Efficient Conversion of m-Cresol to Aromatics on a Bifunctional Pt/HBeta Catalyst

Abstract

The catalytic conversion of meta-cresol (3-methylphenol) was investigated over HBeta, Pt/SiO2, and Pt/HBeta catalysts at 400 °C and atmospheric pressure. The acid sites of zeolite HBeta catalyze methyl transfer reactions (isomerization and transalkylation), yielding cresol isomers (para- and ortho-cresol), dimethylphenol (xylenol) isomers, and phenol. Pt alone catalyzes hydrodeoxygenation and hydrogenation reactions, leading to toluene as the major product and methylcyclohexane as the minor product. Bifunctional Pt/HBeta catalyzes both methyl transfer reactions and hydrodeoxygenation reactions at the same time, producing toluene, benzene, and xylenes. The Pt/HBeta catalyst is about 10 times more active than the Pt/SiO2 catalyst toward hydrodeoxygenation, with a turnover frequency (on the basis of Pt only) 3 times higher, highlighting the significant role of acid sites in the metal-catalyzed hydrodeoxygenation reactions of phenolics. While Pt/HBeta and Pt/SiO2 exhibit similar rates of coke formation, the former has a higher stability than the latter under the same reaction conditions.

An Overview on Catalytic Hydrodeoxygenation of Pyrolysis Oil and Its Model Compounds

“…Thus, compared with H-Beta and Pt/SiO 2 catalysts, less phenolic compounds and saturated hydrocarbons were obtained on the bifunctional catalyst [74]. In addition, a similar result was carried out from the HDO of m-cresol over the bifunctional Pt/HBeta catalyst [75]. Dwiatmoko et al performed HDO of phenolic monomers over Ru catalysts supported on five different carbon materials.…”

Vapor phase hydrodeoxygenation and hydrogenation of m-cresol on silica supported Ni, Pd and Pt catalysts

“…These minor products include: methane, light hydrocarbons (LH, sum of hydrocarbons longer than methane but shorter than C 6 ), benzene (Ben), phenol (Ph), xylenols (Xol), cyclohexanone (CHone) and cyclohexanol (CHol). The presence of Ph and Xol indicates that transalkylation reaction occurs to a small extent, which is typical on acidic zeolites (Zhu et al, 2010(Zhu et al, , 2011(Zhu et al, , 2014. Nie et al (2014a) suggested that small amounts of unreduced nickel cations act as Lewis acid sites that catalyze this reaction.…”

“…At low reaction temperature (200 1C) and high hydrogen pressures (5 MPa) and in the presence of acid sites, it was suggested that hydrogenation on metal sites (Pd, Pt, Ni) followed by dehydration on acid sites, and then hydrogenation to cyclohexanes on metal sites is the major pathway Hong et al, 2010). At high reaction temperature (400 1C) and atmospheric pressure, aromatics are the major products from hydrodeoxygenation of cresol and anisole on the Pt catalysts supported on inert SiO 2 or acidic zeolite (Zhu et al, 2011(Zhu et al, , 2014. At intermediate temperature of 275 1C and 10 MPa hydrogen, Ni, Pd and Pt supported on an inert support (carbon or silica) are active for phenol conversion, with major products being cyclohexanol and cyclohexane (Mortensen et al, 2013).…”

Decomposition Mechanism of Anisole on Pt(111): Combining Single-Crystal Experiments and First-Principles Calculations

“…Even if reaction networks have been proposed, 10,13,14 the full mechanism remains difficult to elucidate experimentally since both the conditions and the support can have effects on the selectivity. 15,16 To gain insights into the reactivity of aromatic oxygenates on noble metal surfaces, many DFT studies have been performed and published. 13,[17][18][19][20][21][22][23][24] Honkela et al showed in particular that the dissociation of phenol into phenoxy was endothermic on Pt(111) and exothermic on Rh(111) and suggested that it may explain the higher propensity of Rh to deoxygenate aromatics.…”