Article
Chemistry, Multidisciplinary
Guoping Yang, Ke Li, Kai Zeng, Yijin Li, Tao Yu, Yufeng Liu
Summary: A recyclable and efficient heterogeneous green catalyst based on the synthesis of Keggin-type polyoxometalate and vitamin B1 analogue was prepared, which catalyzed Oxa-Pictet-Spengler cyclization of arylethanols and aldehydes to afford various substituted isochromans in moderate conditions with excellent yields. The catalyst could be recycled eight times without significant loss of activity, demonstrating its potential for industrial applications.
Article
Engineering, Environmental
Wenjie Deng, Jie Yao, Lei Shi, Wensheng Wei, Fei Chen, Guangwen Xu
Summary: This study discovered a novel organic catalyst 1-ethyl-3-methylimidazolium pyrrole ([EmIm]Py) that exhibited superior activity and practicality in carbonate synthesis, achieving remarkable efficiency even at low temperature. The catalyst outperformed most reported catalysts in various base-catalyzed reactions and showed potential operability in industrial production of dimethyl carbonate (DMC). The mechanism of propylene carbonate (PC) and methanol interesterification over [EmIm]Py catalyst was proposed through a combination of experimental and theoretical studies.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Physical
Abdelrahman O. Ezzat, Ahmed M. Tawfeek, Faruq Mohammad, Hamad A. Al-Lohedan
Summary: Multifunctional pyridinium ionic liquids were used as coating agents to modify magnetite nanoparticles, resulting in controlled particle size and surface charge. The surface modified nanoparticles showed high adsorption capacities for anionic dye from aqueous solutions.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Multidisciplinary
Ke Wang, Yuxia Liu, Shiting Wang, Zhifeng Dai, Yubing Xiong
Summary: The introduction of electron-donating and electron-withdrawing functional groups can affect the catalytic activity, while the length of alkyl group in the cocatalyst significantly impacts the catalytic efficiency.
JOURNAL OF CO2 UTILIZATION
(2021)
Article
Green & Sustainable Science & Technology
Alejandro Belinchon, Ruben Santiago, Elisa Hernandez, Cristian Moya, Pablo Navarro, Jose Palomar
Summary: This work investigates two closed-cycle processes for the regeneration of homogeneous catalysts based on ionic liquids through liquid-liquid extraction. The study demonstrates the efficiency of liquid-liquid extraction as a separation method for cyclic carbonates and ionic liquid catalysts.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Materials Science, Multidisciplinary
Qianmeng Zhao, Jian Chen, Mengqian Fu, Lili Deng, Yunong Li, Qian Su, Weiguo Cheng
Summary: This study developed a new strategy to enhance the catalytic activity of PILs by regulating their structure. A gradient structure with enriched ionic liquids on the surface was formed by shortening the alkyl chain length of the IL monomer, allowing for better utilization of the active sites. The PIL with a 4-carbon alkyl chain exhibited the best catalytic activity, and further analysis revealed that the release of Br- enhanced the catalytic activity.
APPLIED MATERIALS TODAY
(2023)
Article
Chemistry, Applied
Heshan Cai, Junji Chen, Kaixing Cai, Fei Liu, Tianxiang Zhao
Summary: A N-doped porous polymer with protonated ionic liquid sites was prepared by a solvent-free self-assembly synthesis and hydrobromic acid modification. The modified polymer, PIP-HP-HBr, maintained a high specific surface area and exhibited elevated catalytic activity with up to 99% yield of cyclic carbonates under metal/solvent/cocatalyst-free conditions. The PIP-HP-HBr catalyst also showed excellent cycling stability and could be easily recovered. The catalytic mechanism was proposed to be attributed to the synergistic effect of hydrogen bond donor -OH and nucleophilic anion Br-.
MICROPOROUS AND MESOPOROUS MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Guangcai Long, Kai Su, Huinan Dong, Tianxiang Zhao, Chunliang Yang, Fei Liu, Xingbang Hu
Summary: In this study, an effective and straightforward strategy for the synthesis of amino-functionalized ILs@SBA-15 catalysts was proposed via mechanochemical grafting. The as-prepared catalysts exhibited impressive catalytic activity for the one-pot synthesis of cyclic carbonates from olefins and CO2 under metal-and cocatalyst-free conditions. The catalyst could be easily recovered without significant decrease in catalytic activity after multiple cycles. Additionally, a possible catalytic mechanism of the oxidative carboxylation reaction of olefins was proposed based on the results of the control experiment.
JOURNAL OF CO2 UTILIZATION
(2022)
Article
Chemistry, Multidisciplinary
Fang Si, WenHui Yue, Li Su, Weifang Han, ZiBo Yan, Xinming Zhou, Hui Fu
Summary: This study simulated the different catalytic mechanisms of the reaction between CO2 and propargylic alcohol. It was found that metal-assisted catalytic system can enhance the conversion rate and product yield. The PA-activated mechanism was identified as the optimal reaction pathway with intramolecular cyclization as the rate-determining step. The combination of [Ch][Triz] and Ag salts played different roles in promoting the reaction steps.
JOURNAL OF CO2 UTILIZATION
(2022)
Article
Energy & Fuels
Yuke Zhang, Mingyue Qiu, Jie Li, Haonan Wu, Lijuan Shi, Qun Yi
Summary: This study proposes a one-step strategy to construct Lewis pair heterogeneous catalysts for CO2 conversion through the coordination of amino-functionalized poly(ionic liquid) and metal cations. The strength and ratio of Lewis acidic/basic sites can be tuned by regulating the type/content of metal ions, enabling efficient acid/base cooperation in CO2 cycloaddition. The synergistic effect of M2+, Br-, and C-2 proton on the imidazolium ring activates both CO2 and epoxides, leading to high yields and selectivity of cyclic carbonates under atmospheric pressure and low temperature without cocatalyst.
Article
Chemistry, Physical
Zezhong Jiang, Haiyue Wang, Lining Shan, Rongrong Zheng, Xiudan Zhao, Zhangbin Liao, Liying Guo
Summary: Six heteropolyacid ionic liquids were prepared by the ion exchange method and showed good thermal stability. Among them, Bmim(4)[Ti(H2O)TiMo11O39] exhibited the best catalytic performance in the transesterification reaction between phenol and dimethyl carbonate. The catalyst was able to self-assemble with temperature changes and could be recycled through simple washing and filtering.
Article
Chemistry, Applied
Tianxiang Zhao, Guangcai Long, Hua Liang, Wenjie Xiong, Xingbang Hu
Summary: A series of [Im][HCO3]@SBA-15 supported ionic liquids (SILs) catalysts were prepared by anion exchange and solvent-free mehcanochemical grafting strategies for the direct synthesis of cyclic carbonates from olefins and CO2. The as-prepared [Im][HCO3]@SBA-15 catalysts exhibited excellent catalytic activity and selectivity for the one-pot synthesis of cyclic carbonates, providing moderate to excellent yields. The catalysts showed excellent reusability and stability, making them a promising option for CO2 conversion.
MICROPOROUS AND MESOPOROUS MATERIALS
(2023)
Article
Chemistry, Physical
Chaokun Yang, Yanglin Chen, Xin Wang, Jianmin Sun
Summary: This study proposes a catalyst made by combining polymeric ionic liquid (PIL) with mesoporous silica (mSiO(2)) to promote the cycloaddition reaction between carbon dioxide (CO2) and epoxides. The catalyst exhibits excellent catalytic activity and recyclability, making it a promising solution for the effective fixation and utilization of CO2.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Physical
Yuxin Wu, Yuncheng Ding, Jianhong Xu, Yundong Wang, Kathryn Mumford, Geoffrey W. Stevens, Weiyang Fei
Summary: The study developed a continuous-flow microreaction system for the synthesis of propylene carbonate, and comprehensively evaluated the effects of reaction temperature, molar fraction of catalyst, operating pressure, residence time, molar ratio of CO2/PO, and recycling performance of catalyst on the overall performances. Under different reaction conditions, the flow patterns varied between slug flow and annular flow. The results showed that at 140 degrees C and 3.0 MPa with a residence time of 166 s, the yield of propylene carbonate (PC) can reach 99.7%, and the recycling performance of the designed system greatly conforms the future trend of green chemistry.
GREEN ENERGY & ENVIRONMENT
(2021)
Article
Chemistry, Applied
Vatcharaporn Aomchad, Silvano Del Gobbo, Prapussorn Yingcharoen, Albert Poater, Valerio D'Elia
Summary: Rare-earth-based complexes were developed and applied as homogeneous Lewis acid catalysts for the cycloaddition of CO2 and epoxides, achieving high turnovers over 100 under ambient conditions. DFT calculations and advanced buried volume calculations provided insights into the activity differences between complexes, with yttrium and scandium-based salen species exhibiting milder reaction barriers.
