A molecular model for H(2) interactions in aliphatic and aromatic hydrocarbons

Area of Science:

• Computational chemistry
• Physical chemistry
• Molecular modeling

Background:

• Understanding molecular hydrogen interactions with hydrocarbons is crucial for various chemical processes.
• Accurate modeling requires precise potential energy functions and interaction parameters.

Purpose of the Study:

• To develop and validate a computational model for molecular hydrogen interacting with aliphatic and aromatic hydrocarbons.
• To investigate the influence of different hydrocarbon types and mixtures on hydrogen behavior.

Main Methods:

• Ab initio calculations (Møller-Plesset method) for electrostatic properties and energy variations.
• Molecular dynamics simulations using a two-center Lennard-Jones potential for hydrogen.
• Optimization of Lennard-Jones parameters against experimental hydrogen solubility data.
• Test particle insertion method for solubility calculations.

Main Results:

• Optimized model accurately reproduces experimental hydrogen solubility in benzene and cyclohexane.
• Specific interaction parameters for hydrogen-aliphatic and hydrogen-aromatic systems were determined, avoiding standard combining rules.
• Molecular dynamics simulations revealed structural and thermodynamic properties of hydrogen in various hydrocarbon environments.
• Electrostatic charges were found to be irrelevant and computationally expensive for this system.

Conclusions:

• The developed model provides a reliable method for simulating hydrogen-hydrocarbon interactions.
• Excluding Coulombic interactions simplifies the model without compromising accuracy for these systems.
• The findings offer valuable insights for designing chemical processes involving hydrogen and hydrocarbons.