title: Atomistic Molecular Dynamics Simulations of Carbon Dioxide Diffusivity in n-Hexane, n-Decane, n-Hexadecane, Cyclohexane, and Squalane.
abstract: Atomistic molecular dynamics simulations were carried out to obtain the diffusion coefficients of CO2in n-hexane, n-decane, n-hexadecane, cyclohexane, and squalane at temperatures up to 423.15 K and pressures up to 65 MPa. Three popular models were used for the representation of hydrocarbons: the united atom TraPPE (TraPPE-UA), the all-atom OPLS, and an optimized version of OPLS, namely, L-OPLS. All models qualitatively reproduce the pressure dependence of the diffusion coefficient of CO2in hydrocarbons measured recently, and L-OPLS was found to be the most accurate. Specifically for n-alkanes, L-OPLS also reproduced the measured viscosities and densities much more accurately than the original OPLS and TraPPE-UA models, indicating that the optimization of the torsional potential is crucial for the accurate description of transport properties of long chain molecules. The three force fields predict different microscopic properties such as the mean square radius of gyration for the n-alkane molecules and pair correlation functions for the CO2-n-alkane interactions. CO2diffusion coefficients in all hydrocarbons studied are shown to deviate significantly from the Stokes-Einstein behavior.
authors.affiliation: Chemical Engineering Program, Texas A&M University at Qatar , P.O. Box 23874, Doha, Qatar.
authors.forename: Othonas A
authors.initials: OA
authors.lastname: Moultos
authors.affiliation: Chemical Engineering Program, Texas A&M University at Qatar , P.O. Box 23874, Doha, Qatar.|Environmental Research Laboratory, National Centre for Scientific Research "Demokritos" , 15310 Aghia Paraskevi Attikis, Greece.
authors.forename: Ioannis N
authors.initials: IN
authors.lastname: Tsimpanogiannis
authors.affiliation: Department of Chemical and Biological Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Athanassios Z
authors.identifier: 0000-0002-8152-6615
authors.initials: AZ
authors.lastname: Panagiotopoulos
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus , London, SW7 AZ, United Kingdom.
authors.forename: J P Martin
authors.identifier: 0000-0002-6403-2488
authors.initials: JP
authors.lastname: Trusler
authors.affiliation: Chemical Engineering Program, Texas A&M University at Qatar , P.O. Box 23874, Doha, Qatar.
authors.forename: Ioannis G
authors.identifier: 0000-0002-2409-6831
authors.initials: IG
authors.lastname: Economou