Excess Enthalpies for the Binary Systems of N-Alkane + 1 ... · Excess Enthalpies for the Binary Systems of N-Alkane + 1-Alkanol at 313.15 K Kwon, Cheong Hoon Thermodynamics and Properties

Excess Enthalpies for the Binary Systems of N-Alkane + 1-Alkanol at 313.15 K

Kwon, Cheong Hoon

Thermodynamics and Properties Lab. Dept. of Chemical and Biological Engineering, Korea Univ.


Introduction

The Needs of Excess Enthalpy

Excess enthalpy data of binary mixture are important in

understanding the nature of interactions between the molecules.

Excess enthalpy data plays an important role in chemical

engineering process design and operation.

System : N-alkane + 1-alkanol

Temperature condition : 313.15K


Types of Calorimeter

Three types of calorimeter: Batch calorimeter, Displacement calorimeter, Flow calorimeter

Flow calorimeter

① To make measurements over a wide range of pressure and temperature conditions

② The measurements of the excess enthalpy canbe made for gases as well as liquids

③ To require large amounts of chemicals


Materials

Isothermal microcalorimeter

n-alkanen-octanen-nonanen-decane

1-alkanol Ethanol

1-propanol1-butanol

A B


Apparatus

Model CSC 4400 (Calorimetry Sciences Corporation)

Pump : a set of HPLC pump ( Model Acuflow Series II )

Accuracy of flow rate : ± 2%

Auxiliary equipments

Air bath

Back pressure regulator

Control gas : compressed helium gas

Circulator ( constant temperature )

Isothermal Microcalorimeter ( IMC )


Experimental apparatus


Isothermal microcalorimeter(Model : CSC4400)

HPLC Pump HPLC Pump

Back-pressureregulator

PressureGauge

Pressureregulator

MonitoringUnit

Reagentreservoir

Reagent reservoir

WasteFluid line

Electrical line

Air Bath

Block diagram of experimental apparatus


DifferentialAmplifier

CalibrationHeaters

CoolingSystem

Temperaturecontroller

Printer /Plotter

Keyboard

Monitor

TemperatureMonitor

Access Tubes Thermal Shunts

Sam

ple

Ref

. Cel

l

ThermoelectricSensor

Water Bath

Heat SinkHeat Sink

Water Bath

com

pute

r

Block diagram of IMC


Schematic diagram of flow mixing cell

Inlet B

Mixed Outlet

Inlet A

Inlet FlowThermalEquilibration

ThermalShunt

Flow HeatExchanger

Mixing Tee

Top Access Cover

HPLCPump A

HPLCPump B

Sample A Sample B


Determination

T & P

Determination

T & P

Procedure

I M C

Setting

I M C

Stabilization

Total

Flow RateBase Line

Excess

Enthalpy


Comparison literature data and experimental data

To test the accuracy of calorimeter measurements, System : Octane + Ethanol [ at 298.15K ]

Redlich-Kister Correlation

Where, x is the mole fraction of componentAi is the adjustable parameter

Result S. D. ; 2.62%

=

−− −−=⋅k

i

ii

E xAxxmolJH1

11 )21()1(/


Redlich-Kister Correlation

0.0 0.2 0.4 0.6 0.8 1.00

200

400

600

800

x1

HE (J / mol)

Comparison experimental data HE and literature value from n-octane + ethanol at 298.15K. • , This work ; ,Ramalho R.S., Ruel M.Can. J. (1968); , Zhu S., Shen S., Benson G..C., Lu B.C.-Y (1994)


NLF-HB Theory(1)

Configurational partition function (Ωc)

Helmholtz Free Energy(Ac) derivation

Nonrandom Lattice Fluid Theory EosChemical potential , Fugacity

application

Equilibria of vapor-liquid,vapor-solid,liquid-liquid phase,and Multiphase equilibria including UCST behaviors

Heat of mixing non polar- non polar, non polar- polar, polar- polar binary mixtures of simple and complex molecules


NLF-HB Theory(2)

Helmholtz Free Energy expansion Expression for ( A ) Thermodynamic properties

Partition Function

In a three-dimension lattice,

The coordination number : z =10

Unit cell volume : VH = 9.75 cm3/mol

Effective surface area : 2)2( +−= iii rzzq


NLF-HB Theory (3)

Configurational partition function (Ωc)

Physical term

HBPHYS ΩΩ=ΩΩPHYS : [ Physical term ]… You et al. (1994)

ΩHB : [ Chemical term ] … Extension of Veytsman statistics ( Park et al. 2001 )

)exp( cNRR Uggc β−=Ω

)βUexp(

!2

NΠ!ΠN

!2

NΠΠN

!N!N

!ΠN!NΩc C

2ij

ii

2ij

o

iio

z/2

r

q

i

r −

=


∏ ∏∏∏= = =

−

=

−=ΩN

j

M

k

N

l

Hkl

Hkl

NNklH

kl

Hkl

Hl

Hl

M

kHk

Hk

HB NAPNN

NN

NN H

klHkl

1 1 1

)(0

0

00

1 0

00 )exp()(

!!

!!

!! 0

β

Hydrogen bonding term

Expression of excess enthalpy

+−+= ipureC

imixtureCE PVUxPVUH ,)()(

iNN

cc

TA

NT

NU

,0

−=

∂∂ββ

The molar configurational internal energy for mixture

NLF-HB Theory (4)

Connection of thermodynamic function with configurational functionccA Ω−= lnβ


NLF-HB Theory (5)

Physical Parameters

① Coordination number : z =10

② Lattice volume : VH = 9.75 cm3/mol

③ Pure parameters (ri, εii) :

])/ln([)( 000 TTTTTrTTrrr cbai −++−+=

])/ln([)(/ 000 TTTTTTTk cbaii −++−+= εεεε


NLF-HB Theory(6)

Hydrogen Bonding Parameters

klU klS

molJ /101.25 3×− molJ /5.26−molJ /105.15 3×− molJ /6.16−

alcohols

water

Hydrogen bonding parameters for NLF-HB EOS

HBkl

HBkl

HBkl TSUA −=

The binary interaction parameters

TBAkij /+=)1()( 2/1ijjjiiij k−= εεε


Coefficients, AK, and Standard Deviation, s, for the Representation of HE

Results & Discussions (1)


Pure parameters and temperature ranges of the NLF-HB equation of state




Excess enthalpy HE at 313.15K for alkane(1) + alkanol(2). Experimental data ; • , octane +ethanol ; , octane + 1-propanol; , octane +1-butanol

0.0 0.2 0.4 0.6 0.8 1.00

200

400

600

800

1000

1200

x1

HE

(J /

mol

)



Excess enthalpy HE at 313.15K for alkane(1) + alkanol(2). Experimental data ; • , nonane+ethanol ; , nonane + 1-propanol; , nonane +1-butanol

0.0 0.2 0.4 0.6 0.8 1.00

200

400

600

800

1000

1200

x1

HE

(J /

mol

)



Excess enthalpy HE at 313.15K for alkane(1) + alkanol(2). Experimental data ; • , decane + ethanol ; , decane + 1-propanol ; , decane + 1-butanol

0.0 0.2 0.4 0.6 0.8 1.00

200

400

600

800

1000

1200

x1

HE

(J /

mol

)


Binary interaction parameters from NLF-HB



The features of this work

1. All excess enthalpies have positive values and their graphical shapesare asymmetric.

2. They have maximum value of the mole fraction between 0.60 ml/minand 0.80 ml/min.

3. The HE data was increased for all systems with the addition of thecarbon number.

4. As compared the HE experimental results by following each 1-alkanolsystems, the discrepancies were wholly smaller at n-alkane systemsof mixing with 1-propanol than those with ethanol and 1-butanol.

Summary

Documents

Excess Enthalpies for the Binary Systems of N-Alkane + 1 ... · Excess Enthalpies for the Binary Systems of N-Alkane + 1-Alkanol at 313.15 K Kwon, Cheong Hoon Thermodynamics and Properties