Abstract: In the temperature range of 823.15-923.15 K, the adsorption and diffusion properties of eicosane (C₂₀H₄₂), anthracene (C₁₄H₁₀) and p-dibutylcyclohexane (C₁₄H₂₈) in 5 nm pore channels of calcium oxide were studied by Monte Carlo and molecular dynamics methods. The adsorption isotherm, molecular diffusion kinetics, probability density distribution and radial distribution function of the three molecules in the calcium oxide pore channels were analyzed. The analysis of adsorption isotherm showed that the adsorption capacity of C₁₄H₁₀ in calcium oxide pore was the highest, the adsorption capacity of C₁₄H₂₈ was the lowest at 923.15 K, and the adsorption capacity of C₂₀H₄₂ was the lowest at 823.15 K; C₂₀H₄₂ and C₁₄H₁₀ were multi-layer adsorption, while C₁₄H₂₈ was mono-layer adsorption. Molecular diffusion dynamics analysis showed that the diffusion coefficient of C₂₀H₄₂ was the largest, followed by that of C₁₄H₂₈, and that of C₁₄H₁₀ was the smallest. The diffusion performance is mainly affected by temperature and molecular configuration. According to the activation energy of diffusion, the diffusion of C₁₄H₁₀ is most affected by temperature, followed by that of C₁₄H₂₈, and that of C₂₀H₄₂ is the smallest. The analysis of probability density distribution and radial distribution function showed that there were three adsorption layers of C₁₄H₁₀ near the surface at distances of 0.4, 0.7 and 1.1 nm, while C₂₀H₄₂ and C₁₄H₂₈ had three adsorption layers at 0.5 nm from the surface.

Key words: eicosane, anthracene, p-dibutylcyclohexane, calcium oxide, adsorption, diffusion, molecular simulation