Effect of boron on ZSM-5 catalyst for methanol to propylene conversion

Xu, Aina; Ma, Hongfang; Zhang, Haitao; Weiyong, Dingye; Fang, Dingye

doi:10.2478/pjct-2013-0075

Cited by 38 publications

(18 citation statements)

References 30 publications

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“…Catalytic activity tests, in most cases, are performed using fresh catalysts at raw material conversion near to 100% [15,16]. The selectivity of product formation was estimated for fresh catalyst at zero time on stream (i.e., initial selectivity) [4,17,18]. However, the activity of the fresh catalyst that is estimated based on conversion of raw material to hydrocarbons, decreases during the reaction due to blocking of Brønsted acid sites by coke.…”

Section: Introductionmentioning

confidence: 99%

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

et al. 2019

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The reaction of dimethyl ether to olefin over HZSM-5/Al2O3 catalysts modified by Zr and Mg and stabilized by hydrothermal treatment has been studied. Regardless of the introduction method and the nature of the metal, the dependence of the key products selectivity on X(DME) over hydrothermally treated steady-state catalysts does not change, and the experimental points are described by the same curves. Metal introduction and the corresponding changes in the acid sites distribution do not change the ratio of main reaction rates, only the absolute values of the formation rate of the products are changed. Zr doping leads to the greatest activity in the DME conversion due to an equable decrease in the total acidity of the sample. On the other hand, the Mg-modified sample has a higher amount of weak acid sites, which reduces activity. At low DME conversion, methanol is one of the primary reaction products which formed from DME simultaneously with propylene in alkene cycle. At high DME conversion, the methanol acts as a main reagent which leads to ethylene formation in the arene cycle. Based on the results, the role of the metal in the reaction chemistry is considered and the mechanism of product formation from DME over steady-state catalyst is proposed, which describes both the participation of DME and the methanol produced.

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Section: Introductionmentioning

confidence: 99%

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

et al. 2019

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“…The acidity of catalyst plays an important role in catalytic activity through MTO reaction, and acid adjustment is the most significant affecting factor for product distribution and catalytic stability [10][11][12][13][14][15][16][17][18]. Many methods could adjust the catalysts acid properties for a better catalytic performance.…”

Section: Introductionmentioning

confidence: 99%

Effect of magnesium modification over H-ZSM-5 in methanol to propylene reaction

et al. 2015

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H-ZSM-5-based catalyst is a recognized catalyst which is particularly selective towards the formations of light olefins in the methanol reaction. A series of H-ZSM-5 (SiO 2 /Al 2 O 3 = 38) modified with different amounts of magnesium have been investigated. All the samples were characterized by X-ray diffraction instrument (XRD), temperature-programmed desorption of NH 3 (NH 3 -TPD) and Fourier Transform Infrared Spectoscopy (FT-IR). The results indicated that the impregnation of H-ZSM-5 (SiO 2 /Al 2 O 3 = 38) zeolite with various magnesium loading amount significantly affected the strength of acid sites and decreased the concentration of both weak and strong acid sites. As a result of modification, magnesium mainly interacted with strong Brønsted acid sites, thus generated new medium strong acid sites and enhanced the yield of propylene. The optimum acid property for methanol to propylene (MTP) reaction was gotten over 4.0 Mg-ZSM-5 (4.0 wt% Mg) zeolite catalyst. The maximum yield of propylene was 10.62 wt% over 4.0 Mg-ZSM-5 zeolite catalyst by the 30 min on stream. Coke which was mostly formed on strong Brønsted acid sites, would cause the catalysts deactivation, so the reduction of strong Brønsted acid sites could enhance the catalytic stability.

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“…The production of some Lewis acid sites in the structure of 2% Ba-ZSM-5 may correspond to the combination of promoter species with bridging hydroxyl groups and formation of extra-framework Al. 53−55 On account of the partial dealumination and formation of new Lewis acid sites, the literature review revealed that impregnation of some promoters such as Mg, 26 Mo, 54,55 B, 23 and Ni 47 increases the number of Lewis acid sites. This phenomenon can be explained by the interaction of the promoter with the framework Al atoms.…”

Section: Nh 3 -Tpd Analysismentioning

confidence: 99%

“…It is reported that, weak acidity not only contributes methanol to the DME reaction; it can also participate in the methylation/alkylation reaction cycle and produce light olefins (especially propylene). 22,23,48 The increase of weak acid site density can improve propylene production and has a positive effect on catalyst stability. 62 Likewise, the strength of strong acid sites of DZSM-5 decreases relative to HZSM-5, leading to an intensity reduction of secondary reaction performance and conversion decrement of light olefins to precursors of coke.…”

Section: %) and Light Olefins (6738%) And A Propylene/ethylene Ratmentioning

confidence: 99%

“…It should be mentioned that the acidity of catalysts has a significant effect on MTP reaction and that the number and strength of acid sites affect methanol conversion and product distribution. 22,23 Modification of catalysts by metal or metal oxide as promoters is an effective procedure for adjusting the acidity of the HZSM-5. 24 Numerous studies have evaluated catalyst promoters for MTP reaction and the results indicated that the yield of propylene was improved by incorporating metal species such as Mn, 25,26 Fe, 8 Ca, 25,27 Ce, 8,25 Ba, 28 , and Cs 26 into the HZSM-5 catalyst.…”

Section: Introductionmentioning

confidence: 99%

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Synergetic effect of Mn, Ce, Ba, and B modification and moderate desilication of nanostructured HZSM-5 catalyst on conversion of methanol to propylene

Saravi¹,

Taghizadeh²

2018

Turk J Chem

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Modified mesoporous HZSM-5 catalysts were prepared by controlled desilication using a mixture of NaOH and TPAOH (tetrapropylammonium hydroxide) and impregnation of metals (Mn, Ce, and Ba) and metalloid B. The catalytic performances of all prepared catalysts for methanol to propylene (MTP) reaction were evaluated in a fixed bed reactor under atmospheric pressure at 480°C. The parent and modified catalysts were characterized by XRD, ICP-OES, FE-SEM, NH 3-TPD, FT-IR, BET, and TGA techniques. The catalyst loaded with 2 wt.% manganese on desilicated HZSM-5 demonstrated the best catalytic performance in terms of the highest selectivity of C = 2 to C = 4 olefins (about 93%) and about 52% selectivity of propylene at near 99% methanol conversion in the MTP reaction for a long operation (264 h). The improved catalytic performance can be attributed to the high surface area and the formation of mesopores on the zeolite crystals in conjunction with the appropriate acidity.

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Effect of boron on ZSM-5 catalyst for methanol to propylene conversion

Cited by 38 publications

References 30 publications

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

Effect of magnesium modification over H-ZSM-5 in methanol to propylene reaction

Synergetic effect of Mn, Ce, Ba, and B modification and moderate desilication of nanostructured HZSM-5 catalyst on conversion of methanol to propylene

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