23rd International Symposium on Chemical Reaction Engineering &
CHULALONGKORN UNIVERSITY
7th Asia Pacific Chemical Reaction Engineering Symposium
www.chula.ac.th
BangkokThailand7 - 10 Sep 2014
PF-04
Density of Ethyl Acetate-Palm Oil Mixture in Supercritical Condition
1
2
C. Komintarachat , R. Sawangkeaw and S. Ngamprasertsith
1
3,4*
Program in Petrochemistry, Faculty of Science, Chulalongkorn University, 254 Phyathai Road, Patumwan, Bangkok 10330, Thailand
2
3
The Institute of Biotechnology and Genetic Engineering, Chulalongkorn University,
254 Phayathai Rd., Institute Bldg. 3, Pathumwan, Bangkok 10330, Thailand
Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road,
Pathumwan, Bangkok 10330, Thailand
4
Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University,
254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand
*Corresponding author: somkiat.n@chula.ac.th
Abstract: The interesterification of palm oil in supercritical ethyl acetate in continuous system to produce biofuel is complex to understand
thermodynamic properties during extreme condition, particularly density of two reactants. In this study, an indirect procedure for density measurement
of palm oil and ethyl acetate mixture in a batch system at high temperature and pressure was experimentally investigated using isochoric method. Its
apparatus comprise a constant volume reactor which was individually loaded with a mixture of ethyl acetate and palm oil in different molar ratios (10:1
3
to 30:1) and global densities (0.26 to 0.53 g/cm ). During temperature increment, the changing of pressure was recorded in real-time to obtain the
pressure-temperature relationship. After measuring the change of pressure at various global densities, the pressure-temperature related specific global
density diagram was successfully constructed. At high global densities and high molar ratios of ethyl acetate to palm oil, the transition point took place
closing to the estimated critical point of the mixture. The results will be further employed as database for accurately residence time calculation in
continuous reactor, especially for biofuel production from palm oil in supercritical ethyl acetate.
Keywords: Palm oil, supercritical ethyl acetate, density, isochoric method
Introduction
Methodology
Therefore, the temperature and pressure
determination at constant global density by
isochoric method is readily and convenient for
mixture at supercritical conditions. In this study,
the relationship of global density, molar ratio of
ethyl acetate (ETA) to palm oil, phase transitions at
supercritical condition have been studied. The
obtaining data is valuable for estimating the
residence times for the continuous production of
biofuel in supercritical ethyl acetate for future
work.
160
O
HC
H2C
O
O
C
O
R1
O
C
O
R2
O
C
R3
Triglyceride
O
+
3 CH3C OCH2CH3
Ethyl acetate
C2H5
O
C
O
R1
C2H5
O
C
O
R2
C2H5
O
C
R3
FAEE
+
H2C
C
O
O
CH3
HC
C
O
O
CH3
H2C
C
O
CH3
Pressure (bar)
(2) aluminum foil
(3) tubular furnace
(4) temperature controller

80
0
(5) temperature monitor (6) pressure gauge
400
500
Tempeature (K)
600
700
Comparison of the observation and Kay’mixing rule
prediction
Molar
ratio
A predetermined mass of ethyl acetate and palm oil
was added to the cell. The temperature was increased
slowly from room temperature to 673 K and was kept
at desired level until no variation of the pressure was
observed. The information during the process will be
generated P-T diagram. The discontinuity of slope of
the isochoric line indicates phase transition point .
Results
10
20
30
Mole fraction
Ethyl acetate Palm oil
0.91
0.95
0.97
0.09
0.05
0.03
Observed value *
T c (K) P c (bar)
567
553
537
71
65
59
Predicted value
T c (K) P c (bar)
562
544
537
36
37
38
*Average values obtained from density of 0.35, 0.44 and 0.53 g/
cm3
Conclusions
The density determination of ETA and palm oil system
in SC condition has been accomplished in this work by
indirect isochoric method.
The ETA: oil molar ratio and global density affected the
60
critical point of mixture.
50
The phase transition point from the VLE region to SC
40
region also approximately located and the transition
points were lowered by increasing of global density
and ETA: oil molar ratio.
PR EOS
30
Experimental
20
350
500
Temperature (K)
650
Acknowledgements
Comparison of the experimental and calculation from
Peng-Robinson equation of state (PR EOS)
160
Pressure (bar)
120
To investigate the relationship among pressure,
temperature and global density of palm oil and
ethyl acetate (ETA) mixture in supercritical
conditions by using isochoric method.

40
(1) measurement cell
Triacetin
Objective

120
The interesterification reaction of palm oil
and ETA.
O


Pressure (bar)
The knowledge of the density of pure fluids
and their mixtures is the great importance for the
design of industrial equipment in chemical
engineering [1]. Due to the complex theory of fluid
mixtures, most studies have to be experimentally
carried out to understand the thermodynamic
behavior of fluids. A phase behavior in the
supercritical (SC) reactor during the homogeneous
reaction, depending on the reactants and reaction
conditions [2]. This is due to the fact that, at this
condition, the combination of two substances in
homogeneity is difficult to directly observe.
Recently, Velez et al. [3] measured the density of
reacting mixtures between sunflower oil and SC
alcohols by isochoric technique.
H2C
The pressure vs. temperature of ETA and palm oil
mixtures in 20:1 molar ratio in different global densities
The authors acknowledge the Program in Petrochemistry
and Polymer Science of the Faculty of Science and
Ratchadaphiseksomphot Endowment Fund of Chulalongkorn
University (RES560530071-EN) for financial support.

References


80
[1] S. Peper, R. Dohrn, J. Supercrit. Fluid. 66 (2012) 2–15.
[2] T. Pinnarat, P.E. Savage, Industrial & Engineering Chemistry
Research 47 (2008) 6801-6808.
40
0
400
500
600
Temperature (K)
700
[3] A. Velez, P. Hegel, G. Mabe, E.A. Brignole, Industrial & Engineering
Chemistry Research 49 (2010) 7666-7670.