0.0436
287.95 298.95 308.35 313.15 315.15 320.25 323.75
3.508 3.732 3.808 3.815 3.829 3.785 3.801
0.0391 0.0436 0.0485 0.0537 0.0594 0.0666 0.0732 0.0790 0.0682 0.0782 0.0857 0.0941 0.1014 0.1101
T1/K
Table 3. Experimental Mole Fraction Solubilities and Activity Coefficients of Ferrocenylmethanol x1
γ1
307.55 310.35 313.95 318.85 324.35
1.170 1.177 1.197 1.235 1.279
0.0404 0.0479 0.0562 0.0646 0.0715 0.0755
319.15 326.35 332.45 338.05 343.05 345.05
3.732 3.645 3.491 3.376 3.342 3.277
0.0106 0.0116 0.0124 0.0134 0.0152 0.0175 0.0186
322.15 325.45 328.55 331.45 335.55 340.25 342.75
15.074 14.812 14.713 14.333 13.741 12.994 12.802
0.0458 0.0476 0.0491 0.0510 0.0528 0.0544 0.0579
327.15 329.15 331.55 333.15 335.15 336.75 339.35
3.874 3.871 3.934 3.902 3.913 3.912 3.857
292.45 297.35 302.15 306.55 310.05 314.95 318.05 322.35
3-Pentanone 2.113 0.0882 2.135 0.0910 2.148 0.1123 2.143 0.1243 2.092 0.1363 2.074 0.1625 2.014 0.1625 2.040
327.05 329.45 339.35 345.15 350.65 360.95 360.95
2.006 2.038 1.989 1.994 2.000 1.992 1.992
282.95 292.55 299.75 305.85 309.75 313.35
0.952 1.059 1.148 1.203 1.218 1.213
317.65 322.45 330.95 341.35 355.35
1.233 1.248 1.353 1.443 1.589
BuOMe
EtOH
Hexane
Toluene 0.1186 0.1293 0.1411 0.1605 0.1858
rocenes. Two methods were chosen to represent the solute activity coefficients (γ1) from the so-called correlation equations describing the excess Gibbs free energy of mixing (GE): the Wilson and the UNIQUAC equations. The exact mathematical forms of the equations are given in refs 8 and 9. On the basis of the results for similar systems, a modified version of the Wilson equation was applied.10 The parameters of the equations were found by an optimization technique using the maximum neighborhood method for minimization n
Ω)
∑[T
exptl i
- Tcalcd (x1,P1,P2)]2 i
(2)
i)1
denotes an experimental value of the temperwhere Texptl i ature for a given concentration x1i, Tcalcd is the temperai ture calculated for a given concentration x1i, and parameters P1 and P2 were obtained by solving the nonlinear eq 1 and the expression for the logarithm of the activity according to the assumed model. The nonlinear equations
T1/K
x1
γ1
T1/K
γ1
303.95 305.15 306.45 307.95 309.85 312.45 315.25 318.95
2.191 2.053 2.010 1.930 1.853 1.799 1.754 1.721
308.05 309.25 310.95 312.35 314.15 315.35 316.95 318.35
2.899 2.873 2.851 2.812 2.776 2.736 2.702 2.626
0.0107 0.0114 0.0120 0.0125 0.0130 0.0137 0.0143 0.0152 0.0157 0.0160 0.0166 0.0168 0.0176 0.0182 0.0184
324.85 325.15 326.35 326.15 326.75 327.15 328.05 328.95 329.15 329.95 330.85 331.05 332.95 334.35 334.15
47.890 45.224 44.371 42.398 41.234 39.726 39.007 37.453 36.453 36.487 36.140 35.747 35.975 35.925 35.469
0.0427 0.0495 0.0580 0.0675 0.0778 0.0902 0.1007 0.1110 0.1214
285.05 287.25 290.35 292.85 295.55 298.75 300.55 301.95 303.15
Benzene 3.487 0.1269 3.249 0.1406 3.083 0.1494 2.884 0.1629 2.734 0.1796 2.618 0.1998 2.483 0.2223 2.355 0.2518 2.234
0.0444 0.0495 0.0551 0.0603 0.0657 0.0703 0.0751 0.0854 0.0970
285.05 287.95 290.65 293.05 294.95 297.45 299.75 303.05 306.05
BuOMe 3.356 0.1088 3.330 0.1138 3.277 0.1206 3.251 0.1274 3.173 0.1360 3.221 0.1429 3.246 0.1515 3.166 0.1622 3.058
0.0015 0.0025 0.0026 0.0032 0.0035 0.0038 0.0045 0.0051 0.0052 0.0059 0.0065 0.0069 0.0075 0.0082 0.0091 0.0098
286.95 299.35 300.95 304.95 306.85 307.65 310.65 313.15 313.15 315.35 316.65 317.95 319.15 321.15 322.75 323.65
0.0599 0.0692 0.0792 0.0898 0.1008 0.1111 0.1203 0.1297 0.1409 0.1461 0.1525 0.1608 0.1702 0.1799 0.1883
279.15 283.05 285.95 288.95 291.65 293.55 295.35 296.95 298.95 299.35 300.35 301.25 302.95 303.55 304.45
2.009 2.003 1.939 1.898 1.854 1.793 1.757 1.717 1.686 1.647 1.629 1.589 1.584 1.527 1.500
0.1991 0.2112 0.2195 0.2346 0.2522 0.2607 0.2736 0.2859 0.2978 0.3121 0.3288 0.3464 0.3644 0.3807 0.4049
305.25 306.35 307.05 309.05 310.35 311.15 312.15 313.25 314.15 314.85 315.35 317.15 318.95 320.15 322.25
1.454 1.418 1.394 1.385 1.339 1.327 1.302 1.287 1.268 1.235 1.189 1.189 1.189 1.177 1.173
0.0741 0.0957 0.1226 0.1533 0.1794 0.2012 0.2221 0.2318 0.2461 0.2600
283.65 289.55 294.75 298.75 303.05 307.25 309.55 310.65 311.25 312.75
3-Pentanone 1.913 0.2743 1.818 0.2945 1.690 0.3091 1.540 0.3314 1.507 0.3561 1.530 0.3813 1.485 0.4130 1.470 0.4596 1.410 0.5086 1.395
313.95 315.45 316.85 318.15 319.95 321.45 324.25 328.35 330.85
1.369 1.332 1.320 1.278 1.251 1.219 1.215 1.219 1.177
0.0416 0.0708 0.0888 0.1121 0.1349 0.1616 0.1939
297.15 302.75 306.25 309.15 312.45 314.35 316.65
Toluene 5.387 0.2281 3.783 0.2637 3.362 0.3155 2.908 0.3584 2.664 0.4100 2.351 0.4876 2.093
319.05 321.15 323.35 326.25 329.15 332.75
1.905 1.747 1.552 1.478 1.396 1.290
Hexane 107.510 95.482 99.284 89.361 86.127 81.120 75.736 72.215 70.413 65.941 62.929 61.308 58.171 56.052 53.214 50.472 EtOH
Journal of Chemical and Engineering Data, Vol. 46, No. 6, 2001 1629
Figure 1. Solubility of ferrocene: 0, in hexane; b, in benzene; 9, in toluene; O, in ethanol; 4, in 3-pentanone; ], in n-butyl methyl ether. The dotted line represents the ideal solubility.
Figure 2. Solubility of ferrocenylmethanol: 0, in hexane; b, in benzene; 9, in toluene; O, in ethanol; 4, in 3-pentanone; ], in n-butyl methyl ether. The dotted line represents the ideal solubility.
Figure 3. Solubility of 1-ferrocenylethanol: 0, in hexane; b, benzene; 9, in toluene; O, in ethanol; 4, in 3-pentanone; ], in n-butyl methyl ether. The dotted line represents the ideal solubility.
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Journal of Chemical and Engineering Data, Vol. 46, No. 6, 2001
Table 4. Experimental Mole Fraction Solubilities and Activity Coefficients of 1-Ferrocenylethanol x1
T1/K
γ1
0.0830 0.0986 0.1148 0.1335 0.1531 0.1758 0.1979
293.25 296.35 299.95 302.45 304.85 307.25 309.45
1.965 1.854 1.813 1.704 1.614 1.526 1.460
0.0940 0.1110 0.1267 0.1456 0.1679 0.1954
295.75 302.15 305.75 307.95 311.45 314.15
1.904 2.027 2.011 1.887 1.839 1.726
0.0858 0.1047 0.1242 0.1414 0.1626
291.15 296.95 300.35 302.95 305.35
1.756 1.785 1.700 1.637 1.546
0.0059 0.0086 0.0113 0.0143 0.0175 0.0241
295.25 301.95 306.95 311.05 314.15 319.45
29.609 25.978 23.420 21.253 19.236 16.568
0.0778 0.1011 0.1190 0.1412 0.1548
283.85 288.55 291.85 296.65 298.95
1.459 1.350 1.300 1.309 1.297
0.0630 0.0837 0.1030 0.1210 0.1458 0.1778 0.2162
292.95 298.75 301.45 303.95 306.75 311.05 314.15
2.558 2.381 2.132 1.981 1.809 1.714 1.561
x1
T1/K
γ1
0.2257 0.2500 0.2721 0.3006 0.3375 0.3869 0.4718
312.15 314.35 316.15 318.85 321.65 325.05 331.15
1.400 1.359 1.323 1.304 1.268 1.228 1.207
0.2261 0.2596 0.2955 0.3246 0.3507 0.3649
317.75 320.95 323.15 325.85 327.05 327.95
1.675 1.613 1.517 1.499 1.439 1.420
0.1872 0.2082 0.2353 0.2660
309.65 312.25 314.45 317.05
1.554 1.523 1.448 1.393
0.0322 0.0431 0.0586 0.0794 0.0897 0.0944
324.85 328.95 332.05 335.55 336.45 337.55
14.650 12.400 9.988 8.141 7.395 7.254
0.1707 0.1858 0.2086 0.2366 0.2840
301.25 304.05 307.85 311.35 317.25
1.277 1.294 1.312 1.301 1.313
0.2672 0.3086 0.3717 0.4336 0.5109
318.35 321.35 325.15 328.95 333.35
1.445 1.374 1.282 1.231 1.189
Benzene
BuOMe
EtOH
Hexane
3-Pentanone
Toluene
Table 5. Analyses of the Solubility Data of Ferrocenes by the Wilson Equation: Values of the Parameters and Measures of Deviations solvent benzene
BuOMe
σ/K 10-3 a12/(kJ‚mol-1) 10-3 a21/(kJ‚mol-1)
0.59 -3.1162 113.5473
0.47 1.1076 6.4138
σ/K 10-3 a12/(kJ‚mol-1) 10-3 a21/(kJ‚mol-1)
0.92 2.1677 1.3092
0.42 0.3234 6.2104
σ/K 10-3 a12/(kJ‚mol-1) 10-3 a21/(kJ‚mol-1)
0.84 0.9433 1.2091
0.74 -0.0331 2.7437
EtOH Ferrocene 0.63 2.9050 10.8449
σ)
[∑
]
(Texptl - Tcalcd )2 i i
i)1
(n - l)
3-pentanone
toluene
2.90 1.2085 114.3930
0.93 -0.9272 7.9817
4.54 -2.5600 125.6193
Ferrocenylmethanol 0.99 9.3327 5.7239
0.50 0.3372 1.8969
0.74 0.4448 1.3704
1.14 3.9287 1.1053
1-Ferrocenylethanol 0.50 -1.4395 3.2815
0.37 6.1826 4.5501
0.92 -1.7359 3.4555
0.83 2.0771 0.8212
were solved using the secant method. The root-meansquare deviation of the temperatures defined by eq 3 was used as a measure of the goodness of fit n
hexane
1/2
the melting point) and l is the number of adjustable parameters. The Wilson equation has been tested with a parameter Λij in the form
(3)
Λ12 ) (V2/V1) exp[-(g12 - g11)/RT]
where n is the number of experimental points (including
Λ21 ) (V1/V2) exp[ - (g12 - g22)/RT]
(4)
Journal of Chemical and Engineering Data, Vol. 46, No. 6, 2001 1631 Table 6. Analyses of the Solubility Data of Ferrocenes by the UNIQUAC Equation: Values of the Parameters and Measures of Deviations solvent benzene
BuOMe
EtOH
hexane
3-pentanone
toluene
2.98 3808.56 -832.69
1.06 3154.02 -1177.10
1.79 7084.58 -2297.57
σ/K ∆g12/(J‚mol-1) ∆g 21/(J‚mol-1)
0.54 4420.40 -1944.77
0.47 2258.33 -334.43
Ferrocene 0.65 4633.30 501.48
σ/K ∆g12/(J‚mol-1) ∆g 21/(J‚mol-1)
0.98 354.38 718.74
0.41 2333.29 -646.29
Ferrocenylmethanol 1.21 -2075.24 6443.37
0.49 1125.19 27.31
0.75 586.14 -18.86
1.51 -268.86 1609.16
σ/K ∆g12/(J‚mol-1) ∆g21/(J‚mol-1)
0.85 680.08 100.29
0.73 1445.41 -544.58
1-Ferrocenylethanol 0.50 2216.36 -652.77
0.63 -776.67 3138.94
0.95 1817.86 -1033.53
0.89 -262.77 1047.45
where
(g12 - g11) ) a12/T;
a12 * f(T)
(g12 - g22) ) a21/T;
a21 * f(T)
(4)
(5)
(5) (6)
V2 and V1 are the molar volumes of pure solute and solvent in the liquid phase, respectively, gij is the molar energy of interaction between the i and j components, and aij is the binary interaction parameter. The pure component structural parameters r (volume parameter) and q (surface parameter) in UNIQUAC were obtained in accordance with the methods suggested by Vera et al.11 and relationships from Hofman and Nagata.12 Table 5 lists the results of fitting the solubility curves by the Wilson equation and Table 6 those by the UNIQUAC equation. Better approximation was obtained with the UNIQUAC equation (root-mean-square deviations do not exceed 1.8 K) in comparison with the Wilson equation.
(11)
Literature Cited
(12)
(1) Togni, A., Hayashi, T., Eds. Ferrocenes; VCH: Weinheim, Germany, 1995. (2) Kajdas, C.; Domoniak, M.; Firkowski, A.; Dıbrowski, J. R.; Misterkiewicz, B. Tribochemistry of Some Ferrocene Derivatives. ASLE Trans. 1983, 26, 21-24. (3) Mason, R. W.; McGrouther, K.; Ranatunge-Bandarage, P. R. R.; Robinson, B. H.; Simpson, J. Toxicology and Antitumor Activity
(7)
(8) (9)
(10)
of Ferrocenylamines and Platinum Derivatives. Appl. Organomet. Chem. 1999, 13, 163-173. Haiduc, I.; Silvestru, C. Organometallics in Cancer Chemotherapy; CRC Press: Boca Raton, FL, 1989. Misterkiewicz, B. A Simple Synthesis and Purification of 1-Ferrocenylalkyl Alcohols. J. Organomet. Chem. 1982, 224, 43-47. Misterkiewicz, B.; Dabard, R.; Patin, H. Substitution Electrophile du Ferrocene et du Dimethylferrocene par les Derives Carbonyles Protones. Tetrahedron 1985, 41, 1685-1692. Doman´ska, U.; Serwatowski, J.; Sporzyn´ski, A.; Dabrowski, M. Solubilities of Organoboron Compounds in Organic Solvents. 1. Solid-liquid Equilibria of Some Pyrazaboles + Heptane or + 2-Propanol. Thermochim. Acta 1993, 222, 279-290. Wilson, G. M. Vapour-Liquid Equilibrium. XI. A New Expression for the Excess Free Energy of Mixing. J. Am. Chem. Soc. 1964, 86, 127-130. Abrams, D. S.; Prausnitz, J. M. Statistical Thermodynamics of Liquid Mixtures: A New Expression for the Excess Gibbs Energy of Partly or Completely Miscible Systems. AIChE J. 1975, 21, 116-128. Doman´ska, U.; Kniaz´, K. Solubility of Normal Alkanoic Acids in Selected Organic Binary Solvents Mixtures. Negative Synergetic Effect. Fluid Phase Equilib. 1990, 58, 211-227. Vera, J. H.; Sayegh, G. S.; Ratcliff, G. A. A Quasi-Lattice Local Composition Model for the Excess Gibbs Free Energy of Liquid Mixtures. Fluid Phase Equilib. 1977, 1, 113-135. Hofman, T.; Nagata, I. Determination of Association Constant for Alcohols Based on Ethers and Homomorphs. Fluid Phase Equilib. 1986, 25, 113-128.
Received for review July 10, 2001. Accepted September 5, 2001.
JE010197Q
