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Infinite dilute diffusion coefficients ( D 12 ) of normal alkanes (C1 to C14) in 1-octanol (C8-OH), as well as primary alkanols (C1-OH to C14-OH) in n-octane (C8) have been studied using molecular dynamics simulation in the temperature range from 298 to 374 K and at atmosphere pressure. Simulated D 12 values for short-chain solute molecules show a good agreement with the experimental ones taken from literature, while for the long-chain solute molecules the overestimation is large. Besides, the structures of solute molecules in above fluid mixtures are investigated by calculating radial distribution functions, radius of gyration, end-to-end distance, and root mean square fluctuation of atomic positions. These results confirm long-chain n -alkanes and n -alkanols molecules are curved and curled up, which we call it flexibility. Moreover, flexibilities for solute molecules (5 ≤ n ≤ 9) are symmetric but for much long-chain solute molecules like n-tetradecane (C14) and 1-tetradecanol (C14-OH) are asymmetric. We believe that strong chain-chain interactions are existed between different long-chain molecules, and it will result in the solute and solvent molecules are intertwisted. The serious overestimation of simulated D 12 for long-chain solute molecules can be reasonably explained by the intertwist effect. [ABSTRACT FROM AUTHOR]

Self-diffusion of methanol, ethanol, 1-propanol and 2-propanol has been studied by molecular dynamics simulation in the temperature range between the melting pressure curve and 478 K at pressures up to 300 MPa. The simulation results on self-diffusion of methanol, ethanol and 2-propanol (for 2-propanol, at high temperatures) agree well with experiment, which suggests that the simulation method is a powerful tool to obtain self-diffusion coefficients over wide range of temperature and pressure, under which it is rather difficult for experiments. The local structures of methanol, ethanol and 2-propanol are investigated by calculating the radial distribution functions, H-bond numbers, coordination numbers and the ratios of H-bond number divided by coordination number. The correlation between self-diffusion and structural properties, and the influence of temperature and pressure on them are discussed. The degree of forming H-bond space network in methanol, ethanol and water is higher than that in 2-propanol, and they are all higher than those in ammonia and methylamine. The simulation results demonstrate that the effect of hydrogen bonding on the translational dynamics in methanol and ethanol is more pronounced than that in 2-propanol. [ABSTRACT FROM PUBLISHER]

Intradiffusion coefficients of acetylacetone (AcAc) andmethanol/ethanol/1-propanol/1-butanolwere measured in binary liquid mixtures over the whole concentrationrange at 303.15 K by the 1H diffusion-order spectroscopy(DOSY) nuclear magnetic resonance (NMR) method based pulse field gradient(PFG). The solvent effect on the enol-keto tautomeric equilibriumas well as differences in intradiffusion coefficients (D) between two tautomers were also studied. The experimental resultsshow that from methanol to 1-butanol, the differences in Dbetween the enol and keto tautomer vary from 5 % to 26 % at differentconcentrations of AcAc. The densities and viscosities of binary liquidmixtures of AcAc with the above four alkanols have also been determinedat 303.15 K and employed to calculate the excess molar volumes anddeviations in viscosity over the entire range of mole fractions. Isothermsof VEas a function of mole fraction ofAcAc show positive deviations in methanol and ethanol but negativedeviations in 1-propanol and 1-butanol, whereas all isotherms of Δηas a function of mole fraction of AcAc record negative deviations.The VEand Δη are fitted toa Redich–Kister type equation. The measured results are interpretedin terms of molecular interactions in the solutions. [ABSTRACT FROM AUTHOR]

Modification of Fe-tricarboxylate based metal–organic gels yielded tert-butyl substituted or phosphine-functionalised gels in alcohols or DMF, which were prepared from 5-tert-butylisophthalic acid and 5-diphenylphosphanylisophthalic acid, respectively. Owing to their permeability, such phosphine-functionalised metal–organic gels can act as a new type of functionalisable porous scaffold. The phosphorus-containing gel was subsequently functionalised with Pd(ii) by immersion in a solution of Pd(COD)Cl2(COD = 1,5-cyclooctadiene). The subsequently functionalised Pd(ii)-immobilised gel and its xerogel/aerogel showed high activity in the catalysis of Suzuki C–C coupling comparable to unsupported complexes. The gel/xerogels could be reused under ambient atmosphere. [ABSTRACT FROM AUTHOR]