Article pubs.acs.org/jced
Thermal Conductivity of Liquid 2‑Methoxyethyl Acetate, 2‑Ethylhexyl Acetate, and Diethyl Succinate Xiaojing Li, Jiangtao Wu,* and Zhigang Liu MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi’an Jiaotong University, Xi’an Shaanxi 710049, People’s Republic of China ABSTRACT: The thermal conductivity of 2-methoxyethyl acetate, 2-ethylhexyl acetate, and diethyl succinate in liquid phase was reported. The measurements of 2-methoxyethyl acetate and 2-ethylhexyl acetate, covering a temperature range from (233 to 373) K and pressure up to 20 MPa, have been performed by a transient hot-wire technique with two anodized tantalum hot wires. The measurements of diethyl succinate ranged from (263 to 383) K and atmospheric pressure to 20 MPa. The experimental data were represented by polynomial functions of pressure and temperature for the purpose of interpolation. The relative uncertainty of the present thermal conductivity data was estimated to be ± 2.0 % with a coverage factor of k = 2.
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INTRODUCTION The idea of using oxygen to produce a cleaner burning of diesel fuels is half a century old. Since that early work, numberous researchers have reported the addition of a variety of oxygenated compounds to diesel fuel.1 The use of an oxygenating agent with oil to adjust the fuel constitution has been considered as one of possible approaches for improving the emission characteristics of diesel engines. Several major classes of chemical additives have been considered for diesel oxygenates: alcohols, ethers, ketones, glycol ethers, glycol esters, lactones, and carbonates.2 After literature investigation and systematically evaluating some potential oxygenating agents' physical and chemical characteristics, 2-methoxyethyl acetate, 2-ethylhexyl acetate, and diethyl succinate are considered promising candidates. Gong et al.3 showed that 2-methoxyethyl acetate was a good oxygenated additive of diesel for compression−ignition engines. They compared some properties of 2-methoxyethyl acetate, dimethyl carbonate, dimethoxymethane, dimethyl ether, and diesel. As an oxygenated additive, 2-methoxyethyl acetate had the following advantages. 2-Methoxyethyl acetate could avoid the drawback of vapor blocks in the fuel system, because the boiling point of 2-methoxyethyl acetate was the highest and the nearest to that of diesel among these oxygenates. The energy density of 2-methoxyethyl acetate was the highest among the four oxygenates. When the same volumetric fuel blends were delivered, the engine would get more energy when fueled with diesel/2-methoxyethyl acetate blend. 2-Methoxyethyl acetate had a good solubility in diesel. In their experiments, there was no phase separation occurring in diesel/2-methoxyethyl acetate blends. However, dimethyl carbonate had the problem of solubility in diesel and it was easily separated when absorbing water. Dimethoxymethane and dimethyl ether had very low boiling points. When they were mixed with diesel, the blends needed to be pressured; otherwise, © 2012 American Chemical Society
separation or vapor blocks would be inevitable. There were abundant acetic acid and ethylene glycol monomethyl ether sources for synthesis of 2-methoxyethyl acetate. Their experiment showed that the engine emissions of smoke, hydrocarbons (HC), and CO were reduced when 2-methoxyethyl acetate was added in diesel. However, it had a little effect on NOx emissions. In all cases, the potential of designing new fuel mixtures that incorporate oxygenates critically depends upon the knowledge of thermophysical properties of the fluids. The thermal conductivity is an important part of that knowledge base. In this work, we present thermal conductivity measurements on three oxygenated esters in liquid phase.
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EXPERIMENTAL SECTION 2-Methoxyethyl acetate, 2-ethylhexyl acetate, and diethyl succinate were purchased from Aladdin Chemistry Co. Ltd., China. The mass purities of the three oxygenated esters were better than 0.99. No additional purification was performed. The details of these chemicals are given in Table 1. Table 1. Chemical Specifications chemical name
source
2-methoxyethyl acetate 2-ethylhexyl acetate diethyl succinate
Aladdin Chemistry Co. Ltd., China Aladdin Chemistry Co. Ltd., China Aladdin Chemistry Co. Ltd., China
initial mass fraction purity
purification method
> 0.99
none
> 0.99
none
> 0.99
none
Received: July 12, 2012 Accepted: August 22, 2012 Published: September 6, 2012 2863
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Table 2. Thermal Conductivity of Liquid 2-Methoxyethyl Acetatea
a
Tr
p
λ
Tr
p
λ
Tr
p
λ
K
MPa
W·m−1·K−1
K
MPa
W·m−1·K−1
K
MPa
W·m−1·K−1
234.05 234.59 236.02 233.65 234.24 235.02 234.04 234.44 235.71 233.82 234.28 234.64 233.7 234.3 234.42 256.15 256.84 257.47 256.1 256.33 257.52 255.45 256.78 257.54 256.31 256.81 257.25 255.26 255.63 256.4 275.32 275.85 276.29 275.1 275.94 275.76 275.85 276.09 276.84 275.89 275.88 276.87 275.95
0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0
0.1656 0.1655 0.1660 0.1678 0.1681 0.1668 0.1686 0.1685 0.1686 0.1694 0.1692 0.1689 0.1702 0.1705 0.1703 0.1628 0.1630 0.1629 0.1648 0.1643 0.1640 0.1664 0.1661 0.1659 0.1675 0.1674 0.1679 0.1686 0.1682 0.1690 0.1603 0.1609 0.1605 0.1624 0.1623 0.1621 0.1642 0.1636 0.1639 0.1655 0.1658 0.1651 0.1667
276.17 276.74 277.01 295.22 295.37 295.87 296.37 295.73 296.17 296.58 297.1 295.1 295.75 296.74 297.11 295.49 295.37 296.84 296.11 297.03 297.68 314.9 315.4 315.91 315.91 316.31 316.36 315.15 315.78 316.36 315.78 315.83 316.68 315.04 315.86 336.04 336.28 336.70 336.32 336.79 337.22 336.30
20.0 20.0 20.0 0.1 0.1 0.1 0.1 5.0 5.0 5.0 5.0 10.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0
0.1667 0.1662 0.1661 0.1571 0.1560 0.1563 0.1561 0.1591 0.1584 0.1581 0.1580 0.1608 0.1603 0.1604 0.1601 0.1617 0.1619 0.1614 0.1632 0.1638 0.1639 0.1519 0.1521 0.1526 0.1549 0.1555 0.1545 0.1571 0.1563 0.1567 0.1590 0.1580 0.1588 0.1603 0.1596 0.1475 0.1474 0.1476 0.1498 0.1495 0.1496 0.1509
336.83 337.18 337.12 338.16 338.70 336.84 337.68 338.63 356.01 356.41 356.56 355.20 355.68 355.65 355.26 355.48 355.66 356.85 355.44 355.92 356.34 355.72 356.15 356.56 375.76 376.21 376.92 376.75 376.11 376.89 376.76 376.05 376.87 377.6 375.87 375.82 376.25 376.71 375.76 376.23 376.27 376.73
10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 15.0 20.0 20.0 20.0 20.0
0.1514 0.1510 0.1541 0.1542 0.1542 0.1561 0.1556 0.1560 0.1428 0.1431 0.1425 0.1458 0.1457 0.1448 0.1479 0.1480 0.1477 0.1472 0.1494 0.1505 0.1499 0.1517 0.1519 0.1519 0.1382 0.1378 0.1378 0.1377 0.1409 0.1402 0.1410 0.1436 0.1426 0.1427 0.1460 0.1453 0.1452 0.1448 0.1482 0.1473 0.1480 0.1473
Standard uncertainties u are u(Tr) = 0.01 K, u(p) = 0.1 MPa and the combined expanded uncertainty Uc is Uc(λ) = 0.02·λ (level of confidence = 0.95).
The volume of the sample needed in the measurements did not exceed 30 cm3. The transient hot-wire apparatus was immersed completely in a thermostatic bath (Fluke, Model 7037). The temperature was measured with a platinum resistance thermometer. The total uncertainty of the temperature for the thermal conductivity measurements was less than ± 10 mK. The data acquisition instrument used in this work was made up of several components: a Wheatstone bridge, Keithley 2400 Source Meter, four Agilent 34410A digital multimeters, Keithley 7001 switch systems and an industrial computer. All the data acquisition and instrument control were performed by a computer via the IEEE-488 interfaces. The pressure of liquids in the cell was achieved by a HPLC pump (Beijing Satellite manufactory, Model 2PB05C) with the pressure
The present measurements of thermal conductivity were obtained with a transient two-wire technique. The experimental system used in this work was the same as that previously employed for the measurement of 1,2-dimethoxyethane, dimethyl ether, diethyl ether, diisopropyl ether, and dibutyl ether.4−6 Because the system has been described in a previous publication, only a brief introduction was given here. The main part of the system consisted of a pressure vessel, thermostatic bath, data acquisition instrument, HPLC pump, and pressure transducer. The apparatus used two anodized tantalum wires that were 25 μm in diameter and had lengths of 29 mm and 58 mm, respectively. The two wires and support were placed in the pressure vessel and sealed with the seal connector and nut. The outer cavity around the hot wires was stainless steel (SSL 316) and had a inner diameter of 10 mm. 2864
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Table 3. Thermal Conductivity of Liquid 2-Ethylhexyl Acetatea Tr
p
λ
Tr
p
λ
Tr
p
λ
K
MPa
W·m−1·K−1
K
MPa
W·m−1·K−1
K
MPa
W·m−1·K−1
236.98 237.87 238.15 237.23 238.6 239.43 237.14 238.64 239.5 237.83 237.9 238.65 236.69 237.89 238.49 255.44 258.36 258.31 255.58 255.73 257.53 256.36 257.05 258.36 255.73 256.27 256.94 255.67 256.24 256.74 275.57 277.69 278.39 275.68 276.56 278.48 276.34 276.82 278.65 276.08 276.61 277.62
0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0
0.1389 0.1391 0.1390 0.1405 0.1403 0.1404 0.1415 0.1417 0.1416 0.1430 0.1431 0.1429 0.1443 0.1444 0.1438 0.1363 0.1363 0.1361 0.1382 0.1377 0.1376 0.1399 0.1397 0.1390 0.1409 0.1408 0.1407 0.1420 0.1423 0.1420 0.1331 0.1331 0.1330 0.1354 0.1343 0.1344 0.1366 0.1361 0.1366 0.1377 0.1372 0.1374
276.71 276.87 277.71 296.2 297.69 298.41 296.14 296.63 298.26 296.29 297.51 298.43 296.19 296.56 297.36 298.36 296.02 296.75 298.13 316.29 317.28 318.02 315.70 315.99 317.68 315.46 315.74 317.25 315.33 316.91 317.76 316.23 315.64 317.51 318.11 336.49 337.04 338.66 337.39 337.82 337.85 338.98
20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 5.0
0.1393 0.1392 0.1394 0.1294 0.1293 0.1290 0.1312 0.1308 0.1309 0.1332 0.1325 0.1326 0.1344 0.1338 0.1338 0.1340 0.1358 0.1359 0.1356 0.1248 0.1247 0.1250 0.1270 0.1268 0.1265 0.1284 0.1281 0.1284 0.1304 0.1310 0.1304 0.1328 0.1324 0.1322 0.1318 0.1200 0.1201 0.1198 0.1223 0.1222 0.1219 0.1216
337.02 337.46 338.84 338.99 337.87 338.69 339.1 336.93 339.05 339.42 356.99 356.69 357.29 355.71 356.65 357.21 356.18 357.52 357.48 355.36 356.17 357.31 356.63 357.4 358.21 375.83 376.61 377.52 375.91 375.86 376.6 375.73 376.71 376.83 376.09 377.29 377.41 377.74 375.68 377.45 378.14
10.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 15.0 20.0 20.0 20.0
0.1237 0.1236 0.1243 0.1237 0.1257 0.1258 0.1260 0.1276 0.1278 0.1276 0.1154 0.1148 0.1155 0.1179 0.1177 0.1178 0.1196 0.1197 0.1194 0.1220 0.1222 0.1219 0.1243 0.1245 0.1244 0.1109 0.1111 0.1110 0.1141 0.1142 0.1140 0.1158 0.1162 0.1155 0.1179 0.1185 0.1178 0.1175 0.1197 0.1197 0.1199
a Standard uncertainties u are u(Tr) = 0.01 K, u(p) = 0.1 MPa and the combined expanded uncertainty Uc is Uc(λ) = 0.02·λ (level of confidence = 0.95).
of the hot wire. In Figures 2, 5, and 8, the temperature dependence data of the thermal conductivity of 2-methoxyethyl acetate, 2-ethylhexyl acetate, and diethyl succinate along five isobars were shown, respectively. As can be seen in the graph, the thermal conductivity decreased with temperature. The pressure dependence of the thermal conductivity of three esters at different temperatures was presented in Figures 1, 4, and 7, respectively. The thermal conductivity increased with pressure. The results of the (λ, T, P) for each ester has been represented by an equation of the form, for the purpose of interpolation only
readings acquired. A resistance pressure transducer (Micro Sensor Co. Ltd., Model MPM480) ranged from (0 to 40) MPa was used to measure the pressure with an uncertainty of 0.1 MPa.
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RESULTS AND DISCUSSION The thermal conductivity of 2-methoxyethyl acetate and 2ethylhexyl acetate were measured up to 20 MPa from (233.15 to 373.15) K, spacing 20 K. The melting point of diethyl succinate was 252.15 K, so the measurement of diethyl succinate was performed at (263.15 to 383.15) K from atmospheric pressure to 20 MPa at five isobars, (0.1, 5, 10, 15, and 20) MPa. The experimental temperature, pressure, and thermal conductivity were present in Tables 2−4, respectively. The values of Tr = T0 + 0.5ΔT, where T0 is the temperature in the thermostatic bath and ΔT is the temperature rise
3
λ /W·m−1·K−1 =
3
∑ ∑ aij(T /K)i (P /MPa) j i=0 j=0
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Table 4. Thermal Conductivity of Liquid Diethyl Succiantea
a
Tr
p
λ
Tr
p
λ
Tr
p
λ
K
MPa
W·m−1·K−1
K
MPa
W·m−1·K−1
K
MPa
W·m−1·K−1
265.06 266.38 267.04 264.81 266.47 266.94 265.83 266.13 267.83 265.23 265.57 266.08 265.83 265.94 266.81 285.63 286.33 287.75 285.62 286.14 286.61 287.43 285.16 285.71 286.36 285.68 286.27 286.56 287.36 284.87 285.41 286.76 304.47 305.66 307.33 306.12 306.79 307.29
0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0
0.1559 0.1561 0.1561 0.1565 0.1571 0.1572 0.1586 0.1582 0.1589 0.1602 0.1596 0.1594 0.1615 0.1602 0.1607 0.1527 0.1528 0.1527 0.1539 0.1537 0.1538 0.1535 0.1556 0.1554 0.1555 0.1570 0.1569 0.1562 0.1563 0.1580 0.1579 0.1578 0.1484 0.1483 0.1482 0.1497 0.1501 0.1502
305.72 306.44 306.84 307.27 304.53 306.12 306.80 304.85 305.64 306.39 326.02 326.76 327.56 327.21 327.81 328.57 329.63 327.17 328.07 328.62 327.58 328.35 329.69 327.69 328.56 330.11 345.53 346.63 347.16 345.49 346.11 345.99 345.80 346.44 347.34 346.18 346.52
10.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0
0.1518 0.1519 0.1513 0.1510 0.1529 0.1529 0.1529 0.1551 0.1543 0.1549 0.1436 0.1433 0.1437 0.1448 0.1449 0.1449 0.1453 0.1466 0.1471 0.1469 0.1489 0.1484 0.1481 0.1503 0.1502 0.1501 0.1385 0.1384 0.1385 0.1404 0.1404 0.1402 0.1422 0.1423 0.1419 0.1448 0.1442
346.65 345.18 346.59 346.94 365.09 365.79 366.50 365.16 365.59 367.17 365.15 366.11 366.72 365.54 366.57 367.31 366.54 366.05 366.66 367.25 386.08 386.36 387.25 386.02 386.15 386.70 386.95 385.51 385.95 386.80 386.93 385.95 386.50 387.06 385.28 385.96 386.63
15.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0 20.0 0.1 0.1 0.1 5.0 5.0 5.0 5.0 10.0 10.0 10.0 10.0 15.0 15.0 15.0 20.0 20.0 20.0
0.1446 0.1462 0.1462 0.1461 0.1339 0.1341 0.1339 0.1359 0.1360 0.1358 0.1381 0.1380 0.1379 0.1395 0.1399 0.1397 0.1409 0.1409 0.1415 0.1415 0.1284 0.1279 0.1278 0.1309 0.1301 0.1304 0.1303 0.1325 0.1326 0.1327 0.1321 0.1349 0.1349 0.1352 0.1379 0.1384 0.1378
Standard uncertainties u are u(Tr) = 0.01 K, u(p) = 0.1 MPa and the combined expanded uncertainty Uc is Uc(λ) = 0.02·λ (level of confidence = 0.95).
Figure 1. Pressure dependence of the thermal conductivity of 2methoxyethyl acetate at different temperatures: ☆, 373 K; ◇, 353 K; ▷, 333 K; ◁, 313 K; ▽, 293 K; △, 273 K; ○, 253 K; □, 233 K; , the lines calculated from the correlation.
Figure 2. Temperature dependence of the thermal conductivity of 2-methoxyethyl acetate at different temperatures: ◁, 20 MPa; ▽, 15 MPa; △, 10 MPa; ○, 5 MPa; □, 0.1 MPa; , the lines calculated from the correlation. 2866
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Figure 3. Relative differences Δλ/λ = (λexp − λcal)/λcal of the experimental thermal conductivity λexp for different temperatures and pressures from the value λcal obtained from eq 1 for pure 2-methoxyethyl acetate: □, this work.
Figure 6. Relative differences Δλ/λ = (λexp − λcal)/λcal of the experimental thermal conductivity λexp for different temperatures and pressures from the value λcal obtained from eq 1 for pure 2-ethylhexyl acetate: □, this work.
Figure 4. Pressure dependence of the thermal conductivity of 2ethylhexyl acetate at different temperatures: ☆, 373K; □, 353 K; ◇, 333 K; ▷, 313 K; ◁, 293 K; ▽, 273 K; △, 253 K; ○, 233 K; , the lines calculated from the correlation.
Figure 7. Pressure dependence of the thermal conductivity of diethyl succinate at different temperatures: ▷, 383 K; ◁, 363 K; ◇, 343 K; ▽, 323 K; △, 303 K; ○, 283 K; □, 263 K, , the lines calculated from the correlation.
Figure 8. Temperature dependence of the thermal conductivity of diethyl succinate at different temperatures: ◇, 20 MPa; ▽, 15 MPa; △, 10 MPa; ○, 5 MPa; □, 0.1 MPa; , the lines calculated from the correlation.
Figure 5. Temperature dependence of the thermal conductivity of 2-ethylhexyl acetate at different temperatures: ◁, 20 MPa; ▽, 15 MPa; △, 10 MPa; ○, 5 MPa; □, 0.1 MPa; , the lines calculated from the correlation.
tabulated thermal conductivity data had an uncertainty of better than ± 2.0 % with a coverage factor of k = 2. The average absolute deviations of experiment data of 2methoxyethyl acetate, 2-ethylhexyl acetate, and diethyl succinate
The derived values of all the coefficients are shown in Table 5. Accounting for all of the random errors of measurement, and following our previous discussion, it was estimated that the 2867
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Article
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Fax: +86-29-82668789. Funding
The work was financed by the National Natural Science Foundation of China (Grant No. 51076128) and National Natural Science Foundation of China (Grant No. 50836004). Notes
The authors declare no competing financial interest.
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(1) Song, K. H.; Nag, P.; Ligzinger, T. A.; Haworth, D. C. Effects of Oxygenated Additives on Aromatic Species in Fuel-Rich, Premixed Ethane Combustion: a Modeling Study. Combust. Flame 2003, 135, 341−349. (2) Bruno, T. J.; Lovestead, T. M.; Riggs, J. R.; Jorgenson, E. J.; Huber, M. L. Comparison of Diesel Fuel Oxygenate Additives to the Composition-Explicit Distillation Curve Method. Part 1: Linear Compounds with One to Three Oxygens. Energy Fuels 2011, 25, 2493−2507. (3) Gong, Y. F.; Liu, S. H.; Guo, H. J.; Hu, T. G.; Zhou, L. B. A New Diesel Oxygenate Additive and Its Effects on Engine Combustion and Emissions. Appl. Therm. Eng. 2007, 27, 202−207. (4) Wu, J. T.; Zheng, H. F.; Qian, X. H; Li, X. J.; Assael, M. J. Thermal Conductivity of Liquid 1,2-Dimethoxyethane from 243 to 353 K at Pressures up to 30 MPa. Int. J. Thermophys. 2009, 30, 385−396. (5) Wu, J. T.; Li, X. J.; Zheng, H. F.; Assael, M. J. Thermal Conductivity of Liquid Dimethyl ether from (233 to 373) K at Pressures up to 30 MPa. J. Chem. Eng. Data 2009, 54, 1720−1723. (6) Li, X. J.; Wu, J. T.; Dang, Q. Thermal Conductivity of Liquid Diethyl ether, Diisopropyl Ether, and Di-n-butyl Ether from (233 to 373) K at Pressures up to 30 MPa. J. Chem. Eng. Data 2010, 55, 1241− 1246.
Figure 9. Relative differences Δλ/λ = (λexp − λcal)/λcal of the experimental thermal conductivity λexp for different temperatures and pressures from the value λcal obtained from eq 1 for pure diethyl succinate: □, this work.
Table 5. Coefficients Employed in Eq 1 coefficients aij
2-methoxyethyl acetate
2-ethylhexyl acetate
diethyl succinate
a00 a01 a02 a03 a10 a11 a12 a13 a20 a21 a22 a23 a30 a31 a32 a33
8.0700·10−2 5.4569·10−3 −1.0333·10−3 −3.8183·10−5 9.8312·10−4 −4.7757·10−5 9.3289·10−6 −3.5167·10−7 −3.3742·10−6 1.4544·10−7 −2.7732·10−8 1.0628·10−9 3.0967·10−9 −1.4038·10−10 2.7005·10−11 −1.0524·10−13
3.4599·10−2 8.4495·10−3 −2.2904·10−3 1.0072·10−4 1.2073·10−3 −6.3244·10−5 2.0024·10−5 −9.1405·10−7 4.2031·10−6 1.4022·10−7 −5.5563·10−8 2.6697·10−9 4.0765·10−9 −7.1214·10−11 4.8691·10−11 −2.5147·10−12
9.1064·10−2 −4.2696·10−2 6.6661·10−3 −2.4907·10−4 8.2693·10−4 3.9433·10−4 −6.1803·10−5 2.3191·10−6 −2.8476·10−6 −1.1975·10−6 1.8962·10−7 −7.1468·10−10 2.4741·10−9 1.2086·10−9 −1.9250·10−10 7.2880·10−12
REFERENCES
from those calculated by the equation were 0.24 %, 0.22 %, and 0.24 %, and the maximum absolute deviations were 0.79 %, 0.63 %, and 0.79 % as shown in Figures 3, 6, and 9, respectively. To the best of our knowledge, comprehensive experimental data of the liquid thermal conductivity of the three esters was not found in the published literatures. Hence, there were no comparisons in this work.
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CONCLUSION Thermal conductivity of 2-methoxyethyl acetate, 2-ethylhexyl acetate, and diethyl succinate has been measured with a transient hot-wire instrument employing for two electrical-insulated tantalum wires. Measurements were made at five isobars, (0.1, 5, 10, 15, and 20) MPa. The range of temperatures was (233 to 373) K for 2-methoxyethyl acetate and 2-ethylhexyl acetate and (263 to 383) K for diethyl succinate. The total uncertainty in the reported data was ± 2.0 %. Correlation equations for thermal conductivity of the three oxygenated esters were obtained as a function of pressure and temperature. The average absolute deviation between measured and calculated values from correlation equation were 0.24 %, 0.22 %, and 0.24 %, and the maximum absolute deviations were 0.79 %, 0.63 %, and 0.79 %, respectively. 2868
dx.doi.org/10.1021/je300778e | J. Chem. Eng. Data 2012, 57, 2863−2868
