Physical Chemistry for the Life Sciences. By Peter Atkins and Julio de Paula.

Mohrdieck, Camilla

doi:10.1002/cphc.200600131

Cited by 3 publications

(2 citation statements)

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“…There is one EMIM-Cl molecular unit in the simulation cell. We applied the Lennard-Jones potential [22][23][24] to describe interaction between water molecules and methane molecules, as well as the Lorentz-Berthelot mixing rule [25] for interaction parameters. The specific interaction parameters between the molecules [26] are shown in Table 1.…”

Section: Molecular Model and Simulation Methodsmentioning

confidence: 99%

Inhibition Mechanism of EMIM-Cl to Methane Gas Hydrate by Molecular Dynamics Simulation

Xin

Xu²,

Li³

et al. 2022

Energies

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Deep-water gas well testing is a key technology for obtaining reservoir production and physical property parameters. However, gas hydrates could easily form and cause blockage in the low-temperature and high-pressure environment on the seafloor. Therefore, it is extremely important to inhibit hydrate growth in deep-water operations. Ionic liquid is a type of hydrate inhibitor with both thermodynamic and kinetic effects. However, its intrinsic inhibiting mechanism is still unclear. By using molecular dynamics simulation, the growth process of methane hydrate in the 1-ethyl-3-methylimidazole chloride (EMIM-Cl)-containing system at the pressure of 15 MPa and temperature of 273.15 K was studied. The system energy and angular order parameters (AOP) were extracted as the evaluation indicators. It was found that the time for the complete growth of methane hydrate in the EMIM-Cl-containing system was about 10 ns, longer than that in the pure water, indicating that EMIM-Cl showed an obvious inhibition effect to hydrate growth. The results also implied that the joint action of hydrogen bond and steric hindrance might be the inhibition mechanism of EMIM-Cl. Some six-membered rings in hydrate crystal large cage structures evolved from five-membered rings under the effect of EMIM, which partly contributed to the delay of hydrate formation.

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Section: Molecular Model and Simulation Methodsmentioning

confidence: 99%

Inhibition Mechanism of EMIM-Cl to Methane Gas Hydrate by Molecular Dynamics Simulation

Xin

Xu²,

Li³

et al. 2022

Energies

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“…ΔH ‡ represents the difference in energy between ground state and the transition state in a chemical reaction. The higher activation enthalpy means the more energy required for the products to form in an activated state (Atkins and De Paua, 2006). In general, a reaction will take place faster if the value of ΔH ‡ and E a are low.…”

Section: Dsc Kineticsmentioning

confidence: 99%

Oxidation kinetics of hazelnut oil treated with ozone

Uzun

İbanoğlu

2018

Grasas y Aceites

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SUMMARY:The present study investigates the oxidation kinetics of hazelnut oil ozonated in different treatment periods (1, 5, 60 and 180 min). The kinetic rate constant (k) was taken as the inverse of oxidation onset time (T o ) observing a linear relationship from the plot of lnT o to isothermal temperatures (373, 383, 393, and 403 K) carried out at differential scanning calorimetry. Kinetic parameters, activation energy (E a ), activation enthalpy (ΔH ‡ ) and entropy (ΔS ‡ ) were calculated based on the Arrhenius equation and activated complex theory. k values showed an exponential rise with the increase of ozone treatment time. The increase in k correlated well with the increase in the peroxide and free fatty acid values of all samples. E a and ΔH ‡ of the ozone treated oils showed a reducing trend and reflected an increased oxidation sensitivity after ozone treatment. Consistently, an increase in ΔS ‡ indicated a faster oxidation reaction with an increase in ozone exposure time. However, no significant difference was observed in k, E a , ΔH ‡ , ΔS ‡ (p < 0.05) as a function of storage period, after the hazelnut oil was treated with ozone for 1 min. KEYWORDS: DSC; Hazelnut oil; Kinetics of oxidation; OzoneRESUMEN: Cinética de oxidación del aceite de avellana tratado con ozono. El presente estudio investiga la ciné-tica de oxidación del aceite de avellana ozonizado durante diferentes períodos (1, 5, 60 y 180 min). La constante de velocidad cinética (k) se tomó como la inversa del tiempo de inicio de la oxidación (To) observando una relación lineal cuando se representa el lnTo con las temperaturas isotérmicas (373, 383, 393 y 403 K) llevadas a cabo en calorimetría de barrido diferencial. Los parámetros cinéticos, energía de activación (Ea), entalpía de activación (ΔH ‡ ) y entropía (ΔS ‡ ) se calcularon sobre la base de la ecuación de Arrhenius y de la teoría compleja activada. Los valores de k mostraron un aumento exponencial con el aumento del tiempo de tratamiento de ozono. El aumento de k se correlacionó bien con el aumento de peróxidos y de los ácidos grasos libres de todas las muestras. Ea y ΔH ‡ de los aceites tratados con ozono mostraron una tendencia reductora que refleja una mayor sensibilidad a la oxidación de los aceites después del tratamiento con ozono. Consistentemente, un aumento de ΔS ‡ indicó una reacción de oxidación más rápida con un aumento del tiempo de exposición al ozono. Sin embargo, no se observó diferencia significativa en k, Ea, ΔH ‡ , ΔS ‡ (p <0.05) en función del período de almacenamiento, después de que el aceite de avellana fue tratado con ozono durante 1 min.

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