Identifying the roles of acid–base sites in formation pathways of tolualdehydes from acetaldehyde over MgO-based catalysts

Abstract

Basic (M–O)-type centers convert C4 intermediates to renewable xylene analogs and proximal acid sites tune isomeric selectivity.

Engineering a Copper Single‐Atom Electron Bridge to Achieve Efficient Photocatalytic CO2 Conversion

“…As shown in Figure 3d, the gradually increasing bands at 1251 cm −1 can be assigned to the vibrations of *COO − , which is favorable for the formation of a *COOH intermediate [9a] . A band at 1323 cm −1 corresponds to bidentate carbonate (b‐CO 3 2− ) groups due to chemisorbed CO 2 on the photocatalyst [9b] . A new band at around 1565 cm −1 is ascribed to *COOH groups, which are regarded as one of the most crucial intermediates for converting CO 2 to CO [9c] .…”

Screening of Catalysts for the Methyl Vinyl Ether Reaction in H2

“…Based on the above information and discussion as well as the relevant literature, a reaction pathway of MVE hydrogenation to methylbenzene over CuO/Al 2 O 3 at 400–450 °C is proposed in Scheme . It starts with hydrocracking of MVE to MeCHO and MeOH on the catalyst’s surface, followed by condensation of MeCHO and/or MeOH to C 3+ aldehydes/ketones, such as propionaldehyde, butyraldehyde, 3-methyl-2-butanone, and 2-butenal reported in the literature, , then dehydration, dehydrogenation, and cyclization of these C 3+ aldehydes/ketones to benzene, methylbenzaldehyde, and trimethylbenzene, − and then hydrodeoxygenation and methylation of methylbenzaldehyde and methylation of benzene and trimethylbenzene by MeOH to hexamethylbenzene. , It is noted that the conversion of C 3+ aldehydes/ketones is far more complex and the products may include heavy polycyclic aromatic hydrocarbons as reported in the literature . It is also reported that the reaction of benzene and MeCHO easily produces heavy polycyclic aromatic hydrocarbons .…”

Direct synthesis of p-methyl benzaldehyde from acetaldehyde via an organic amine-catalyzed dehydrogenation mechanism

“…Construction of value-added products with aromatic rings from low-molecular weight molecules is a long-standing research topic ( Jiao et al., 2016 ; Li et al., 2019 ; Cheng et al., 2017 ; Tempelman et al., 2015 ; Moteki et al., 2016 ; Hulea, 2018 ). Extensive researches have reported the production of methyl benzaldehyde from biomass-derived acetaldehyde over MgO and Ca 10 (OH) 2 (PO 4 ) 6 ( Wang et al., 2019 ; Lusardi et al., 2020 ; Zhang et al., 2016 ; Moteki et al., 2017 ). However, the selectivity of methyl benzaldehydes (MBA) in proceeding was no exceeding 30% ( Scheme 1 B), among which, p -MBA was less than 3% ( Moteki et al., 2016 ; Wang et al., 2019 ), far from meeting the industrial production requirements.…”

“…However, the selectivity of methyl benzaldehydes (MBA) in proceeding was no exceeding 30% ( Scheme 1 B), among which, p -MBA was less than 3% ( Moteki et al., 2016 ; Wang et al., 2019 ), far from meeting the industrial production requirements. This insufficient selectivity was attributed to the complex network of competing reactions in acetaldehyde cascade processes, resulting in broad product distributions ( Moteki et al., 2016 ; Lusardi et al., 2020 ).…”