Catalysis Science & Technology
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2019
·Vol. 9
·期 24
·6875-6883
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IF 5.726
Yanlong Qi,Shijun Liu,Zaizhi Liu,Long Cui,Lingyun Huang,Yinxin Yang,Ruiyao Wu,Quanquan Dai,Jianyun He,Wei Dong,Chenxi Bai
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 CeO2 catalysts 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 CeO2 and 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/SiO2 was proposed involving a radical mechanism.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Jingjing Zhai,Fen You,Suting Xu,Ao Zhu,Xiaohui Kang,Yat-Ming So,Xiaochao Shi
A PNP-pincer ligand provides a versatile ligation framework, which is highly useful in organometallic chemistry and catalytic chemistry. In this work, by a de novo strategy, a simple and efficient synthetic pathway, has been developed to prepare the new iminodibenzyl-based PNP pincer proligand imin-RPNP(Li or H) (R = isopropyl, phenyl). By employing salt metathesis or direct alkyl elimination, we successfully synthesized a series of iminodibenzyl-PNP rare-earth-metal (Ln = Sc, Y, Dy, Ho, Er, Tm, Lu) complexes and characterized them by NMR and X-ray diffraction analyses. Upon addition of a borate and triisobutylaluminum (TIBA), the rare-earth-metal complexes 2-Y, 2-Dy, 2-Ho, 2-Er, and 2-Tm bearing the imin-PhPNP ligand exhibited unexpectedly high 3,4-selectivity (up to 95%) for the polymerization of 1,3-dienes (isoprene and myrcene); in particular, the chosen yttrium complex 2-Y promoted the 1,3-diene polymerization in a living manner. A computational study suggested that the sterically congested configuration around the metal center imposed by the imin-RPNP ligand might be the main reason for this unusual selectivity.
研究领域:
有机金属化学
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催化化学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
·
IF 7.632
Yanlong Qi,Zaizhi Liu,Shijun Liu,Long Cui,Quanquan Dai,Chenxi Bai
The transformation of renewable feedstocks into high-value chemicals is a sustainable and eco-friendly energy technology. In this work, a functionalized 1,3-diene (1-(2-furyl)-1,3-butadiene, F-diene), with significant importance in high-performance elastomer production, was produced from a furfural–acetone adduct. Heteropolyacids were developed as efficient and eco-friendly catalysts, and a 96% selectivity toward F-diene was obtained. The relationship between catalyst structure and catalytic efficiency (conversion, selectivity, and formation rate) suggests that F-diene production is dependent on both the Keggin structure and the acidity (the amount of Brønsted and Lewis acids) of the catalysts. Linear fitting of the F-diene formation rate and acidity indicates that the catalytic capacity enhancement is linearly correlated with the amount of Brønsted acid sites, and the importance of Lewis acids is also deduced. Finally, Ce species was employed to improve the initial activity of the catalysts and yielded 93% selectivity toward F-diene after 5 h on stream. Thus, a synergistic effect between Brønsted and Lewis acids on this reaction was revealed, especially in the initial stage of the reaction.
研究领域:
化学工程
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催化科学
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可再生能源
✓ 已验证
DOI
高影响因子
Polymers
·
2017
·Vol. 9
·期 10
·526
·
IF 3.364
Hui Zhang,Yaoguang Xu,Yuqi Li,Zexiang Lu,Shilin Cao,Mizi Fan,Liulian Huang,Lihui Chen
A facile cellulose solvent 1,3-diallyl-2-ethylimidazolium acetate ([AAeim][OAc]) with high electrical conductivity has been designed and synthesized for the first time, via a quaternization reaction and ion exchange method. The dissolution characteristics of cellulose in this solvent were studied in detail. Meanwhile, the co-solvent system was designed by adding an aprotic polar solvent dimethyl sulfoxide (DMSO) in [AAeim][OAc]. The effects of temperature and the mass ratio of DMSO to [AAeim][OAc] on the solubility of cellulose were studied. Furthermore, the effects of regeneration on the molecular structure and thermal stability of cellulose were determined by Fourier transform infrared spectroscopy (FT-IR), thermal gravity analysis (TGA) and X-ray diffraction (XRD). The findings revealed that the synthesized ionic liquid (IL) has a relatively low viscosity, high conductivity and a good dissolving capacity for bamboo dissolving pulp cellulose (Degree of Polymerization: DP = 650). The macromolecular chain of the cellulose is less damaged during the dissolution and regeneration process. Due to the increased number of “free” anions [OAc]−and cations [AAeim]+, the addition of DMSO can significantly increase the solubility of the cellulose up to 12 wt % at the mass ratio of 3:1, indicating that the synthesized IL has a potential application in the electrospinning field.Keywords:1,3-diallyl-2-ethylimidazolium acetate;ionic liquid;co-solvent system;solubility of cellulose;electrospinning
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
GREEN CHEMISTRY
·
2019
·Vol. 21
·期 14
·3911-3919
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IF 9.405
Yanlong Qi,Shijun Liu,Long Cui,Quanquan Dai,Jianyun He,Wei Dong,Chenxi Bai
The synthesis of functionalized 1,3-dienes has received increasing attention due to their importance in the practical development of high-performance elastomers. In the present work, furfural and acetone, acting as renewable feedstocks, are first employed to produce a functionalized 1,3-diene containing a furan group (1-(2-furyl)-1,3-butadiene, F-diene). After selective hydrogenation of the CO group, the aldol adduct (4-(2-furanyl)-3-buten-2-ol, FAH) shows a nearly complete conversion, with an excellent selectivity (as high as 92%) towards F-diene over ceria-based catalysts in a fixed bed. BET, TEM, XRD, XPS, Raman, TPD, TPR and TGA were conducted to identify the relationship between the catalytic performance and catalyst structure. A plausible reaction pathway for the dehydration of FAH over ceria-based catalysts was proposed using a radical mechanism, which suggested the importance of the Ce4+–Ce3+ redox cycle for the dehydration of FAH to F-diene. Furthermore, the ceria-based catalysts exhibited a notable carbon resistance.
研究领域:
化学工程
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催化
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可再生化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）