Fully catalytic upgrading synthesis of 5-Ethoxymethylfurfural from biomass-derived 5-Hydroxymethylfurfural over recyclable layered-niobium-molybdate solid acid

• Published in: Applied catalysis. B, Environmental Vol. 256; p. 117786
• Main Authors: Yang, Fu, Tang, Jingjing, Ou, Rui, Guo, Zengjing, Gao, Shuying, Wang, Yinzhu, Wang, Xuyu, Chen, Lei, Yuan, Aihua
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 05.11.2019; Elsevier BV
• Subjects: Acids; Alcohols; Biomass; Catalysis; Catalysts; Catalytic activity; Chemical synthesis; Conversion; Electromagnetic fields; Ethanol; Etherification; Ethoxymethylfurfural; Fructose; Hydroxymethylfurfural; Industrial applications; Interlayers; Lewis acid; Low frequency; Molybdate; Molybdenum; Multilayers; Multiple-layer; Niobium; Organic chemistry; Polyoxometalates; Polyoxometallates; Resource exploitation; Selectivity; Solid acid; Substrates; Polyoxometalates; Biomass; Multiple-layer; Solid acid; Etherification; Ethoxymethylfurfural
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.117786

We report robust multilayer-like polyoxometalates as solid acid catalyst with precisely-tuned compositions including Nb and Mo toward acquiring controllable Brønsted acid amounts via a thermal-sintering and acidification process for entirely catalytic generation of promising 5-Ethoxymethylfurfural from 5-Hydroxymethylfurfural. [Display omitted] •Multilayer-like polyoxometalates(H1.15Nb1.15Mo0.85O6) was developed as solid acid catalyst.•The regulation of acid amount and interlayer space of Nb-Mo oxides layer simultaneously can be enabled.•The entirely catalytic generation of 5-Ethoxymethylfurfural from 5-Hydroxymethylfurfural can be realized.•The resulted catalyst shows durable catalytic activity without any activity loss during the eight recycling. Biomass-derived resources exploited in depth toward the synthesis of high value-added chemicals is very promising, but still limited by the applicable catalyst. In this paper, we report regulated robust multilayer-like polyoxometalates(Niobium molybdate) specific to the catalytic synthesis of promising 5-Ethoxymethylfurfural (EMF). The present solid acid catalysts resulted from precisely-tuned compositions of Nb and Mo toward acquiring controlled Brønsted acid amounts and interlayer space coupling with specific Lewis acid sites are demonstrated to be the determining factors for tuning conversion and selectivity in the synthesis of EMF, respectively. The characterization results indicate that the increment in Nb moiety is beneficial to produce more accessible acid sites and the enlarged interlayer space in the catalyst, thereby promoting the acid-catalyzed conversion. As a result, the full conversion(Conv. 100%) of 5-hydroxymethylfurfural into the 5-Ethoxymethylfurfural (Select. >99%) by etherification with ethanol within only 60 min was realized as the record-high yield under the solvent-free condition, far outperforming several traditional catalysts. In addition, the rational 67% yield of EMF was received when using fructose as an initial reactant. Ulteriorly, the resultant catalyst inherits the superior catalytic activity in the substrate expansion experiments in the presence of different alcohols. More importantly, the resulted catalyst shows durable catalytic activity without any activity-loss during the eight recycling, which reveals the huge potential industrial application prospect.