Influence of the state of Zn species over Zn-ZSM-5/ZSM-11 on the coupling effects of cofeeding n-butane with methanol

Combination of the exothermic methanol aromatization with the endothermic n-butane aromatization provides a good way to meet the increasing demand for aromatics. Here, a series of Zn-ZSM-5/ZSM-11 catalysts were prepared with different introduction methods. The influence of location and state of Zn species on the coupling effects of cofeeding n-butane with methanol were investigated in detail. UV-vis, H-2-TPR and XPS spectra were applied to reveal the state of the Zn species on different catalysts. Quantitative results of NH3-TPD and Pyridine-FTIR were provided to compare the acidity changes of the catalyst after Zn loading. Physical mixing method led to high portion of bulk ZnO particles outside the channel which could promote the formation of C-2-C-4 light alkane in cofeeding reaction. Ion exchange and impregnation modes were beneficial for the formation of Zn-O-Zn bridging species in the micropore channel. Zn-O-Zn bridging species was found to increase the promoting effect of cofeeding n-butane with methanol on aromatics selectivity. (C) 2016 Published by Elsevier B.V

A Highly Ion-Selective Zeolite Flake Layer on Porous Membranes for Flow Battery Applications

Zeolites are crystalline microporous aluminosilicates with periodic arrangements of cages and well-defined channels, which make them very suitable for separating ions of different sizes, and thus also for use in battery applications. Herein, an ultra-thin ZSM-35 zeolite flake was introduced onto a poly(ether sulfone) based porous membrane. The pore size of the zeolite (ca. 0.5nm) is intermediary between that of hydrated vanadium ions (>0.6nm) and protons (99% and an energy efficiency of >81% at 200mAcm(-2), which is by far the highest value ever reported. These convincing results indicate that zeolite-coated membranes are promising in battery applications

Shaped binderless ZSM-11 zeolite catalyst prepared via a dry-gel conversion method: Characterization and application for alkylation of benzene with dimethyl ether

Shaped binderless ZSM-11 zeolite catalysts were synthesized via a dry-gel conversion technique from 70ZSM-11/30SiO(2) mix extrudates. 1,6-hexanediamine combined with tetrabutylammonium bromide was proved to be the best structure directing agent for the synthesis of the binderless ZSM-11 catalyst, without adding other alkaline materials. The 70HZSM-11/30SiO2 mix serials materials crystallized for different times were detected by X-ray diffraction (XRD), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy-energy dispersive spectroscopy (STEM-EDS) techniques, and so on. In order to investigate the possible crystallization mechanism, the textural and structural properties of 70HZSM-11/30SiO(2) mix serials samples were further characterized by N-2 adsorption-desorption. Acid properties were determined by temperature-programed desorption of NH3 (NH3-TPD) and pyridine adsorption-infrared (Py-IR) measurements. In the alkylation of benzene with dimethyl ether, the serials catalysts exhibited different benzene conversions. 70HZSM-11/30SiO(2) mix showed the lowest benzene conversion while sample 70HZSM11/30SiO(2) mix-6.5h synthesized only for 6.5h displayed a higher benzene conversion, even higher than the value over 70HZSM-11/30Al(2)O(3) mix. Extending the crystallization time, the obtained samples displayed the increased benzene conversion in general under the same reaction conditions. In the end, the relation of physicochemical properties with the reaction performance was investigated. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved

Dystrophin hydrophobic regions in the pathogenesis of Duchenne and Becker muscular dystrophies

The aim of our study was to determine the role of dystrophin hydrophobic regions in the pathogenesis of Duchenne (DMD) and Becker (BMD) muscular dystrophies, by the Kyte-Doolittle scale mean hydrophobicity profile and 3D molecular models. A total of 1038 cases diagnosed with DMD or BMD with the in-frame mutation were collected in our hospital and the Leiden DMD information database in the period 2002-2013. Correlation between clinical types and genotypes were determined on the basis of these two sources. In addition, the Kyte-Doolittle scale mean hydrophobicity of dystrophin was analyzed using BioEdit software and the models of the hydrophobic domains of dystrophin were constructed. The presence of four hydrophobic regions is confirmed. They include the calponin homology CH2 domain on the actin-binding domain (ABD), spectrin-type repeat 16, hinge III and the EF Hand domain. The severe symptoms of DMD usually develop as a result of the mutational disruption in the hydrophobic regions I, II and IV of dystrophin – those that bind associated proteins of the dystrophin-glycoprotein complex (DGC). On the other hand, when the hydrophobic region III is deleted, the connection of the ordered repeat domains of the central rod domain remains intact, resulting in the less severe clinical presentation. We conclude that mutational changes in the structure of hydrophobic regions of dystrophin play an important role in the pathogenesis of DMD

Size-controlled synthesis of hierarchical ferrierite zeolite and its catalytic application in 1-butene skeletal isomerization

Nano-ferrierite zeolite aggregates with hierarchical porosity were successfully prepared by using pyrrolidine as sole organic structure-directing agent. SEM and TEM images revealed that nano-sized crystals (40-60 nm) stacked together loosely to form irregular clusters. Influence of crystallization temperature and initial gel compositions (pyrrolidine content, alkalinity, water content) on the synthesis of ferrierite zeolite were investigated in detail. Low crystallization temperature and high alkalinity were beneficial to form nano-ferrierite zeolite aggregates with high hierarchical porosity (total pore volume: 0.461 cm(3)/g). Compared with commercialized ferrierite zeolite, hierarchical nano-ferrierite aggregates showed better catalytic stability and product selectivity in the 1-butene skeletal isomerization reaction. (C) 2016 Elsevier Inc. All rights reserved

One-pot synthesis of high silica MCM-22 zeolites and their performances in catalytic cracking of 1-butene to propene

MCM-22 zeolites with high SiO(2)/Al(2)O(3) (Si/Al(2)) ratios were synthesized by a one-pot procedure with the assisting of boron. Based on this boron-containing method, the Si/Al(2) ratios of the MCM-22 zeolites could be greatly extended from 30 to 600 in control by tuning the Si/Al(2) ratios of the starting gels. ICP-AES and (11)B MAS NMR results demonstrated that a small part of the boron still existed in the framework of the MCM-22 after calcination and ammonium exchange. However, the residual boron species had little influence on the physicochemical properties of the MCM-22 samples evidenced by XRD, BET. TG-DTA, NH(3)-TPD, and Py-IR determinations. The reaction of catalytic cracking of I-butene to propene was carried out to study the performances of the high silica MCM-22 catalysts. Increasing of the Si/Al(2) ratios in the MCM-22 zeolites suppressed the formation of byproducts such as propane and aromatics effectively, and the optimal selectivity towards propene was obtained on the sample with a Si/Al(2) ratio of 158. (C) 2008 Elsevier Inc. All rights reserved

A shaped binderless ZSM-11 zeolite catalyst for direct amination of isobutene to tert-butylamine

A shaped binderless and two binder-containing ZSM-11 zeolite catalysts were prepared and characterized by powder X-ray diffraction,N-2 adsorption-desorption, and pyridine adsorption-infrared measurements. The binderless catalyst was synthesized using a dry-gel conversion technique, in which 1,6-hexanediamine and tetrabutylammonium bromide were used as structure-directing agents and no other alkaline materials were added. The catalytic performance of the zeolites in the direct amination of isobutene to tert-butylamine was evaluated in a fixed-bed reactor. By virtue of its high crystallinity as well as its good mechanical strength, the shaped binderless ZSM-11 catalyst showed a higher rate of formation of tert-butylamine than did the binder-containing catalysts. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

Rapid synthesis of ferrierite zeolite through microwave assisted organic template free route

Ferrierite (FER) zeolite has been successfully synthesized within 2-3 h through microwave assisted crystallization without using organic structure directing agent. Crystallization temperature and seed content were found to be two of the key factors. XRD patterns and SEM images of the samples taken at different periods of time revealed that seeds were only partially dissolved during the crystallization process and silicate (alumino) species in the gel grew upon the surface of the partially dissolved seed. A core-shell zeolite growth model was proposed. Compared with original seed zeolite, as-synthesized FER zeolite had more regular morphology and larger particle size. The FER crystal size could be controlled in the range of 0.4-3.0 mu m by adjusting the particle size of the seeds. FER obtained through microwave assisted rapid synthesis showed similar catalytic performance in 1-butene skeletal isomerization with the FER obtained through conventional hydrothermal synthesis