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The abstraction reaction of hydrogen from formaldehyde by OH radical plays an important role in formaldehyde oxidation. The reaction involves a bimolecular association to form a chemically activated hydrogen-bonded reaction complex followed by a unimolecular reaction of the complex to generate the products. The reaction rate is usually considered to be pressure-independent by assuming equilibrium between the reactants and the complex. However, our nonequilibrium calculations based on the chemically significant eigenmode of the master equation, carried out with our recently developed TUMME program, indicate that the reaction complex makes the rate constant dependent on pressure at low temperatures (T < 200 K). The calculations include anharmonicity, variational effects, and multi-dimensional tunneling. We find that the reaction rate constant reaches a low-pressure limit at pressures below 10 Torr over the whole investigated temperature range (20–1800 K), which explains why the available low-temperature experiments, which are for pressures below 2 Torr, did not observe the pressure dependence. A new extension of the TUMME master-equation program is used to explore the time evolutions of the concentrations of the OH radical and the complex under pseudo-first-order conditions. The time-dependent evolution of the concentrations of the complex at a low temperature provide direct evidence for the stabilization of the reaction complex at high pressures, and it shows the negligible role of the stabilized reaction complex at low pressures. The picture that emerges is qualitatively consistent with our previous study of the reaction of methanol with OH in that the tunneling in the unimolecular step from the complex to the products affects the phenomenological reaction rate constants differently at high and low pressures and leads to a significant pressure effect. [ABSTRACT FROM AUTHOR]

A novel-Pd/CuO–Ni(OH)2/C catalyst utilizing carbon black as a support was successfully synthesized using hydrazine hydrate reduction and galvanic replacement strategies and was subsequently tested for activity in the electrocatalytic oxidation of ethanol. The observed peak current density (3.74 A mgPd−1) for Pd/CuO–Ni(OH)2/C was 19.68 times higher than that of commercial Pd/C (0.19 A mgPd−1). The as-synthesized Pd/CuO–Ni(OH)2/C (hereafter denoted as PdCuNi/C) catalyst exhibited a significantly improved electrocatalytic activity and durability compared with Pd/C, PdNi/C, PdCu/C and the PdCuNi/C catalysts reduced in N2/H2 at different temperatures. The reason for this is that the high dispersion of Pd resulted in the exposure of more active sites on the surface of the catalyst. The excellent CO2 selectivity of Pd/CuO–Ni(OH)2/C (22.5%) for the ethanol electronic oxidation reaction (EOR) was observed using in situ Fourier transform infrared spectroscopy (FTIR) spectra and could be attributed to the synergistic effect of Pd, CuO and Ni(OH)2 and the presence of the OHad adsorption at Ni(OH)2 at a low potential. [ABSTRACT FROM AUTHOR]

Hydrogen abstraction reactions of (cyclo)alkanes by radicals play a fundamental role in both combustion and atmospheric chemistry. In this work, we select three common radicals in the pyrolysis of hydrocarbon fuels: hydrogen radical (H.a.dot;), methyl radical (ĊH3), and ethyl radical (ĊH2CH3) to investigate the kinetics of their hydrogen abstraction reactions with cyclopentane. The rate constants over a broad temperature range of 150–3000 K are calculated by using the multi-structural variational transition state theory in the small-curvature tunneling approximation (MS-CVT/SCT), by which the multi-structural torsional (MS-T) anharmonicity of partition functions, variational effects, and corner-cutting tunneling are all included in dynamics calculations. We stress the particular importance of considering the MS-T anharmonicity in the rate constant calculation for the reaction with the ethyl radical compared to those with hydrogen and methyl radicals. The MS-T anharmonicity significantly accelerates the reaction with the ethyl radical in the whole temperature range, and in particular, it increases the rate constant by a factor of >−9 at 1000 K. We also found that the tunneling effect drastically increases the rate constants at low-temperatures by up to 3–5 orders of magnitudes. The calculated reaction rate constants have an order of. [ABSTRACT FROM AUTHOR]

The modification of 2-amino-6-chloropurine on polyamidoamine was performed to synthesize a derivative, AP-PAMAM, which was then employed as a carrier for p53 gene delivery to achieve anti-tumor efficacy. Using a human prostate tumor cell line PC-3 as a model, enhanced expression level of p53 gene could be detected by RT-PCR, qPCR and western blotting. Based on the successful p53 gene transfection, an obvious anti-proliferative effect could be obtained, which was identified to be associated with the simultaneous induction of cell apoptosis and cell cycle arrest at the G1 phase. The cell apoptosis was elucidated to be triggered by the activation of the mitochondria-dependent apoptotic signaling pathway. In addition, AP-PAMAM/p53 transfection could restrain the migration of tumor cells as demonstrated by wound healing and Transwell migration assays. Notably, AP-PAMAM-mediated p53 delivery exhibited a stronger inhibitory effect on both cell proliferation and migration than the PAMAM/p53 group. In summary, AP-PAMAM/p53 transfection provided a promising route to achieve the p53-based gene therapy. [ABSTRACT FROM AUTHOR]

Correction for 'A kinetics study on hydrogen abstraction reactions of cyclopentane by hydrogen, methyl, and ethyl radicals' by Wenqi Chen et al., Phys. Chem. Chem. Phys., 2021, 23, 7333–7342, DOI: 10.1039/D1CP00386K. [ABSTRACT FROM AUTHOR]