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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]

Abstract: In this paper a carbon ionic liquid electrode (CILE) was fabricated with ionic liquid N-hexylpyridinium hexafluorophosphate, which was further modified by a graphene (GR)-MnO2 nanocomposite to get an electrode denoted as GR-MnO2/CILE. Due to the presence of GR-MnO2 nanocomposite on the electrode surface the electrochemical performances of the modified electrode were greatly enhanced. The fabricated electrode showed strong electrocatalytic ability to the electrochemical reaction of rutin with a pair of well-defined redox peaks appeared. Compared with other modified electrodes, the increase of redox peak currents and the decrease of peak-to-peak separation appeared, which could be attributed to the synergistic effects of the materials used. Electrochemical parameters of rutin on GR-MnO2/CILE were calculated with the electron transfer coefficient as 0.5, the electron transfer number as 1.81, the apparent heterogeneous electron transfer rate constant as 1.61s−1 and the diffusion coefficient as 1.57×10−4 cm2/s. Under the selected conditions the reduction peak current was in linear with rutin concentration from 0.01 to 500.0μmol/L with the detection limit as 2.73nmol/L (3σ) by differential pulse voltammetry. The proposed method was further applied to the rutin tablet samples determination with satisfactory results. [Copyright &y& Elsevier]