Thermal decomposition of ZSM—5 and silicalite precursors

Parker, L.M.; Bibby, D.M.; Patterson, Joseph E.

doi:10.1016/0144-2449(84)90056-3

Cited by 146 publications

(78 citation statements)

References 11 publications

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“…The decomposition takes place at higher temperatures for samples N2 and N3 than for N1 and N4. By analogy with ZSM-5 [18] and some aluminophosphates [15], this effect can be interpreted as an indication of a more pronounced template-lattice interaction.…”

Section: Template Decomposition In Sapo-5mentioning

confidence: 94%

Thermal decomposition of organic templates in silicoaluminophosphate molecular sieves with various structures

Minchev¹,

Weyda²,

Minkov³

et al. 1991

Journal of Thermal Analysis

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The decomposition of organic templates in molecular sieves SAPO-5, SAPO-11, SAPO-20, SAPO-34 and SAPO-37 was investigated by TG, DTG and DTA. In the ease of SAPO-5, the decompositions of various organic templates were studied. The effects of the type of crystal structure, the pore size and the channel system on the complete removal of the organic material were considered.The silicoaluminophosphate molecular sives, denoted SAPO-n, are new materials whose physical, chemical and catalytic properties have been the subject of considerable interest [1][2][3][4][5][6][7]. Microporous oxides SAPO-n can be considered to originate from Si incorporation into a hypothetical aluminium phosphate lattice. When Si substitutes one P, a negatively charged framework is formed and, after decomposition of the template, aeid sites are also generated. These are of considerable importance in modifying the earboniogenie activity of these materials [1,2]. In the presence of suitable organic templates, silieoaluminophosphates with different crystal structures have been synthesized [1, 8,9]. This work continues our previous investigations on the removal of the templating agent from aluminophosphate-based molecular sieves, by means of simultaneous thermal analysis (TG-DTG-DTA) methods [10]. We now

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Section: Template Decomposition In Sapo-5mentioning

confidence: 94%

Thermal decomposition of organic templates in silicoaluminophosphate molecular sieves with various structures

Minchev¹,

Weyda²,

Minkov³

et al. 1991

Journal of Thermal Analysis

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“…It is generally accepted that physisorbed water is removed at $353 K, but the endothermal peak situated among 353 and 473 K has been assigned to the template desorption [7], template decomposition [15] and water desorption [32±37]. The speci®c assignments are dependent on the template molecule [38] as well as on the framework topology of the molecular sieve.…”

Section: Synthesis Of Vapo-11 Materialsmentioning

confidence: 99%

On the synthesis of vanadium containing molecular sieves by experimental design from a VOSO4·5H2O·Al(iPrO)3·Pr2NH·H2O gel: occurrence of VAPO-41 as a secondary structure in the synthesis of VAPO-11

Frunză¹,

Voort²,

Vansant³

et al. 2000

Microporous and Mesoporous Materials

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Section: Rende 87030 Rende (Cs) Italymentioning

confidence: 99%

“…The state of tetrapropylammonium (TPA) ions, occluded in ZSM-5 channels has been most thoroughly investigated by thermal analysis combined with mass spectrometry [7] or 13C-NMR spectroscopy [8]. TPA ions decompose by the Hoffman reaction to give an olefin and trialkylamine [7].The three DTA peaks (B, C1 and C2) have been assigned [8] to decomposition of different TPA species occluded into the zeolitic channels. In the case of Al-free silicalite, the low temperature (ca 380 ~ peak B is attributed [9] to less strongly held or "outer shell" strained TPA ions.…”

mentioning

confidence: 99%

Thermal behaviour of the tpa IONS in ZSM-5 zeolite: II. Effect of crystal size and grinding of silicalite-1

Crea

Giordano

Mostowicz

et al. 1990

Journal of Thermal Analysis

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RENDE, 87030 RENDE (CS), ITALYThermal decomposition of Silicalite-1 crystals of various size was studied. The crystals were in as-made form and upon grinding. The DTA and DTG curves show differences in the temperature of thermal decomposition of TPA species occluded in the as-made crystals. These differences disappear upon grinding. The explanation of this phenomena is given.Silicalite-1, the Al-free analogue of ZSM-5 zeolite was first prepared by E. M. Flanigen et al. [1]. It has the same crystal structure as the ZSM-5 zeolite which has been applied as a catalyst in MTG and other petrochemical processes [2].Synthesis of the ZSM-5 zeolite and its aluminium deficient end-member silicalite has been the topic of a large number of investigations [3]. The parameters affecting the growth of large silicalite crystals and the effect of reactant concentration on crystal morphology have been reported by Hayhurst et aL [4,5].The organic compounds used as either structure-directing and/or space filling species in a high-silica zeolite synthesis are generally occluded in the zeolite channels and cavities either in an intact or in a modified state [3,6]. The state of tetrapropylammonium (TPA) ions, occluded in ZSM-5 channels has been most thoroughly investigated by thermal analysis combined with mass spectrometry [7] or 13C-NMR spectroscopy [8]. TPA ions decompose by the Hoffman reaction to give an olefin and trialkylamine [7].The three DTA peaks (B, C1 and C2) have been assigned [8] to decomposition of different TPA species occluded into the zeolitic channels. In the case of Al-free silicalite, the low temperature (ca 380 ~ peak B is attributed [9] to less strongly held or "outer shell" strained TPA ions. A peak C1 (ca. 425 ~ is assigned to inner ions neutralizing SiO-negative charges of John Wiley & Sons, Limited, Chichester Akadgrm'ai Kiad6, Budapest

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Thermal decomposition of ZSM—5 and silicalite precursors

Cited by 146 publications

References 11 publications

Thermal decomposition of organic templates in silicoaluminophosphate molecular sieves with various structures

Thermal decomposition of organic templates in silicoaluminophosphate molecular sieves with various structures

On the synthesis of vanadium containing molecular sieves by experimental design from a VOSO4·5H2O·Al(iPrO)3·Pr2NH·H2O gel: occurrence of VAPO-41 as a secondary structure in the synthesis of VAPO-11

Thermal behaviour of the tpa IONS in ZSM-5 zeolite: II. Effect of crystal size and grinding of silicalite-1

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