Recent advances in the synthesis of hydrothermally stable mesoporous aluminosilicates (MAs) by assembling precursors shed light on their applications in residue fluid catalytic cracking. Reducing the n(H2O)/n(SiO2) ratio and thus reducing waste discharge is the key for practical applications of MAs. In this study, the synthesis of hydrothermally stable MAs with a decreased n(H2O)/n(SiO2) ratio has been developed based on seed-assisted crystallization. Crystal seeds were partly dissolved to microcrystallites on which a large amount of zeolite precursors are assembled and crystallized. As a direct result of the assembly priority of crystal seeds, the concentration and viscosity of the liquid phase in the synthesis system will be decreased greatly. Afterward, the remaining precursors with proper concentration and viscosity can be assembled with the surfactant micelles. Therefore, the H2O amount could be largely decreased by the introduction of crystal seeds.

Self-assembly of block copolymer and zeolite Y precursors is an important way to prepare well-ordered mesoporous aluminosilicates (MAs). However, when the concentration of block copolymer is high (low amount of water), the cooperative templating mechanism (which bases the coordination of the inorganic precursor with micelles) is disturbed and well-ordered mesoporous structures will not form. A means to obtain hydrothermally stable MAs with decreased water amount is remains a challenging goal. Here, we report a urea additive method to solve this problem. In this procedure, the addition of urea could increase the hydrophilic strength of poly(ethylene oxide) (PEO) moieties of P123 micelles, which would strengthen their assembly ability. As a result, mesostructured ordering would be improved with greatly decreased water amount. Meanwhile, the P123 utilization efficiency rises. This strategy provides a facile route to synthesize MAs with reduced consumption of water and high P123 utilization efficiency, which is beneficial to industrial application.

Hierarchical zeolite Y prepared by sequential acid washing and alkaline treatment in the presence of surfactant micelles, has been emerging as one of the most promising approach to introduce controlled mesoporosity into zeolite Y crystals. However, the synthesis of mesostructured Y by a simple procedure still remains a challenge. Herein, the goal was achieved by designing of a low-cost surfactant [(CH3O)3SiC3H6N(CH3)2C16H37]Cl (denoted as “TPHAC”). In this strategy, dealumination arose from coordination of -Si-(OH)3 (product of hydrolysis of THPAC) with framework aluminum ions and controlled mesoporosity was introduced into zeolite crystals through a surfactant approach, which exhibits a potential way to synthesize mesoporous Y zeolite from NaY with low Si/Al.

Zeolite Y with intracrystalline mesopores has been emerging as one of the most potential materials in the catalytic cracking of large molecules. Our group has reported the synthesis of zeolite Y with intracrystalline mesopores with the formula [(CH3O)3SiC3H6N(CH3)2C18H37]Cl (denoted as “TPOACl”). However, the fabrication of mesoporous zeolite Y with a decreased organic template remains a significant challenge. In this study, a novel surfactant [(CH3O)3SiC3H6N(CH3)2C16H33]Cl (denoted as “TPHAC”) was designed and synthesized using low-cost industrial raw materials, which was found suitable for the formation of mesoporosity utilizing greatly decreased amount of the surfactant. The possible differences in the synthesis mechanisms of TPOACl and TPHAC have been discussed. The enhanced hydrophilicity of the hydroxyl groups and the subsequent decrease in the micelle aggregation number (MAN) are proposed to be the key to underline the decreased amount of surfactant in the successful synthesis. The material shows excellent hydrothermal stability and a higher mesoporous surface area ratio than TPOACl. The prepared mesoporous zeolite Y showed much higher catalytic activity and selectivity in heavy oil cracking than that prepared from TPOACl.

Recent reports on the synthesis of mesoporous aluminosilicates (MAs) with hydrothermal stability opened up a promising way to cracking large molecules. However, a large amount of organic template and a low zeolite yield remained unresolved for the practical application of MAs. In this article, an efficient and green route for synthesizing MAs with high hydrothermal stability is developed, which is characterized by a high product yield and a significantly decreased amount of organic template. By fine-tuning the amount of crystal seeds, MAs with high hydrothermal stability were obtained. Compared with the direct synthesis procedure, the seed-assisted (SA) route considerably improved the zeolite yield and decreased the synthesis cost. Characterization results elucidated that MA seeds embedded in the gel after partial dissolution provided a crystal growth surface, leading to the significant decrease of organic templates. Utilization of P123 for SA-2 (cr, 24 h) is 1.26 g zeolite per g P123, 2.4 times that of CS-C (0.52 g zeolite per g P123, CS-C is short for calcined crystal seeds). Moreover, the zeolite yield of SA-2 (cr, 24 h) is 50.2 g zeolite per L, 2.4 times that of CS-C (21.3 g zeolite per L). Our achievements shed light on the industrial application of MAs in FCC.

•Template P123 was effectively removed by ultrasonic extraction from MA.•MA treated by ultrasonic extraction shows excellent structural performance.•The recovered P123 have been reused as the template in the synthesis procedure of MA.High synthesis cost of mesoporous aluminosilicates (MA) limits their practical application. Recycling of copolymer template employed in preparation of MA is an effective way to reduce the synthesis cost. An ultrasonic extraction strategy for recycling of organic template P123 in MAs is reported. Effects of different extraction parameters on P123 recovery are investigated and the optimum conditions are obtained. 75.0% P123 is recovered from MAs within 10 min by one-step ultrasonication. Characterizations indicated that the resulting P123-free MA (MA-U) exhibits excellent properties compared with that of calcined products. Moreover, recovered P123 can be employed to synthesize high hydrothermally stable MA. This investigation provides a facile strategy to recycle P123 from MA.

Mesoporous aluminosilicates (MA) with high hydrothermal stability obtained by assembly of zeolite Y precursors are attractive for the potential application in heavy oil catalytic cracking. A relatively more eco-friendly synthesis of MA with low synthesis cost and waste water discharge is particularly appealing. We report on the green synthesis of MA via a multiple-assembly/one-pot-crystallization (MA/OC) process by recycling the non-reacted reagents in the assembly mother liquor after separating the assembly solid product. This approach was achieved by exact supplementary compensation of the consumed raw materials and correct pH adjustment for the assembly liquor after each cycle of assembly. The assembly solid products in 5 cycles were collected and crystallized in one-pot in the mother liquor. Characterization results indicated that consumption of P123 and water discharge of MAOC-5 could be reduced to 51.5% and 27.3% of those of conventional MA-1. Meanwhile, the product yield of MAOC-5 is 102.66 g L−1, 4.8 times that of MA-1. This strategy suggests a relatively more eco-friendly and low cost route for the synthesis of hydrothermally stable MA.

A facile and direct approach for the synthesis of mesoporous zeolite Y by using [(CH3O)3SiC3H6N(CH3)2-C18H37]Cl as template is presented. Under the basic condition of the Y synthesis system, (CH3O)3Si– bonds hydrolyze to −Si–OH, and yield −Si–O–Al– and −Si–O–Si– linkages that anchor the template in zeolite framework. Afterward, micelles formed by −C18H37 lead to the formation of mesoporosity within zeolite Y crystals. This material, which introduces intracrystalline mesoporosity into zeolite Y, shows superior catalytic performance when used in heavy oil catalytic cracking.

Recent reports on the synthesis of mesoporous aluminosilicates (MAs) with hydrothermal stability opened up a promising way to cracking large molecules. However, a large amount of organic template and a low zeolite yield remained unresolved for the practical application of MAs. In this article, an efficient and green route for synthesizing MAs with high hydrothermal stability is developed, which is characterized by a high product yield and a significantly decreased amount of organic template. By fine-tuning the amount of crystal seeds, MAs with high hydrothermal stability were obtained. Compared with the direct synthesis procedure, the seed-assisted (SA) route considerably improved the zeolite yield and decreased the synthesis cost. Characterization results elucidated that MA seeds embedded in the gel after partial dissolution provided a crystal growth surface, leading to the significant decrease of organic templates. Utilization of P123 for SA-2 (cr, 24 h) is 1.26 g zeolite per g P123, 2.4 times that of CS-C (0.52 g zeolite per g P123, CS-C is short for calcined crystal seeds). Moreover, the zeolite yield of SA-2 (cr, 24 h) is 50.2 g zeolite per L, 2.4 times that of CS-C (21.3 g zeolite per L). Our achievements shed light on the industrial application of MAs in FCC.