Anisole production by alkylation of phenol over ZSM5

Renavd, M.; Chantal, Pierre D.; Kaliaguine, Serge

doi:10.1002/cjce.5450640511

Cited by 48 publications

(18 citation statements)

References 16 publications

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“…Various zeolites have been studied for this reaction. These include H-Y [7][8][9][10], H-ZSM-5 [7,[11][12][13], H-mordenite [6] and H-beta [14]. However, these zeolites have shown poor paraselectivity with p:o-cresol ratios not exceeding 0.7.…”

Section: Introductionmentioning

confidence: 92%

An investigation into factors which influence the formation of p-cresol in the methanol alkylation of phenol over MCM-22 and ZSM-5

2004

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Section: Introductionmentioning

confidence: 92%

An investigation into factors which influence the formation of p-cresol in the methanol alkylation of phenol over MCM-22 and ZSM-5

2004

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“…With MFI zeolites, at temperature higher than 350°C Kaliaguine et al [2,53] found that the reaction leads to a variety of products, amongst which the most relevant were cresols and xylenols. A mechanism was proposed in which diphenyl ether and anisole (the two products of etherification) are the reaction intermediates and interact with Brønsted sites and carbonium ions to yield C-methylated products.…”

Section: Catalyst Activity and Deactivation Ratementioning

confidence: 99%

Methylation of phenol over high-silica beta zeolite: Effect of zeolite acidity and crystal size on catalyst behaviour

Bregolato

Bolis

Busco

et al. 2007

Journal of Catalysis

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A systematic investigation has been carried out, aiming at elucidating several aspects of the gas/solid methylation of phenol over high Si/Al ratio BEA-structured zeolite in protonated form. The catalysts have been characterized by several techniques, such as XRD, SEM, BET, ICP, FT-IR, TGA, micro-calorimetry and modelling by ab initio calculations. The correlation between these characteristics and kinetics and mechanistic features of the catalytic reaction, as well as of catalyst deactivation, showed that these zeolites are very active for the present reaction, leading to cresols and anisole as primary products. As catalyst deactivation proceeds, the selectivity to cresols and anisole increases substantially, together with a rapid decrease of selectivity to poly-alkylated species. Catalyst surface acidity is prevalently made of medium-to-low-strength silanolsbased acid sites of Brønsted type. High-strength Lewis acid sites are either almost absent, especially when metal cations partially substitute for protons, or play a role essentially in catalyst deactivation. Stacking faults in the zeolite framework, generated by the 2 intergrowth of at least two BEA polymorphs, lead to an increase of the concentration of silanols-based acid sites. Deactivation is essentially due to the interaction of phenol and oxygenated products with the strong Lewis acid sites. For time-on stream values longer than a few hours, self oligomerisation-cyclisation of methanol to olefins and aromatics, followed by further alkylation to aromatic C atoms, contributes more significantly to catalyst deactivation. At higher temperature all the zeolites deactivate at a comparable rate, whereas at lower temperature initial catalytic activity is higher for larger crystal size zeolite, due to the longer diffusion time of bulkier coke precursors within zeolite pores. At any conversion level and at any temperature the anisole/cresols ratio is systematically lower for the larger crystal size zeolite, since the secondary transformations of anisole to cresols, by both intra-molecular rearrangement and inter-molecular alkylation of phenol, is favoured by the longer residence time of anisole within the zeolite pores.

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“…Solid bases, in particular MgO, selectively alkylate phenol in ortho-position, producing essentially o-cresol and 2,6 xylenol [5,6]. Solid acids such as silicaalumina, Nafion-H resin, HPA/SiO 2 , and zeolites HBEA and HY, convert phenol to a mixture of anisole, cresols, xylenols and methylanisoles [7][8][9][10][11][12][13]. Brønsted solid acids promote the O-alkylation of phenol [10,11] while Lewis solid acids (SiO 2 -Al 2 O 3 ) and zeolites containing similar amounts of Lewis and Brønsted acid sites (HBEA, HY) favor the C-alkylation of phenol [7,14].…”

Section: Introductionmentioning

confidence: 99%

Study of the Alkylation of Phenol with Methanol on Zn(H)-Exchanged NaY Zeolites

et al. 2011

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The gas-phase alkylation of phenol with methanol was studied at 473 K on zeolite NaY exchanged with Zn ?2 (samples Zn(x)NaY) or H ? (samples Na(x)HY) cations. Zeolite NaY contained only weak and medium Lewis acid sites. The addition of Zn ?2 formed essentially strong Lewis acid sites. In contrast, the exchange of NaY with H ? generated Brønsted acid sites and decreased the density of Lewis acid sites. Zeolite NaY was inactive at 473 K, but after its exchange with Zn 2? efficiently promoted the phenol methylation reaction. Phenol conversion and the selectivities to o-and p-cresols increased with the Zn content in the sample. The exchange of Na ? with H ? also activated the parent NaY zeolite. At similar phenol conversion levels, Na(x)HY samples formed more anisole and less cresols than Zn(x)NaY. All the Zn(x)NaY and Na(x)HY samples deactivated on stream, but the catalyst activity decay increased with the exchange degree.

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Anisole production by alkylation of phenol over ZSM5

Cited by 48 publications

References 16 publications

An investigation into factors which influence the formation of p-cresol in the methanol alkylation of phenol over MCM-22 and ZSM-5

An investigation into factors which influence the formation of p-cresol in the methanol alkylation of phenol over MCM-22 and ZSM-5

Methylation of phenol over high-silica beta zeolite: Effect of zeolite acidity and crystal size on catalyst behaviour

Study of the Alkylation of Phenol with Methanol on Zn(H)-Exchanged NaY Zeolites

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