Isooctane !Short name 540-84-1 !CAS number 2,2,4-Trimethylpentane !Full name (CH3)2CHCH2C(CH3)3 !Chemical formula {C8H18} Isobutyltrimethylmethane !Synonym 114.22852 !Molar mass [g/mol] 165.77 !Triple point temperature [K] 372.358 !Normal boiling point [K] 544.0 !Critical temperature [K] 2572.0 !Critical pressure [kPa] 2.12 !Critical density [mol/L] 0.303 !Acentric factor 0.0 !Dipole moment [Debye]; Smyth, C.P. and W.N. Stoops, J. Am. Chem. Soc., 50, 1883-1890 (1928). NBP !Default reference state 10.0 !Version number 1262 !UN Number :UN: br-alkane !Family :Family: 5496.658 !Heating value (upper) [kJ/mol] :Heat: 1S/C8H18/c1-7(2)6-8(3,4)5/h7H,6H2,1-5H3 !Standard InChI String :InChi: NHTMVDHEPJAVLT-UHFFFAOYSA-N !Standard InChI Key :InChiKey: f174a9b0 (octane) !Alternative fluid for mixing rules :AltID: c2dd9ef0 !Hash number from InChI Key :Hash: !The fluid files contain general information about the fluid in the first 15 to 20 lines, followed by sections for the ! equations of state, transport equations, and auxiliary equations. Equations of state are listed first. The NIST recommended ! equations begin with a hash mark (#). The secondary equations begin with the @ symbol. These symbols can be swapped to ! select a secondary equation as primary and the primary as secondary. The equation of state section also contains auxiliary ! equations for the ideal gas heat capacity or ideal gas Helmholtz energy. Below the equations of state (both primary and ! secondary) are the transport equations, first viscosity and then thermal conductivity. These are then followed by the ! secondary equations if available. The transport section also contains auxiliary equations required to calculate either the ! dilute gas state or the critical enhancement. At the end of the file are additional but not necessary auxiliary equations, ! including simple equations for the vapor pressure, saturated liquid and vapor densities, melting line (for some fluids), and ! sublimation line (for even fewer fluids). This section also contains the equations for dielectric constant and surface ! tension if available. The sections are divided by different symbols (these being _-+=^*~) to aid the eye in locating a ! particular section. Secondary equations are indented 10 spaces to avoid confusion with the NIST recommended equations. The ! end of the fluid file is marked with @END. Anything below that is ignored. ! compiled by A.K. Lemmon, NIST Physical and Chemical Properties Division, Boulder, Colorado ! 02-01-09 AKL, Original version. ! 08-02-10 TMB, Add preliminary EOS. ! 08-02-10 TMB, Add ancillary equations. ! 01-13-11 EWL, Add final EOS. ! 03-08-11 MLH, Revise preliminary transport. ! 04-06-13 EWL, Add dipole moment. ! 04-17-14 EWL, Add surface tension coefficients of Mulero et al. (2014). ! 05-17-16 MLH, Revise ECS transport. ! 02-09-17 MLH, Revise ECS transport. ________________________________________________________________________________ #EOS !---Equation of state--- FEQ !Helmholtz equation of state for isooctane of Blackham et al. (2018). :TRUECRITICALPOINT: 544.0 2.12 !True EOS critical point [K, mol/L] (where dP/dD=0 and d^2P/dD^2=0 at constant T) :DOI: ? ?``````````````````````````````````````````````````````````````````````````````` ?Blackham, T.M., Lemmon, A.K., and Lemmon, E.W., ? to be submitted to Int. J. Thermophys., 2018. ? !``````````````````````````````````````````````````````````````````````````````` 165.77 !Lower temperature limit [K] 600.0 !Upper temperature limit [K] 1000000.0 !Upper pressure limit [kPa] 6.97 !Maximum density [mol/L] CPP !Pointer to Cp0 model 114.22852 !Molar mass [g/mol] 165.77 !Triple point temperature [K] 0.00001796 !Pressure at triple point [kPa] 6.96 !Density at triple point [mol/L] 372.358 !Normal boiling point temperature [K] 0.303 !Acentric factor 544.0 2572.0 2.12 !Tc [K], pc [kPa], rhoc [mol/L] 544.0 2.12 !Reducing parameters [K, mol/L] 8.314472 !Gas constant [J/mol-K] 10 4 4 12 0 0 0 0 0 0 0 0 !# terms and # coefs/term for normal terms, Gaussian terms, and Gao terms 0.0568901 1.0 4. 0. !a(i),t(i),d(i),l(i) 1.96155 0.3 1. 0. -2.81164 0.75 1. 0. -0.815112 1.11 2. 0. 0.326583 0.55 3. 0. -1.60893 2.2 1. 2. -0.454734 3.7 3. 2. 1.08306 1.53 2. 1. -0.722876 2.1 2. 2. -0.0434052 0.9 7. 1. 1.96648 0.88 1. 2. 2. -0.75 -0.59 1.44 0.66 0. 0. 0. -0.465082 1.1 1. 2. 2. -1.13 -1.45 0.68 0.90 0. 0. 0. -0.409398 2.75 3. 2. 2. -0.87 -0.50 0.51 0.54 0. 0. 0. 0.0232131 1.0 3. 2. 2. -4.73 -10.52 0.8 0.18 0. 0. 0. eta beta gamma epsilon EXP[eta*(delta-epsilon)^2+beta*(tau-gamma)^2] #AUX !---Auxiliary function for Cp0 CPP !Ideal gas heat capacity function for isooctane of Blackham and Lemmon (2018). ? ?``````````````````````````````````````````````````````````````````````````````` ?Blackham, T.M., Lemmon, A.K., and Lemmon, E.W., 2018. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 1.0 8.314472 !Reducing parameters for T, Cp0 1 3 0 0 0 0 0 !Nterms: polynomial, exponential, cosh, sinh 10.76 0.0 15.48 775.0 34.42 1900.0 21.42 5100.0 #AUX !---Auxiliary function for PX0 PX0 !Helmholtz energy ideal-gas function for isooctane of Blackham and Lemmon (2018). ? ?``````````````````````````````````````````````````````````````````````````````` ?Blackham, T.M., Lemmon, A.K., and Lemmon, E.W., 2018. ? !``````````````````````````````````````````````````````````````````````````````` 1 2 3 0 0 0 0 0 !Nterms: ai*log(tau**ti); ai*tau**ti; ai*log(1-exp(bi*tau)) 9.76 1.0 !ai, ti for [ai*log(tau**ti)] terms 8.1401504838649998 0.0 !aj, ti for [ai*tau**ti] terms -4.3415749539204382 1.0 !aj, ti for [ai*tau**ti] terms 15.48 775.0 !aj, ti for [ai*log(1-exp(-ti/T)] terms 34.42 1900.0 21.42 5100.0 -------------------------------------------------------------------------------- @EOS !---Cubic equation of state--- PRT !Translated Peng-Robinson equation for isooctane. ? ?``````````````````````````````````````````````````````````````````````````````` ?Volume translation of Peng Robinson EOS. ? Translation computed so that sat. liquid density at Tr=0.7 matches FEQ Helmholtz equation ? of state for isooctane of Lemmon (2004). ? !``````````````````````````````````````````````````````````````````````````````` 165.3 !Lower temperature limit [K] 1000. !Upper temperature limit [K] 100000.0 !Upper pressure limit [kPa] 6.96 !Maximum density [mol/L] CPP !Pointer to Cp0 model 114.2285 !Molar mass [g/mol] 0.303 !Acentric factor from preliminary FEQ EOS 543.8 !Critical temperature [K] 2560 !Critical pressure [kPa] from preliminary FEQ EOS 2.22 !Critical density [mol/L] from preliminary FEQ EOS 8.314472 !Gas constant [J/mol-K] 1 !Number of parameters -0.0058658 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ #TRN !---ECS Transport--- ECS !Extended Corresponding States model (Octane reference) for isooctane. :DOI: 10.6028/NIST.IR.8209 ? ?``````````````````````````````````````````````````````````````````````````````` ?Huber, M.L., "Models for the Viscosity, Thermal Conductivity, and Surface Tension ? of Selected Pure Fluids as Implemented in REFPROP v10.0," NISTIR 8209, 2018. ? doi: 10.6028/NIST.IR.8209 ? ?VISCOSITY ? Padua, A.A.H., Fareleira, J.M.N.A., and Calado, J.C.G., "Density and Viscosity Measurements of 2,2,4-Trimethylpentane (Isooctane) from 198 K to 348 K and up to 100 MPa," J. Chem. Eng. Data, 41:1488-1494, 1996. ? Zambrano, J.R., et al., "Contributing to Accurate High Pressure Viscosity Measurements: Vibrating Wire Viscometer and Falling Body Viscometer Techniques," J. Chem. Thermo., 96:104-116, 2016. ? ?The estimated uncertainty for the liquid phase at pressures to 100 MPa is 5%, ? 10% for the gas phase. ? ?THERMAL CONDUCTIVITY ? Watanabe, H., "Thermal Conductivity and Thermal Diffusivity of Sixteen Isomers of Alkanes: CnH2n+2(n=6 to 8)," J. Chem. Eng. Data, 48:124-136, 2003. ? Naziev, Y.M. and M.A. Aliev, "Study of the Thermophysical Properties of n-Undecane; n-Heptadecane and n-Octadecane at Various Temperatures and Pressures," Izv. Vyssh. Uchebn. Zaved., Neft Gaz, 16:73-76, 1973. ? ?The estimated uncertainty of the liquid phase is 7% for pressures to 100 MPa, ? 10% for the gas phase, and larger in the critical region. ? ?The Lennard-Jones parameters were estimated by fitting to data. ? !``````````````````````````````````````````````````````````````````````````````` 165.77 !Lower temperature limit [K] 600.0 !Upper temperature limit [K] 100000.0 !Upper pressure limit [kPa] 15.0 !Maximum density [mol/L] (limit of ECS-thermo fit) FEQ OCTANE.FLD VS1 !Model for reference fluid viscosity TC1 !Model for reference fluid thermal conductivity NUL !Large molecule identifier 1 !Lennard-Jones flag (0 or 1) (0 => use estimates) 0.588 !Lennard-Jones coefficient sigma [nm] 635.7 !Lennard-Jones coefficient epsilon/kappa [K] 1 0 0 !Number of terms in f_int term in Eucken correlation, spare1, spare2 0.00115 0. 0. 0. !Coefficient, power of T, spare1, spare2 2 0 0 !Number of terms in psi (visc shape factor): poly,spare1,spare2 1.09755 0. 0. 0. !Coefficient, power of Tr, power of Dr, spare -0.0223075 0. 1. 0. !Coefficient, power of Tr, power of Dr, spare 2 0 0 !Number of terms in chi (t.c. shape factor): poly,spare1,spare2 0.827544 0. 0. 0. !Coefficient, power of Tr, power of Dr, spare 0.0391177 0. 1. 0. !Coefficient, power of Tr, power of Dr, spare TK3 !Pointer to critical enhancement auxiliary function #AUX !---Auxiliary function for the thermal conductivity critical enhancement TK3 !Simplified thermal conductivity critical enhancement for isooctane of Perkins et al. (2013). ? ?``````````````````````````````````````````````````````````````````````````````` ?Perkins, R.A., Sengers, J.V., Abdulagatov, I.M., and Huber, M.L., ? "Simplified Model for the Critical Thermal-Conductivity Enhancement in Molecular Fluids," ? Int. J. Thermophys., 34(2):191-212, 2013. doi: 10.1007/s10765-013-1409-z ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 9 0 0 0 !# terms: CO2-terms, spare, spare, spare 1.0 1.0 1.0 !Reducing parameters for T, rho, tcx [mW/(m-K)] 0.63 !Nu (universal exponent) 1.239 !Gamma (universal exponent) 1.02 !R0 (universal amplitude) 0.063 !Z (universal exponent--not used for t.c., only viscosity) 1.0 !C (constant in viscosity eqn = 1/[2 - (alpha + gamma)/(2*nu)], but often set to 1) 0.256e-9 !Xi0 (amplitude) [m] 0.059 !Gam0 (amplitude) [-] 7.71e-10 !Qd_inverse (modified effective cutoff parameter) [m] 816.0 !Tref (reference temperature)=1.5*Tc [K] ******************************************************************************** @TCX !---Thermal conductivity--- TC5 !Pure fluid thermal conductivity model for isooctane of Chung et al. (1988). ? ?``````````````````````````````````````````````````````````````````````````````` ?Chung, T-H., Ajlan, M., Lee, L.L. and Starling, K.E. ? "Generalized Multiparameter Correlation for Nonpolar and Polar Fluid Transport Properties" ? Ind. Eng. Chem. Res. 1998, 27, 671-679. ? !``````````````````````````````````````````````````````````````````````````````` 165.77 !Lower temperature limit [K] 600.0 !Upper temperature limit [K] 1000000.0 !Upper pressure limit [kPa] 6.97 !Maximum density [mol/L] 0.63 !Lennard-Jones coefficient sigma [nm] =0.809vc*(1/3)A 431.99 !Lennard-Jones coefficient epsilon/kappa [K] =Tc/1.2593 0.3 0. 0. !w, mur, kappa for Chung 0 !Additional parameters for Chung TK3 !Pointer to critical enhancement auxiliary function @ETA !---Viscosity--- VS5 !Pure fluid viscosity model for isooctane of Chung et al. (1988). ? ?``````````````````````````````````````````````````````````````````````````````` ?Chung, T-H., Ajlan, M., Lee, L.L. and Starling, K.E. ? "Generalized Multiparameter Correlation for Nonpolar and Polar Fluid Transport Properties" ? Ind. Eng. Chem. Res. 1998, 27, 671-679. ? !``````````````````````````````````````````````````````````````````````````````` 165.77 !Lower temperature limit [K] 600.0 !Upper temperature limit [K] 1000000.0 !Upper pressure limit [kPa] 6.97 !Maximum density [mol/L] 1 !Number of terms associated with dilute-gas function NUL !Pointer to reduced effective collision cross-section model; not used 0.63 !Lennard-Jones coefficient sigma [nm] =0.809vc*(1/3)A 431.99 !Lennard-Jones coefficient epsilon/kappa [K] =Tc/1.2593 1.0 1.0 !Reducing parameters for T, eta 0.22826 0.5 !=0.021357*SQRT(MW) [Chapman-Enskog term] 0 !Number of terms for initial density dependence 0.3 0.0 0.0 0.0 0 !w, mur, kappa for Chung 0 !Additional parameters for Chung NUL !Pointer to the viscosity critical enhancement auxiliary function (none used) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #STN !---Surface tension--- ST1 !Surface tension model for isooctane of Mulero et al. (2014). :DOI: 10.1063/1.4878755 ? ?``````````````````````````````````````````````````````````````````````````````` ?Mulero, A. and Cachadiņa, I., ? "Recommended Correlations for the Surface Tension of Several Fluids ? Included in the REFPROP Program," ? J. Phys. Chem. Ref. Data, 43, 023104, 2014. ? doi: 10.1063/1.4878755 ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 1 !Number of terms in surface tension model 543.87 !Critical temperature used in fit (dummy) 0.04794 1.209 !Sigma0 and n #PS !---Vapor pressure--- PS5 !Vapor pressure equation for isooctane of Blackham et al. (2018). ? ?``````````````````````````````````````````````````````````````````````````````` ?Functional Form: P=Pc*EXP[SUM(Ni*Theta^ti)*Tc/T] where Theta=1-T/Tc, Tc and Pc ? are the reducing parameters below, which are followed by rows containing Ni and ti. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 544.0 2572.0 !Reducing parameters 5 0 0 0 0 0 !Number of terms in equation -7.7985 1.0 8.1280 1.5 -7.3106 1.6 -3.9392 4.0 -1.6732 16.0 #DL !---Saturated liquid density--- DL1 !Saturated liquid density equation for isooctane of Blackham et al. (2018). ? ?``````````````````````````````````````````````````````````````````````````````` ?Functional Form: D=Dc*[1+SUM(Ni*Theta^ti)] where Theta=1-T/Tc, Tc and Dc are ? the reducing parameters below, which are followed by rows containing Ni and ti. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 544.0 2.12 !Reducing parameters 3 0 0 0 0 0 !Number of terms in equation 1.1535 0.286 1.3709 0.54 0.38804 3.3 #DV !---Saturated vapor density--- DV3 !Saturated vapor density equation for isooctane of Blackham et al. (2018). ? ?``````````````````````````````````````````````````````````````````````````````` ?Functional Form: D=Dc*EXP[SUM(Ni*Theta^ti)] where Theta=1-T/Tc, Tc and Dc are ? the reducing parameters below, which are followed by rows containing Ni and ti. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 544.0 2.12 !Reducing parameters 5 0 0 0 0 0 !Number of terms in equation -2.5793 0.366 -6.4934 1.11 -18.631 3.0 -54.123 6.4 -123.58 14.0 @END c 1 2 3 4 5 6 7 8 c2345678901234567890123456789012345678901234567890123456789012345678901234567890