4427-96-7Relevant articles and documents
Coupling reactions of CO2 with neat epoxides catalyzed by PPN salts to yield cyclic carbonates
Sit, Wing Nga,Ng, Siu Man,Kwong, Kar Yan,Lau, Chak Po
, p. 8583 - 8586 (2005)
The off-the-shelf reagent PPN+Cl- and PPN-manganese carbonylates [PPN]+[Mn(CO)4L]- (L = CO, PPh3) are good catalysts for the coupling reactions of CO2 with neat epoxides without the use of organic solvents to afford cyclic carbonates. PPN salts with weak nucleophilic anions such as PPN +BF4- and PPN+OTf- are, however, inactive for the coupling reactions.
Highly Active Chromium Complexes Supported by Constrained Schiff-Base Ligands for Cycloaddition of Carbon Dioxide to Epoxides
Kiriratnikom, Jiraya,Laiwattanapaisarn, Nattiya,Vongnam, Kunnigar,Thavornsin, Nopparat,Sae-Ung, Pornpen,Kaeothip, Sophon,Euapermkiati, Anucha,Namuangruk, Supawadee,Phomphrai, Khamphee
, p. 6147 - 6151 (2021)
Novel constrained Schiff-base ligands (inden) were developed based on the well-known salen ligands. Chromium complexes supported by the constrained inden ligands were successfully synthesized and used as catalysts for the synthesis of cyclic carbonates from epoxides and carbon dioxide (CO2). The catalyst having tert-butyl (tBu) groups as substituents in combination with tetrabutylammonium bromide (TBAB) as a cocatalyst exhibited very high catalytic activity with a turnover frequency of up to 14800 h-1 for the conversion of CO2 and propylene oxide into propylene carbonate exclusively at 100 °C and 300 psi of CO2 under solvent-free conditions. The catalyst was found to be highly active for various epoxide substrates to produce terminal cyclic carbonates in 100% selectivity.
A Thermomorphic Polyethylene-Supported Imidazolium Salt for the Fixation of CO2 into Cyclic Carbonates
Grollier, Kevin,Vu, Nam Duc,Onida, Killian,Akhdar, Ayman,Norsic, Sébastien,D'Agosto, Franck,Boisson, Christophe,Duguet, Nicolas
, p. 1696 - 1705 (2020)
An imidazolium catalyst supported on thermomorphic polyethylene (PE) was prepared from 1-methylimidazole and polyethylene iodide (PE?I). The catalyst was characterized by 1H and 13C NMR, SEC and MALDI-ToF mass spectrometry. Its catalytic activity was evaluated in the ring-opening of epoxides with carbon dioxide to give cyclic carbonates under solvent-free conditions. The catalyst proved to be active at low catalyst loading (down to 0.1 mol%) and allows the reaction to occur at low CO2 pressure (1–5 bar) and moderate temperature (100 °C). A range of terminal and internal epoxides was converted to the corresponding cyclic carbonates with high yields and selectivities. The recyclability of the catalyst was studied and no significant loss of activity was observed after 5 runs. (Figure presented.).
Synthesis of heterobimetallic Ru-Mn complexes and the coupling reactions of epoxides with carbon dioxide catalyzed by these complexes
Man, Man Lok,Lam, King Chung,Sit, Wing Nga,Ng, Siu Man,Zhou, Zhongyuan,Lin, Zhenyang,Lau, Chak Po
, p. 1004 - 1015 (2006)
The heterobimetallic complexes [(η5-C5H 5)Ru(CO)(μ-dppm)Mn(CO)4] and [(η5-C 5Me5)Ru(μ-dppm)(μ-CO)2Mn(CO) 3] (dppm= bisdiphenylphosphinomethane) have been prepared by reacting the hydridic complexes [(η5-C5H5)Ru(dppm) H] and [(η-C5Me5)Ru(dppm)H], respectively, with the protonic [HMn(CO)5] complex. The bimetallic complexes can also be synthesized through metathetical reactions between [(η5-C 5R5)Ru-(dppm)Cl] (R = H or Me) and Li+ [Mn(CO)5]-. Although the complexes fail to catalyze the hydrogenation of CO2 to formic acid, they catalyze the coupling reactions of epoxides with carbon dioxide to yield cyclic carbonates. Two possible reaction pathways for the coupling reactions have been proposed. Both routes begin with heterolytic cleavage of the Ru-Mn bond and coordination of an epoxide molecule to the Lewis acidic ruthenium center. In Route I, the Lewis basic manganese center activates the CO2 by forming the metallocarboxylate anion which then ring-opens the epoxide: subsequent ring-closure gives the cyclic carbonate. In Route II, the nucleophilic manganese center ring-opens the ruthenium-attached epoxide to afford an alkoxide intermediate; CO2 insertion into the Ru-O bond followed by ring-closure yields the product. Density functional calculations at the B3LYP level of theory were carried out to understand the structural and energetic aspects of the two possible reaction pathways. The results of the calculations indicate that Route II is favored over Route I.
Bifunctional zinc and magnesium Schiff-base complexes containing quaternary ammonium side-arms for epoxide/CO2coupling reactions
Chainok, Kittipong,Laiwattanapaisarn, Nattiya,Phomphrai, Khamphee,Virachotikul, Arnut
, p. 12399 - 12403 (2021)
Novel bifunctional zinc and magnesium Schiff-base complexes containing quaternary ammonium halide side-arms were developed. Zinc complex1Et-I(0.02 mol%) having an iodide anion has shown the highest TOF for the propylene oxide/CO2coupling reaction of up to 459 h?1. This TOF value was maintained even when the catalyst loading was reduced to 0.005 mol%.
Mesoporous Ta–W Composite Oxides: A Highly Effective and Reusable Acid–Base Catalysts for the Cycloaddition Reaction of Carbon Dioxide with Epoxides
Liu, Gui,Liu, Junhua,Mao, Weizhong,Miao, Shiwen,Wang, Fang,Yin, Bingqian
, (2021)
Cycloadditions of epoxides and carbon dioxide into corresponding cyclic carbonates were performed over mesoporous Ta–W composite oxides prepared by a modified hydrolytic method. The best yields of styrene carbonate were obtained when the Ta/W mole ratio was 2:1 (labeled as Ta0.67W0.33Os). Under optimal reaction conditions, the conversion of styrene oxide and selectivity of styrene carbonate reached 95 and 97%, respectively. These Ta–W composite oxides have been extensively characterized by several techniques. X-ray diffraction (XRD) patterns and Transmission Electron Microscope (TEM) revealed that Ta2O5 was completely dispersed in WOx. Scanning electron microscopy (SEM) exhibited that the particle size distributions become more and more uniform with increment of tungsten content. CO2 and NH3 temperature-programmed desorption (CO2 and NH3-TPD) revealed that Ta0.67W0.33Os catalyst had the strongest acid and base strength. X-ray photoelectron spectroscopy (XPS) shows that the strongest acid–base sites of Ta0.67W0.33Os catalyst origin from its highest lattice oxygen concentration and W 4f5/2 species with Bronsted acidity. We discussed the reaction kinetics and proposed a possible mechanism, indicating the excellent catalytic activity is attributed to the cooperative action of acidic and neighboring basic sites on the catalyst surface. Graphic Abstract: Cycloaddition reactions of carbon dioxide with epoxides into corresponding cyclic carbonates were performed over mesoporous Ta–W composite oxides prepared by a modified hydrolytic method. The best yields for cyclic carbonates were obtained when the Ta/W mole ratio was 2:1 (denoted as Ta0.67W0.33Os). Acid-base synergy, specific surface area and mesoporous structure could be ascribed to the main reasons for the highest catalytic activity of Ta0.67W0.33Os catalyst. Meanwhile, reaction kinetics was discussed and a possible reaction pathway was proposed.[Figure not available: see fulltext.]
Method for preparing cyclic carbonate by immobilizing CO2 under catalysis of organic boric acid
-
Paragraph 0119-0124, (2021/06/22)
The invention discloses a synthesis method for synergistically catalyzing carbon dioxide immobilization through weak Lewis acid phenylboronic acid and tetrabutylammonium bromide. According to the method, CO2 is immobilized by epoxide, and a cyclic carbonate product is generated. The method comprises the following step: under the concerted catalysis of phenylboronic acid and tetrabutylammonium bromide, performing reaction on epoxide as shown in a formula IV, a formula V or a formula VI and carbon dioxide to respectively obtain a cyclic carbonate product as shown in a formula I, a formula II or a formula III. According to the method, raw materials are convenient and easy to obtain, reaction conditions are mild, operation is easy and convenient, and the yield can reach 97%.