Use of ab initio quantum mechanics calculations in group contribution methods. 2; Test of new groups in UNIFAC
Journal Article
·
· Industrial and Engineering Chemistry Research; (United States)
- Dept. of Chemical Engineering, Univ. of Delaware, Newark, DE (US)
In this paper the authors show that functional groups identified previously from ab initio molecular orbital calculations lead to better UNIFAC predictions of vapor --- liquid equilibrium, especially for mixtures involving molecules in which proximity effects are important. The authors also find that, for the functional groups we have defined, in many cases it is generally not necessary to distinguish between subgroups. This reduces the total number of main groups and subgroups that must be considered. For some hydrogen-bonding mixtures, neither the new nor the old functional groups lead to satisfactory excess Gibbs free energy predictions. This is in agreement with our previously reported supermolecule calculations which showed that hydrogen-bonding energies did not satisfy group additivity and therefore could not be accounted in group contribution methods.
- OSTI ID:
- 7282367
- Journal Information:
- Industrial and Engineering Chemistry Research; (United States), Journal Name: Industrial and Engineering Chemistry Research; (United States) Vol. 30:5; ISSN IECRE; ISSN 0888-5885
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
08 HYDROGEN
080800* -- Hydrogen-- Properties & Composition
661100 -- Classical & Quantum Mechanics-- (1992-)
664100 -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
CALCULATION METHODS
CHEMICAL BONDS
DISPERSIONS
ELEMENTS
ENERGY
EQUILIBRIUM
FLUIDS
FREE ENERGY
GASES
HYDROGEN
LIQUIDS
MECHANICS
MIXTURES
MOLECULAR ORBITAL METHOD
NONMETALS
PHYSICAL PROPERTIES
PROXIMITY EFFECT
QUANTUM MECHANICS
THERMODYNAMIC PROPERTIES
VAPORS
080800* -- Hydrogen-- Properties & Composition
661100 -- Classical & Quantum Mechanics-- (1992-)
664100 -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
CALCULATION METHODS
CHEMICAL BONDS
DISPERSIONS
ELEMENTS
ENERGY
EQUILIBRIUM
FLUIDS
FREE ENERGY
GASES
HYDROGEN
LIQUIDS
MECHANICS
MIXTURES
MOLECULAR ORBITAL METHOD
NONMETALS
PHYSICAL PROPERTIES
PROXIMITY EFFECT
QUANTUM MECHANICS
THERMODYNAMIC PROPERTIES
VAPORS