Hydrodeoxygenation of m-cresol over gallium-modified beta zeolite catalysts

Ausavasukhi, Artit; Huang, Yi; To, Anh T.; Sooknoi, Tawan; Resasco, Daniel E.

doi:10.1016/j.jcat.2012.03.003

Cited by 126 publications

(72 citation statements)

References 49 publications

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“…Vitolo et al [25] reported not only on the transformation of pyrolysis oil, but also on catalyst regeneration over ZSM-5, which could at least to a certain extent be achieved by calcination in air. Noble metal particles supported and other active metals on zeolites were used as an alternative [26][27][28][29] Thereby, also ring-opening and corresponding hydrogenated intermediates were observed at 350-450 °C and 20-50 bar [28]. As zeolites alone suffer from carbon deposition and deactivation, the addition of noble metals supported on zeolites appeared beneficial [26,28].…”

Section: Introductionmentioning

confidence: 99%

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Continuous Catalytic Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H-MFI-90

et al. 2015

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Hydrodeoxygenation of guaiacol in the presence of 1-octanol was studied in a fixed-bed reactor under mild conditions (50-250 °C) over platinum particles supported on silica (Pt/SiO2) and a zeolite with framework type MFI at a Si/Al-ratio of 45 (Pt/H-MFI-90). The deoxygenation selectivity strongly depended on the support and the temperature. Both guaiacol and octanol were rapidly deoxygenated in the presence of hydrogen over Pt/H-MFI-90 at 250 °C to cyclohexane and octane, respectively. In contrast, Pt/SiO2 mostly showed hydrogenation, but hardly any deoxygenation activity. The acidic sites of the MFI-90 support lead to improved deoxygenation performance at the mild temperature conditions of this study. Significant conversions under reaction conditions applied already occurred at temperatures of 200 °C. However, during long-term stability tests, the Pt/H-MFI-90 catalyst deactivated after more than 30 h, probably due to carbon deposition, whereas Pt/SiO2 was more stable. The catalytic activity of the zeolite catalyst could only partly be regained by calcination in air, as some of the acidic sites were lost. OPEN ACCESSCatalysts 2015, 5 1153

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Section: Introductionmentioning

confidence: 99%

“…Furthermore, gallium-modified beta zeolites were reported at 400-450 °C and 1 bar of H2. m-Cresol was mainly transformed into aromatic products, like toluene, benzene and xylene [29]. Higher hydrogen pressures were beneficial for catalyst performance and stability.…”

Section: Introductionmentioning

confidence: 99%

Continuous Catalytic Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H-MFI-90

et al. 2015

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“…Several strategies have been proposed to improve bio-oil properties. An extensive amount of work has focused primarily on hydrodeoxygenation of phenolic compounds [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] while some work has focused on improving carbon retention and enhancing molecular weight mainly by alkylation reactions [19][20][21][22][23][24]. Molecular weight enhancement of bio-oil molecules may become important for the production of molecules with the appropriate length to use them as components of the gasoline and, particularly, of the diesel pools.…”

Section: Introductionmentioning

confidence: 99%

“…Hydroalkylation of phenolics compounds, on the other hand, has a significant advantage over hydroalkylation of aromatics [31,32]. In the presence of bifunctional metal/acid catalysts, phenolic molecules can undergo hydrogenation/dehydration reactions [10][11][12][13][14]16], which have among their intermediate products cyclohexanols and cyclohexenes, which are potential alkylation agents for phenolic rings via electrophilic aromatic substitution [31,32]. For example, Hong et al [31] observed the hydroalkylation of phenol using Pt/HY, while Zhao et al [32] used Pd/Hb.…”

Section: Introductionmentioning

confidence: 99%

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Anaya

Zhang

Tan

et al. 2015

Journal of Catalysis

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a b s t r a c tThe liquid-phase hydroalkylation of m-cresol catalyzed by zeolite catalysts doped with noble metals was investigated at 473 K and 5200 kPa of H 2 . Metals (Pt and Pd) were incorporated in HY (Si/Al = 30) and HMor (Si/Al = 10) zeolites by incipient wetness impregnation. The structural properties of the samples were characterized by NMR, XPS, and BET. Hydroalkylation of m-cresol involves a series of steps that start with the ring saturation to 3-methylcyclohexanone (MCONE), which is the primary product and is further hydrogenated to methylcyclohexanol (MCNOL) on the metal function. This, in turn, is dehydrated on the acid sites to 3-methylcyclohexene, which readily alkylates the unreacted m-cresol to form bicyclic compounds that fall in the desirable fuel range. In these bifunctional catalysts, differences in intrinsic hydrogenation activity of metals play an important role in determining the final selectivity to alkylated products. In fact, the ratio of number of acid sites (n A ) to exposed metal sites (n M ) can be tuned to maximize the selectivity toward bicyclic compounds because this selectivity is determined by the fate of the intermediate 3-methylcyclohexene (MCENE). That is, if the C@C hydrogenation on the metal is fast compared to alkylation on the acid site, the selectivity decreases. However, if the hydrogenation is too slow, the overall product yield decreases. Thus, to optimize the hydroalkylation yield, a delicate metal/acid balance is required. Moreover, in the absence of metal, the zeolite would deactivate very quickly. Therefore, having the metal and acid functions together is also important for extending the catalyst life. Finally, it has been observed that 3D-pore zeolites, such as HY, are preferred over 1D-pore zeolites such as HMor, which sharply diminish the formation of alkylation compounds, despite being more acidic than HY.

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“…For example, phenol was deoxygenated with high selectivity (above 60%) to benzene at 513 K over Ni/HZSM-5 [10] and at 723 K with CoMoP/MgO catalyst [11]. Similarly, cresol (p-cresol or m-cresol) was also hydrotreated by many researchers at atmospheric pressure over different catalysts to obtain toluene with high selectivity of toluene [12][13][14][15][16][17][18][19][20]. Another pathway to convert lignin into aromatics is catalytic fast pyrolysis producing xylenes with selectivity less than 23%, as reported by Huber et al [21].…”

Section: Introductionmentioning

confidence: 99%

High Selectively Catalytic Conversion of Lignin-Based Phenols into para-/m-Xylene over Pt/HZSM-5

2016

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Abstract:High selectively catalytic conversion of lignin-based phenols (m-cresol, p-cresol, and guaiacol) into para-/m-xylene was performed over Pt/HZSM-5 through hydrodeoxygenation and in situ methylation with methanol. It is found that the p-/m-xylene selectivity is uniformly higher than 21%, and even increase up to 33.5% for m-cresol (with phenols/methanol molar ratio of 1/8). The improved p-/m-xylene selectivity in presence of methanol is attributed to the combined reaction pathways: methylation of m-cresol into xylenols followed by HDO into p-/m-xylene, and HDO of m-cresol into toluene followed by methylation into p-/m-xylene. Comparison of the product distribution over a series of catalysts indicates that both metals and supporters have distinct effect on the p-/m-xylene selectivity.

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Hydrodeoxygenation of m-cresol over gallium-modified beta zeolite catalysts

Cited by 126 publications

References 49 publications

Continuous Catalytic Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H-MFI-90

Continuous Catalytic Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H-MFI-90

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

High Selectively Catalytic Conversion of Lignin-Based Phenols into para-/m-Xylene over Pt/HZSM-5

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