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As a direct conversion route for the production of ethylene from methane, the oxidative coupling of methane (OCM) is highly promising. The Mn2O3‐Na2WO4/SiO2 catalyst doped with 44 μm anatase‐TiO2, consisting of 5 wt% TiO2, 5 wt% Mn2O3, 8 wt% Na2WO4 and balance SiO2 was prepared, achieving ∼22 % CH4 conversion with ∼72 % selectivity towards C2−C3 hydrocarbons even at the relatively low temperature of 700 °C. This catalyst was found to run stably for at least 300 h without signs of deactivation, which provides promising and comparable low‐temperature activity and selectivity but a more cost‐effective alternative to the previously‐reported Mn2O3‐Na2WO4/Ti‐MWW catalyst containing expensive Ti‐MWW zeolite. XRD and Raman analyses revealed that the in situ formation of MnTiO3 in the TiO2‐doped catalyst is responsible for the gains in low‐temperature OCM activity. In addition, TPR and TPO results also indicated that MnTiO3 activates O2 more readily at ∼650 °C, while three‐step switchover experiments clearly demonstrated that MnTiO3 could trigger facile redox behavior at low reaction temperatures. Thus, the MnTiO3‐induced redox cycle for O2 activation enables this TiO2‐doped catalyst to provide superior CH4 conversion at 700 °C. [ABSTRACT FROM AUTHOR]

Inorganic metal (hydro)oxide supports with appropriate basicity or acid‐base properties can promote oxidative esterification of furfural over Au‐based catalysts, however, they suffer the problems of easy inactivation induced by the leaching of the components in this water‐producing reaction and the shield of catalytic sites by product adsorption. In this work, we report efficient and stable oxidative esterification of furfural over Au nanoparticles anchored in aminopropyl‐grafted silica aerogel. The support is insoluble and possesses no strong Lewis acid sites to adsorb oxygen‐containing products or intermediates, reducing the probability of catalyst deactivation induced by adsorption. In 7 cycles of reactions, the catalyst maintained the initial activity without any treatments, the yields of alkyl furoate kept above 98 %, and no agglomeration and leaching of Au occurred. Moreover, the roles of Au, alkyl chain, −NH2 group and Au‐activated O species in reactions were clarified, and accordingly, a possible catalytic mechanism involving oxidative dehydrogenation was given. [ABSTRACT FROM AUTHOR]

To develop efficient heterogeneous catalytic systems for base-catalyzed reactions, two benzimidazole-containing porous organic polymers, BPOP-1 and BPOP-2, were synthesized. As a result of the difference in building units, BPOP-1 exhibits a granular morphology, and BPOP-2 is composed of tiny particles. N2 adsorption measurements show that BPOP-1 is a nonporous framework, whereas BPOP-2 displays good adsorption abilities towards N2, H2, and CO2. Both BPOP-1 and BPOP-2 exhibit a higher catalytic activity in the Knoevenagel condensation reaction than their homogeneous molecular counterpart, and the activity of BPOP-2 is superior to that of BPOP-1. Theoretical calculations show that the Lewis basicity of the N atoms in BPOP-1 is identical to that in BPOP-2. The prominent catalytic performance of BPOP-2 is mainly attributed to its high specific surface area and microporous character. Moreover, the permanent chemical stability of the structural framework endows BPOP-2 with an outstanding recyclability. [ABSTRACT FROM AUTHOR]