Marzena Dzida, Mirosław Chorążewski
University of Silesia, Institute of Chemistry, Szkolna 9, Katowice
The effect of temperature and pressure
on the thermodynamic and acoustic properties of pentanols
at temperatures from (293 to 318) K and pressures up to 100 MPa
Investigated alcohol
CH3 CH2 CH2 CH2 CH2 OH
pentan-1-ol
CH3
CH3 CH2 C CH3
OH
2-methyl-2-butanol
CH3
CH3 CH2 CH CH2 OH
2-methyl-1-butanol
CH3 CH2 CH CH2 CH3
OH
pentan-3-ol
Aim:
Study of the influence of the structure of the alcohol
and the position of the hydroxyl group in the alcohol molecules
on temperature and pressure dependence of the thermodynamic properties
Physicochemical properties of isomeric pentanols at 298.15 K
2-methyl-1-butanol pentan-1-ol 2-methyl-2-butanol pentan-3-ol
K 153 153 10 85
b.p. / 0C 127.7 137.3 102.4 115.5
Hvap / kJ mol-1 54.1 56.9 51.5 52.9
Cp / J mol-1 K-1 213.88 208.14 247.60 253.39
/ kg m-3 815.02 810.84 804.29 817.18 r 15.63 15.13 5.78 13.35
/ D 1.88 1.65 1.70 1.64
gk 2.42 2.75 0.9 2.63
Ultrasonic speed measurements
temperature range 293 – 318 Kpressure range 0.1 – 100 MPamethod pulse-echo-overlap
accuracy 0.5 m s-1 (0.1 MPa); 1 m s-1 (p 0.1 MPa)
Density measurements
temperature range 293 – 318 Kpressure 0.1 MPamethod vibrating-tube densimeter (Anton Paar DMA 5000)
accuracy 0.05 kg m-3
Heat capacity measurements
temperature range 284 – 368.75 K pressure 0.1 MPamethod differential scanning calorimeter Micro DSC III
(University of Łódź)
accuracy 0.25 %
Experiment
High pressure ultrasonic cell
(1) pressure chamber (2) plug (3) transducer (4) reflector (5) acoustic tube (6) high pressure capillary(7) high pressure cable
Żak A., Dzida M., Zorębski M., Ernst S., A high pressure system for measurements of the speed of sound in liquids, Rev. Scient. Instr. (2000) 71, 1756-1768.
Dzida M., Chorążewski M., Zorębski M., Mańka R., Modification of a high pressure device for speed of sound measurements in liquids, J. de Physique IV (2006) 137, 203-207.
Speeds of sound in 2-methyl-1-butanol plotted against temperature at elevated
pressures: (●) 0.1 MPa, (▲) 30.39 MPa, (■) 60.79 MPa, () 101.32 MPa
290 300 310 3201100
1200
1300
1400
1500
1600
1700u
/ (m
· s-1
)
T / (K)
Determination of the pT data by the acoustic method
2
1
uS
Isothermal compressibility is related to isentropic one by the following relationship:
pS
pST C
T
C
VT
22
T
T p
1
pT C
T
up
2
2
1
pC
Tdp
u p
p
pΔ
1Δ
2
2
2
1
pT
TCp
p ΔΔ 2
where
Laplace formula:
Temperature dependences of the molar heat capacities of (▲) 2-methyl-1-butanol, (●) pentan-1-ol**, (■) 2-methyl-2-butanol*,
and () pentan-3-ol***at atmospheric pressure
*M. Dzida, P. Góralski, J. Chem. Thermodyn. 41 (2009) 402-413**M. Zábranský, V. Růžička and V. Majer, J. Phys. Chem. Ref. Data 19 (1990) 719–762
***C. A. Cerdeiriña, J. Troncoso, D. González-Salgado, G. García-Miaja, G. Hernández-Segura, D. Bessières, M. Medeiros, L. Romaní and M. Costas, J. Phys. Chem. B 111 (2007) 1119–1128
275 300 325 350 375180
200
220
240
260
280
300
320
T /(K)
Cp /
(J· m
ol-1
· K
-1)
Isobaric molar heat capacities as function of pressure of 2-methyl-1-butanol at () 293.15 K and (Δ) 318.15 K,
pentan-1-ol* at (●) 293.15 K and (○) 318.15 K, 2-methyl-2-butanol* at (■) 293.15 K and (□) 318.15 K,
and pentan-3-ol** at () 293.15 K and () 318.15 K (calorimetric measurement) *M. Dzida, J. Chem. Eng. Data (2009) in press
**C. A. Cerdeiriña, J. Troncoso, D. González-Salgado, G. García-Miaja, G. Hernández-Segura, D. Bessières, M. Medeiros, L. Romaní and M. Costas, J. Phys. Chem. B 111 (2007) 1119–1128
0 20 40 60 80 100190
205
220
235
250
265
280
p / (MPa)
Cp /
(J· m
ol-1
· K
-1)
Isobaric thermal expansion of (▲) 2-methyl-1-butanol, (●) pentan-1-ol*, (■) 2-methyl-2-butanol*, and () pentan-3-ol** at 303.15 K
*M. Dzida, J. Chem. Eng. Data 54 (2009) 1034-1040**Calculated from densities reported by D. González-Salgado, J. Troncoso, F. Plantier, J. L. Daridon, D. Bessières,
J. Chem. Thermodyn. 38 (2006) 893-899
0 20 40 60 80 1000.6
0.7
0.8
0.9
1.0
1.1
1.2
p / (MPa)
p ·
10
3/
(K-1
)
Isothermal compressibility of () 2-methyl-1-butanol, (●) pentan-1-ol*, (■) 2-methyl-2-butanol*, and () pentan-3-ol** at 303.15 K
*M. Dzida, J. Chem. Eng. Data 54 (2009) 1034-1040**D. González-Salgado, J. Troncoso, F. Plantier, J.L. Daridon, D. Bessières, J. Chem. Thermodyn. 38 (2006) 893-899.
0 20 40 60 80 1000.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
p / (MPa)
T ·
10
9/
(Pa-1
)
pTp
TpVS
TVU
pVTT
int
pT
pT
p
int
Internal pressure
pC
T
uTp
p
pp
12
2int1
Internal pressure is related to a work of intermolecular forces that accompany the change of volume.
315
320
325
330
335
340
345
350
355
360
365
370
0 20 40 60 80 100p / MPa
p in
t · 1
0 -6
/ (P
a )
280
285
290
295
300
305
310
315
0 20 40 60 80 100p / MPa
p in
t · 1
0 -6
/ (P
a )
Pressure dependence of internal pressure
(●) 293.15 K; (○) 298.15 K; (■) 303.15 K; (□) 308.15 K; (▲) 313.15 K; (Δ) 318.15 K() 323.15 K; () 333.15 K; (+) 343.15 K; (ӿ) 353.15 K; (—) 363.15 K; (-) 368.15 K
pentan-1-ol 2-methyl-2-butanol
2-methyl-1-butanolpentan-3-ol
0 20 40 60 80 100300
310
320
330
340
350
360
370
380
p / MPa
p in
t · 1
0 -6/
(Pa)
0 20 40 60 80 100300
310
320
330
340
350
360
370
380
p / MPa
p in
t · 1
0 -6
/ (P
a)
0 20 40 60 80 100280
285
290
295
300
305
310
315
320
p / MPa
p in
t · 1
0 -6/
(Pa)
Summary
The effect of pressure on isobaric heat capacity and isobaric thermal expansion for 2-methyl-1-butanol and pentan-1-ol is smaller than that for 2-methyl-2-butanol and pentan-3-ol and for isothermal compressibility this effect is the highest for 2-methyl-2-butanol
Heat capacity, isobaric thermal expansion, and isothermal compressibility
For 2-methyl-1-butanol, pentan-1-ol, and pentan-3-ol the internal pressure as function of pressure shows maximum.
For 2-methyl-2-butanol, the internal pressure increases with increasing pressure.
Internal pressure
For 2-methyl-2-butanol, pentan-1-ol, and pentan-3-ol the crossing points of the isotherms of internal pressure are observed.
For 2-methyl-2-butanol, pentan-1-ol, and pentan-3-ol the internal pressure decreases with increasing temperature at pressures up to the crossing point and then it increases with the increase of temperature.
For 2-methyl-1-butanol the internal pressure increases with increasing temperature.