Vapour pressures and enthalpies of vaporization of aliphatic esters

Fluid Phase Equilibria 334 (2012) 70–75

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Vapour pressures and enthalpies of vaporization of aliphatic esters Artemiy A. Samarov a , Alyanus G. Nazmutdinov a,∗ , Sergey P. Verevkin b,∗∗ a b

Samara State Technical University, 443100 Samara, Russia Department of Physical Chemistry, University of Rostock, 18059 Rostock, Germany

a r t i c l e

i n f o

Article history: Received 11 April 2012 Received in revised form 6 July 2012 Accepted 1 August 2012 Available online 10 August 2012 Keywords: Esters Vapour pressure Enthalpy of vaporization Transpiration method

a b s t r a c t Molar enthalpies of vaporization of n-alkyl formates (with alkyl groups C5 –C8 ), n-alkyl propanoates (with alkyl groups C5 –C8 ) and n-pentyl acetate were obtained from the temperature dependence of the vapour pressure measured by the transpiration method. A large number of the primary experimental results on temperature dependences of vapour pressures have been collected from the literature and have been treated uniformly in order to derive vaporization enthalpies at the reference temperature 298.15 K. The available data were successfully checked for internal consistency. © 2012 Elsevier B.V. All rights reserved.

1. Introduction

2. Experimental

Current efforts to address challenges in the energy economy include the use of biofuels. In order to assess the level of emissions and combustion properties of biodiesel, detailed fundamental studies are necessary. Biodiesel is usually an ill defined complex of the long-chain saturated and unsaturated methyl esters. That is why chemical kinetic and thermodynamic studies are carried out by means of fuel surrogates or model compounds. Small-chain methyl esters such as alkyl formates, acetates, and propanoates have been proposed as surrogates for biodiesel [1]. Good quality thermodynamic data for the model compound—vapour pressure, vaporization enthalpies, and critical parameters are the basis for the development of their equations of state. Reliable thermodynamic properties for the simple model compounds are further used for evaluation and validation of the ignition and the combustion mechanisms, and finally for the application of this knowledge to complex mixtures related to biofuels. This paper extends our previous studies [2–5] on the systematic investigation of aliphatic esters. We report here a systematic determination of vapour pressures and vaporization enthalpies of a series of n-alkyl formates and n-alkylpropanoates. We used our new experimental results together with the data already available from the literature to obtain practical correlation equations that could be used to predict values for as yet unmeasured esters.

2.1. Materials and purity of the sample

∗ Corresponding author. ∗∗ Corresponding author. Tel.: +49 381 498 6508; fax: +49 381 498 6524. E-mail addresses: [email protected] (A.G. Nazmutdinov), [email protected] (S.P. Verevkin). 0378-3812/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fluid.2012.08.003

Samples of esters were of commercial origin with the certified purities of 99%. Samples were additionally purified by fractional distillation at the reduced pressure using a spinning band column. The degree of purity was determined using a gas chromatograph equipped with a flame ionization detector. No impurities (greater than 0.02 mass%) could be detected in the samples used for the vapour pressure measurements.

2.2. Vapour pressure measurements Vapour pressures and enthalpies of vaporization of esters were determined using the transpiration method in a saturated N2 stream [2] and applying the Clausius–Clapeyron equation. About 0.5 g of the sample was mixed with glass beads and placed in a thermostated U-shaped tube having a length of 20 cm and a diameter of 0.5 cm. Glass beads with diameter of 1 mm provide a surface which is large enough for vapour–liquid equilibration. At constant temperature (±0.1 K), a nitrogen stream was passed through the Utube and the transported amount of gaseous material was collected in a cooling trap. The flow rate of the nitrogen stream was measured using a soap bubble flow meter and optimized in order to reach the saturation equilibrium of the transporting gas at each temperature under study. The amount of condensed substance was determined by GC analysis using an external standard (hydrocarbon n-Cn H2n+2 ). The saturated vapour pressure pti at each temperature Ti was calculated from the amount of product collected within a definite period

A.A. Samarov et al. / Fluid Phase Equilibria 334 (2012) 70–75

71

of time, and the small value of the residual vapour pressure at the temperature of condensation was added. The latter was calculated from a linear correlation between ln(pi ) and T−1 obtained by iteration. Assuming that Dalton’s law of partial pressures applied to the nitrogen stream saturated with the substance i of interest is valid, values of pi were calculated: pi =

mi · R · Ta ; V · Mi

V = VN2 + Vi ;

(VN2  Vi )

(1)

where R = 8.314472 J K−1 mol−1 , mi is the mass of transported compound, Mi is the molar mass of the compound, and Vi is its volume contribution to the gaseous phase. VN2 is the volume of transporting gas and Ta is the temperature of the soap bubble meter. The volume of transporting gas VN2 was determined from the flow rate and time measurements. Data of pi have been obtained as a function of temperature and were fitted using following equation [6]: R ln pi = a +

b g + l Cp ln T

T

(2)

T0 g

where a and b are adjustable parameters and l Cp is the difference of the molar heat capacities of the gaseous and the liquid phase, respectively. T0 appearing in Eq. (2) is an arbitrarily chosen reference temperature (which has been chosen to be 298.15 K). Consequently, from Eq. (2) the expression for the vaporization enthalpy at temperature T is derived:

g

Fig. 1. Experimental vaporization enthalpies l Hm (298.15 K) of n-alkyl formates, acetates, and propanoates as a function of the NC (number of carbon atoms in the n-alkyl chain attached to the oxygen): (䊉) formates; () acetates; () propanoate.

g

heat capacities of liquid esters, Cpl , according to a procedure developed by Chickos and Acree [7]. However, in their parameterization the increment specific for formates HCO2 —for Cpl was not included. The missing contribution was assessed with experimental data on Cpl for ethyl formate, propyl formate, and butyl formate collected and the sum of other increments (see details in ESI). Experimental results, parameters a and b are listed in Table 1.

Vaporization enthalpies l Hm appear to be a linear function of the number of carbon atoms in all the n-alkyl acetates [3], dialkyl esters of carboxylic acids [38], and aliphatic nitriles [39] g investigated. The linear correlation of the l Hm -values with the number of C-atoms in the series of homologues is usually the valuable test to check the internal consistency of the experimeng tal results. The plot of l Hm (298.15 K) against the number of C-atoms in the n-alkyl chain of formates is presented in Fig. 1. The dependence of vaporization enthalpy on the total number of C-atoms NC in the molecule is expressed by following equation:

3. Results and discussion

l Hm (298.15 K)/kJ mol−1 = 24.21 + 4.24NC

g

g

l Hm (T ) = −b + l Cp · T

(3)

g

Values of l Cp have been calculated from the isobaric molar

Experimental studies of aliphatic esters have been a popular endeavour. Enthalpies of vaporization are usually measured directly by using calorimetry [8–15] or they could be derived indirectly from the experimental temperature dependencies of vapour pressures. For the sake of comparison, the original published p–T experimental results [16–35] were treated using Eqs. (2) and (3), g and l Hm (298.15 K) were calculated (see Table 2). The comprehensive compilation by Stephenson and Malanowski [36] contains vapour pressure data for some aliphatic esters over a wide range of temperature. Unfortunately, the origin of the data presented there is unclear, methods of measurements are unknown, as well the errors of measurement and the purities of compounds. In spite of this fact, results from Stephenson and Malanowski [36] were also g treated using Eqs. (2) and (3) and l Hm (298.15 K) are also calculated for the sake of comparison with other available results. However, the agreement or disagreement with other data in each case should be questionable. Reliable experimental vapour pressure studies of n-pentyl acetate available in the literature were performed using ebulliometry in the temperature range close to the normal boiling point. In order to avoid any ambiguity due to the large temperature adjustment of the vaporization enthalpy to the reference temperature we have performed additional measurements on n-pentyl acetate (see Tables 1 and 2), but our new result for the vaporization enthalpy at 298.15 K is in close agreement with those from ebulliometry. The collection of the available experimeng tal results and derived l Hm (298.15 K) values for aliphatic esters is presented in Table 2.

g

r = 0.9987

(4)

which is valid for NC ≥ 2. The linearity of Eq. (4) is evidence of the consistency of the experimental data n-alkyl formates selected in this work (see Table 2). Also the linear chain dependence for vaporization enthalpies of n-alkyl propanoates is described by equation: l Hm (298.15 K)/kJ mol−1 = 30.15 + 4.49NC g

r = 0.9979

(5)

This equation is valid for the total C-atoms number NC ≥ 4. In other words the vaporization enthalpy of methyl propanoate is slightly out of the linear correlation. However, the same phenomenon was also observed for n-alkyl acetates (see Fig. 1) where the vaporization enthalpy of methyl acetate lies out of the general linear correlation. Eqs. (4) and (5) could be used to predict enthalpy of vaporization of other representatives with the longer chains. List of symbols

g

l Hm Ta pi Cpl g Cp g l Cp

molar enthalpy of vaporization ambient temperature vapour pressure molar heat capacity of liquid at constant pressure molar heat capacity of gas at constant pressure difference between the molar heat capacities of the gaseous and liquid phase, respectively

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Table 1 Results from measurements of the vapour pressure p of n-alkyl esters using the transpiration method. Ta (K) Pentyl formate;

mb (mg) g l Hm

274.2 274.3 278.3 278.3 281.0 281.0 275.7 283.2 288.2 293.3 298.4 303.3 308.0 305.6 313.3 310.7

V(N2 ) (dm3 )c

Gas-flow (dm3 /h)

(298.15 K) = (45.21 ± 0.09) kJ mol−1 ln(p/Pa) =

0.97 1.94 2.55 1.29 3.15 1.57 2.14 3.70 5.20 7.22 9.92 13.43 17.49 15.21 23.58 20.31

0.090 0.180 0.180 0.090 0.180 0.090 0.180 0.180 0.180 0.180 0.180 0.180 0.180 0.180 0.180 0.180

g

Hexyl formate; l Hm (298.15 K) = (49.98 ± 0.31) kJ mol−1 ln(p/Pa) = 275.4 278.5 283.3 288.2 293.3 293.4 298.4 298.4 303.2 303.3 308.3 308.3 313.4 313.4

3.46 3.28 3.67 3.77 4.94 9.09 12.93 13.02 10.27 10.03 13.78 13.99 18.91 18.70

0.923 0.693 0.531 0.369 0.346 0.623 0.600 0.600 0.346 0.346 0.346 0.346 0.349 0.346

297.46 R

g

3.44 3.33 3.41 3.27 3.34 3.21 3.07 3.10 3.05 3.14 3.49 4.14 5.81 7.15 5.35 9.86

2.767 2.327 2.211 1.765 1.373 0.894 0.587 0.587 0.587 0.409 0.455 0.383 0.383 0.381 0.255 0.383

g

3.60 3.67 4.35 3.65 3.56 3.67 1.05 3.59 3.73 3.08 3.84 4.49 6.61 7.59 8.36 9.65 11.23

4.345 2.897 4.287 1.912 2.317 1.275 0.261 0.869 0.608 0.348 0.313 0.261 0.278 0.271 0.261 0.271 0.261

71.9 ln R

−

−

73893.05 R·(T,K)

−

80.2 ln R

309.50 R

−

80240.19 R·(T,K)

−



88.5 ln R

2.34 3.49 3.49 2.35 2.35 1.53 1.53 1.53 1.53 1.53 1.61 1.53 1.53 1.53 1.53 1.53

Octyl formate; l Hm (298.15 K) = (58.18 ± 0.17) kJ mol−1 ln(p/Pa) = 283.3 288.2 285.7 293.3 290.8 298.4 303.2 303.2 308.2 313.5 318.5 323.5 328.4 331.3 333.4 335.3 338.3

66650.35 R·(T,K)

−

1.39 1.39 1.39 1.39 1.39 1.39 1.39 1.39 1.39 1.39 1.39 1.39 1.39 1.39

Heptyl formate; l Hm (298.15 K) = (53.85 ± 0.22) kJ mol−1 ln(p/Pa) = 276.1 277.6 278.6 280.4 283.3 288.3 293.2 293.2 293.3 298.3 298.3 303.3 308.2 311.0 313.3 316.4

282.14 R

1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08



323.42 R

3.48 3.48 3.48 3.48 3.48 3.48 1.04 3.48 1.04 1.04 1.04 1.04 1.04 1.08 1.04 1.08 1.04

−

87041.03 R·(T,K)

−

96.8 ln R

T,K 298.15



228.33 229.28 300.65 304.59 370.05 369.18 251.83 434.89 610.05 845.25 1160.57 1571.30 2045.14 1779.13 2756.52 2373.90

g

l Hm (kJ mol−1 )

46.94 46.93 46.64 46.64 46.45 46.45 46.83 46.29 45.93 45.57 45.20 44.85 44.51 44.68 44.13 44.31

1.11 −0.74 −1.64 0.56 −9.09 −5.16 9.61 12.59 13.65 −2.74 −4.97 6.52 −10.51 −13.21

51.81 51.56 51.18 50.78 50.37 50.37 49.97 49.97 49.58 49.57 49.17 49.17 48.76 48.76

21.50 24.68 26.56 31.87 41.68 61.25 88.90 89.71 88.35 130.44 130.05 183.01 257.00 317.65 354.93 435.85

−0.34 −0.23 −0.60 0.19 1.30 0.72 0.36 1.17 −0.87 1.05 0.67 −1.81 −1.47 6.43 −6.46 −4.27

55.81 55.68 55.59 55.43 55.17 54.73 54.30 54.30 54.29 53.85 53.85 53.40 52.97 52.72 52.52 52.24

12.98 19.73 15.85 29.64 23.92 44.62 62.20 63.88 94.65 136.77 189.43 265.58 366.46 431.80 494.29 548.78 663.55

0.35 0.25 0.15 −0.10 −0.25 −0.18 −2.63 −1.19 0.81 0.10 −2.61 −0.69 4.18 −0.53 4.15 −0.95 11.74

59.62 59.14 59.38 58.65 58.90 58.16 57.70 57.69 57.21 56.70 56.22 55.73 55.26 54.98 54.77 54.58 54.30



72.41 90.94 131.88 193.50 269.44 275.34 405.56 408.54 557.67 544.82 747.30 758.79 1016.15 1013.45 T,K 298.15

T,K 298.15

(pexp − pcalc ) (Pa)

2.55 1.80 −4.87 −0.93 −0.65 −1.51 −0.68 2.37 2.46 −1.66 −3.61 10.35 −6.34 −5.01 14.76 −4.67

T,K 298.15





p (Pa)d





A.A. Samarov et al. / Fluid Phase Equilibria 334 (2012) 70–75

73

Table 1 (Continued) Ta (K) Pentyl acetate; 274.2 274.3 278.2 275.6 275.6 283.2 280.8 288.2 293.3 298.4 303.3 308.2 306.7 310.6 313.4

mb (mg) g l Hm

V(N2 ) (dm3 )c

Gas-flow (dm3 /h)

(298.15 K) = (47.98 ± 0.15) kJ mol−1 ln(p/Pa) =

3.76 1.54 3.88 3.88 1.70 3.94 4.00 4.37 3.30 4.58 6.17 8.49 7.58 9.69 12.89

0.860 0.345 0.653 0.791 0.345 0.447 0.550 0.344 0.182 0.182 0.177 0.177 0.177 0.177 0.199

290.51 R

g

3.25 3.27 3.32 3.46 3.34 3.42 2.18 3.51 4.36 14.33 14.11 15.24 15.08 15.28 17.45 20.54

1.871 1.683 1.372 0.935 1.122 0.618 0.269 0.300 0.265 0.618 0.448 0.358 0.303 0.270 0.269 0.269

g

3.18 3.46 3.41 3.66 3.30 5.06 2.07 4.96 3.63 3.17 4.36 6.26 7.63 8.36 9.65 11.31

4.345 3.766 2.897 2.015 2.317 1.217 0.361 0.869 0.428 0.271 0.261 0.276 0.268 0.261 0.268 0.271

g

a b c d

2.87 3.01 3.17 3.15 3.23 3.35 3.42 3.40 1.10 3.26 3.04 3.25 3.60 4.26 7.28 6.39

8.116 6.868 5.681 4.683 3.746 2.533 1.686 1.151 0.266 0.531 0.354 0.274 0.268 0.266 0.355 0.283

p (Pa)d T,K 298.15

3.75 3.75 3.75 3.75 3.75 3.71 3.75 1.06 1.06 1.06 1.06 1.06 1.07 1.06 1.07 1.06



85.39 87.09 114.50 95.30 95.55 168.33 139.63 241.29 343.03 475.45 657.98 903.52 807.04 1031.12 1219.13

305.62 R

−

78055.94 R·(T,K)

−

86.6 ln R

324.27 R

−

85392.53 R·(T,K)

−

94.9 ln R

3.48 3.48 3.48 3.45 3.48 1.04 1.08 3.48 1.07 1.08 1.04 1.08 1.07 1.04 1.07 1.08

Octyl propanoate; l Hm (298.15 K) = (66.40 ± 0.16) kJ mol−1 ln(p/Pa) = 293.3 295.7 298.4 300.3 303.3 308.3 313.4 318.5 323.4 328.5 333.3 338.3 340.3 343.0 346.4 348.4



3.74 3.74 3.74 3.74 3.74 1.06 1.08 1.06 1.06 1.06 1.08 1.08 1.08 1.08 1.08 1.08

Hexyl propanoate; l Hm (298.15 K) = (57.10 ± 0.18) kJ mol−1 ln(p/Pa) = 278.3 280.7 283.4 288.2 285.8 298.4 303.2 303.2 308.2 313.3 318.5 323.4 326.4 328.4 330.6 333.3

−

78.3 ln R

2.06 2.07 2.06 2.06 2.07 2.06 2.06 2.06 1.09 1.09 1.06 1.06 1.06 1.06 1.06

Pentyl propanoate; l Hm (298.15 K) = (52.24 ± 0.14) kJ mol−1 ln(p/Pa) = 274.1 275.5 278.3 283.4 280.9 288.3 293.3 298.4 303.3 308.2 313.4 318.5 320.7 323.4 325.6 328.4

−

71325.79 R·(T,K)

350.64 R

−

99639.15 R·(T,K)

−

111.5 ln R







T,K 298.15



29.95 33.42 41.39 63.15 50.87 94.03 137.36 198.43 278.91 392.51 532.78 719.50 842.26 956.79 1097.72 1292.60 T,K 298.15



17.64 22.10 28.27 43.54 34.17 99.32 136.94 136.27 202.42 279.31 399.35 542.22 680.37 764.57 860.19 996.14 T,K 298.15



4.65 5.75 7.32 8.83 11.29 17.30 26.56 38.70 54.10 80.43 112.49 155.03 175.97 209.78 268.06 295.19

Temperature of saturation. Mass of transferred sample, condensed at T = 243 K. Volume of nitrogen, used to transfer mass m of sample. Vapour pressure at temperature T, calculated from m and the residual vapour pressure at T = 243 K.

(pexp − pcalc ) (Pa)

g

l Hm (kJ mol−1 )

0.66 1.68 −1.88 0.25 0.87 −0.67 −1.70 −1.16 −1.88 −8.02 −1.98 13.67 −6.05 5.41 12.67

49.86 49.85 49.54 49.75 49.75 49.16 49.34 48.76 48.36 47.96 47.58 47.20 47.32 47.01 46.79

0.60 0.15 −0.62 −0.66 −1.24 0.29 0.80 1.19 2.14 9.33 −0.89 −9.33 11.80 −17.80 −7.20 3.86

54.32 54.20 53.96 53.52 53.73 53.09 52.66 52.22 51.79 51.37 50.92 50.48 50.29 50.05 49.86 49.62

−0.15 −0.02 0.18 0.93 −0.43 2.85 −2.24 −2.92 3.06 −6.05 −3.20 −9.07 13.96 14.05 3.80 −10.65

58.99 58.76 58.50 58.04 58.27 57.08 56.62 56.62 56.15 55.66 55.17 54.71 54.42 54.23 54.02 53.76

0.03 −0.04 −0.04 0.11 −0.04 0.04 0.48 −0.06 −1.96 −0.08 0.40 −1.18 −1.78 −1.18 7.62 1.12

66.94 66.67 66.37 66.16 65.83 65.27 64.70 64.13 63.58 63.02 62.48 61.92 61.70 61.40 61.02 60.80

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A.A. Samarov et al. / Fluid Phase Equilibria 334 (2012) 70–75

Table 2 g Compilation of data on enthalpies of vaporization l Hm of esters (numbers given in bold were selected for the correlations). g

g

g

Techniquea

T-Range

l Hm /Tav

Cpl (−l Cp )b

l Hm (K)c

Ref.

C E S E C

304.5 294.0–304.8 261.2–305.2

28.2 ± 0.3

120.6 (41.9)

28.5 ± 0.3 27.6 29.4 ± 0.8 28.4 28.6

[8] [16] [37] [17] [9]

C E C E E

326.5

30.1 ± 0.2

144.3 (48.1)

304.0–327.7 300.0–326.5 308.2–341.5

31.4 ± 0.1 30.9 ± 0.1

31.5 ± 0.2 32.2 32.1 32.1 ± 0.1 32.2 ± 0.1

[8] [17] [9] [18] [19]

N/A N/A C E C C E E

230.0–355.0 354.0-518.0 353.2 299.3–355.4 325.9–363.4 298.15 328.0–370.6 302.4–353.0

172.1 (55.3)

35.1 38.7 35.5 ± 0.5 36.4 37.6 37.5 36.6 ± 0.1 36.4 ± 0.1

[36] [36] [8] [16] [9] [10] [20] [18]

C E E C

37.1 ± 0.3

200.3 (62.7)

E E E C

378.3 302.2–385,5 353.7–379.7 298.15 295.0–380.0 295.4–367.8 362.9–392.4 313.2–358.7 345.8–363.4

42.1 ± 0.3 40.5 41.0 ± 0.1 41.3 39.8 40.0 ± 0.6 42.4 ± 0.1 40.5 ± 0.1 41.2

[8] [15] [21] [10] [36] [22] [23] [24] [9]

Pentyl formate [554-12-1] Hexyl formate [554-12-1] Heptyl formate [554-12-1] Octyl formate [554-12-1]

T T T T

274.2–313.3 275.4–313.4 276.1–316.4 283.3–338.3

45.65 50.30 54.17 57.08

236.0 (71.9) 267.9 (80.2) 299.8 (88.5) 331.7 (96.8)

45.2 ± 0.1 50.0 ± 0.3 53.8 ± 0.2 58.2 ± 0.2

This work This work This work This work

Acetates Methyl acetate [79-20-9] Ethyl acetate [141-78-6] Propyl acetate [109-60-4]

C C C

298.15 298.15 298.15

191.9 (60.5)

32.3 35.6 39.1 ± 0.2

[10] [10] [11]

Butyl acetate [123-86-4]

E C

298.15

222.8 (68.5)

43.6 ± 0.2

[11]

Pentyl acetate [628-63-7]

E DTA E DTA DTA T

321.4–462.3 330.1–379.8 331.0–503.8 291.7–421.6 298–393 274.1–328.4

42.7 ± 0.2 45.0 40.9 46.6 35.4 48.48

260.6 (78.3)

48.6 ± 0.4 49.3 49.6 ± 0.4 50.3 ± 0.7 38.7 48.0 ± 0.2

[26] [40] [41] [42] [43] This work

Hexyl acetate [142-92-7] Heptyl acetate [112-06-1] Octyl acetate [112-14-1]

T T T

274.5–309.1 276.5–306.1 274.5–309.2

52.5 ± 0.3 57.9 ± 0.2 61.4 ± 0.4

287.6 (85.4) 315.7 (92.7) 344.4 (100.1)

51.9 ± 0.3 57.1 ± 0.2 60.7 ± 0.4

[3] [3] [3]

N/A N/A N/A E E E C C C C E C

315.6-346.3 231.0–353.0 353.0–486.0

164.9 (53.5)

35.7 36.3 38.3 34.5 ± 4.2 36.3 ± 0.1 36.6 ± 0.1 35.2 ± 0.2 35.9 36.3 ± 0.3 36.0 ± 0.7 36.7 ± 0.1 35.8 ± 0.1

[36] [36] [36] [27] [28] [29] [8] [10] [13] [14] [30] [12]

196.8 (61.7)

38.6 38.7 38.9 ± 0.1 39.7 ± 0.1 39.1 ± 0.1 39.3 40.0 ± 0.1 42.8 39.1 ± 0.1

[8] [8] [22] [28] [15] [10] [31] [36] [32]

Compounds Formates Methyl formate [107-31-3]

Ethyl formate [109-94-4]

Propyl formate [110-74-7]

Butyl formate [592-84-7]

Propanoates Methyl propanoate [554-12-1]

Ethyl propanoate [105-37-3]

C C E E C C E E

30.0 ± 0.8

293.3–313.4

32.5 ± 0.5 23.0 ± 0.1 34.9 ± 0.1

36.7 ± 0.1 38.1 ± 0.6 37.5 ± 0.1 38.2 ± 0.1

293.7–351.9 330.7–364.3 352.2 298.15 298.15 298.15 315.6–346.3 298.15

35.2 ± 0.1 33.9 ± 0.1 32.3 ± 0.2

371.0 370.8 296.2–358.2 306.9–371.5 298.15 298.15 322.1–379.7 372.0–538.0

34.1 34.2 ± 0.2 37.3 ± 0.1 37.3 ± 0.1

34.9 ± 0.1

37.0 ± 0.1 35.4 ± 0.1

A.A. Samarov et al. / Fluid Phase Equilibria 334 (2012) 70–75

75

Table 2 (Continued) Compounds

Propyl propanoate [106-36-5]

Butyl propanoate [590-01-2]

Pentyl propanoate [624-54-4] Hexyl propanoate [2445-76-3] Octyl propanoate [142-60-9] a b c

Techniquea

T-Range

g

g

l Hm /Tav

Cpl (−l Cp )b

35.7 ± 0.2

228.7 (70.0)

E

350.6–388.3

C E N/A C E E

393.7 258.9–395.5 313.3 366.6–408.2 336.0–394.1

E N/A E C

305.6–366.1 305-417 403.0–431.5 417.9

47.8 ± 0.2

T T T

274.1–328.4 278.3–333.3 293.3–348.4

52.13 56.53 64.03

g

l Hm (K)c

Ref.

39.9 ± 0.1

[33]

42.4 ± 0.2 42.6 42.2 43.2 44.6 ± 0.1 43.9 ± 0.1

[8] [34] [35] [10] [20] [18]

260.6 (78.3)

50.4 ± 0.2 49.8 49.3 ± 0.1 48.5 ± 0.4

[22] [36] [23] [8]

292.5 (86.6) 324.4 (94.9) 388.2 (111.5)

52.2 ± 0.1 57.1 ± 0.2 66.4 ± 0.2

This work This work This work

42.1 38.3 ± 0.1 39.4 ± 0.1

40.0 ± 0.1 39.1 ± 0.4

Techniques: T, transpiration; S, static; DTA, differential thermoanalysis; E, ebulliometry; C, calorimetry. The molar heat capacity and the difference between liquid and gaseous phases (see text). g Derived using Eqs. (2) and (3) with the molar heat capacity difference l Cp .

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