Solubilities of Substituted Ferrocenes in Organic Solvents - Journal of


Oct 24, 2001 - ... Tm1 the melting temperature, and T the equilibrium temperature of ..... Abrams, D. S.; Prausnitz, J. M. Statistical Thermodynamics ...
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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