The extraction of phenolic compounds from biomass is an important way to replace chemical synthesis techniques, and catalytic pyrolysis of biomass is an effective method to obtain phenolic compounds with high selectivity. In this work, cobalt-modified montmorillonite K-10(CMT) catalyst was prepared by using cobalt salt and montmorillonite K-10(MMT), and used to catalyze the pyrolysis of corn stalk(CS) to produce phenol-rich bio-oil. The catalytic pyrolysis characteristics reflected by the liquid and gaseous components were compared using gas chromatography-mass spectrometry(GC-MS) and online mass spectrometry(online MS), and the catalytic pyrolysis behavior of corn stalk was analyzed by using the thermogravimetric analyzer(TGA). The addition of catalyst resulted in the increase of apparent activation energy of pyrolysis process but increased selectivity for phenolic compounds. Compared with the blank sample, the relative content of phenolic compounds in bio-oil increased by 11.99 %, and the selectivity of alkyl-phenols was stronger. In addition, the results also showed that the synthesized catalyst promoted the production of H 2 and CH 4 during the catalytic pyrolysis. The optimum ratio of the prepared catalyst was 6%Co/15%MMT. These works provide an alternative approach to upgrading bio-oil product.
In this study, we have successfully prepared a heterogeneous catalyst (K-10 clay-Mo) by the immobilization of bis(acetylacetonato) dioxo-molybdenum(VI) [MoO2(acac)2] on montmorillonite K-10 clay. The structure of the resultant catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electronic microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The catalytic activity of K-10 clay-Mo was tested in the aerobic oxidation of 5-hydroxymethylfurfural (HMF). Although a molecule of HMF contains one hydroxyl group and one aldehyde group, to our surprise, the catalyst showed high catalytic activity for the oxidation of the aldehyde group of HMF into 5-hydroxymethyl-2-furancarboxylic acid (HMFCA). A variety of important reaction parameters such as the reaction temperature, catalyst amount, and solvent were explored. HMFCA could be obtained in a high yield of 86.9% with a HMF conversion of 100% after a short reaction time of 3 h in toluene. More importantly, the catalyst K-10 clay-Mo could be reused several times without a significant loss of its catalytic activity.
Li Na,Wang Bing,Sun Jing-yong,Wang Xiao-jing,Sun Jie
Twelve 4-aryl-3,4-dihydrocoumarins were synthesized by the condensation of phenols with the corresponding substituted cinnamic acids in the presence of nitrobenzene and sulfated montmorillonite K-10. This method displayed the property of green chemistry with respect of reuse of the catalyst. These compounds were evaluated for hydroxyl radical scavenging activity in vitro. Results showed that compounds with 7,8-dihydroxy groups had relatively strong hydroxyl radical scavenging activity.
Various substituted neoflavonoid derivatives were synthesized using sulfated montmorillonite K-10 as a catalyst. This method is environmental friendly, sustainable and economical, convenient in isolation and purification processes, with little byproducts, using earth-abundant catalysts and has relatively high yield. Those neoflavonoid derivatives were screened for antioxidant, a-glucosidase inhibitory, aldose reductase 2 (ALR2) inhibitory and advanced glycation end-product formation inhibitory effects. Most compounds exhibited significant antioxidant and advanced glycation end-product (AGE) formation inhibitory activities. It was interesting to note that out of thirty compounds, 8k and 8l were found to have greater ALR2 inhibitory activity than the standard drug quercetin. The pharmacological studies suggested neoflavonoid with adjacent 7,8-dihydroxy groups were more effective in inhibiting ALR2. Antidiabetic activity studies had shown that compounds 8l and 8m were equipotent to the standard drug glibenclamide in vivo. In summary, the target compound 8l provided a potential drug design concept for the development of therapeutic or prophylactic agents of diabetes and diabetes complications.
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