Synthesis of hierarchical nanocrystalline β zeolite as efficient catalyst for alkylation of benzene with benzyl alcohol

Abstract

Hierarchical β zeolite with enhanced transport and specific catalytic activity of acid sites in Friedel–Crafts alkylation was achieved by using amphiphilic organosilane surfactant as mesopores-directing agent and crystal growth inhibitor.

Structure–Property Relationship in the Lanthanum Grafted Zeolite and Its Application as an Efficient Acido-Basic Catalyst for C–C/C–O Bond Formation Reactions

“…The P-β, La@β, and DeAlβ catalysts showed a broad range of pore width ranging between 2 and 8 nm, while the La@DeAlβ catalysts showed pore width ranging between 5 and 12 nm. All samples showed pores in the mesopore range, suggesting the presence of some inter-crystalline pores due to the stacking of nanocrystals of beta zeolites . The increment in the pore width in the case of the La@DeAlβ catalyst can be explained on the basis of occurrence of inter crystal expansion during the grafting of lanthanum …”

“…The surface area and porosity of the catalysts were determined using the N 2 adsorption–desorption technique and the isotherms for all catalysts are shown in Figure S4A. All catalysts showed the type IV isotherm with a hysteresis loop, which indicates the presence of micropores as well as mesopores . The surface area for the P-β catalyst was observed to be 485 m 2 /g, which was decreased to 448 m 2 /g in the case of the La@β catalyst (Table , entries 1 and 2).…”

“…All catalysts showed the type IV isotherm with a hysteresis loop, which indicates the presence of micropores as well as mesopores. 14 The surface area for the P-β catalyst was observed to be 485 m 2 /g, which was decreased to 448 m 2 /g in the case of the La@β catalyst (Table 2, entries 1 and 2). A similar decrease was observed in pore volume in the case of the La@β catalyst compared to that in P-β.…”

“…All samples showed pores in the mesopore range, suggesting the presence of some inter-crystalline pores due to the stacking of nanocrystals of beta zeolites. 14 The increment in the pore width in the case of the La@DeAlβ catalyst can be explained on the basis of occurrence of inter crystal expansion during the grafting of lanthanum. 58 Transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM−EDX) analysis of P-β, DeAlβ, and La@ DeAlβ was done to reconfirm the dealumination and introduction of lanthanum.…”

“…Among several catalytic properties, acid and base functions are well-known for their vital roles in catalyzing many industrially important reactions. − In general, acid catalysts are known to catalyze reactions like etherification, acetalization, dehydration, alkylation, etc. − On the other hand, catalysts with a base function are well-known for the reactions like aldol condensation, dehydration, carbonylation, etc. − In few reactions, both acid and base functions are anticipated to play a crucial role either through direct catalysis or through a promoter effect. , A careful study of the literature shows that the synergistic correlation between acid–base functions of a catalyst improves the catalytic activity. , Similarly, acido-basic catalysts like metal-modified mixed oxides showed very good catalytic performance for aldol condensation, etherification, and carbonylation. ,− However, mixed oxide-based catalysts face drawbacks like moisture sensitivity, poor recyclability, alternation of the acid/base function during the reaction, metal leaching, metal agglomeration, etc. Overall, it is still a great challenge to develop an efficient and stable bi-functional catalyst with highly dispersed acid and base active sites.…”