Effects of steaming-made changes in physicochemical properties of Y-zeolite on cracking of bulky 1,3,5-triisopropylbenzene and coke formation

Bazyari, Amin; Khodadadi, Abbas Ali; Hosseinpour, Negahdar; Mortazavi, Yadollah

doi:10.1016/j.fuproc.2009.06.002

Cited by 53 publications

(39 citation statements)

References 31 publications

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“…Other gases (C 4 -), ethylbenzene, n-propylbenzene, 1,3,5-tri-methylbenzene and isobutylbenzene were observed as minor products. Previous reports about the cracking of TIPB over acidic catalysts [4,5,22] showed the same main products with the exception of C 15 H 22 , which was only reported by Falco et al [23], who observed that the selectivity to this product was high at short reaction times, showing an unstable behavior. 1,4-DIPB, which is always observed with low yields, can be formed by isomerization from 1,3-DIPB, a reaction which occurs easily on acidic catalysts [22].…”

Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 51%

“…Previous reports about the cracking of TIPB over acidic catalysts [4,5,22] showed the same main products with the exception of C 15 H 22 , which was only reported by Falco et al [23], who observed that the selectivity to this product was high at short reaction times, showing an unstable behavior. 1,4-DIPB, which is always observed with low yields, can be formed by isomerization from 1,3-DIPB, a reaction which occurs easily on acidic catalysts [22]. Besides the three cracking steps of the alkyl side chains, which are clearly dominant, other side reactions leading to minor products in the conversion of TIPB, such as disproportionation, isomerization and condensation [4,21,24,34] have been reported.…”

Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 51%

“…However, most important properties (average mesopore size, specific surface area, crystallinity, acidity) maintained the trends observed with the zeolites before steaming (values not shown). As discussed, the molecules of 1,3,5-tri-isopropylbenzene, having a critical diameter of 9.5 Å , can be considered relatively bulky, and have been extensively used as a model reactant to reveal diffusion limitations in catalytic cracking catalysts [4,5,7,10,[21][22][23][24][25]. Thermal cracking experiments at 500°C and 16 s showed that TIPB conversion was 6.6 %, with a compound (C 15 H 22 ) which is a derivative from cadine, with a naphthenic-aromatic structure, being the most important product.…”

Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 99%

“…In effect, dealkylation of TIPB to yield 1,3-DIPB and C3 = , 1,3-DIPB dealkylation to yield IPBz and C3 = , and IPBz dealkylation to yield Bz and C3 = is mostly accepted as the main reaction course [4,5,[21][22][23]. Then, the yield of 1,3-DIPB is the neat result of both TIPB (primary cracking) and its own dealkylation to IPBz and after that to Bz, both of them defining the secondary cracking.…”

Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 99%

“…In the catalytic experiments, other hydrocarbons such as C 15 H 22 and 1,4-DIPB, were also observed besides these dealkylation products, as the consequences of side reactions. C 15 H 22 can be formed by the cyclization of alkyl groups in the aromatic ring [23,32], while 1,4-DIPB can be formed from the isomerization of 1,3-DIPB [22]. It can be assumed that the formation of these two hydrocarbons is very fast.…”

Section: Impact Of Secondary Cracking Reactions Simple Kinetic Modelmentioning

confidence: 99%

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Impact of the Desilication Treatment of Y Zeolite on the Catalytic Cracking of Bulky Hydrocarbon Molecules

2015

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Mesoporosity was induced on a USY zeolite by means of an alkaline leaching process. Samples were immersed in 0.05, 0.10 and 0.20 M NaOH solutions during 15 min at room temperature and then were exchanged with NH 4? ions and calcined to yield the acid forms. The formation of mesopores with size ranging from 20 to 100 Å increased with the concentration of NaOH. The modified zeolites were used at 30 wt% to formulate cracking catalysts with an inert SiO 2 matrix. The catalytic performance of these catalysts in the conversion of 1,3,5-tri-isopropylbenzene was evaluated in a batch, fluidized bed reactor at 450, 500 and 530°C, with a catalyst to oil relationship of 4.7 and contact times up to 16 s. The catalysts with the modified zeolites were more active in the cracking of these bulky molecules than the one with the parent, unmodified zeolite; moreover, the selectivity to the products of primary cracking reactions increased. These results reveal an enhanced diffusion of the reactant molecules to the zeolite active sites and of the products out of the catalyst particles.

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Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 51%

Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 51%

Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 99%

Section: 35-tri-isopropylbenzene Cracking At 500°cmentioning

confidence: 99%

Section: Impact Of Secondary Cracking Reactions Simple Kinetic Modelmentioning

confidence: 99%

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Impact of the Desilication Treatment of Y Zeolite on the Catalytic Cracking of Bulky Hydrocarbon Molecules

2015

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Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl₂O₄‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability

et al. 2023

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Catalysts with different ZnAl 2 O 4 contents impregnated in beta zeolite were synthesized and their catalytic activity in glycerol dehydration to allyl alcohol was investigated. The materials were characterized by XRD, XRF, FTIR, DRIFTS-pyridine, NH 3 -TPD, and N 2 physisorption. In addition, the surface electrostatic potential maps were generated by a molecular mechanics approach. The XRD patterns indicated a high dispersion of the ZnAl 2 O 4 , evidenced by the absence of reflections in the diffractograms, except for the sample containing the highest spinel content. The FTIR spectra indicated the presence of zinc aluminate spinel in the zeolite matrix. The DRIFTS-pyridine and NH 3 -TPD analyses indicated that the incorporation of ZnAl 2 O 4 modifies the acidic properties of the zeolite concerning the number, type, and distribution of acid sites. The N 2 physisorption tests showed the maintenance of the micro and mesoporous properties of H-BEA after modification, despite the reduction of the specific area and pore volume values. The samples impregnated with the ZnAl 2 O 4 phase showed larger mesopores sizes, which may favor its catalytic performance. The catalytic tests indicated the allyl alcohol production for the impregnated materials, which the best results were obtained by the sample containing 2 % of ZnAl 2 O 4 , with 90.65 % glycerol conversion and 37 % allyl alcohol selectivity due to appropriate tuning of the acidic and textural properties, as well as the presence of basic sites evidenced by CO 2 -TPD analysis and electrostatic potential maps. The presence of acid-base sites is essential to conduct hydrogen transfer, according to the proposed mechanism, generating allyl alcohol. Finally, the results with a longer reaction period showed greater stability for the sample impregnated with low spinel content, whose coke deposition was smaller, which may be related to the larger size of secondary mesopores.

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Catalytic Cracking of 1,3,5‐Triisopropylbenzene and Low‐Density Polyethylene over Hierarchical Y Zeolites and Al‐SBA‐15

Mensah,

Yan,

Rawal

et al. 2023

ChemCatChem

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Catalytic cracking of high molecular weight hydrocarbons underpins the production of fossil fuels from petroleum vapour and the recycling of polyolefin waste plastic. However, thermal cracking over conventional microporous solid acids is hindered by poor mass‐transport. Here we explore the performance of hierarchical H‐Y zeolites and Al‐SBA‐15 for the catalytic cracking of 1,3,5‐triisopropylbenzene (1,3,5‐TIPB) and low‐density polyethylene (LDPE) in a continuous fixed‐bed flow reactor. Single and multiple demetallation strategies (dealumination, desilication and/or acid washing) were used to create hierarchical mesoporosity in H‐Y zeolite and modify the solid acidity. Physicochemical properties were studied by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), gas adsorption, in‐situ Fourier transform infrared (FTIR), and 29Si and 27Al nuclear magnetic resonance (NMR). Dealumination and sequential dealumination‐desilication‐acid washing promote the selective deep cracking of both feedstocks; HNO3 dealuminated H‐Y produces six times more propene from 1,3‐5‐TIPB, and ~30% more benzene and xylenes from LDPE, than the parent H‐Y.

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Effects of steaming-made changes in physicochemical properties of Y-zeolite on cracking of bulky 1,3,5-triisopropylbenzene and coke formation

Cited by 53 publications

References 31 publications

Impact of the Desilication Treatment of Y Zeolite on the Catalytic Cracking of Bulky Hydrocarbon Molecules

Impact of the Desilication Treatment of Y Zeolite on the Catalytic Cracking of Bulky Hydrocarbon Molecules

Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl₂O₄‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability

Catalytic Cracking of 1,3,5‐Triisopropylbenzene and Low‐Density Polyethylene over Hierarchical Y Zeolites and Al‐SBA‐15

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Effects of steaming-made changes in physicochemical properties of Y-zeolite on cracking of bulky 1,3,5-triisopropylbenzene and coke formation

Cited by 53 publications

References 31 publications

Impact of the Desilication Treatment of Y Zeolite on the Catalytic Cracking of Bulky Hydrocarbon Molecules

Impact of the Desilication Treatment of Y Zeolite on the Catalytic Cracking of Bulky Hydrocarbon Molecules

Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl2O4‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability

Catalytic Cracking of 1,3,5‐Triisopropylbenzene and Low‐Density Polyethylene over Hierarchical Y Zeolites and Al‐SBA‐15

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Product

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Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl₂O₄‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability