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After modifications of rare earth and phosphorus, the acidity density and the strength in the pores of zeolite Y (PREUSY) are improved effectively; the surface acidity is suitably reduced and weakened owing to the interaction of rare earth cation and phosphate anion. NH3-TPD analysis showed that the acid distribution of the modified zeolite is more concentrated on the range of intermediate and strong acidity. This kind of modification can direct more hydrocarbons to enter into the pores to be converted and remarkably reduces the possibility of naphtha olefins forming through a surface cracking reaction. In addition, because naphtha olefin reduction does not completely depend on olefin saturation through secondary hydrogen transfer reaction, this kind of reaction mode can decrease the excessive cracking of mediate distillate and can improve the diesel oil yield (LCO) effectively. Some reaction pathways were proposed. [Copyright &y& Elsevier]

• A process to make P containing Y zeolite more stable. • P is incorporated into the framework by P for Si(4Al) isomorphous substitution. • Si(4Al) becomes the more stable site P(4Al) in the Y zeolite framework. • The P species in DPY zeolite are more difficult to loss than usual P modify. • The distribution of P species in DPY zeolite is more uniform. It's a dream to make zeolites more stable so as to keep the activity and stability of the catalyst. Phosphorus modification is an effective method, however, the known post-modification predominantly presents as non-framework P, and the P-loss is a big trouble in application. We have discovered that in the reaction of PCl 3 or SiCl 4 + PCl 3 with NaY zeolite, a portion of P enters the framework of the zeolite, forming a PO 4 -AlO 4 structure. Further investigations revealed that P cannot be incorporated into the framework through P for Al isomorphous substitution, but rather through isomorphous substitution with Si(4Al). PCl 3 exhibits two effects in reaction: at lower quantities, it mainly undergoes isomorphous substitution with Si(4Al); at higher quantities, it leads to zeolite dealumination generating aluminum vacancies, which disrupt the zeolite framework or promotes Si for Al isomorphous substitution. After hydrothermal aging at 800 °C for 4 h, the stable presence of framework PO 4 -AlO 4 implies that the weakest site Si(4Al) becomes the more stable site P(4Al) in the Y zeolite framework. Compared with the JPY (prepared by impregnating (NH 4) 2 HPO 4 solution to high silica Y zeolite) sample, after 10 cycles of hydrothermal and water washing treatment, the P 2 O 5 loss rate of DPY (prepared by SiCl 4 + PCl 3 with NaY) zeolite ranged from 0.4 % to 3.5 %, significantly lower compared to the range of 18.7 % to 25.9 % observed in the JPY sample. This indicates that in DPY zeolite, the interaction between P and the zeolite is stronger and less prone to loss. Moreover, P is more uniformly distributed on the surface and bulk phase of DPY than JPY sample. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Mesoporous aluminosilicates (MAs) with high hydrothermal stability have been obtained by assembly of zeolite Y precursors. However, there are still one problem needed to be addressed before MAs could be used in practical applications: high consumption of P123 and H 2 O for per g product. A means to highly efficient synthesis of MAs is remains a challenging goal. Herein, this goal was achieved on the basis of synergic co-assembly of sodium dodecyl dimethylbenzenesulfonate (SDMBS) with copolymers in high P123 concentration solution. In this strategy, the enhancement of P123 micelles hydration leads to increased assembly ability of P123 micelles with aluminosilicates species, resulting in the formation of hydrothermally stable MAs with high yields determining a decreased amounts of P123 and water per g of the product. In addition, the evolution of the structure and hydration degree of micelles as a function of SDMBS concentration and their impact on the formation characteristics of obtained materials have been studied. Stretching effect on P123 micelles results in the increased d 100 and mesopore size. Enhancement of micelles hydration results in decreased d 100 and pore size. This strategy provides a facile route to synthesize MAs at high concentration of P123. Meanwhile, an insight into understanding the self-assembly of triblock copolymers in preparing ordered MAs is also presented. [ABSTRACT FROM AUTHOR]

Optimizing the accessibility of zeolite Y, the main active component in fluid catalytic cracking (FCC) catalyst, is a crucial strategy to improve the heavy oil cracking performance of FCC catalysts. Four FCC catalysts with different Y zeolite content were prepared via in-situ crystallization method by adjusting the crystallization time. The distribution characteristics of the Y zeolite in in-situ crystallized catalysts have been characterized by scanning electron microscopy (SEM), laser confocal fluorescence microscopy and high-resolution field emission scanning electron microscopy (HR-FESEM). A unique structural feature of the FCC catalysts has been achieved, with the Y zeolite component mainly distributing in the outer layer of microspheres. The results of adsorption rate of macromolecule probes reveal that the appropriate zeolite layer thickness and topology were beneficial to the mass transfer performance and acid accessibility of FCC catalyst. The effective utilization ratios of zeolite in the novel FCC catalysts for heavy oil cracking on advanced catalyst equipment (ACE) is in good correspondence with the mass transfer performance of macromolecules and the accessibility of acid sites. It could be confirmed that the excellent heavy oil conversion performance of a FCC catalyst does not depend on the content of zeolite, but rather on the distribution characteristics are in favor of the accessibility of zeolite components. [Display omitted] • An interested FCC catalyst with unique zeolite distribution was obtained by in-situ crystallization of kaolin microspheres. • Y zeolite component is effectively controlled to grow over the skin layer of FCC catalyst microspheres. • The excellent diffusivity and the accessibility of heavy oil molecular have been significantly optimized. • The in-situ crystallization FCC catalyst display excellent heavy oil conversion performance. [ABSTRACT FROM AUTHOR]

Zeolite Y with intracrystalline mesopores has been synthesized by controlling a ternary balance (chemical anchoring of the template on zeolite framework, mesoporous self-assembly around the template, and crystallization of zeolite Y). The rapid hydrolysis of (CH 3 O) 3 Si- to -Si-OH and the subsequent linkage to zeolite framework were crucial for the formation of intracrystalline mesopores. The high concentration of OH- in the initial systems favors the self-assembly of well-ordered mesophases due to the high stability of Dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOACl) micelles. The well-ordered mesopores transfer to wormlike because the solubility of TPOACl increase with the decreased alkalinity by prolonging crystallization of zeolite Y. The materials with relatively well crystallized zeolite Y and high mesopores surface area showed better catalytic properties than the conventional Y and alone well-ordered mesoporous materials. The obtained sample exhibited improved catalytic performance in heavy oil cracking. The yield of the light fraction (gasoline + diesel) of the Cat-2 catalysts is 63.4 wt%, much higher than that of Cat-1 (49.9 wt%) and the Coke yield of Cat-2 is 12.1%, much lower than that of Cat-3 (15.2%). [ABSTRACT FROM AUTHOR]

Connectivity of mesopores in zeolites, which is a key factor for the high efficiency catalyst design, is still a challenge to be generated without using organic template. Herein, a hierarchical porous Y zeolite (USY B ) was synthesized by introducing catalytic amounts of boron into the framework of NaY, followed by steaming. The introduction of framework boron promoted the hydrolysis of the surrounding Si O Al and Si O B bonds in steaming treatment. When the boron was dislocated from framework, it could further create more mesopores by steaming. It was deemed that boron played catalytic like role for leading to generate well interconnected mesoporosity. As a result, the mesopore volume of the zeolite increased by 46% relatively. The influence of the generated interconnected mesoporosity on the higher activity was evidenced in both iso -octane (i.e. 2,2,4-trimethylpentane) and 1,3,5-triisopropylbenzene (TIPB) cracking over USY B zeolite. Compared with conventional USY zeolite, there would be 2.1% increase in the yield of gasoline for the cracking of heavy oil over USY B catalyst. [ABSTRACT FROM AUTHOR]

We report a facile strategy for synthesis of hydrothermally stable mesoporous aluminosilicates (MAs) from zeolite Y precursors by adding small amount of Tween-20. By the addition of suitable amount of Tween-20, P123-Tween complex micelles formed due to the interaction between hydrophobic chain of Tween and PPO units of P123. The hydrophilicity of the complex micelles was enhanced due to the incorporation of PEO units of Tween. As a result of this, the micelles could be well dispersed and MAs with reduced particle size could be readily obtained. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous ultra-stable Y zeolite with outstanding performance for heavy oil cracking was prepared through the combination of desilication and dealumination. Atomic removal of silicon atoms from the starting NaY zeolite framework during desilication was reported. Nucleation and propagation of mesopores in the following dealumination process was studied. Si(0Al) and Si(1Al) atoms are selectively removed from zeolite framework by desilication. Consequently, silanol nests and unique hydroxyl nests with framework associated Al-OH were created in the framework of the desilicated zeolite. The artificial defects effect the initiation of mesopores in crystal parts where used to be rich in framework silicon and unfavorable for mesopore formation and promote the propagation and coalescence of mesopores. Catalytic studies revealed improved activity and lifetime in the crack of 1,3,5-triisopropylbenzene and showed increased gasoline and light cycle oil selectivity when the conversion of a heavy oil was compared. [Copyright &y& Elsevier]

Abstract: Hydrothermally stable composite materials with hierarchical macro–meso–micro-porous structure were successfully synthesized via in situ assembly of preformed zeolite Y nanoclusters on kaolin using cetyltrimethylammonium bromide as template under alkaline conditions. The characterization results show that the mesophase in the composite contains primary and secondary structural building units of zeolite Y. The building units contribute micropores in the composite with acidity similar to that of zeolite Y, whereas the macroporous kaolin substrate contributes macropores. This hierarchical macro–meso–micro-porous structure increases the accessibility of the active sites in the composite to reactants and thus confers superior catalytic performance on the resulting catalyst in cracking heavy crude oil. The present work demonstrates that the in situ assembly of zeolitic nanoclusters on substrates (e.g., kaolin) can provide a novel route for fabricating composite materials with hierarchical pore structure. [Copyright &y& Elsevier]

• The new adsorption sites ([Cu+···NH 3 ···H+ species) in Cu(I)-NH 4 Y can be fabricated. • The Cu(I)-NH 4 Y shows good adsorption desulfurization and regeneration performance. • Thiophene adsorption selectivity of adsorbent is improved in the presence of aromatics or olefins. • The "S-M" bonding mechanism between thiophene and [Cu+···NH 3 ···H+ species can be proposed. • This work breaks out traditional high-temperature preparation concept of adsorbents. Cu modified Y zeolite adsorbents have performed excellent adsorption desulfurization performance. Adsorption selectivity of thiophenic sulfur compounds, however, still remained a lower level in the presence of aromatics and olefins. In this work, we aim to address the above challenge, using Cu(I)-NH 4 Y zeolites obtained by liquid phase ion-exchanged method. Based on the coordination chemistry theory, the new adsorption active sites ([Cu+···NH 3 ···H+ species) can be facilely fabricated at lower temperature (ca. 150 °C) and under H 2 atmosphere. The desulfurization experimental results indicate that the outstanding breakthrough sulfur capacity (ca. 31.0 mg (S) · g−1) can be achieved by the Cu(I) 0.10 -NH 4 Y adsorbent, which is about 2.3 folds as high as the best one reported. After regeneration with three cycles, the adsorbent still remains a high sulfur capacity. Importantly, the thiophene adsorption selectivities of adsorbent have been improved in the presence of aromatics or olefins, which are about 44.5% and 6.3%, respectively. Meanwhile, the direct "S-M" bonding mechanism between thiophene and [Cu+···NH 3 ···H+ species can be really proposed. Besides, the alkylation reaction between thiophene and olefins is significantly attenuated, mainly ascribed to the majority of strong Brønsted acid sites being masked. The new design idea of effective active sites in the zeolite adsorbents breaks out the traditional high-temperature preparation concept of excellent desulfurization adsorbents and can provide a new direction in the future. [ABSTRACT FROM AUTHOR]

• Effective Ce species active sites are fabricated via low calcination temperature. • Remarkable sulfur adsorption capacity can be achieved by the CeY 0.075 C 150 zeolite. • The CeY 0.075 C 150 adsorbent can perform good regeneration performance. • This facile strategy can reduce preparation cost and save energy consumption. Ce-containing materials attracted much attention in adsorption desulfurization due to their excellent adsorption selectivity. Identification and fabrication of specific Ce species as effective adsorption active sites, however, still remained ambiguous which had impeded the development of a potential desulfurization adsorbent. In this paper, series of CeY zeolites were synthesized via liquid phase ion exchange method. The implication of Ce loadings and calcination temperatures on the nature of Ce species active sites that can be present in the Y zeolite was a major focus of this work. Specially, the chemical speciation and location of Ce species in the CeY adsorbents were analyzed by the intelligent gravimetric analyser (IGA), XRD, in situ FTIR spectroscopy, and XPS techniques. The prepared CeY adsorbents were tested in terms of their sulfur breakthrough adsorption capacities using a fixed-bed column and model fuels. The experimental results indicate that more effective Ce(III) hydroxylated species as adsorption active sites, located in the supercages of CeY 0.075 C 150 zeolite, are facilely fabricated as low as the calcination temperature (ca. 150 °C) and the suitable Ce loading (ca. 12.31 wt%). Remarkable sulfur breakthrough adsorption capacity can be achieved by using the new CeY 0.075 C 150 adsorbent, which is no less ca. 5 folds than that of the reported CeY adsorbents to the best of our knowledge, especially for the 2-methylthiophene capture (ca. 18 folds). After regenerated with two cycles, the adsorbent still remains high sulfur breakthrough adsorption capacity. Importantly, this controllable method to construct specific Ce species as active sites in the CeY zeolites should play an instructive role for the development of the directional design of effective adsorption active sites in other excellent desulfurization adsorbents. [ABSTRACT FROM AUTHOR]