Zincoaluminophosphate Molecular Sieves with AFI and ATS Topologies: Synthesis by Dry-Gel Conversion Methods and Their Catalytic Properties in the Isopropylation of Biphenyl

Saha, Shyamal Kumar; Maekawa, Hiroyoshi; Waghmode, Suresh B.; Mulla, Shafeek A. R.; Komura, Kenichi; Kubota, Yoshihiro; Sugi, Yoshihiro; Cho, Sung June

doi:10.2320/matertrans.46.2659

Cited by 18 publications

(8 citation statements)

References 27 publications

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“…[35] However,s everale lements have been subjectt o rigorous study by employing advanced spectroscopict echniques, which have confirmed framework incorporation. [36] Metal-substituted AlPO-5 materials have been tested as catalysts in severalr eactions, including methanol to hydrocarbons, [37] ethylation and propylation of aromatics, [38,39] cracking of alkanes, [40] and aromatic isomerization. [41] In this work, we aim to study the effect of metal incorporation into the AlPO-5 structure and the effect of the created BAS on the MTH reaction.…”

Section: Introductionmentioning

confidence: 99%

A Systematic Study of Isomorphically Substituted H‐MAlPO‐5 Materials for the Methanol‐to‐Hydrocarbons Reaction

et al. 2017

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Substituting metals for either aluminum or phosphorus in crystalline, microporous aluminophosphates creates Brønsted acid sites, which are well known to catalyze several key reactions, including the methanol to hydrocarbons (MTH) reaction. In this work, we synthesized a series of metal‐substituted aluminophosphates with AFI topology that differed primarily in their acid strength and that spanned a predicted range from high Brønsted acidity (H‐MgAlPO‐5, H‐CoAlPO‐5, and H‐ZnAlPO‐5) to medium acidity (H‐SAPO‐5) and low acidity (H‐TiAlPO‐5 and H‐ZrAlPO‐5). The synthesis was aimed to produce materials with homogenous properties (e.g. morphology, crystallite size, acid‐site density, and surface area) to isolate the influence of metal substitution. This was verified by extensive characterization. The materials were tested in the MTH reaction at 450 °C by using dimethyl ether (DME) as feed. A clear activity difference was found, for which the predicted stronger acids converted DME significantly faster than the medium and weak Brønsted acidic materials. Furthermore, the stronger Brønsted acids (Mg, Co and Zn) produced more light alkenes than the weaker acids. The weaker acids, especially H‐SAPO‐5, produced more aromatics and alkanes, which indicates that the relative rates of competing reactions change upon decreasing the acid strength.

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Section: Introductionmentioning

confidence: 99%

A Systematic Study of Isomorphically Substituted H‐MAlPO‐5 Materials for the Methanol‐to‐Hydrocarbons Reaction

et al. 2017

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“…The metalloaluminophosphate analogs, MAPO-36 (M: Si, Mg, Zn) of ATS topology, also gave selectivities for 4,4 0 -DIPB of 20-40 % in the similar level as SSZ-55 [11,15,25]. Further, [Fe]-SSZ-24, with isomorphously substituted [Al]-SSZ-24 also gave the similar level of the selectivities for 4,4 0 -DIPB [26].…”

Section: The Effects Of Zeolite-type On the Isopropylation Of Bpmentioning

confidence: 90%

Alkylation of Biphenyl over Zeolites: Shape-Selective Catalysis in Zeolite Channels

Sugi

Vinu

2015

Catal Surv Asia

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Steric interaction of reactants, products, and transition state intermediates with zeolites with 12-and 14-membered ring pore entrances is discussed in the alkylation of biphenyl (BP) by propene, 1-butene, and 2-methylpropene as alkylating agents. The selectivities for the least bulky 4,4 0 -dialkylbiphenyl (4,4 0 -DAB) depended on the types of zeolite and alkylating agent. The zeolites are classified as two types: Category I: mordenite (MOR), SSZ-24 (AFI), SSZ-31 (STO), CIT-5 (CFI), MCM-68 (MSE), and ZSM-12 (MTW) with straight (or slightly corrugated) channels with 12-MR or 14-MR pore entrances. Category II: SSZ-42 (IFR), SSZ-55 (ATS), SSZ-60 (SSY), Y (FAU), b (BEA), CIT-1 (CON), UTD-1 (DON), and SSZ-53 (SFH) with large channels. Category I zeolites have shape-selective natures in their channels in the isopropylation. Among them, MOR supported the highest selectivities around 85 % for 4,4 0 -diisopropylbipneyl (4,4 0 -DIPB) at moderate temperatures as 250 o C. The selectivities of 4,4 0 -DIPB are: MOR [ AFI, MSE [ MTW, CFI, STO: the differences are due to the recognition of 4,4 0 -and 3,4 0 -DIPB by the channels. Category II zeolites allow the accommodation and the formation of bulky DIPB isomers in their channels, resulting in non-shape selective catalysis under kinetic and/or thermodynamic controls. Bulky alkylating agents, 1-butene and 2-methylpropene, enhance selective formation of the least bulky 4,4 0 -DAB: 4,4 0 -di-sec-butylbiphenyl (4,4 0 -DSSB) and 4,4 0 -di-tert-butylbiphenyl (4,4 0 -DTBB), respectively, even over Category II zeolites. The bulky moieties enhance the exclusion of bulky isomers by their interaction with zeolite channels. The selectivities for 4,4 0 -DSSB were increased remarkably to higher than 80 % for Category I zeolites and to 70 % for ATS in Category II zeolites in the sec-butylation. However, kinetic and thermodynamic controls still worked with the formation of bulky isomers over Category II zeolites: IFR, FAU, BEA, CON, DON, and SFH in the secbutylation. The high selectivities for 4,4 0 -DTTB higher than 80 % were observed for the zeolites, except FAU in the tertbutylation. These results indicate that the selectivities for 4,4 0 -DAB are controlled primarily by space and shape of zeolite channels for active sites, and not always by the size of pore entrances.

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“…In contrast, no isomerization of 4,4 0 -DIPB occurred at the internal acid sites over H-MOR. [3][4][5] These selectivities for 4,4 0 -DIPB of SSZ-24 zeolites are in the similar level to those of SAPO-5 and MAPO-5 molecular sieves with the AFI topology, 11,[13][14][15] whereas the selectivity for 4,4 0 -DIPB is lower than those for H-MOR. [4][5][6][7][8] The differences in the selectivity for 4,4 0 -DIPB are due to the structural difference between H-MOR and molecular sieves with AFI topology.…”

mentioning

confidence: 81%

“…Our previous relevant findings on the subjects have been published on the alkylation of BP over H- [Al]-SSZ-31, 10 H-[Al]-CIT-5, 11 SAPO-5, 12 and MAPO-5 (M: Mg, Ca, Sr, Ba, and Zn). [13][14][15] H-[Al]-SSZ-24 zeolite is a high-silica large-pore molecular sieve, which is isostructural with AlPO 4 -5 (AFI topology), 16 and is expected to work as a potential catalyst for shape-selective alkylation of polynuclear aromatics because of its straight twelve-membered ring (12-MR) channel structure. SSZ-24 zeolite was first synthesized by Zones as its pure-silica form using 1-trimethylammonioadamantane as a structure-directing agent (SDA).…”

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confidence: 99%

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Shape-Selective Alkylation of Biphenyl over H-[Al]-SSZ-24 Zeolites with AFI Topology

Itō¹,

Maekawa²,

Kawagoe³

et al. 2007

Bulletin of the Chemical Society of Japan

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H-[Al]-SSZ-24 zeolites with AFI topology were synthesized through the alumination of [B]-SSZ-24 zeolites, and applied for the alkylation of biphenyl (BP). H-[Al]-SSZ-24 zeolites have high activity for the isopropylation. The shapeselective formation of 4,4 0-diisopropylbiphenyl (4,4 0-DIPB) occurred at moderate temperature; however, the selectivity for 4,4 0-DIPB decreased with an increase in the reaction temperature. Isomerization of 4,4 0-DIPB occurred at higher temperatures over internal and external acid sites when there are enough acid sites inside the channels. The channels can discriminate 4,4 0-DIPB from the other DIPB isomers in their transition states; however, they can not prevent the isomerization of 4,4 0-DIPB at higher temperatures. The selectivity for the least bulky 4,4 0-dialkylbiphenyl increased with the bulkiness of alkylating agents in the order: isopropylation < s-butylation < t-butylation. These results strongly support the shape-selective formation of the least bulky products inside the channels of H-[Al]-SSZ-24 zeolites.

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Zincoaluminophosphate Molecular Sieves with AFI and ATS Topologies: Synthesis by Dry-Gel Conversion Methods and Their Catalytic Properties in the Isopropylation of Biphenyl

Cited by 18 publications

References 27 publications

A Systematic Study of Isomorphically Substituted H‐MAlPO‐5 Materials for the Methanol‐to‐Hydrocarbons Reaction

A Systematic Study of Isomorphically Substituted H‐MAlPO‐5 Materials for the Methanol‐to‐Hydrocarbons Reaction

Alkylation of Biphenyl over Zeolites: Shape-Selective Catalysis in Zeolite Channels

Shape-Selective Alkylation of Biphenyl over H-[Al]-SSZ-24 Zeolites with AFI Topology

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