7498-85-3Relevant articles and documents
Hybrid mesoporous organosilicas with molecularly imprinted cavities: Towards extended exposure of active amino groups in the framework wall
Huo, Hang,Xu, Xianzhu,Zhao, Tingting,Li, Yudong,Jiang, Yanqiu,Lin, Kaifeng
, p. 4508 - 4517 (2018)
Hybrid molecularly imprinted mesoporous silicas were synthesized by co-condensation of tetraethoxysilane and functional organosilica precursors of HQP and BPAP, in which hydroquinone (HQ) and bisphenol A (BPA) were linked as imprinting molecules. Owing to
Mg2+-derived mesoporous ultra-high silica twelve-membered-ring basic zeolites: Straightforward synthesis and catalytic performance
Xie, Jingyan,Wen, Haimeng,Zhang, Wei,Zhou, Yu,Wang, Jun
, p. 1164 - 1173 (2016)
Mg2+-derived mesoporous ultra-high silica twelve-membered-ring zeolites with multiple topologies (MOR, BEA and MTW) were straightforwardly synthesized by a one-pot route, where the crucial step was the co-hydrolysis/condensation of silica source and magnesium salt under moderate acidic conditions. SiO2/Al2O3 ratios can be adjusted from ～30 to as high as 410, thus generating superior basicity that was further improved by the incorporation of Mg species. A mesoporous structure was self-formed without the assistance of any template or special strategy. Catalysis tests showed high activity of these zeolites in a typical base reaction, Knoevenagel condensation, even for the bulky substrates due to the enhanced mass transfer arising from the mesopores. This methodology provides a promising approach towards target synthesis of valuable Mg2+-derived mesoporous ultra-high silica zeolites with tunable acid/base properties, which can even act as an efficient mesoporous zeolitic solid base.
Prolinamide functionalized polyacrylonitrile fiber with tunable linker length and surface microenvironment as efficient catalyst for Knoevenagel condensation and related multicomponent tandem reactions
Zhu, Hai,Xu, Gang,Du, Huimin,Zhang, Chenlu,Ma, Ning,Zhang, Wenqin
, p. 217 - 229 (2019/05/16)
A series of new prolinamide polyacrylonitrile fiber catalysts with tunable length of alkyl linker and different linker group were prepared by covalent bonding for the first time and well characterized by mechanical strength, FT-IR, XRD, EA, TGA, SEM and water contact angel. The catalytic activities of these fiber catalysts were evaluated in Knoevenagel condensation and one-pot Knoevenagel-Michael multicomponent tandem reactions to synthesize α, β-unsaturated nitrile and 2-amino-4H-chromene derivatives in water. The result show that the suitable linker length attaching amines to fiber matrix as well as the constructed hydrophobic microenvironment by linker group within the surface layers of fiber materials effectively promotes the reactions. In addition, the good swollen capacity of fiber in solvent ensure that the reaction proceed well. Fiber catalyst PANPA?2F modified by prolinamide with a C2 alkyl chain exhibited the best catalytic performance and can be easily recovered and reused for at least ten consecutive cycles without significant loss of catalytic activity and active sites leaching.
Direct fabrication of strong basic sites on ordered nanoporous materials: Exploring the possibility of metal-organic frameworks
Liu, Wei,Zhu, Li,Jiang, Yao,Liu, Xiao-Qin,Sun, Lin-Bing
, p. 1686 - 1694 (2018/03/21)
Heterogeneous strong base catalysts possessing ordered nanoporous structure are highly expected due to their high activity and shape selectivity in diverse reactions. However, their fabrication remains a great challenge because quite high temperatures (600-700 °C) are compulsory for the generation of strong basicity on conventional ordered nanoporous materials (i.e., zeolites and mesoporous silicas). Here, we report for the first time direct fabrication of strong basic sites on metal-organic frameworks (MOFs) by using guest-host redox (GHR) interaction between base precursors and low-valence metal centers (e.g., Cr3+), which breaks the tradition of thermo-induced decomposition of base precursors. It is fascinating that base precursor KNO3 can be converted to strong basic species on MIL-53(Cr) at 300 °C, which is much lower than that on zeolite Y (700 °C) and mesoporous silica SBA-15 (600 °C). The resultant solid base exhibits strong basicity, ordered nanoporous structure, and high activity and shape selectivity in base-catalyzed reactions.
