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.
p”
concentration-dependent constants in eq 5 and 6, K-2 Reglslry No. LIIO,, 13765-03-2.
PI,
Literature Cited (1) Nalbandyan, A. G.; Alaverdyan, A. V. Izv. Akad. NaukSSSR: Neorg. Mater. 1085, 2 7 , 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, 7 3 , 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
705-7IO. (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, 2 2 , 789-792. (10) Benson, S.W. J. Am. Chem. Soc. 1078, 100, 5640-4. (11) Wojciechowski, B. I n Industrial Crystallkation 7 8 ; 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+
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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.
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+
+
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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
424
Journal of Chemical and Engineering Data, Vol. 33, No. 4, 1988 Table I. Physical ProDerties of Pure ComDounds refractive index density ?(D,,298.15 K) ~(298.15 K)/kg m-3 compound this study lit. this study lit. dimethyl carbonate 1.3667 1.3687" 1063.6 1069.4" hexane 1.3723 1.37226 654.7 654.84 heptane 1.3851 1.38511 679.5 679.46 octane 1.3951 1.39505 698.5 698.62 decane 1.4097 1.40967 726.3 726.35 cyclohexane 1.4235 1.42354 773.9 773.89 methylcyclohexane 1.4206 1.42058 765.1 765.06 benzene 1.4979 1.49792 873.7 873.6 toluene 1.4941 1.49396 862.4 862.2 tetrachloromethane 1.4574 1.4570 1584.4 1584.3 "Reference 13 (293.15K).
r-----02
0
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X
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Flgure 1. Excess molar enthalpy H E for dlmethyl carbonate (1) n-alkane (2) mixtures versus x , , the mole fraction of component 1: (0) hexane; (0)heptane: (A)octane; (A)decane. Full curves represent the smoothing eq 1 with the coefficients of Table 111. available for the carbonate group, -0-CO-0- in the frame of predictive group-contribution methods, such as UNiFAC (6). For these reasons we have initiated a systematic study of the thermodynamic properties of mixtures containing dialkyl or polymethylene carbonates. I n this paper we report excess molar enthalpies H E for dimethyl carbonate (1) hexane (2), heptane (2), octane (2), decane (2), cyclohexane (2), methylcyclohexane (2), benzene (2), toluene (2), or tetrachloromethane (2) at 298.15 K and atmospheric pressure. Vapor-liquid equilibrium data have been reported in the literature (7) for dilute solutions ( x , < 0.15) of dimethyl carbonate (1) in methylcyclohexane (2) or toluene (2).
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0.6
0.4
0.2
0.3
1
X
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Figure 2. Excess mohr enthalpy HEfor dlmethyl carbonate (1) cyclic alkanes (2) mixtures versus x the mole fraction of component 1: (0) cyclohexane; (0) methylcyclohexane. Full curves represent the smoothlng eq 1 with the coefficients of Table 111.
',
Experlmental Section A standard Calvet type microcalorimeter, equipped with a batch mixing cell with small (
