On the impact of co-feeding aromatics and olefins for the methanol-to-olefins reaction on HZSM-5

Sun, Xianyong; Mueller, Sebastian; Shi, Hui; Haller, Gary L.; Sanchez‐Sanchez, Maricruz; Veen, A.C. van; Lercher, Johannes A.

doi:10.1016/j.jcat.2014.03.013

Cited by 139 publications

(192 citation statements)

References 43 publications

Supporting

Mentioning

180

Contrasting

Unclassified

Order By: Relevance

“…The relative propagation of the olefins-based catalytic cycle is therefore not affected by the olefin co-feed [29]. Both Ilias et al [15,16] and Sun et al [29], in independent studies, reported that co-reacting MBs with methanol/DME on H-ZSM-5 under a wide range of reaction temperatures (548-723 K) enhances the propagation of the aromatics-based catalytic cycle and results in higher selectivity toward MBs as well as ethene.…”

Section: Introductionmentioning

confidence: 97%

“…Ilias et al [15,16] showed that co-feeding small amounts of propene (4 kPa) with 70 kPa DME on H-ZSM-5 at 548-623 K increased the propagation of the olefins-based catalytic cycle and resulted in higher selectivity toward C 3 and C 4 -C 7 aliphatic hydrocarbons. Experimental investigation by Sun et al [29], on the other hand, showed that co-feeding C 3 -C 6 olefins (10-40 C%) with methanol at higher temperature (723 K) and higher DME conversion conditions did not selectively enhance the propagation of the olefins-based catalytic cycle, and no increase in C 3 + selectivity was observed. Sun et al [29] suggested that the addition of olefins enhances the aromatization of higher olefins, which increases the concentration of aromatics inside the zeolite pores, thereby enhancing the propagation of both the aromatics-based and the olefins-based catalytic cycles.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental investigation by Sun et al [29], on the other hand, showed that co-feeding C 3 -C 6 olefins (10-40 C%) with methanol at higher temperature (723 K) and higher DME conversion conditions did not selectively enhance the propagation of the olefins-based catalytic cycle, and no increase in C 3 + selectivity was observed. Sun et al [29] suggested that the addition of olefins enhances the aromatization of higher olefins, which increases the concentration of aromatics inside the zeolite pores, thereby enhancing the propagation of both the aromatics-based and the olefins-based catalytic cycles. The relative propagation of the olefins-based catalytic cycle is therefore not affected by the olefin co-feed [29].…”

Section: Introductionmentioning

confidence: 99%

“…Sun et al [29] suggested that the addition of olefins enhances the aromatization of higher olefins, which increases the concentration of aromatics inside the zeolite pores, thereby enhancing the propagation of both the aromatics-based and the olefins-based catalytic cycles. The relative propagation of the olefins-based catalytic cycle is therefore not affected by the olefin co-feed [29]. Both Ilias et al [15,16] and Sun et al [29], in independent studies, reported that co-reacting MBs with methanol/DME on H-ZSM-5 under a wide range of reaction temperatures (548-723 K) enhances the propagation of the aromatics-based catalytic cycle and results in higher selectivity toward MBs as well as ethene.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mechanistic studies of methanol-to-hydrocarbons conversion on diffusion-free MFI samples

Khare

Bhan

2015

Journal of Catalysis

View full text Add to dashboard Cite

Aromatics-based catalytic cycle Olefins-based catalytic cycle MFI Diffusion free Ethene selectivity Low space velocity High conversion a b s t r a c t Self-pillared pentasil MFI ($1 nm diffusion length) exhibited low ethene selectivity (1.1%) at <100% conversion for the catalytic reaction of dimethyl ether (DME) at 723 K and $60 kPa DME pressure suggesting that the aromatics-based catalytic cycle is intrinsically suppressed in the pores of MFI under these reaction conditions. Co-feeding toluene or p-xylene with DME increased the number of chain carriers of the aromatics-based cycle, thereby enhancing its propagation and resulting in a 2-3-fold increase in ethene selectivity. Co-feeding propene or 1-hexene, however, did not have an effect on the product distribution, suggesting that the olefins-based hydrocarbon pool is saturated in the pores of MFI. At high temperature (723 K) and low DME space velocity (62.5 mol C [mol Al-s] À1 ), conditions resulting in complete DME/methanol conversion, the catalyst bed comprises two stages: The first stage performs methanol-to-hydrocarbons chemistry in the presence of DME/methanol; the second stage begins after 100% DME conversion is achieved and is characterized by the absence of DME/methanol. The aromatics-based methylation/cracking cycle is absent in the second stage as methylbenzenes cannot dealkylate in the absence of DME/methanol, and the dominant pathway to ethene formation under these reaction conditions is olefin inter-conversion.

show abstract

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mechanistic studies of methanol-to-hydrocarbons conversion on diffusion-free MFI samples

Khare

Bhan

2015

Journal of Catalysis

View full text Add to dashboard Cite

show abstract

“…[35][36] In contrast, SAPO-34 has large 12-member-ring cavities with small (3.8 × 3.8 Å) pore openings that enrich aromatic intermediates, promoting the aromatic-based cycle to produce more ethene 37 (a termination product of this cycle, see Scheme 1). Likewise, the MTH product distribution over ZSM-5 can be tuned by varying the reaction conditions (e.g., feed compositions [38][39][40] and zeolite crystal sizes 4,[41][42] ) to adjust the relative propagation of these two catalytic cycles.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Influence of Mesoporosity in Zeolite Beta on Its Catalytic Performance for the Conversion of Methanol to Hydrocarbons

et al. 2015

View full text Add to dashboard Cite

Hierarchically porous zeolite Beta (Beta-MS) synthesized by a soft-templating method contains remarkable intra-crystalline mesoporosity, which reduces the diffusion length in zeolite channels down to several nanometers and alters the distribution of Al among distinct crystallographic sites. When used as a catalyst for the conversion of methanol to hydrocarbons (MTH) at 330 o C, Beta-MS exhibited a 2.7-fold larger conversion capacity, a 2.0-fold faster reaction rate, and a remarkably longer lifetime than conventional zeolite Beta (Beta-C). The superior catalytic performance of Beta-MS is attributed to its hierarchical structure, which offers full accessibility to all catalytic active sites. In contrast, Beta-C was easily deactivated because a layer of coke quickly deposited on the outer surfaces of the catalyst crystals, impeding access to interior active sites. This difference is clearly demonstrated by using electron microscopy combined with electron energy loss spectroscopy to probe the distribution of coke in the deactivated catalysts. At both low and high conversions, ranging from 20% to 100%, Beta-MS gave higher selectivity towards higher aliphatics (C 4 -C 7 ) but lower ethene selectivity compared to Beta-C. Therefore, we conclude that a hierarchical structure decreases the residence time of methylbenzenes in zeolite micropores, disfavoring the propagation of the aromatic-based catalytic cycle. This conclusion is consistent with a recent report on ZSM-5 and is also strongly supported by our analysis of soluble coke species residing in the catalysts.Moreover, we identified an oxygen-containing compound, 4-methyl-benzaldehyde, in the coke, which has not been observed in the MTH reaction before.

show abstract

Methanol to Hydrocarbons

Dai

Liu

et al. 2022

Heterogeneous Catalysis for Sustainable Energy

View full text Add to dashboard Cite

On the impact of co-feeding aromatics and olefins for the methanol-to-olefins reaction on HZSM-5

Cited by 139 publications

References 43 publications

Mechanistic studies of methanol-to-hydrocarbons conversion on diffusion-free MFI samples

Mechanistic studies of methanol-to-hydrocarbons conversion on diffusion-free MFI samples

Investigating the Influence of Mesoporosity in Zeolite Beta on Its Catalytic Performance for the Conversion of Methanol to Hydrocarbons

Methanol to Hydrocarbons

Contact Info

Product

Resources

About