Enhanced selectivity to propene in the methanol to hydrocarbons reaction by use of ZSM-5/11 intergrowth zeolite

Conte, Marco; Xu, Bin; Davies, Thomas E.; Bartley, Jonathan K.; Carley, Albert Frederick; Taylor, Stuart Hamilton; Khalid, Kharim; Hutchings, Graham J.

doi:10.1016/j.micromeso.2012.05.001

Cited by 62 publications

(31 citation statements)

References 61 publications

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“…Hadi et al [16] used ion exchange procedure to exchange some acidic H + ions in the framework with Ca, Mn, Cr, Fe, Ni, Ag, and Ce ions. Some other strategies, such as changing the medium of zeolite preparation (fluoride route) [17], altering Si/Al ratio, synthesizing distorted zeolite framework, building hierarchical zeolite materials [1,18,19], preparing composite molecular sieves [20,21], and synthesizing the nanosheet framework to decrease long channels [22], were employed. In addition, several research groups focused on tuning the reaction conditions, e.g., increasing the reaction temperature, decreasing the partial pressure of methanol, changing the reactor design [23], and introducing a co-feed of methanol containing water to the MTO reaction [24].…”

Section: Introductionmentioning

confidence: 99%

H-ZSM-5 Materials Embedded in an Amorphous Silica Matrix: Highly Selective Catalysts for Propylene in Methanol-to-Olefin Process

et al. 2019

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H-ZSM-5 materials embedded in an amorphous silica were successfully synthesized with three different Si/Al ratios (i.e., 40, 45, and 50). The presence of the MFI structure in the synthesized samples was confirmed by X-ray diffraction (XRD), Fourier transform infra-red (FT-IR), and solid state-nuclear magnetic resonance (SSNMR) techniques. The morphology and textural properties of the samples were investigated by scanning electron microscopy (SEM), TEM, and N2-physisorption measurements. Furthermore, acidic properties of the synthesized catalysts have been studied by NH3-TPD and FT-IR spectroscopy of CO adsorption studies. Variation of the Si/Al ratio affected the crystal morphology, porosity, and particle size, as well as the strength and distribution of acid sites. The synthesized zeolite materials possessed low acid-site density and exhibited high catalytic activity in the methanol-to-olefin (MTO) reaction. To study the intermediate species responsible for catalyst deactivation, the MTO reaction was carried out at high temperature (500 °C) to accelerate catalyst deactivation. Interestingly, the synthesized catalysts offered high selectivity towards the formation of propylene (C3=), in comparison to a commercial microporous crystalline H-ZSM-5 with Si/Al = 40, under the same reaction conditions. The synthesized H-ZSM-5 materials offered a selectivity ratio of C3=/C2= 12, while it is around 2 for the commercial H-ZSM-5 sample. The formation of hydrocarbon species during MTO reaction over zeolite samples has been systematically studied with operando UV-vis spectroscopy and online gas chromatography. It is proposed that the strength and type of acid sites of catalyst play a role in propylene selectivity as well as the fast growing of active intermediate species. The effective conversion of methanol into propylene in the case of synthesized H-ZSM-5 materials was observed due to possession of weak acid sites. This effect is more pronounced in H-ZSM-5 sample with a Si/Al ratio of 45.

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Section: Introductionmentioning

confidence: 99%

H-ZSM-5 Materials Embedded in an Amorphous Silica Matrix: Highly Selective Catalysts for Propylene in Methanol-to-Olefin Process

et al. 2019

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“…The evidences are the strong decrease of the intensity of the reections (051) and (303), and the disappearance of the reection (133) in the XRD patterns of HZSM-5/ 11(78) compared with those of HZSM-5(80). 27 A further evidence of HZSM-5/11(78) intergrowth zeolite is the peak at 2q of 45.5 . In the patterns of pure HZSM-5(80) the peak at 2q of 45.5 is always clearly observed, while in the patterns of intergrowth zeolite HZSM-5/11(78) this peak is strongly diminished (Fig.…”

Section: Characterization Of the Catalystsmentioning

confidence: 97%

“…Composite co-crystalline zeolite HZSM-5/11(78) was synthesized by using the reported method. 27 NaOH (Fisher, 3.25 g) and meteorological silica (Fisher, 37.5 g) were added to distilled water (160 ml) with strong stirring to give a solution (solution 1). NaAlO 2 (Fisher, 0.75 g) and tetrabutylammonium bromide (Aldrich, 10 g) were added to distilled water (30 ml) with vigorous stirring to generate another clear solution (solution 2).…”

Section: Materials and Catalystsmentioning

confidence: 99%

“…This zeolite is a co-crystalline porous tectosilicate, that is a three-dimensional framework of silicate tetrahedra with SiO 2 , comprising an intergrowth between zeolites HZSM-5 and HZSM-11. 27 Therefore, a co-crystalline zeolite HZSM-5/11(78) was synthesized and tested in the conversion of glycerol with ammonia to pyridine bases in a x-bed reactor. The catalytic results indicated that the co-crystalline zeolite HZSM-5/11(78) had good performance compared to other zeolites such as HZSM-5(80), HZSM-11(80) and the physical mixture of HZSM-5(80) and HZSM-11(80) known as HZSM-5/ HZSM-11(80).…”

Section: Introductionmentioning

confidence: 99%

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Enhanced selectivity in the conversion of glycerol to pyridine bases over HZSM-5/11 intergrowth zeolite

et al. 2017

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“…Recently, a number of great works on organotemplate‐free synthesis of zeolites have been achieved. Typically, Okubo and his co‐workers synthesized the NES‐type zeolite using EU‐1 seed crystals under the OSDA‐free conditions,78 Li and his co‐workers reported the seed‐directed synthesis of EMT zeolite from an organotemplate‐free system,79 Liu and his co‐workers showed the organotemplate‐free synthesis of ZSM‐35 zeolite using MCM‐49 zeolite seeds,80 and Xu and his co‐workers demonstrated an organotemplate‐free synthesis of ZSM‐5/11 intergrowth using the mixed zeolite seeds 81…”

Section: Organotemplate‐free Synthesis Of Zeolitesmentioning

confidence: 99%

Understanding Mechanism and Designing Strategies for Sustainable Synthesis of Zeolites: A Personal Story

Wang

Xiao

2016

The Chemical Record

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Zeolites with intricate micropores have been widely studied for a long time as an important class of porous materials in different areas of industrial processes such as gas adsorption and separation, ion exchange, and shape-selective catalysis. However, their industrial syntheses are not sustainable, and normally require the presence of expensive organic templates and a large amount of solvents such as water. The presence of organic templates not only increases zeolite cost but also produces harmful gases during the removal of these templates by calcination, while the use of solvents significantly increases the amount of polluted water. This Personal Account briefly summarizes recent sustainable routes for the synthesis of zeolites in our group according to our understanding of the synthetic mechanism, and mainly focuses on the organotemplate-free synthesis of zeolites in the presence of zeolite seeds, the design of environmentally friendly templates, and solvent-free synthesis of zeolites.

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Enhanced selectivity to propene in the methanol to hydrocarbons reaction by use of ZSM-5/11 intergrowth zeolite

Cited by 62 publications

References 61 publications

H-ZSM-5 Materials Embedded in an Amorphous Silica Matrix: Highly Selective Catalysts for Propylene in Methanol-to-Olefin Process

H-ZSM-5 Materials Embedded in an Amorphous Silica Matrix: Highly Selective Catalysts for Propylene in Methanol-to-Olefin Process

Enhanced selectivity in the conversion of glycerol to pyridine bases over HZSM-5/11 intergrowth zeolite

Understanding Mechanism and Designing Strategies for Sustainable Synthesis of Zeolites: A Personal Story

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