Aluminium chloride: A new aluminium source to prepare SAPO-34 catalysts with enhanced stability in the MTO process

Álvaro-Muñoz, Teresa; Márquez‐Álvarez, Carlos; Sastre, Enrique

doi:10.1016/j.apcata.2013.12.016

Cited by 53 publications

(34 citation statements)

References 52 publications

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“…It has been reported that the deactivation rate was substantially decreased by water addition to the feed. Researchers have attempted to increase the stability of H-SAPO-34, the archetypal MTO catalyst, 39,40 by decreasing the particle size, [41][42][43] creating a secondary network of meso-and macropores 44 and addition of water in the feed [9][10][11]23,45,46 . For H-SAPO-34 catalysts at 400 °C it was reported that an optimal feed consists of 73-80 mol % water to minimize the coking rate and maximize the olefin selectivity.…”

Section: Introductionmentioning

confidence: 99%

Insight into the Effect of Water on the Methanol-to-Olefins Conversion in H-SAPO-34 from Molecular Simulations and in Situ Microspectroscopy

et al. 2016

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The role of water in the methanol-to-olefins (MTO) process over H- has been elucidated by a combined theoretical and experimental approach, encompassing advanced molecular dynamics simulations and in-situ micro-spectroscopy. First principle calculations at the molecular level point out that water competes with methanol and propene for direct access to the Brønsted acid sites. This results in less efficient activation of these molecules, which are crucial for the formation of the hydrocarbon pool. Furthermore, lower intrinsic methanol reactivity towards methoxide formation has been observed. These observations are in line with a longer induction period observed from in-situ UV-Vis micro-spectroscopy experiments. These experiments revealed a slower and more homogeneous discoloration of H-SAPO-34, while insitu confocal fluorescence microscopy confirmed the more homogeneous distribution and larger amount of MTO intermediates when co-feeding water. As such it is show that water induces a more efficient use of the H-SAPO-34 catalyst crystals at the microscopic level. The combined experimental theoretical approach gives a profound insight into the role of water on the catalytic process at the molecular and single particle level.

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Section: Introductionmentioning

confidence: 99%

Insight into the Effect of Water on the Methanol-to-Olefins Conversion in H-SAPO-34 from Molecular Simulations and in Situ Microspectroscopy

et al. 2016

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“…43 As it was mentioned previously, the crystal size has been proven to be a key parameter controlling the catalytic behaviour of zeolitic materials in the methanol transformation to olefins, being possible to enhance significantly the stability of the catalysts by decreasing the crystallite size to the nanometer scale. 22,23,27,47 Besides, it is known for some SAPO materials that the silicon concentration in the synthesis gel influences the size of the obtained crystals. 32 The crystallite size and morphology of the SAPO samples obtained have been studied by scanning electron microscopy (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…In this sense, the particle size and the presence of hierarchical porosity have been widely correlated with the diffusion limitations in the micropores, showing that smaller or mesopore-modified crystals exhibit an enhanced stability in the process. 22,23,[27][28][29][30] Other parameter that strongly affects the catalytic performance is the acidity of the materials. This property depends on the content and distribution of silicon in the SAPO framework; considering the Si distribution as the kind of Si environments formed.…”

Section: Introductionmentioning

confidence: 99%

“…13,21 Since the fast deactivation is the main drawback of SAPO materials as catalysts for the MTO transformation, great efforts have been devoted to the optimization of the physicochemical properties of SAPO-34 in order to improve its catalytic performance. 4,[22][23][24][25][26] Extensive studies indicate that there are some key parameters to be controlled in order to improve the properties of SAPO materials as MTO catalysts. In this sense, the particle size and the presence of hierarchical porosity have been widely correlated with the diffusion limitations in the micropores, showing that smaller or mesopore-modified crystals exhibit an enhanced stability in the process.…”

Section: Introductionmentioning

confidence: 99%

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Complex relationship between SAPO framework topology, content and distribution of Si and catalytic behaviour in the MTO reaction

Pinilla-Herrero

Márquez‐Álvarez

Sastre

2017

Catal. Sci. Technol.

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Three small-pore silicoaluminophosphates containing relatively large cavities in their structure (LEV, LTA and SAV) have been hydrothermally synthesized with various silicon concentrations. The effect of the silicon content and distribution on both the physicochemical and the catalytic properties of the SAPO molecular sieves was studied. Remarkable differences in the Si incorporation were found, showing that the topological features and the structure directing agent employed in each case play an important role, controlling not just the Si location in the framework, but also the amount of Si incorporated. In all the cases, the formation of Si islands, associated to stronger acid sites, was favoured by the use of higher concentrations of the Si source in the synthesis gel. However, it has been found that framework topology can have greater influence than acidity on the catalytic behaviour of SAPO materials in the MTO transformation.

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“…Zeolites with shape selectivity, high surface area, and high thermal stability, such as ZSM-5, TS-1, and SAPO-34 [1][2][3][4][5][6][7], are increasingly common in the field of catalysis, because microporous materials with selected properties and functions are in extreme demand in the contemporary chemical industry. SAPO-34, a silicoaluminophosphate zeolite with a large chabazite (CHA) framework structure and small 8-ring pore (0.38 nm 9 0.38 nm), has attracted great attention as a catalyst in a number of reactions, such as hydrogen purification, CO 2 /CH 4 separation, the dehydration of fructose into HMF, and the conversion of methanol-to-olefins (MTO) [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Performance of Methanol-to-Olefins Catalytic Reactions by the Addition of PEG in the Synthesis of SAPO-34

Wang

Sun

et al. 2017

Trans. Tianjin Univ.

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SAPO-34, a silicoaluminophosphate zeolite, has been synthesized by the hydrothermal method with the addition of different molecular weights of polyethylene glycol (PEG), and has been characterized with XRD, SEM, N 2 adsorption-desorption, FT-IR, and NH 3 temperatureprogrammed desorption (NH 3 -TPD). We studied SAPO-34 as a catalyst in the methanol-to-olefins (MTO) reaction, in a fixed-bed reactor. The results show that the chain length of PEG has a great influence on the particle size and morphology of SAPO-34. PEG acts as inhibitor in the crystallization process. With the increase of the chain length of PEG used in the synthesis, from a relative molecular weight of 400-6000, the morphology of SAPO-34 changes gradually from cubic to nanoplate-like and then changes to cubic again. The particle size decreases markedly at first and then increases to some extent. The catalytic stability in the MTO reaction also increases first and then decreases, with all the catalysts having almost the same selectivity to olefins. When the sample is synthesized with PEG800, the particles become nanoplate-like with a thickness of 46 nm on average, and the catalytic stability is appreciably prolonged, which is attributed to the shorter diffusion paths of the reactants in the zeolite.

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Aluminium chloride: A new aluminium source to prepare SAPO-34 catalysts with enhanced stability in the MTO process

Cited by 53 publications

References 52 publications

Insight into the Effect of Water on the Methanol-to-Olefins Conversion in H-SAPO-34 from Molecular Simulations and in Situ Microspectroscopy

Insight into the Effect of Water on the Methanol-to-Olefins Conversion in H-SAPO-34 from Molecular Simulations and in Situ Microspectroscopy

Complex relationship between SAPO framework topology, content and distribution of Si and catalytic behaviour in the MTO reaction

Performance of Methanol-to-Olefins Catalytic Reactions by the Addition of PEG in the Synthesis of SAPO-34

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