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Results for “ALKANE”
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Microporous Metal–Organic Frameworks for Adsorptive Separation of C5–C6 Alkane Isomers
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Exploring the Chemical Space of Linear Alkane Pyrolysis via Deep Potential GENerator
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Hydration of Linear Alkanes is Governed by the Small Length-Scale Hydrophobic Effect
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Phase Equilibria of Water/CO 2 and Water/ n -Alkane Mixtures from Polarizable Models
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Adsorption Thermodynamics and Intrinsic Activation Parameters for Monomolecular Cracking of n-Alkanes on Bronsted Acid Sites in Zeolites
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Modeling C–H Bond Activation and Oxidations of Alkanes over Cu–MOR Using First-Principles Methods
Direct conversion of methane to methanol can significantly boost the economic value of shale gas utilization. However, the stable C–H bond makes methane partial oxidation a challenging catalysis task. At low temperatures, C–H bond activation is kinetically sluggish. On the other hand, methane is likely oxidized fully into CO2 at high temperatures, which will lower methanol selectivity. Several Cu–oxo complexes such as mono(μ-oxo)dicopper, bis(μ-oxo)dicopper, and copper trioxo anchored in the mordenite (MOR) zeolite framework are shown to balance catalytic activity and product selectivity for the methane-to-methanol conversion. In this work, the thermodynamic stability of Cu–oxo complexes was evaluated as active centers for C–H bond activation using the BEEF-vdW functional within the density functional theory (DFT) framework, and the bis(μ-oxo)dicopper moiety was identified as the most stable configuration. The catalytic reactivity of these complexes was then tested with the activation of the first C–H bond of light hydrocarbons (i.e., methane, ethane, and propane), as well as subsequent oxidation steps to corresponding alcohols. Site II of the Cu–trioxo cluster with highest spin density remains as the most potent active site by enabling the lowest energy barrier for initial methane activation when electronic spin crossing was considered. Energy barriers for the first C–H activation step follow a decreasing order of methane, ethane, and propane.
Changes in Reactivity as Chemistry Becomes Confined to an Interface. The Case of Free Radical Oxidation of C 30 H 62 Alkane by OH
Here, we examine in a simple organic aerosol the transition between heterogeneous chemistry under well-mixed conditions to chemistry under interfacial confinement. A single reaction mechanism, shown to reproduce observed OH oxidation chemistry for liquid and semisolid C 30 H 62 , is used in reaction-diffusion simulations to explore reactivity over a broad viscosity range. The results show that when internal mixing of the aerosol is fast and the particle interface is enriched in C-H groups, ketone and alcohol products, formed via peroxy radical disproportionation, predominate. As viscosity increases the reactions become confined to a shell at the gas-aerosol interface. The confinement is accompanied by emergence of acyloxy reaction pathways that are particularly active when the shell is 1 nm or less. We quantify this trend using a reaction-diffusion index, allowing the parts of the mechanism that control reactivity as viscosity increases to be identified.