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Constructing zeolite catalysts with excellent mass transfer and active site accessibility is the key to improving their catalytic efficiencies. Herein, a zeolite subcrystal catalyst with high short-range ordering but X-ray amorphism is prepared to minimize the existing molecular mass-transfer barrier of conventional zeolite catalysts. Various characterizations confirm its size of smaller than 10 nm, definite MFI framework, complete opened micropore channel, and abundant accessible acid sites. Moreover, physical and chemisorption results reveal that the high short-range ordering MFI zeolite subcrystal possesses negligible intracrystalline diffuse limitation and utmost accessibility for the active site. As anticipated, the zeolite subcrystal catalyst not only demonstrates high cracking efficiency in polyolefin cracking reactions but also exhibits outstanding catalytic activity and resistance to carbon deposition in macromolecular furfuryl alcohol etherification reaction. The controlled MFI zeolite subcrystal catalyst synthesis strategy is expected to extend to a variety of microporous materials. [ABSTRACT FROM AUTHOR]

Context:The leaves ofPyrola decorateH. Andr (Pyrolaceae), known as Luxiancao, have long been used for treating kidney deficiency, gastric haemorrhage and rheumatic arthritic diseases in traditional Chinese medicine. Objective:The phytochemicals and antioxidant capacitiesin vitroofP. decorateleaves were investigated. Materials and methods:Ethanol, petroleum ether, acetidin,n-butyl alcohol and aqueous extracts ofPyrola decorateleaves were prepared by solvent sequential process, and then isolated and purified to obtain phytochemicals. Cell viability was measured by MTT assay. PC12 cells were pretreated for 24 h with different extractions ofP. decorateleaves at concentrations of 0.1, 0.5, 1, 5 and 10 mg/mL, then H2O2of 0.4 mM was added in all samples for an additional 2 h. The antioxidant capacities of betulin, ursolic acid and monotropein were determined in PC12 cells against H2O2induced cytotoxicityin vitroas well. Results:Nine compounds (1–9) were isolated and structurally determined by spectroscopic methods, especially 2D NMR analyses. Ethanol extract treated groups showed inhibitory activity with IC50value of 10.83 mg/mL. Betulin, ursolic acid and monotropein were isolated fromP. decorate, and demonstrated with IC50values of 6.88, 6.15 and 6.13 μg/mL, respectively. Discussion and conclusions:In conclusion,Pyrola decorateis a potential antioxidative natural plant and worth testing for further pharmacological investigation in the treatment of oxidative stress related neurological disease. [ABSTRACT FROM PUBLISHER]

Multiple and complex crystallization process of zeolite including complementary single-molecule condensation and particle assembly, and alternately dominant nucleation and growth behavior, plays the critical role in zeolite crystallization but meanwhile makes us hard to study the respective effects. Herein, we strip nuclei from the synthetic solution and find that high-ordered nucleus (subcrystal) is the premise to ignite high-speed growth of zeolite crystal. The high-ordered subcrystals with the size of only 6-10 nm possess regular aperture structure and microporous area similar to zeolite nanocrystal. Interestingly, a unitary oriented aggregation process of the subcrystals towards nanosheets is well observed and characterized where single-molecule addition process is greatly repressed. If a wider range of zeotype nuclei can be expanded, a new synthetic strategy of zeotype materials with heterogeneous framework and active sites may be expected, which may novelize zeolite catalytic properties., (© 2021 Wiley-VCH GmbH.)