- Synthesis of Ionic Liquids as Novel Nanocatalysts for Fixation of Carbon Dioxide with Epoxides by Using a Carbon Dioxide Balloon
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Abstract: In the present study, the nanocatalyst of imidazolium based ionic liquids (ILs) is synthesized for the fixation of carbon dioxide (CO2) under moderate conditions by utilizing a balloon of CO2 with commercially available epoxides. IL incorporated porous dendritic fibrous nanosilica (DFNS) catalyst (IL/DFNS) was designed and synthesized. The synthesized catalyst was characterized using N2 absorption desorption isotherm, XPS, SEM, EDX, TGA, HR-TEM, and AFM. For cyclic carbonate, an environmental friendly catalyst of porous IL/DFNS indicate highly impressive catalytic efficiency from CO2 through CO2 fixation and epoxides under mild condition. Attendance of polar hydroxyl and anion exchange nature groups of IL frame work to high surface area is known as the main aspect to be reliable for elevated catalytic efficiency and also advance in stability of catalyst and providing a proper recyclability. Graphic Abstract: [Figure not available: see fulltext.].
- Zhang, Pu,Zhiani, Rahele
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p. 2254 - 2266
(2020/02/18)
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- Method for preparing methocarbamol
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The invention discloses a method for preparing methocarbamol. The method comprises the steps that guaifenesin serves as a raw material, alkali and 4-dimethylaminopyridine serve as a catalyst, carbonicester serves as an esterification agent, and a compound shown in the formula (I) is obtained through an esterification reaction, the compound shown in the formula (I) reacts with ammonia water through an ammoniation reaction to obtain the methocarbamol shown in the formula (II), and the reaction equation of the methocarbamol is that the alkali is hydroxide or carbonate of the first main alkali metal group. Accordingly, guaifenesin serves as a raw material, the alkali and DMAP serves as the catalyst, the carbonic ester is catalyzed to be esterified and then ammonified and crystallized, and themethocarbamol is obtained. A nucleophilic reagent DMAP is used for catalysis, the carbonic ester can rapidly and highly selectively complete the reaction with hydroxide radical, and the high-yield guaifenesin ester is obtained; in addition, the dosage of the carbonic ester is small, safety and environmental protection are achieved, pollution is small, the economic benefit is high, operation is easy, and the method is suitable for industrial production.
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Paragraph 0036-0037; 0038-0039; 0040-0041; 0042-0055
(2019/07/16)
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- Bifunctional phase-transfer catalysts for fixation of CO2 with epoxides under ambient pressure
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A series of bifunctional phase-transfer catalysts with a quaternary onium center and a hydrogen-bonding donor group were prepared for the fixation of CO2 with commercially available epoxides under mild conditions by using a CO2 balloon (1 atm). In the presence of 2.5 mol% of achiral bifunctional phase-transfer catalysts, cyclic carbonates were obtained in good to excellent yields (up to 95%). Additionally, optical carbonates and epoxides were obtained through the kinetic resolution of rac-epoxides by 1 mol% of chiral bifunctional phase-transfer catalysts with low enantioselectivities. These catalysts featured a simple synthetic route, good modularity and high efficiency.
- Li, Yue-Dan,Cui, Dong-Xiao,Zhu, Jun-Chao,Huang, Ping,Tian, Zhuang,Jia, Yan-Yan,Wang, Ping-An
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supporting information
p. 5231 - 5237
(2019/10/11)
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- Chemical modifications of lignin for the preparation of macromers containing cyclic carbonates
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An epoxidized lignin derivative was prepared directly inserting epichlorohydrin on the phenolic functionalities. The epoxidized lignin was then converted to cyclic carbonates through the coupling reaction of CO2 with the oxirane rings. Imidazolium based ionic liquids, acting as both solvents and catalysts, were successfully employed in the carbonation reaction. Moreover, the ionic liquid was reused up to three times without significant loss in activity. Finally, an exhaustive spectroscopic characterization was carried out on the epoxidized and carbonated lignins by quantitative 31P and 13C NMR analyses.
- Salanti, Anika,Zoia, Luca,Orlandi, Marco
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p. 4063 - 4072
(2016/07/21)
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- Pd/C: An efficient and heterogeneous protocol for oxidative carbonylation of diols to cyclic carbonate
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The present protocol involves highly efficient and practical approach for the synthesis of cyclic carbonate via oxidative carbonylation of diols, glycerol, and its derivatives using Pd/C as a heterogeneous, inexpensive, and recyclable catalyst. The effect of various reaction parameters, such as solvent, base, time, and temperature was investigated and applied for the synthesis of value added cyclic carbonates in a good to excellent yield within shorter reaction time. The developed catalytic system circumvents the use of ligand and dehydrating agent with an additional advantage of palladium catalyst recovery and reuse for up to four consecutive cycles.
- Chavan, Sujit P.,Bhanage, Bhalchandra M.
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supporting information
p. 1199 - 1202
(2014/02/14)
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