933-40-4Relevant articles and documents
In-situ crystallization route to nanorod-aggregated functional ZSM-5 microspheres
Li, Bin,Sun, Bo,Qian, Xufang,Li, Wei,Wu, Zhangxiong,Sun, Zhenkun,Qiao, Minghua,Duke, Mikel,Zhao, Dongyuan
, p. 1181 - 1184 (2013)
Herein, we develop a reproducible in situ crystallization route to synthesize uniform functional ZSM-5 microspheres composed of aggregated ZSM-5 nanorods and well-dispersed uniform Fe3O4 nanoparticles (NPs). The growth of such unique microspheres undergoes a NP-assisted recrystallization process from surface to core. The obtained magnetic ZSM-5 microspheres possess a uniform size (6-9 μm), ultrafine uniform Fe 3O4 NPs (～10 nm), good structural stability, high surface area (340 m2/g), and large magnetization (～8.6 emu/g) and exhibit a potential application in Fischer-Tropsch synthesis.
Remarkable Effect of Pore Size on the Catalytic Activity of Mesoporous Silica for the Acetalization of Cyclohexanone with Methanol
Iwamoto, Masakazu,Tanaka, Yasuhiro,Sawamura, Naoki,Namba, Seitaro
, p. 13032 - 13033 (2003)
The catalytic activity of mesoporous silica (MCM-41) for the acetalization of cyclohexanone shows a volcano-shaped dependence on the pore diameter. The diameter of the cyclohexanone molecule is ca. 0.75 nm, while its acetalization with methanol was well accelerated on MCM-41 with a pore diameter of approximately 1.9 nm, and smaller or larger pores were not suitable for the catalysis. The catalytic activity was independent of the Al concentration. Copyright
Facile synthesis of hollow zeolite microspheres through dissolution-recrystallization procedure in the presence of organosilanes
Tao, Haixiang,Ren, Jiawen,Liu, Xiaohui,Wang, Yanqin,Lu, Guanzhong
, p. 179 - 188 (2013)
Hollow zeolite microspheres have been hydrothermally synthesized in the presence of organosilanes via a dissolution-recrystallization procedure. In the presence of organosilanes, zeolite particles with a core/shell structure formed at the first stage of hydrothermal treatment, then the core was consumed and recrystallized into zeolite framework to form the hollow structure during the second hydrothermal process. The influence of organosilanes was discussed, and a related dissolution-recrystallization mechanism was proposed. In addition, the hollow zeolite microspheres exhibited an obvious advantage in catalytic reactions compared to conventional ZSM-5 catalysts, such as in the alkylation of toluene with benzyl chloride. Copyright
Scale-Up of a Continuous Extraction Process for Driving an Equilibrium-Limited Reaction to Completion
Tudesco, Michael T.,Moschetta, Eric G.,Voight, Eric A.
, p. 1564 - 1569 (2018)
We report a strategy for implementing a scalable continuous extraction to drive an equilibrium-limited reaction to completion. Our approach is simple, requiring only standard equipment and glassware, and can be designed to meet the needs of the process (e.g., reduced cycle time or reduced solvent use) with minimal development time. We investigated the process parameters, such as the flow rate of fresh n-heptane (extracting solvent) into the system, at a 0.5-5 g scale and reduced the overall time and total amount of n-heptane needed to drive the reaction to completion. The improved conditions for the extraction were demonstrated at the 50 g scale, leading to a similar yield of the desired product and total reaction time as at the 5 g scale, verifying that our reactions and extraction conditions were scalable. In particular, our fit-for-purpose approach is customizable to a number of systems and can be implemented in a short period of time with a limited amount of material.
CoFe2O4 Nanocrystals Mediated Crystallization Strategy for Magnetic Functioned ZSM-5 Catalysts
Li, Bin,Yildirim, Erol,Li, Wei,Qi, Dianpeng,Yu, Jiancan,Wei, Jiaqi,Liu, Zhiyuan,Sun, Zhenkun,Liu, Yong,Kong, Biao,Xue, Zhaoteng,Liu, Zhuangjian,Yang, Shuo-Wang,Chen, Xiaodong,Zhao, Dongyuan
, (2018)
Zeolites have many applications in the petrochemical and fine chemical industry and their functionalization does expand the spectrum of potentials. However, the integration of functional nanocrystals into zeolite frameworks with controlled size, dispersion, and crystallization behavior still remains a significant challenge. Here, a new synthesis of magnetic functioned ZSM-5 zeolite catalysts via a CoFe2O4 nanocrystal mediated crystallization strategy is reported. It is found that high crystallinity of CoFe2O4 nanocrystals results in a well-dispersed encapsulation of them into a single-crystal of ZSM-5 due to non-further-grown nanocrystals during the fast ZSM-5 growth. On the contrary, low crystallinity of CoFe2O4 nanocrystals leads to the polycrystalline zeolite growth due to the secondary growth of nanocrystals accompanied by the zeolite crystallization and large lattice mismatch between them. The successful encapsulation of small CoFe2O4 nanocrystals (≈4 nm) into single crystals lies on the preattachment of them into solid silica gel. During the growth of ZSM-5 crystals, no secondary growth of nanocrystals happens and its motion is restricted. The encapsulation of magnetic CoFe2O4 nanocrystals not only endows magnetic function into zeolites for the first time, but also does not impact catalytic performance of ZSM-5 in acetalization of cyclohexanone with methanol, which is highly promising in catalytic industries.
Synthesis and catalytic performance of ZSM-5/MCM-41 composite molecular sieve from palygorskite
Jiang, Jinlong,Wu, Mei,Yang, Yong,Duanmu, Chuansong,Chen, Jing,Gu, Xu
, p. 1883 - 1889 (2017)
ZSM-5/MCM-41 composite molecular sieve has been hydrothermally synthesized through a two-step crystallization process using palygorskite (PAL) as silicon and aluminum source. The products were characterized by various means and their catalytic properties for acetalization of cyclohexanone and esterification of acetic acid and n-butanol were also investigated. In the first step ZSM-5 zeolite could be formed from the acid-treated PAL after hydrothermal treatment using tetrapropylammonium bromide as template. XRD patterns, N2 adsorption and desorption data, and TEM images show that the composite obtained in the secondary step had a well-ordered mesoporous MCM-41 phase and a microporous ZSM-5 zeolite phase. Compared with ZSM-5, ZSM-5/MCM-41 composite possessed more total acid amount, weak acid sites and large pore structure due to the formation of MCM-41 and exhibited higher catalytic activity for the acetalization and esterification reaction.
Practical acetalization and transacetalization of carbonyl compounds catalyzed by recyclable PVP-I
Cao, Fu-Rong,Lu, Guangying,Ren, Jiangmeng,Wang, Di,Zeng, Bu-Bing
, (2021/06/21)
A novel PVP-I catalyzed acetalizations/transacetalizations of carbonyl compounds has been developed processing with a mild and easy handling fashion. Different types of Acyclic and cyclic acetals were prepared from carbonyl compounds or their acetals successfully. Further applications of newly developed catalytic combination were testified. This protocol featured with simplicity of operation, mild reaction condition, short reaction time, recyclable of catalyst and broad substrates scope with excellent yields.
A novel, mesoporous molybdenum doped titanium dioxide/reduced graphene oxide composite as a green, highly efficient solid acid catalyst for acetalization
He, Junkai,Kankanam Kapuge, Tharindu,Kerns, Peter,Meguerdichian, Andrew G.,Suib, Steven L.,Thalgaspitiya, Wimalika R. K.
, p. 3786 - 3795 (2020/04/03)
A novel, mesoporous composite of Mo doped TiO2/reduced graphene oxide is synthesized to be used as a highly efficient heterogeneous acid catalyst. The composite has a high surface area (263 m2 g-1) and a monomodal pore size distribution with an average pore diameter of 3.4 nm. A comprehensive characterization of the synthesized material was done using PXRD, Raman, BET, SEM, EDX, TEM, TGA, and XPS. The composite exhibited excellent catalytic activity (1.6 h-1 TOF, >99% GC yield, and >99% selectivity) towards acetalization of cyclohexanone at room tempertaure within 30 minutes. The catalyst was reusable up to 4 reaction cycles without any significant loss in the activity and the acidic site calculations showed that the reaction is mostly driven by the weak acidic sites on the composite.
Facile synthesis of acetal over a supported novel Br?nsted and lewis acid ionic liquid catalyst
Liu, Ruifeng,Dai, Liming,Zhao, Qian,Xie, Yingjie,Jiang, Tingshun
, p. 4396 - 4405 (2019/05/08)
A novel Br?nsted and Lewis acid ionic liquid (IL) chlorinated butyrolactam chlorozincinate (CPCl-ZnCl2) was synthesized by a hydrothermal process and characterized by Fourier transform infrared (FT-IR). The Fe-SBA-15 mesoporous materials with different Si/Fe mole ratios were prepared by direct synthesis method. The supported ionic liquid (IL/Fe-SBA-15) with various IL contents were prepared by a wet impregnation method and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and N2 physical adsorption. The acidity was measured by FT-IR spectroscopy using pyridine as probes. The catalytic property was tested in acetalization of cyclohexanone with ethylene glycol. The results demonstrated that the IL/Fe-SBA-15 catalysts were of higher catalytic activity compared to Fe-SBA-15. Under optimal conditions, the acetalization could reach to 92.6% cyclohexanone conversion with 99.3% acetal selectivity. After 5 cycles, the cyclohexanone conversion decreased slightly. Also, the catalyst showed good catalytic property in the other acetalization of cyclohexanone and benzyl alcohol.
Silver-Catalyzed Olefination of Acetals and Ketals with Diazoesters to β-Alkoxyacrylates
Li, Jiawen,Qian, Bo,Huang, Hanmin
supporting information, p. 7090 - 7094 (2018/11/23)
The first silver-catalyzed reaction of acetals or ketals with diazoesters leading to trisubstituted or tetrasubstituted β-alkoxyacrylates is now reported. A broad range of acetals and ketals bearing different substituents is compatible with this protocol and thus provides an attractive approach for the synthesis of complex β-alkoxyacrylates. The power of this method was further demonstrated by the successful synthesis of picoxystrobin, which is one of the most popular agricultural fungicides commercialized by Dupont.
