Scientific paper The (p,p,T) Properties and Apparent Molar Volumes V^ of LÌNO3 + C2H5OH Huseyn Israfilov,1 Rasim Jannataliyev,1,2 Javid Safarov,1,2* Astan Shahverdiyev1 and Egon Hassel2 1 Department "Heat and Refrigeration Techniques", Azerbaijan Technical University, H. Javid Avn. 25, AZ1073 Baku, Azerbaijan. ' Lehrstuhl für Technische Thermodynamik, Universität Rostock, 18059, Rostock, Germany. * Corresponding author: E-mail: javid.safarov@uni-rostock.de Phone: + 49 381 4989415; fax: + 49 381 4989402 Received: 15-10-2008 Dedicated to Professor Josef Barthel on the occasion of his 80'' birthday Abstract The (p,p,T) properties and apparent molar volumes V, of LiNOj in ethanol at temperatures T = (298.15 to 398.15) K and pressures up to p = 40 MPa are reported. The vibration tube densimeter method used during the experiments. The experiments were carried out at molalities of m = (0.12071, 0.26234, 60237, 0.97956, 1.83765, 2.62045 and 3.27773) mol kg-1 using lithium nitrate. An empirical correlation for the density of (LiNO3 + C2H5OH) with pressure, temperature and molality has been derived. The short form of equation of state was developed for the technical calculations. Apparent molar volume and thermal properties of LiNO3 in ethanol were calculated using the equation of state. Keywords: Apparent molar volume, density, partial molar volume, vibration tube densimeter, isothermal compressibility, isobaric thermal expansibility, lithium nitrate 1. Introduction In absorption heat pump systems, compression of the heat transfer fluid is achieved thermally in a solution circuit which consists of an absorber, a solution pump, a generator and an expansion valve. Vapour of refrigerant with low pressure from the evaporator is absorbed in the absorbent and this process generates heat. The solution is pumped to high pressure and then enters the generator, where the heat transfer fluid is boiled off with an external heat supply at a high temperature. The vapour of refrigerant is condensed in the condenser while the absorbent is returned to the absorber via the expansion valve. Heat is extracted from the heat source in the evaporator. Useful heat is given off at medium temperature in the condenser and in the absorber. In the generator high-temperature heat is supplied to run the process. A small amount of electricity may be needed to operate the solution pump. The efficiency of an absorption heat transfer cycle lagely depends on the physical and chemical properties of the heat transfer fluid. The problems of using conventional aqueous solutions of electrolytes were discussed in our previous publications on methanol and ethanol solutions of electrolytes.1-3 Total analysis of the thermody-namic properties of non-aqueous electrolyte solutions were carried out by Prof. Barthel and his research group.4-6 This work is a continuation of the study of solutions of electrolytes for their fu-ture application as heat transfer fluids in absorption systems. These systems (alco-hol solutions of electrolyte) could replace aqueous solutions at temperatures below the freezing point of water. Ethanol has a freezing temperature lower than methanol and can improve the circu-lation of heat transfer agents in the closed system. The (p,p,T) properties and apparent molar volumes V, of the LiNOj in ethanol at T = (298.15 to 398.15) K and pressures up to p = 40 MPa are reported. An empirical correlation for the density of (LiNO3 + C2H5OH) with pressure, temperature and molality has been derived. Various literature works7-10 with thermodynamic properties of LiNO3 in ethanol are available. Glugla etC investigated the partial molar volume of monovalent salts and polar molecules in organic solvents. High volume injection and flow dilatometers were used during the experiments. The temperature bath used with this apparatus controlled temperature fluctuation to within 0.001 °C. The volume change was always less than 0.0001 ml and frequently less than 0.00005 ml. The apparent molar volumes of LiNO3 in ethanol were measured at temperature T = 298.15 K, molalities m = (0.00201 to 2.4085) mol kg1 and at p = 0.1 MPa. The partial molar volumes measured in aprotic solvents with this apparatus were accurate to better than ±2 %. Eliseeva etc.8 in 1999, investigated the density of LiNO3 + ethanol at T = 298.15 K and at molalities m = (0.1048 to 3.0026) mol kg-1 using a well known vibrationtube densimeter method. The uncertainties of measurements of this work is 2 x 10-6 g cm-3. Marcus and Hefter,10 in 2004, after the analysis of available literature results decided the apparent molar volume at infinite dilution, as V'^ = -5 cm3 mol1 at T = 298.15 K. Verevkin et al., in 2006, measured the vapor pressure p of (LiNO3 + C2H50H) solutions at T = (298.15 to 323.15) K. The experiments were carried out in the molality range m = (0.19125 to 2.21552) mol kg1. The An-toine equation was used for the empirical description of the experimental vapor pressure results, and the Pitzer- Mayorga model with inclusion of Archer's ionic strength dependence of the third virial coefficient for the calculated osmotic coefficients were used for the evaluation of the osmotic, activity coefficients (0, Y and activity of solvent as from the experimental vapor pressure results. The (p, p, T) properties of these solutions are not available in the literature. 2. Experimental Section The (p,p,T) measurements were studied using a new modernized high pressure - high temperature vibrating tube densimeter DMA HPM (Anton-Paar, Austria). The schematic principle of the vibration tube densimeter is shown in Figure 1. The measurements with a vibrating tube are based on the dependence between the period of oscillation of a unilaterally fixed U-tube Hastelloy C-276 and its mass. This mass consists of the U-tube material and the mass of the fluid filled into the U-tube. The behavior of the vibrating tube can be described by the simple mathematical-physical model of the undamped spring-mass system.11 The characteristic period of oscillation t (^s) of this model is described by the following equation: (1) \ 19 Figure 1: A new modernized high pressure - high temperature vibrating tube densimeter DMA HPM: 1 - Flask for the probe; 2, 7, 16, 17 - Valves; 3, 11 - Fitting; 4 - Pressure inten-sifier; 5 - Pressure sensor HP-1; 6 - Pressure sensor P-10; 8 - Valve for the closing of system during the experiments; 9 - Display mPDS2000V3 for the temperature and frequency control; 10 - Vacuum indicator; 12 - Visual window; 13 - Vibration tube; 14 - Interface mode; 15 -PC; 18 - Thermostat F32-ME; 19 - Vacuum pump; 20 - Thermos for cooling. where: t is the period of oscillation of the vibration tube, ^s; m0 is mass of the empty vibrating tube, kg; V is volume of the vibrating tube, m3; p is sample density, kg m 3 and k is the spring constant, N m1. The period of oscillation measurement and the temperature control is implemented within the DMA HPM control system, which consists of a measuring cell (13) and a modified mPDS2000V3 control unit (9) connected to a PC (15) via an interface (14). The temperature in the measuring cell was controlled using a thermostat (18) F32-ME (Julabo, Germany) with an error of ±10 mK and was measured using the (lTS-90) Pt100 thermometer with an experimental error of ±15 mK. Pressure was created by a pressure intensifier (4) (Type 37-6-30, HlP, USA) and measured by pressure transmitter (6) (P-10, WlKA Alexander Wiegand GmbH & Co., Germany) with a measuring error of 0.1%. The observed reproducibility and estimated maximum uncertainty of the density measurements at temperatures T = (298.15 to 398.15) K and at pressures up to p = 40 MPa is within ±0.1-0.3 kg m 3. All high pressure valves (2, 7, 8, 16, 17), tubes, fittings (3 and 11) etc. were supplied by SlTEC and NOVA (Switzerland). Rearrangement of the equation and substitution of the mechanical constants lead to the classical equation for vibrating tube densimeters: P=A-BT\ (2) where: p is the sample density, kg m 3 and t is the period of oscillation, ^s. The parameters A and B were determined by substance calibration measuring the period of oscillation of at least two samples with known density. Wa-ter12 (twice-distilled), ethanol13-15 and NaCl (aq)16-17 in various molalities were used as reference substances for the calibration of the installation. Unfortunately, the parameters A and B are highly temperature and also pressure dependent. Therefore, the parameters must be determined for each temperature and pressure separately or, like in this work, the classical equation must be expanded with temperature and pressure-dependent terms. For measurements at T = (298.15 to 398.15) K and up to p = 40 MPa an extended calibration equation with 14 significant parameters is employed:18 (3) i i +/{7-/K)(/)/MPa), where: a0, a1, a2, a3, b1, b2, c, d0, d1, d2, d3, e1, e2 and fare the parameters of the these extended vibrating tube equations. Before starting the experiment only the valve of the flask (1) was closed. The sample filled into the measuring cell was under vacuum, which is connected to the installation. Vacuum is applied over (3 to 4) hours using a vacuum pump (19) (Model S 1.5, Leybold, Germany) until a minimal pressure [(3 to 5) Pa] has been reached (measured with digital vacuum indicator (10) THERMOVAC TM 100 (Leybold, Germany). The valve (17) is closed and the valve of the flask is opened. The investigated substance is filled into the measuring system. For the tracing of flow of the measured sample a special window (12) was constructed between valves (16) and (17). After filling of the system, the valves (2) and (16), which separate the high pressure connections (bold lines in Fig.1) from others, were closed. The experiments were started usually at low pressures in the measured cell (0.8-1.0 MPa). Temperature stabilization was around two hours. The period of oscillation of the vibration tube is taken from the display of the mPDS2000V3 control system (9). To check the apparatus and procedures of the measurements and the accuracy of calibration before engaging in measurements on solutions, the density of double distilled water, ethanol and NaCl (aq) with various molalities were measured, compared with the values of literature results and good comparison were obtained. LiNO3 (w > 0.998) was supplied from Merck, Germany and was used without further purification. Before experiment it was dried about 48 h in a special cell by heating at 413.15 K and reduced pressure (around 7-8 Pa). Ethanol (w > 0.998) was supplied from Merck, Germany and was degassed by vacuum distillation using a Vi-greux column with a height of 90 cm. The final purity of the ethanol was checked by gas chromatography (w > 0.999) and Karl-Fischer titration (water content <50 ppm). For the preparation of samples, flasks with LiNO3 and ethanol were connected to the vacuum pump using a glass adapter. Before the opening of valves of flasks air in the glass adapter was evacuated. Ethanol, in the top flask, flew to the down flask, where was LiNO3 under vacuum. The samples were obtained by successive dilutions of the concentrated solutions. The solutions were prepared by mass using an electronic scale ED224S (Sartorius, Germany) with a resolution of 0.0001 g. 3. Results and Discussion The (p,p,T) properties and apparent molar volumes V^ of (LiNO3 + C2H5OH) were studied at T = (298.15 to 398.15) K, pressures up to p = 40 MPa and molalities m = (0.12071, 0.26234, 0.60237, 0.97956, 1.83765, 2.62045, and 3.27773) mol kg-1 of lithium nitrate. Experiments were carried out in the T = 25 K and p = 5 MPa intervals. The experimental (p,p,T) results are listed in Table 1. Table 1. Experimental values of pressure p/MPa, density p/kg m 3, temperature T/K, isothermal compressibility kT • 106/MPa ', isobaric thermal expansivity ap • 106/K-1, difference in isobaric and isochoric heat capacities (cp-cv)/(Jkg-1K-1) of the (LiNOj + C2H5OH). p/MPa P /kgm T/K kT^ 106 a /M Pa1 106/K-1 K1 (cp-c,) /Jkg-1K- p/MPa P /kg m-3 T/K kT^ 106 /MT Pa-1 ap • 106/K p K-1 (c p v) /Jkg-'K- m = 0.12071 mol^ kg-1 0.214 5.012 10.023 15.412 20.026 25.621 30.012 35.032 39.984 0.321 5.412 9.989 15.014 20.002 25.001 29.996 35.478 39.989 0.245 5.025 10.003 15.301 19.998 25.065 29.997 35.001 39.998 0.365 5.142 10.003 15.621 19.998 25.004 29.996 35.030 39.997 0.894 5.004 10.006 15.201 20.003 25.621 29.998 35.002 39.996 791.56 795.70 799.81 804.05 807.53 811.56 814.59 817.89 821.00 769.50 774.59 778.98 783.52 787.76 791.87 795.77 799.80 802.93 745.71 751.36 756.89 762.47 767.14 771.82 776.15 780.37 784.29 719.91 726.71 733.03 739.89 744.90 750.33 755.36 760.16 764.57 691.62 698.72 706.73 714.38 720.88 727.87 732.97 738.49 743.49 298 298 298 298 298 298 298 298 298 323 323 323 323 323 323 323 323 323 348 348 348 348 348 348 348 348 348 373 373 373 373 373 373 373 373 373 398 398 398 398 398 398 398 398 398 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 .15 1145.1 1077.7 1015.3 955.5 909.4 859.3 823.8 787.0 754.1 1377.0 1277.2 1198.1 1122.3 1056.6 997.2 944.4 893.3 855.8 1697.4 1559.9 1438.0 1326.3 1240.7 1161.3 1093.2 1031.2 977.3 2145.2 1934.3 1760.2 1592.0 1481.1 1371.0 1277.5 1195.1 1124.8 2798.2 2505.0 2217.3 1978.6 1799.3 1627.4 1513.9 1401.4 1307.7 1086.9 1051.5 1018.4 986.1 961.0 933.3 913.3 892.5 873.6 1181.7 1132.0 1091.9 1052.9 1018.7 987.3 959.0 931.2 910.6 1330.3 1265.8 1207.7 1153.5 1111.3 1071.7 1037.1 1005.3 977.2 1535.1 1442.4 1364.5 1287.8 1236.4 1184.6 1140.0 1100.1 1065.6 1819.5 1698.4 1577.4 1474.9 1396.5 1320.0 1268.8 1217.2 1173.6 m = 0.26234 mol • kg- 0.215 5.001 10.003 15.210 19.998 25.006 29.996 35.006 39.997 798.01 802.13 806.18 810.22 813.79 817.36 820.76 824.01 827.09 298 298 298 298 298 298 298 298 298 .15 .15 .15 .15 .15 .15 .15 .15 .15 1115.8 1050.5 990.6 935.0 888.8 845.3 806.2 770.8 738.9 1089.6 1054.3 1021.5 990.5 964.4 939.5 916.8 896.1 877.1 388.5 384.4 380.8 377.4 374.9 372.4 370.6 368.9 367.5 425.9 418.5 412.8 407.4 402.9 398.9 395.4 392.2 389.9 486.7 475.9 466.5 458.1 451.8 446.1 441.4 437.2 433.8 569.4 552.3 538.4 525.4 517.0 509.1 502.5 497.1 492.7 681.1 656.2 632.2 612.8 598.7 585.7 577.6 570.0 564.1 397.6 393.3 389.5 386.1 383.4 380.9 378.8 376.9 375.3 0.324 5.004 10.006 15.745 19.998 25.006 29.992 35.004 39.998 0.326 5.006 9.997 15.006 19.998 25.008 29.998 35.004 39.998 0.385 5.009 10.213 15.008 19.998 25.318 29.994 35.006 39.994 0.748 5.004 10.009 15.621 19.998 25.026 29.996 35.007 39.992 775.93 780.50 785.22 790.30 793.91 797.95 801.77 805.39 808.79 752.51 757.87 763.39 768.48 773.36 777.91 782.19 786.26 790.09 727.08 733.49 740.23 745.94 751.60 757.10 761.66 766.25 770.59 699.11 706.37 714.29 722.22 728.01 734.12 739.79 745.05 749.99 323.15 323.15 323.15 323.15 323.15 323.15 323.15 323.15 323.15 348.15 348.15 348.15 348.15 348.15 348.15 348.15 348.15 348.15 373.15 373.15 373.15 373.15 373.15 373.15 373.15 373.15 373.15 398.15 398.15 398.15 398.15 398.15 398.15 398.15 398.15 398.15 1338.9 1251.6 1168.6 1086.4 1032.1 975.2 924.7 879.6 839.6 1637.4 1511.7 1394.0 1295.1 1207.9 1132.9 1067.2 1008.8 957.2 2057.1 1866.4 1688.3 1553.1 1431.5 1323.9 1241.9 1165.2 1097.7 2675.9 2390.4 2119.5 1884.1 1731.6 1586.1 1463.7 1359.8 1270.0 1172.7 1128.8 1086.4 1043.8 1015.3 984.9 957.6 933.0 910.8 1298.5 1239.7 1183.8 1136.0 1093.3 1056.0 1022.9 993.1 966.4 1480.9 1397.5 1318.1 1256.8 1200.8 1150.5 1111.6 1074.8 1041.9 1751.0 1632.7 1518.3 1416.9 1350.0 1285.2 1229.9 1182.3 1140.5 m = 0.60237 mol • kg -1 0.362 5.006 10.008 14.995 19.998 25.006 29.994 35.004 39.998 0.415 5.009 10.621 15.048 19.998 25.005 29.997 35.006 39.998 0.514 813.11 817.04 820.95 824.76 828.39 831.79 835.10 838.27 841.29 790.94 795.34 800.49 804.32 808.37 812.27 815.94 819.40 822.62 768.00 298.15 298.15 298.15 298.15 298.15 298.15 298.15 298.15 298.15 323.15 323.15 323.15 323.15 323.15 323.15 323.15 323.15 323.15 348.15 1055.1 996.2 941.4 891.5 846.8 807.3 770.9 737.8 707.8 1260.0 1181.3 1096.5 1038.0 980.2 928.0 881.9 840.9 804.7 1521.4 1078.2 1045.2 1014.0 985.2 959.0 935.5 913.5 893.3 874.7 1143.8 1104.3 1061.0 1030.7 1000.3 972.6 947.7 925.2 905.2 1235.1 427.7 421.5 415.7 410.1 406.5 402.8 399.7 397.1 394.8 476.4 467.0 458.5 451.5 445.5 440.5 436.4 432.9 429.9 547.2 532.3 518.7 508.8 500.1 492.8 487.5 482.8 478.9 652.5 628.6 606.3 587.4 575.6 564.8 556.2 549.3 543.7 404.0 400.2 396.7 393.6 390.9 388.5 386.5 384.7 383.1 424.2 419.4 414.4 411.2 408.1 405.5 403.3 401.5 400.0 454.6 p/MPa P /kg m-3 T/K fcp • 106 «p • 106/K-1 /IMPa-1 K-1 (Cp-Cv) /Jkg-1K-1 p/MPa P /kgm-3 T/K kp^ 106 /IMPa-1 ap • 106/K-1 p K-1 (Cp-Cv) /Jkg-1K-1 5.002 773.02 348.15 1412.3 1184.6 447.5 19.998 782.75 373 15 1254.9 1083.8 446.2 10.006 778.36 348.15 1306.3 1134.8 440.9 25.003 787.47 373 15 1173.6 1045.5 441.3 15.024 783.32 348.15 1216.2 1091.8 435.6 29.941 791.86 373 15 1103.5 1012.0 437.4 20.032 788.04 348.15 1137.2 1053.6 431.2 35.006 796.00 373 15 1041.8 982.3 434.2 25.034 792.36 348.15 1070.2 1020.7 427.8 39.998 799.93 373 15 986.9 955.6 431.6 29.998 796.46 348.15 1010.8 991.2 424.9 0.741 734.42 398 15 2226.0 1538.5 576.5 35.005 800.32 348.15 958.3 964.8 422.6 5.003 741.10 398 15 2008.6 1440.8 555.2 39.986 803.93 348.15 912.1 941.3 420.7 10.214 748.59 398 15 1794.2 1342.8 534.5 0.324 743.06 373.15 1896.3 1386.6 509.2 15.026 754.86 398 15 1635.3 1269.0 519.4 5.102 749.52 373.15 1720.1 1309.3 496.2 19.996 760.76 398 15 1500.7 1205.6 506.9 10.068 755.71 373.15 1569.3 1242.0 485.4 25.004 766.31 398 15 1385.8 1150.8 496.5 15.027 761.42 373.15 1443.9 1185.2 476.8 29.996 771.35 398 15 1290.1 1104.6 488.1 20.129 766.91 373.15 1334.4 1134.9 469.6 35.002 776.12 398 15 1206.6 1063.7 481.1 25.046 771.77 373.15 1245.5 1093.4 464.1 39.992 780.47 398 15 1135.8 1028.8 475.4 29.998 776.33 373.15 1168.3 1057.0 459.6 m = ; 1.83765 mol^ : kg-1 35.106 780.70 373.15 1099.5 1024.1 455.9 0.214 862.26 298 15 910.6 983.6 367.4 39.997 784.73 373.15 1040.2 995.5 453.0 5.002 866.01 298 15 862.0 957.8 366.4 0.624 716.11 398.15 2442.2 1634.3 608.1 10.064 869.65 298 15 817.7 933.9 365.7 4.997 723.29 398.15 2185.5 1524.8 585.6 15.023 873.15 298 15 777.6 911.8 365.1 10.008 730.89 398.15 1948.2 1421.8 565.2 20.004 876.42 298 15 742.3 891.9 364.6 15.406 738.28 398.15 1746.2 1332.4 548.2 25.006 879.59 298 15 709.8 873.3 364.2 20.007 744.09 398.15 1604.6 1268.7 536.7 30.002 882.65 298 15 680.0 856.0 364.0 25.106 749.95 398.15 1475.2 1209.6 526.6 35.014 885.64 298 15 652.3 839.6 363.8 29.996 755.18 398.15 1369.8 1160.8 518.6 39.998 888.41 298 15 627.8 824.9 363.7 35.008 760.14 398.15 1277.9 1117.7 512.1 0.214 840.77 323 15 1061.2 1030.4 384.6 39.994 764.73 398.15 1199.1 1080.4 506.8 5.007 844.96 323 15 998.4 1000.3 383.2 m = 0.97956 mol- kg 1 10.068 849.17 323 15 939.8 971.6 382.2 0.231 829.01 298.15 1002.9 1051.8 396.7 15.924 853.78 323 15 880.2 941.9 381.5 5.512 833.15 298.15 944.0 1018.9 393.6 19.996 856.81 323 15 843.4 923.3 381.2 10.132 836.69 298.15 896.9 992.2 391.1 25.007 860.35 323 15 802.7 902.4 381.1 14.905 840.24 298.15 852.4 966.5 388.8 29.962 863.64 323 15 766.9 883.8 381.1 19.821 843.65 298.15 812.1 942.8 386.8 35.007 866.77 323 15 734.6 866.8 381.3 25.133 847.19 298.15 772.6 919.3 384.9 39.996 869.86 323 15 704.2 850.6 381.7 30.621 850.70 298.15 735.6 896.8 383.2 0.524 818.88 348 15 1249.9 1086.3 401.4 35.004 853.42 298.15 708.4 880.1 382.0 5.008 823.67 348 15 1165.3 1046.8 397.4 39.987 856.31 298.15 680.8 862.8 380.8 10.009 828.39 348 15 1088.5 1010.4 394.2 0.301 806.79 323.15 1190.9 1108.5 413.3 15.712 833.51 348 15 1011.8 973.5 391.2 5.061 811.29 323.15 1115.0 1071.2 409.9 20.005 837.03 348 15 962.8 949.6 389.6 10.245 815.95 323.15 1042.5 1035.0 406.9 25.601 841.38 348 15 906.0 921.6 388.0 15.329 820.13 323.15 982.1 1004.3 404.6 29.993 844.60 348 15 866.4 901.9 387.0 20.214 824.02 323.15 929.6 977.2 402.9 35.004 848.15 348 15 825.1 881.1 386.2 25.024 827.63 323.15 883.8 953.3 401.5 39.996 851.44 348 15 788.9 862.7 385.7 30.005 831.15 323.15 841.7 931.0 400.4 0.921 797.03 373 15 1492.2 1177.3 434.9 35.214 834.59 323.15 802.8 910.1 399.5 5.007 801.74 373 15 1391.5 1129.5 426.7 39.998 837.64 323.15 770.0 892.3 398.9 10.006 807.19 373 15 1284.8 1078.3 418.4 0.301 783.98 348.15 1427.2 1181.9 434.7 15.621 812.90 373 15 1183.3 1028.9 410.7 5.023 789.22 348.15 1320.9 1133.3 428.9 19.997 817.05 373 15 1115.4 995.5 405.7 10.004 794.29 348.15 1226.9 1089.6 424.1 25.412 821.76 373 15 1043.7 959.8 400.8 15.302 799.38 348.15 1140.4 1048.8 420.1 29.998 825.56 373 15 989.8 932.7 397.2 19.994 803.61 348.15 1074.0 1017.1 417.3 35.006 829.31 373 15 939.8 907.3 394.1 25.323 808.01 348.15 1009.6 985.9 414.8 39.997 832.98 373 15 893.6 883.6 391.4 29.954 811.67 348.15 959.5 961.4 413.2 1.024 772.35 398 15 1891.3 1364.8 507.7 35.064 815.51 348.15 910.0 936.9 411.8 5.006 777.99 398 15 1736.4 1289.0 489.7 39.995 818.94 348.15 868.3 916.0 410.8 10.331 785.04 398 15 1563.4 1203.2 469.7 0.365 760.19 373.15 1748.3 1308.3 480.6 15.006 790.63 398 15 1440.5 1141.5 455.5 5.004 766.10 373.15 1599.6 1241.9 469.6 19.985 796.07 398 15 1331.6 1086.1 443.1 10.326 772.49 373.15 1455.5 1176.6 459.4 25.004 801.25 398 15 1236.8 1037.4 432.4 15.032 777.69 373.15 1349.4 1127.8 452.3 29.996 805.94 398 15 1157.6 996.2 423.5 p/MPa P T/K kp^ 106 a : • 106/K-1 (Cp-Cv) /kg • m-3 /]MPa-1 p K-1 /Jkg-1K-1 35.004 810.31 398.15 1089.1 960.2 416.0 39.998 814.43 398.15 1028.7 928.3 409.5 m = 2.62045 mol • kg- 1 0.542 890.14 298.15 823.8 913.6 339.4 4.963 893.17 298.15 789.6 896.2 339.5 9.891 896.55 298.15 753.4 877.6 339.9 15.104 899.98 298.15 718.7 859.6 340.6 19.839 902.87 298.15 690.8 845.1 341.4 25.099 906.26 298.15 659.8 828.9 342.5 29.769 908.94 298.15 636.4 816.5 343.6 35.058 912.04 298.15 610.6 802.8 345.1 39.930 914.74 298.15 589.1 791.3 346.5 1.071 869.76 323.15 949.1 960.9 361.4 4.856 872.84 323.15 908.5 939.0 359.3 9.907 876.78 323.15 859.6 912.4 357.0 15.102 880.58 323.15 815.3 888.1 355.0 19.702 883.86 323.15 779.2 868.1 353.6 25.163 887.55 323.15 740.8 846.6 352.3 29.746 890.53 323.15 711.4 830.0 351.4 35.061 893.73 323.15 681.3 812.8 350.6 39.882 896.67 323.15 655.0 797.7 350.1 1 .054 848.34 348.15 1126.8 1024.6 382.4 4.986 852.06 348.15 1068.4 993.6 377.5 10.025 856.65 348.15 1001.3 957.4 372.0 15.625 861.30 348.15 938.3 922.9 366.9 20.036 864.85 348.15 893.3 897.9 363.3 25.415 868.92 348.15 844.8 870.7 359.5 29.985 872.21 348.15 807.9 849.7 356.7 35.026 875.68 348.15 770.9 828.4 353.9 39.986 878.86 348.15 738.7 809.7 351.5 1.816 827.11 373.15 1346.4 1093.8 400.9 5.020 830.51 373.15 1282.5 1061.5 394.8 9.791 835.54 373.15 1194.4 1016.4 386.3 15.113 840.66 373.15 1112.0 973.4 378.2 19.593 844.80 373.15 1050.3 940.5 372.0 25.103 849.57 373.15 984.0 904.8 365.4 29.987 853.59 373.15 931.9 876.2 360.1 35.029 857.43 373.15 885.2 850.1 355.3 39.927 861.06 373.15 843.4 826.4 350.9 1.945 803.94 398.15 1661.0 1189.2 421.6 4.989 807.76 398.15 1572.9 1148.2 413.2 10.021 814.03 398.15 1440.1 1085.3 400.1 15.024 819.75 398.15 1330.4 1032.1 388.9 20.036 825.07 398.15 1237.0 985.9 379.1 25.412 830.44 398.15 1150.5 942.0 369.8 29.984 834.81 398.15 1085.3 908.3 362.6 35.024 839.23 398.15 1023.7 875.9 355.5 39.987 843.41 398.15 969.1 846.6 349.1 m = 3.27773 mol^ kg- 1 0.788 911.05 298.15 772.5 843.9 301.7 4.975 913.85 298.15 746.3 833.1 303.4 9.774 916.98 298.15 718.2 822.0 305.9 15.102 920.38 298.15 689.2 811.0 309.1 19.854 923.33 298.15 665.1 802.3 312.5 25.104 926.52 298.15 640.2 793.8 316.7 29.832 929.31 298.15 619.3 787.0 320.9 35.093 932.34 298.15 597.5 780.4 326.0 39.824 934.99 298.15 579.2 775.2 330.9 p/MPa p /kg^ m-3 T/K kT^ 106 /]MPa-1 ap • 106/K-1 p K-1 (Cp-Cv) /Jkg-1K-1 0.850 891.23 323.15 883.5 916.1 344.4 5.021 894.40 323.15 846.9 892.7 340.0 9.698 897.85 323.15 809.1 868.5 335.5 15.104 901.68 323.15 769.4 843.2 331.2 19.771 904.86 323.15 738.3 823.3 327.9 24.899 908.23 323.15 706.8 803.4 324.9 29.763 911.28 323.15 679.7 786.2 322.5 35.007 914.43 323.15 653.0 769.3 320.3 39.933 917.36 323.15 629.2 754.3 318.5 1.200 870.24 348.15 1068.0 1003.9 377.5 4.955 873.68 348.15 1019.2 971.8 369.2 9.872 878.09 348.15 960.5 932.5 359.0 14.930 882.24 348.15 908.9 897.5 349.7 19.941 886.13 348.15 863.4 866.2 341.4 24.957 889.88 348.15 822.1 837.3 333.6 29.862 893.39 348.15 785.5 811.4 326.6 35.103 897.01 348.15 749.8 785.7 319.5 39.839 900.14 348.15 720.4 764.3 313.6 1.356 848.46 373.15 1306.7 1068.4 384.2 5.024 852.32 373.15 1241.9 1032.1 375.5 9.873 857.18 373.15 1165.8 988.1 364.6 14.922 862.01 373.15 1095.6 946.2 353.7 19.904 866.53 373.15 1034.5 908.4 343.5 25.102 871.05 373.15 977.3 871.9 333.2 29.841 875.06 373.15 929.7 840.6 324.1 35.104 879.19 373.15 883.4 809.2 314.6 40.019 882.94 373.15 843.8 781.5 305.9 1.254 825.83 398.15 1569.0 1078.9 357.7 4.914 830.12 398.15 1488.8 1046.8 353.1 9.756 835.75 398.15 1391.1 1005.5 346.3 14.924 841.55 398.15 1298.5 963.8 338.5 19.922 846.85 398.15 1220.5 926.4 330.6 24.985 851.92 398.15 1151.2 891.0 322.3 29.758 856.52 398.15 1092.4 859.3 314.2 35.103 861.57 398.15 1032.0 824.8 304.6 39.960 865.87 398.15 983.8 795.7 295.9 Using a program for standard thermodynamic analysis to describe the (p,p,T) properties of ethanol solutions of LiNO3, the equation of state from Ref.19 was used: (5) where: the coefficients of eqn. (5) A, B and C are functions of temperature and molalities m. 1=1 y=0 5 = (=0 ./=0 (6) (7) Table 2: Values of the coefficients a bj, and c-j in Eqs. 5-8. aii bij cii a10 = -3.21735 b„„ = 369.943 000 = -5740.52 a11 = -2.57045 b01 = -4315.07 c01 = 17747.3 a1112 = 4.47684 a13 = -1.33828 b0021 = 598.959 b0032 = 443.751 c02 = -8187.34 c0032 = 809.445 a^d = 0.0141746 a^j = 0.0205901 b1003 = -3.37282 b10 = 35.6259 c1003 = 58.8717 c1110 = -157.626 ci^^ = -0.0335068 b11 = -9.35584 c1121 = 75.4358 a^j = 0.983941 • W-2 b13 = -1.88406 c1132 = -8.79996 a3J = -0.232211 • W-4 a31 = -0.546586 • W-4 b^o = 0.0190504 b31 = -0.101348 c1230 = -0.181846 c2210 = 0.458253 a32 = 0.826651 • W-4 b33 = 0.0388078 c2221 = -0.22754 aJJ = -0.237136 • W-4 b33 = -0.129776 • 10-4 c2223 = 0.0301332 a4J = 0.156498 • W-7 b^0 = -0.18162 • 10-4 c3230 = 0.187835 • 10-3 a41 = 0.471533 • W-7 b31 = 0.921974 • 10-4 c3301 = -0.438936 • 10-3 a42 = -0.664841 • W-7 b33 = -0.476565 • 10-4 033 = 0.225584 • 10-3 a43 = 0.185212 • W-7 b^3 = 0.515993 • 10-5 c3323 = -0.332753 • 10-4 The aij, bij and cij are the coefficients of the polynomials and they are given in Table 2. Eqns. 5-8 describe the experimental, interpolated and extrapolated results between molalities m = (0 to 3.27773) mol kg1 with ±0.011 % average percent, 0.125 kg m-3 standard and 0.084 kg m-3 absolute deviations. During the molality m dependence analysis of experimental results, the (p,p, T) properties of ethanol from Refs.13-15 were used. The short empiric equation (9) can be used for the technical calculation of the (p,p,T) properties of ethanol solutions of LiNO3: p = {d J + d^m^T + d^T^ + d^mT^ + + + d{e,T + e^mT + eJ^ + (9) Equation (9) describe the experimental, interpolated and extrapolated results between molalities m = (0 to 3.27773) mol kg-1 with ±0.031 % average percent, 0.307 kg m-3 standard and 0.247 kg m-3 absolute deviations. The coefficients of the equation (9) d1, d2, d3, d4, d5, d6, e1, e2, e3, e4 and f are given in Table 3. Figures 2-5 show the plots of experimental density pexp of the (LiNOj + C2H5OH) versus pressure p at m = 0.^0237 mol kg-1, at T ^ 298.15 K and in various molali- ties, versus molality m at T = 298.15 K together with literature values and interpolated results at p = 10 MPa, deviations of experimental density pexp. from calculated density Pcai. versus pressure. Figure 2. Plot of pressure p of ethanol solutions of LiNOj vs experimental density p at m = 0.60237 mol kg-1: ♦, 298.15 K; ■, 323.15 K; A, 348.15 K; O, 373.15 K; □, 398.15 K; _calculated by eqs. 5-8. Table 3: Values of the coefficients di, ei and f in Eqn. 9 di ei f d1 = -3.2550435 e1 = 3.6667154436 f= 0.5329543 d12 = 0.10916524 e12 = -1.3891687 d23 = 0.0110161347 e3 = -0.4077081 • W-5 d4 = -0.1795944123 • W-3 e4 = 0.24787472 • W-5 d5 = -0.18886651 • W-3 d6 = -0.90607211 • 10-5 Figure 3. Plot of pressure p of ethanol solutions of LiNOj vs experimental density p at T = 298.15 K: □, m = 0 (from Refs. [13-15]); ♦ , m = 0.12071 mol kg-1; ■, m = 0.26234 mol kg-1; A, m = 0.60237 mol kg-1; •, m = 0.97956 mol kg-1; O, m = 1.83765 mol kg-1; □, m = 2.62045 mol kg-1; A, m = 3.27773 mol kg-1; ___calcu-lated by eqs. 5-8. Figure 4. Plot of experimental density p of ethanol solutions of LiNO3 versus molality m at T = 298.15 K: ♦, p = 0.101 MPa; ■, p = 5 MPa; A, p = 10 MPa; •, p = 15 MPa; O, p = 20 MPa; □, p = 25 MPa; A, p = 30 MPa; O, p = 35 MPa; *, p = 40 MPa; + , ref. [8]; x, interpolated values at p = 10 MPa by eqs. 5-8;_calculated values by eqs. 5-8. The graphical analysis of the temperature dependence of the coefficients of eqn. (5) revealed that, at T Tc, A — 0. Such behavior of A = f(T) may be explained by the fact that, according to Putilov,20 the first term on the right-hand side of eqn. (5), Ap2, is the attractive force (attractor pressure), and the second and third terms are the repulsive Figure 5. Plot of deviations of experimental density pexp. from the calculated by eqs. 5-8 density pcal vs pressure p at T = (298.15 to 398.15) K and all experimental molalities. force (repulsive pressure). As the temperature rises, the spacing between molecules increases, which contributes to a decrease in the attractive force. As the attractive force tends to zero (A — 0) and molecules under the effect of the repulsive force are capable of displacement. The extent of their displacement is defined only by the density of the substance, i.e., external pressure. As a result, the aggregate state changes. Note that the form of eqn. (5) was derived from Putilov's molecular-kinetic theory. The isothermal compressibility k/MPa1 is a measure of the relative volume change of a fluid as a response to a pressure change at the constant temperature: k,={]/p)(dp/dprr' (10) It can be calculated from the experimental (p,p,T) results of ethanol solutions of LiNO3 using eqns. (5-8) as follow: kr= 1 /(lAp' + EBp' + ), (11) The calculated values of the isothermal compressibilities k 106/MPa-1 are given in Table 1 and for molality m = 0.60237 mol kg-1 shown in Figure 6. The other thermal coefficient can be calculated from eqns. (5-8) is a isobaric thermal expansibility ap/K-1, which is the tendency of matter to change in volume in response to a change in temperature. When a sample is heated, its constituent particles move around more vigorously and by doing so generally maintain a greater average separation. Samples that contract with an increase in temperature are very uncommon; this effect is limited in size, and only occurs within limited temperature ranges. Figure 6. Plot of isothermal compressibility k 106/MPa 1 of ethanol solutions of LiNOj versus pressure p at m = 0.60237 mol kg-1 (♦, 298.15 K; ■, 323.15 K; A, 348.15 K; •, 373.15 K; □, 398.15 K). Figure 7. Plot of isobaric thermal expansibilities ap 106/K-1 of ethanol solutions of LiNO1 vs pressure p at m = 2.62045 mol kg-1 (♦, 298.15 K; ■, 323.15 K; A, 348.15 K; •, 373.15 K; □, 398.15 K). The degree of expansion divided by the change in temperature is called the sample's coefficient of thermal expansion and generally varies with temperature. a^^{\lp){dpldT)idpldpy;, (12) Isobaric thermal expansibility ap/K-1 calculated from the experimental (p, p, T) results of ethanol solutions of LiNO1 using the Eqns. (5-8): a = {A'+B'p"- + C'/3'°)/(2/1 + + 120/?'"), (13) where: A', B\ and C"are the derivatives of the A, B, and C: The calculated values of the isobaric thermal expansibility ap x 106/K1 are given in Table 1 and for molality m = 2.62045 mol kg-1 shown in Figure 7. The next important parameter for the investigation is difference in specific heat capacities. Measuring the heat capacity at constant volume can be prohibitively difficult for liquids. That is, small temperature changes typically require large pressures to maintain a liquid at constant volume implying the containing vessel must be nearly rigid or at least very strong. Instead it is easier to measure the heat capacity at constant pressure and solving for the specific heat capacity at constant pressure using mathematical relationships derived from basic thermodynamic laws: Figure 8. Plot of difference in specific isobaric and isochoric heat capacities (cp-cv)/(Jkg-1K-1) of ethanol solutions of LiNO1 at m = 1.83765 mol kg-1 versus pressure p (♦, 278.05 K; ■, 288.15 K; A, 298.19 K; •, 313.18 K; O, 328.15 K; □, 343.18 K; A, 358.15 K; O, 373.15 K). (15) where: cp and cv are the specific heat capacities at constant pressure and volume, respectively. Using the eqns. (5-8), we can find the following relationship: The values of calculated difference in specific heat capacities are given in Table 1 and for molality m = 1.83765 mol kg-1 shown in Figure 8. The apparent molar volume is the volume that should be attributed to the LiNO3 in the (LiNO3 + C2H5OH) solution if one assumes that the ethanol contributes the same volume it has in its pure state. The apparent molar volume, V^, is given by Table 4: Apparent Molar Volumes V^/(cm3mol ') of the LiNOj i OT/molkg 1 p/MPa 0.12071 0.26234 0.60237 0.97956 1.83765 2.62045 3.27773 T = 298.15 K 0.1 10.227 10.991 13.288 15.271 18.302 20.576 22.413 5 10.325 11.765 14.202 16.096 19.012 21.232 23.004 10 10.934 12.630 15.063 16.894 19.677 21.842 23.548 15 11.642 13.522 15.917 17.634 20.293 22.402 24.043 20 12.579 14.501 16.744 18.349 20.882 22.924 24.491 25 13.740 15.451 17.546 19.043 21.429 23.407 24.905 30 14.996 16.431 18.300 19.685 21.944 23.855 25.280 35 16.472 17.501 19.083 20.311 22.445 24.286 25.632 40 18.041 18.604 19.823 20.936 22.918 24.689 25.958 T = 323.15 K 0.1 11.499 11.402 12.712 14.106 16.612 18.707 20.441 5 11.793 12.405 13.881 15.244 17.607 19.614 21.271 10 12.475 13.430 15.005 16.291 18.525 20.448 22.027 15 13.390 14.532 16.084 17.263 19.364 21.199 22.704 20 14.400 15.654 17.069 18.167 20.122 21.882 23.316 25 15.907 16.860 18.047 19.040 20.847 22.520 23.885 30 17.500 18.028 18.993 19.852 21.507 23.103 24.401 35 19.052 19.222 19.885 20.609 22.130 23.646 24.873 40 20.955 20.445 20.778 21.360 22.719 24.157 25.320 T = 348.15 K 0.1 7.309 7.123 8.513 10.084 13.118 15.657 17.808 5 7.928 8.753 10.337 11.833 14.599 16.931 18.910 10 8.935 10.303 12.022 13.402 15.928 18.071 19.891 15 10.306 11.839 13.516 14.814 17.107 19.074 20.751 20 11.896 13.438 14.974 16.116 18.177 19.988 21.523 25 13.844 14.974 16.293 17.300 19.153 20.807 22.221 30 15.863 16.582 17.563 18.408 20.042 21.559 22.850 35 17.960 18.139 18.765 19.430 20.866 22.251 23.425 40 20.269 19.713 19.903 20.419 21.630 22.891 23.957 T = 373.15 K 0.24 -4.110 -3.609 -0.756 2.119 7.061 10.753 13.838 5 -2.621 -0.884 2.223 4.852 9.259 12.570 15.343 10 -0.761 1.774 4.881 7.278 11.227 14.190 16.673 15 1.733 4.349 7.304 9.448 12.941 15.601 17.818 20 4.392 6.792 9.430 11.349 14.451 16.833 18.807 25 7.227 9.191 11.401 13.060 15.800 17.927 19.679 30 10.245 11.493 13.234 14.629 17.021 18.912 20.452 35 13.301 13.777 14.940 16.069 18.131 19.801 21.149 40 16.690 15.986 16.559 17.424 19.157 20.621 21.783 T = 398.15 K 0.52 -25.038 -22.496 -15.886 -10.232 -2.080 2.961 7.035 5 -21.693 -17.582 -11.086 -6.032 1.165 5.677 9.353 10 -17.493 -12.734 -6.590 -2.142 4.153 8.160 11.450 15 -13.135 -8.381 -2.813 1.100 6.642 10.225 13.158 20 -8.737 -4.442 0.483 3.900 8.773 11.976 14.584 25 -4.102 -0.645 3.448 6.379 10.644 13.498 15.797 30 0.627 2.828 6.084 8.588 12.304 14.836 16.846 35 5.316 6.151 8.512 10.587 13.784 16.020 17.755 40 9.834 9.274 10.751 12.394 15.125 17.087 18.559 (17) where: n1 and n2 are the number of moles of pure ethanol and lìno3, respectively; V0 is the molar volume of pure ethanol. Using the density values of (LiNO3 + C2H5OH) and pure ethanol at the high temperatures and pressures, apparent molar volumes V^ of LiNO3 in ethanol were defined by equation (18) and are listed in Table 4: (18) Figure 9. Plot of apparent molar volumes V^ of LiNOj in ethanol vs m at T = 298.15 K: p = 0.1 MPa; p = 5 MPa; A, p = 10 MPa; •, p = 15 MPa, O, p = 20 MPa; □, p = 25 MPa; A, p = 30 MPa; O, p = 35 MPa; *, p = 40 MPa; x, p = 0.1 MPa7; + , p = 0.1 MPa8. Figure 10. Plot of apparent molar volumes V^ of LiNO3 in ethanol vs temperature T at m = 0.97956 mol kg-1: ♦, p = (0.2^3, and 0.52) MPa; ■, p = 5 MPa; A, p = 10 MPa; •, p = 15 MPa, O, p = 20 MPa; □, p = 25 MPa; A, p = 30 MPa; O, p = 35 MPa; *, p = 40 MPa. where: p^ and p^ are densities of ethanol and the solutions, recpectively, m is the molality and M is the molar mass of the dissolved LiNO3. The calculations were carried out using the density results of ethanol and (LiNO3 + C2H5OH) at the same temperatures and pressures. The maximum relative uncertainty21 SV^ in the V^ determination by the investigated concentrations are: SV^ = (2.27) %. Figures 9 and 10 shows the plot of the apparent molar volumes V^ of LiNO3 in ethanol versus m at T = 298.15 K, in various pressures together with literature results and apparent molar volumes V^ of LiNO3 in ethanol versus temperature T at m = 0.97956 mol kg1. The calculated apparent molar volume V^ results were compared with 23 available literature values of [8] at T= 298.15 K and AV^ = 0.383 cm3 mol1 average deviation was found. The apparent molar volume results of Ref.8 at T = 298.15 K were added to Figure 9 for the visual comparison. The partial molar volumes Vi, i = 1,2, are calculated from the slope of tangent (dVm/dx)pT: (19) where: w is mass fraction of LiNO3 and M is the relative molar masses of components of solution. The calculated values of the partial molar volumes of ethanol and LiNO3 are presented in Table 5. Figures 11 and 12 shows the mo-lality dependences of the partial molar volumes Vi of ethanol and LiNO3 at T = 323.15 K and various pressures. Figure 11. Partial molar volumes V- (i = 1,2) of ethanol vs molality m at T = 323.15 K and various pressures calculated by Eqs. 19: ♦, p = 0.101 MPa; ■,p = 5 MPa; A, p = 10 MPa; •, p = 15 MPa, O, p = 20 MPa; □, p = 25 MPa; A, p = 30 MPa; O, p = 35 MPa; *, p = 40 MPa. Table 5: Partial molar volumes V- (i = 1,2) for ethanol (1) and LiNO1 (2) derived from the density measurements. OT/mol kg 1 p/MPa 0.00000 0.12071 0.26234 0.60237 0.97956 1.83765 2.62045 3.27773 V(C2H5OH)/cm3 mol1 T = 298.15 K 0.1 58.66 58.64 58.62 58.57 58.48 58.14 57.75 57.44 5 58.33 58.31 58.30 58.25 58.16 57.83 57.46 57.14 10 58.02 58.00 57.99 57.94 57.86 57.55 57.18 56.86 15 57.72 57.71 57.70 57.66 57.58 57.27 56.92 56.60 20 57.45 57.44 57.43 57.39 57.31 57.02 56.68 56.36 25 57.19 57.18 57.17 57.13 57.06 56.78 56.45 56.14 30 56.94 56.93 56.92 56.89 56.82 56.55 56.23 55.93 35 56.71 56.70 56.69 56.66 56.59 56.33 56.03 55.73 40 56.48 56.48 56.47 56.44 56.37 56.12 55.83 55.55 T = 323.15 K 0.1 60.34 60.33 60.32 60.28 60.20 59.88 59.49 59.12 5 59.94 59.93 59.92 59.88 59.81 59.51 59.13 58.76 10 59.56 59.55 59.54 59.51 59.44 59.16 58.79 58.43 15 59.21 59.20 59.19 59.16 59.10 58.83 58.48 58.12 20 58.88 58.87 58.86 58.84 58.78 58.53 58.19 57.83 25 58.57 58.56 58.56 58.53 58.48 58.24 57.91 57.56 30 58.28 58.28 58.27 58.25 58.19 57.97 57.65 57.31 35 58.01 58.00 58.00 57.97 57.93 57.71 57.41 57.08 40 57.75 57.75 57.74 57.72 57.67 57.46 57.17 56.85 T = 348.15 K 0.1 62.29 62.28 62.27 62.22 62.12 61.74 61.24 60.76 5 61.78 61.77 61.76 61.72 61.63 61.29 60.83 60.37 10 61.31 61.30 61.29 61.25 61.18 60.87 60.44 60.00 15 60.87 60.87 60.86 60.83 60.76 60.48 60.08 59.67 20 60.47 60.47 60.46 60.43 60.37 60.11 59.75 59.36 25 60.10 60.10 60.09 60.07 60.01 59.78 59.44 59.07 30 59.76 59.76 59.75 59.73 59.68 59.46 59.14 58.80 35 59.44 59.43 59.43 59.41 59.36 59.16 58.87 58.56 40 59.13 59.13 59.12 59.10 59.06 58.88 58.61 58.32 T = 373.15 K 0.24 64.61 64.59 64.57 64.48 64.33 63.77 63.10 62.54 5 63.96 63.94 63.92 63.85 63.72 63.22 62.62 62.09 10 63.35 63.34 63.32 63.26 63.14 62.71 62.16 61.67 15 62.80 62.79 62.78 62.72 62.62 62.24 61.75 61.30 20 62.31 62.30 62.29 62.24 62.15 61.80 61.37 60.96 25 61.85 61.85 61.83 61.79 61.71 61.40 61.01 60.65 30 61.44 61.43 61.42 61.38 61.31 61.03 60.69 60.37 35 61.05 61.04 61.03 61.00 60.93 60.69 60.38 60.10 40 60.69 60.68 60.67 60.64 60.58 60.36 60.10 59.85 T = 398.15 K 0.52 67.46 67.41 67.36 67.21 66.96 66.17 65.43 65.05 5 66.61 66.58 66.53 66.40 66.19 65.50 64.82 64.41 10 65.80 65.77 65.73 65.62 65.44 64.84 64.21 63.81 15 65.08 65.06 65.03 64.93 64.78 64.24 63.68 63.29 20 64.45 64.43 64.40 64.32 64.18 63.71 63.20 62.84 25 63.88 63.86 63.84 63.77 63.64 63.22 62.77 62.44 30 63.36 63.35 63.33 63.26 63.15 62.77 62.38 62.09 35 62.89 62.88 62.86 62.80 62.70 62.36 62.02 61.78 40 62.45 62.44 62.42 62.37 62.28 61.98 61.69 61.49 p/MPa 0.00000 0.12071 0.26234 m/mol kg- 0.60237 0.97956 1.83765 2.62045 3.27773 y(LiNO3)/cm3 mol- T = 298.15 K 0.1 10.73 11.91 13.24 16.20 19.10 24.40 28.03 30.43 5 12.10 13.17 14.39 17.12 19.83 24.87 28.44 30.88 10 13.24 14.24 15.37 17.93 20.49 25.32 28.81 31.24 15 14.29 15.22 16.27 18.67 21.08 25.71 29.13 31.55 20 15.22 16.09 17.09 19.35 21.63 26.07 29.39 31.76 25 16.05 16.87 17.81 19.96 22.13 26.39 29.61 31.93 30 16.82 17.60 18.49 20.52 22.60 26.68 29.80 32.05 35 17.50 18.25 19.10 21.05 23.03 26.95 29.95 32.12 40 18.12 18.84 19.66 21.53 23.44 27.19 30.06 32.14 T = 323.15 K 0.1 10.42 11.31 12.32 14.66 17.08 21.91 25.67 28.46 5 12.14 12.91 13.81 15.90 18.09 22.62 26.27 29.04 10 13.59 14.28 15.09 16.98 19.01 23.27 26.80 29.53 15 14.88 15.50 16.22 17.95 19.82 23.84 27.25 29.94 20 16.03 16.59 17.24 18.81 20.55 24.35 27.65 30.28 25 17.05 17.56 18.15 19.60 21.21 24.81 28.01 30.58 30 17.95 18.41 18.95 20.29 21.79 25.23 28.33 30.85 35 18.74 19.16 19.67 20.93 22.35 25.62 28.59 31.02 40 19.47 19.86 20.33 21.50 22.84 25.97 28.84 31.21 T = 348.15 K 0.1 5.86 6.87 8.04 10.75 13.61 19.52 24.28 27.91 5 8.45 9.30 10.28 12.61 15.10 20.39 24.81 28.25 10 10.65 11.37 12.21 14.23 16.42 21.21 25.31 28.56 15 12.50 13.12 13.85 15.62 17.58 21.92 25.72 28.78 20 14.09 14.63 15.27 16.84 18.59 22.56 26.09 28.95 25 15.47 15.95 16.52 17.91 19.50 23.13 26.40 29.09 30 16.74 17.15 17.65 18.88 20.30 23.63 26.68 29.20 35 17.78 18.15 18.61 19.74 21.04 24.09 26.91 29.24 40 18.74 19.08 19.49 20.51 21.70 24.51 27.13 29.30 T = 373.15 K 0.24 -5.03 -3.21 -1.14 3.50 8.13 16.88 23.14 27.50 5 -.90 .63 2.37 6.32 10.30 17.99 23.68 27.74 10 2.61 3.91 5.39 8.77 12.22 19.00 24.14 27.88 15 5.50 6.62 7.90 10.83 13.85 19.86 24.49 27.90 20 7.92 8.90 10.02 12.60 15.27 20.61 24.76 27.84 25 9.98 10.85 11.84 14.13 16.50 21.27 24.99 27.75 30 11.72 12.51 13.41 15.48 17.60 21.85 25.14 27.56 35 13.29 13.99 14.81 16.66 18.57 22.36 25.27 27.41 40 14.63 15.28 16.03 17.72 19.45 22.82 25.37 27.21 T = 398.15 K 0.52 -23.31 -19.74 -15.80 -7.36 .42 12.93 19.60 22.86 5 -16.46 -13.50 -10.22 -3.15 3.46 14.40 20.62 23.98 10 -10.59 -8.13 -5.39 .57 6.21 15.76 21.48 24.78 15 -6.01 -3.90 -1.55 3.58 8.47 16.90 22.11 25.23 20 -2.23 -.41 1.64 6.10 10.38 17.85 22.55 25.43 25 .86 2.47 4.27 8.23 12.02 18.65 22.85 25.44 30 3.42 4.88 6.51 10.06 13.46 19.36 23.06 25.31 35 5.65 6.97 8.45 11.66 14.71 19.96 23.19 25.10 40 7.55 8.78 10.13 13.07 15.84 20.49 23.26 24.80 32.« 10.0 Ü.O 0.5 1.0 I.s 2.0 w/mol ke"' 2.5 3.0 3.5 Figure 12. Partial molar volumes V- (i = 1,2) of LiNOj versus molality m at T = 323.15 K and various pressures calculated with Eqs. 19: ♦, p = 0.101 MPa; ■, p = 5 MPa; A, p = 10 MPa; •, p = 15 MPa, O, p = 20 MPa; □, p = 25 MPa; A, p = 30 MPa; O, p = 35 MPa; *, p = 40 MPa. 4. Conclusion For the first time, the (p,p,T) properties and apparent molar volumes V^ of LiNO3 in ethanol at T = (298.15 to 398.15) K and pressures up to p = 40 MPa are reported. An empirical correlation for the density of the investigated solutions with composition, pressure and temperature has been derived. The measured volumetric results are useful for the absorption refrigeration machines and heat pumps. 5. Acknowledgments The authors thank Prof. Barthel for his helpful information and discussions during the many years of our research in non-aqueous electrolyte solutions field, and wish him happiness, success and health. Dr R. Jannataliyev thanks the German Academic Exchange Service (DAAD) for the support of his research work at the Rostock University of Germany. 6. References 1. E. C. Ihmels, J. Safarov, E. Hassel, J. Gmehling, J. Chem. Thermodyn. 2005, 37, 1318-1326. 2. H. Israfilov, J. Safarov, A. Shahverdiyev, E. Hassel, J. Chem. Eng. Data 2008, 53, 388-397. 3. E. C. Ihmels, J. Safarov, J. Mol. Liq. 2007, 133, 146-151. 4. J. Barthel, R. Neueder, Chemistry Data Series, Vol.XII: Electrolyte Data Collection, Part 1a: Conductivities, Transference Numbers, Limiting Ionic Conductivities of Ethanol Solutions, DECHEMA, Frankfurt, 248 + XVIII pages, 1993. 5. J. Barthel, R. Neueder, R. Meier, Chemistry Data Series: Vol, XII: Electrolyte Data Collection, Part 3: Viscosities of Nona-queous Electrolyte Solutions and their Solvents I: Alcohols, DECHEMA, Frankfurt, 355 + XVII pages, 1997. 6. J. Barthel, H. Krienke, W. Kunz, Physical Chemistry of Electrolyte Solutions, Modern Aspects, Steinkopff, Darmstadt und Springer, Berlin, 1998, 428 p. 7. P. G. Glugla, J. H. Byon, Ch. A. Eckert, J. Chem. Eng. Data 1982, 27, 393-398. 8. O. V. Eliseeva, V. V. Golubev, E. V. Korotkova, (VINITI), Moscow, Russia, 1999, No 12-V99. 9. Y. Marcus, G. Helter, Chem.Rev., 2004,104, 3406-3452. 10. S. Verevkin, J. Safarov, E. Bich, E. Hassel, A. Heintz, J. Chem. Thermodyn. 2006, 38, 611-616. 11. O. Kratky, H. Leopold, H. H. Stabinger, Z. Angew. Physik 1969, 27, 273-277. 12. W. Wagner, A. Pruß, J. Phys. Chem. Ref. Data 2002,31, 387-535. 13. Y. Takiguchi, M. Uematsu, PVT Measurements of Liquid Etha-nol in the Temperature Range from 310 to 363 K at Pressures up to 200 MPa, J. Chem. Thermodyn., 1995, 16, 205-214. 14. Y. Takiguchi, M. Uematsu, Densities for liquid ethanol in the temperature range from 310 K to 480 K at pres-sures up to 200 MPa, Int. J. Thermophys. 1996, 28, 7-16. 15. H. E. Dilon, S. G. Penoncello, A Fundamental Equation for Calcula-tion of the Thermodynamic Properties of ethanol, Int. J. Thermophys., 2004, 25, 2 321-335. 16. R. Hilbert, pVT-Daten von Wasser und von wässrigen Natriumchlorid-Lösungen bis 873 K, 4000 Bar und 25 Gewichtsprozent NaCl, Hochschul Verlag - Freiburg, 1979. 17. D. G. Archer, J. Phys. Chem. Ref. Data 1992, 21, 793-829. 18. E. C. Ihmels, J. Gmehling, In^. Eng. Chem. Res. 2001, 40, 4470-4477. 19. J. T. Safarov, J. Chem. Thermodyn. 2003, 35, 1929-1937. 20. K. A. Putilov, Thermodynamics of Simplest Liquids, Issle-dovaniya po termodinamike (Thermodynamic Studies), Nauka, Moscow, 1973, 105-120. 21. J. T. Safarov, G. N. Najafov, A. N. Shahverdiyev, E. Hassel, J. Mol. Liq. 2005, 116, 157-163. Povzetek Izmerili smo gostote raztopin LiNOj v etanolu v širokem koncentracijskem m = (0.12071, 0.26234, 0.60237, 0.97956, 1.83765, 2.62045, 3.27773) mol kg-1 in temperaturnem območju T = (298.15 to 398.15) K ter pri različnih vrednostih tlaka p = (0.2 do 40 MPa). Odvisnost gostot raztopin LiNOj v etanolu od tlaka temperature in koncentracije smo podali z empirično zvezo. Iz izmerjenih gostot smo izračunali vrednosti navideznih molskih volumnov V LiNOj ter parcialne molske volumne etanola ter LiNO .