A cascade mechanism for a simple reaction: The gas-phase methylation of phenol with methanol

Application of two morphologies of Mn2O3 for efficient catalytic ortho-methylation of 4-chlorophenol

“…A slightly higher formation of 5-chloro-salicylic aldehyde can be attributed to the dehydrogenation of the alcohol. 20 The same type of reaction has been widely reported, such as the intermolecular disproportionation of ethanol into ethane and acetaldehyde, catalyzed by reduced vanadium oxide. 43 Also, benzyl alcohol disproportionated into toluene and benzoic aldehyde.…”

“…The generated formaldehyde had good positive carbon electrophilic properties and the aromatic ring possessed the electron rich delocalized electron cloud. 20 The carbon of formaldehyde attacked the 4-chlorophenate species, forming 5-chloro-salicylic alcohol species with hydroxymethyl moieties. In detail, the positively charged carbon attacked the ortho position of the aromatic ring O to form a transition state intermediate species.…”

“…Among them, metal oxide catalysts play a vital role, such as α-Fe 2 O 3 , 10 TiO 2 , 11 MgO, 12 Mg–Al–hydrotalcite, 13 Fe-doped ZrO 2 composites, 14 Si–Mn composite oxides, 15 CoFe 2 O 4 spinel, 16 V 2 O 5 –ZrO 2 , 17 Mg/Me/O spinel (Me = Al, Cr, Fe), 18 Cu x Mn 3− x O 4 spinel, 19 Mg–Fe–O composite metal oxide. 20 The reason why metal oxides show such high activity and selectivity for ortho -methylation of phenol was mainly based on the vertical adsorption of phenolate species on the surface of the catalyst and the formation of intermediate methyl species. Therefore, in chemical kinetics, methyl species are more likely to attack the ortho position of the phenol ring, forming ortho -substituted phenol ( o -cresol) or di- ortho -substituted phenol (2,6-xylenol).…”

Base Metal‐Catalyzed C‐Methylation Reactions Using Methanol

“…Next, Fe 2 O 3 −SiO 2 −CuO catalyst [39] and Al‐doped FeVO 4 catalysts [40] were developed and applied for the methylation of substituted phenols with methanol in vapor phase medium. Furthermore, Mg/Ga/O [41] and MgO‐based catalysts [42] were found to be outstanding for the phenol methylation with methanol in the gas phase. Even zirconium, tungsten silicon oxides (xZrO 2 −yWO 3 −SiO 2 ) were highly active and selective for the C‐methylation of phenol at the temperature 673 K [43] .…”

Tandem Hydrogenation/Hydrogenolysis of Furfural to 2-Methylfuran over a Fe/Mg/O Catalyst: Structure–Activity Relationship

“…When the temperature was increased from room temperature to 150 • C, new peaks appeared at 2809 and 1092 cm −1 , which were attributed to bridged methoxy species. Further increase of the temperature caused a rapid formation of a species, which could be attributed to a formate isomer, since it displayed a ν s (CH) peak at 2846 cm −1 , a characteristic ν as (COO) at 1600-1610 cm −1 , and the ν s (COO) peaks in the 1379-1339 cm −1 region [35,36].…”