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33. Synergistic decarboxylation over Ce-doped Na/SiO2 facilitating functionalized monomer production from furfural for manufacturing polymers.

Author

Qi, Yanlong, Feng, Ruilin, Liu, Shijun, Cui, Long, Dai, Quanquan, and Bai, Chenxi

Subjects
*FURFURAL, *MONOMERS, *POLYMERS, *HETEROGENEOUS catalysis, *DECARBOXYLATION, *CATALYST structure
Abstract

Functionalized monomers are of utmost importance in producing new polymers and smart materials. Herein, a two-step approach involving heterogeneous catalysis was developed to produce a functionalized monomer (2-vinylfuran) from bio-based furfural, giving an overall yield of 89%. Economic analysis suggests that this facile approach incurs much lower costs, and its practicality improves the availability of 2-vinylfuran. This is due to the delicate structure of the optimized 4Na5Ce/SiO2, where Na species are present at the oxygen vacancies of the ceria that protect the catalyst structure from collapse, and the catalyst consequently displays excellent performance. Density functional theory (DFT) calculations revealed that the reaction occurs on the Na and Ce species. The adsorption of a furan group onto Na led to side reactions, which were suppressed in the presence of Ce, resulting in higher selectivity. Finally, a polymer based on 2-vinylfuran was prepared, which shows good surface properties and thermodynamic stability. [ABSTRACT FROM AUTHOR]

Published
2022
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44. Selectively creating oxygen vacancies on PrCe/SiO2catalysts for the transformation of a furfural–acetone adduct into a functionalized 1,3-dieneElectronic supplementary information (ESI) available. See DOI: 10.1039/c9cy01631g

Author

Qi, Yanlong, Liu, Shijun, Liu, Zaizhi, Cui, Long, Huang, Lingyun, Yang, Yinxin, Wu, Ruiyao, Dai, Quanquan, He, Jianyun, Dong, Wei, and Bai, Chenxi

Abstract

The production of valuable chemicals from renewable resources has attracted wide interest, and the present work focuses on the transformation of a furfural–acetone adduct into a functionalized 1,3-diene which can purposefully improve the interfacial properties of resulting polymer materials. Pr modified CeO2catalysts supported on silica were prepared, and the correlation between catalyst nature and catalytic performance (conversion, selectivity and formation rate) was extensively investigated. A yield of 94% was obtained over the optimized catalyst (PrCe2.11/SiO2), and the yield still remained at >89% after 10 h on stream. Low-temperature adsorption of nitrogen, inductively coupled plasma (ICP), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were employed to clarify the catalyst structure. The results indicated that Ce and Pr species exist as CeO2and Pr6O11, respectively, without the formation of a PrCe solid solution. The migration of Pr leads to its enrichment on the catalyst surface, and the interaction between Pr and Ce plays a crucial role in the uniform dispersion of nanoparticles. More importantly, this suggested that the modification of ceria with Pr can selectively create oxygen vacancies instead of lattice distortions. The correlation between the catalytic performance and catalyst nature implies that the improvement in catalytic performance is linearly correlated with the oxygen vacancy concentration. Besides, a plausible reaction pathway for the transformation of a furfural–acetone adduct over PrCe/SiO2was proposed involving a radical mechanism.

Published
2019
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48. Study of the effect of nanosized carbon black on flammability and mechanical properties of poly(butylene succinate).

Author

Chen, Qing, Wen, Xin, Chen, Hao, Qi, Yanlong, Gong, Jiang, Yang, Hongfan, Li, Yunhui, and Tang, Tao

Subjects
CARBON-black, CARBON compounds, CARCINOGENS, POLYBUTENES, BUTENE
Abstract

Biodegradable poly(butylene succinate)/nanosized carbon black (PBS/CB) nanocomposites were prepared by melt compounding to investigate the effect of CB on flammability and mechanical properties of PBS. In the nanocomposites, CB displayed some positive effect on improving the flame retardancy of PBS, mainly on the decrease of peak of heat release rate, the increase of limited oxygen index value, and the inhibition of melt dripping. It was contributed to the formation of a good carbon layer during combustion and of a network structure in the PBS matrix. Moreover, a good balance on mechanical performances of PBS/CB nanocomposites was achieved with enhanced stiffness and high toughness, which was ascribed to the compatibilization of PBS- g-MA, leading to a good dispersion of nanofillers and strong matrix-nanoparticle interaction. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2015
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49. Stereocatalytic Effect of CeO2 for the Synthesis of trans‐3‐Penten‐2‐ol.

Author

Yan, Siyang, Feng, Ruilin, Liu, Jiaxu, Bai, Chenxi, and Qi, Yanlong

Subjects
*CATALYST structure, *HETEROGENEOUS catalysis, *ISOMERISM, *DEHYDRATION reactions, *LEWIS acids
Abstract

The transformation of biobased alkanediols over heterogeneous catalysts is a major object. Here, a series of catalysts were prepared for 2,4‐pentanediol dehydration to 3‐penten‐2‐ol. Ceria‐based catalysts had a unique property of showing high efficiency. More importantly, a stereocatalytic effect was observed for CeO2, yielding trans‐3‐penten‐2‐ol with a high selectivity. Raman, XPS, TPD, and TPR were carried out to clarify the catalyst structure, and the relationship between the catalyst structure and catalytic performance were studied. The amount of Lewis acid sites can hardly be correlated with the total concentrations of the oxygen vacancies. It was suggested that the geometry structure of the active sites played a crucial role in trans‐3‐penten‐2‐ol production. The oxygen vacancies originating from CeO2 consisted of active sites with a geometrical structure, which were different from those created by Pr doping CeO2. In addition, the Pr doping enhanced the oxygen migration, which resulted in side reactions, consequently, giving a lower selectivity to trans‐3‐penten‐2‐ol. [ABSTRACT FROM AUTHOR]

Published
2024
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50. An In-Situ Self-regeneration Catalyst for the Production of Renewable Penta-1,3-diene.

Author

Feng R, Qi Y, Liu S, Cui L, Dai Q, and Bai C

Abstract

Catalyst deactivation is a problem of great concern for many heterogeneous reactions. Here, an urchin-like LaPO 4 catalyst was easily developed for pentane-2,3-diol dehydration; it has an impressive ability to restore the activity in situ by itself during the reaction, accounting for its high stability. This facilitates the efficient production of renewable penta-1,3-diene from pentane-2,3-dione via a novel approach, where penta-2,3-diol was obtained as an intermediate in 95 % yield under mild conditions., (© 2021 Wiley-VCH GmbH.)

Published
2021
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