Shangru Zhai

Preparation and Catalytic Performance of Mesostructured Aluminosilicate Nano-particles with Wormhole-Like Framework Structure

A facile two-step sol–gel method has been developed for the preparation of mesostructured aluminosilicate nano-particles (Si/Al = 7.5) with wormhole-like but uniform pore structures and highly catalytic activities towards bulky hydrocarbon cracking. It is desirable that, as this synthesis takes place in the absence of alkali cations, the mesoporous nano-particulate material is directly obtained in the acid form, making a subsequent ion-exchange and calcination treatment superfluous.

Synthesis, characterization and catalytic activities of mesoporous AlMSU-X with wormhole-like framework structure

Mesoporous AlMSU-X molecular sieves with high acidity have been prepared from preformed beta nanoclusters under strong acidic conditions in the presence of nonionic TX-100 as structure directors. These materials were characterized by XRD, HRTEM, N2-adsorption, 27Al MAS NMR, NH3-TPD, IR-pyridine adsorption and catalytic cracking of cumene and 1,3,5-triisopropylbenzene. The experimental results showed that Al heteroatoms had been successfully incorporated into the framework structure of mesoporous MSU-X, and so-produced catalysts exhibited superior catalytic properties.

Novel non-surfactant pathway to controllable micro/mesoporous bimodal xerogels

We describe the synthesis and characterization of amorphous micro/mesoporous xerogels using mixed polymethylhydrosiloxane (PMHS) and tetraethyl orthosilicate (TEOS) as the inorganic source in the presence of ethyldiamine (EDA) as catalyst via a controllable sol-gel route, without additional introduction of any structure-directing agent. The resultant materials were thoroughly characterized by X-ray diffraction (XRD), nitrogen adsorption, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and (29)Si MAS NMR. It was interestingly shown from these characterization results that the present amorphous samples exhibited disordered pore structure, high specific surface areas and pore volumes, though neither solvent extraction nor calcination was utilized. More interestingly, the relative content of micropore and mesopore could be finely tuned by facilely adjusting the mass ratio of PMHS to TEOS.

Isopropylation of naphthalene over mesostructured aluminosilicate nanoparticles with wormhole framework structures

The preparation and catalytic properties in isopropylation of naphthalene of nanosized mesostructured alumiosilicate with worm-like framework structures were presented in this work. Catalytic results showed that, under optimum conditions, the present nanocatalyst exhibited high activity making ca. 90 mol% of naphthalene conversion into mono-, di- and triisopropyl substituted derivatives. It should be mentioned that, however, the present nanocatalyst showed no considerable selectivity to objective products, and this may be attributed to its somewhat large mesopores in comparsion with microporous alkylating catalysts.

Synthesis and characterization of mesoporous aluminosilicates from zeolitic precursors and TEOS

Mesoporous aluminosilicates with improved hydrothermal stability were prepared via the controlled coassembly of zeolitic precursors and TEOS in alkaline media. XRD, N 2 sorption, and TEM methods showed that the coassembled sample had hexagonal mesostructures, and the hydrothermal stability was largely improved compared to normal MCM-41. 29 Si MAS NMR spectra indicated that the product had higher cross-linking degree compared to normal MCM-41 through the extra introduction of protozeolitic nanoclusters. 27 Al MAS NMR spectra implied that most Al species had been tetrahedrally incorporated into the framework. The catalytic cracking conversion rate of 1,3,5-triisopropylbenzene over this sample was as high as 97.66%. At the same time, the hydrolysis behavior of TEOS and synergic polymerization process of protozeolitic nanoclusters and silicate oligomers were outlined.

Two-step route to acid AIMSU-X mesostructures templated by neutral TX-100

Abstract Strong acid AlMSU-X mesostructures with narrow pore size distribution and large surface areas have been prepared from performed beta nanoclusters in the presence of nonionic TX-100 as the structure director through a N 0 (N + )XT + pathway in extremely acidic media. XRD, N 2 sorption, TEM, 27 Al MAS NMR, NH 3 -TPD and catalytic test reaction have been applied to characterize the products. The results obtained by these methods indicated aluminum had been successfully incorporated into the mesostructrue framework.

AMI study on the catalytical isomerization of 1-Hexene to 2-Hexene on the surface of aluminosilicate molecular sieves

Abstract The catalytic isomerization mechanism of 1-hexene to 2-hexene on the surface of aluminosilicate molecular sieve has been studied using the semiempirical method of Austin Model 1(AM1) of quantum chemistry. The transition state of the isomerization reaction was optimized and verified by the only virtue frequency. The intrinsic reaction coordinates inferred the reaction paths were calculated. The energy barriers of the isomerization forward and reverse are 159.810 and 177.707 kJ/mol, respectively.