Enantioselective nickel-catalyzed dicarbofunctionalization of 3,3,3-trifluoropropene.

Despite paramount applications of chiral trifluoromethylated compounds in medicinal chemistry and materials science, limited strategies have been developed for catalytic asymmetric synthesis of such valuable fluorinated structures. Here, we report a nickel catalyzed enantioselective dicarbofunctionalization of inexpensive industrial chemical 3,3,3-trifluoropropene (TFP) with readily available tertiary alkyl and aryl iodides. The reaction overcomes the ß-F elimination side reaction of TFP, and proceeds efficiently under mild reaction conditions. The protocol possesses advantages, such as synthetic convenience, high enantioselectivity, and excellent functional group tolerance, providing rapid and straightforward access to chiral trifluoromethylated compounds of medicinal interest.

Influence of surfactant on CO2 adsorption of amine-functionalized MCM-41.

Concerning the increasing greenhouse effect, the development of efficient CO2 adsorbents is very important. In this study, the influence of surfactant on the adsorption performance of amine-functionalized MCM-41 was analysed. The results showed that the residual amount of surfactant in MCM-41 was gradually decreased with the increase of calcination temperature which improved the pore structure. The maximum adsorption capacity (5.495 mmol/g) appeared at PEI-MCM-41-100°C indicated that the adsorption capacity could be improved under the function of surfactant. By calculating the diffusion coefficient of CO2 adsorption process in PEI-MCM-41-100/200/300/400/550°C, the diffusion resistance of CO2 was the lowest in PEI-MCM-41-100°C, which directly proved that the synergism of surfactant and organic amine could reduce the diffusion resistance of CO2 in the pore.

Enhancement of CO2 capture performance of aqueous MEA by mixing with [NH2e-mim][BF4].

Alcohol amine solutions have a high absorption capacity and rate for CO2 capture, however, there are some shortcomings such as high energy-consumption and low stability. To enhance CO2 capture performance of aqueous MEA, a functional ionic liquid ([NH2e-mim][BF4]) was introduced based on the advantages for CO2 capture. Absorbents were prepared with the molar concentration ratio of [NH2e-mim][BF4] to the 30 vol% aqueous MEA of 0 : 10, 1 : 9, 2 : 8, 3 : 7, 4 : 6 and 6 : 4. The density and the viscosity of the investigated absorbents were measured and the effects of the molar fraction of [NH2e-mim][BF4] (n I) and temperature on CO2 absorption performance were investigated. CO2 desorption performance of the solvent at different temperatures was discussed. The stability performance of the absorbent with n I of 2 : 8 (I/M2:8) was examined by five consecutive cyclic tests. The results showed that for pure CO2, the I/M2:8 displayed the highest absorption performance at 303 K under 1 bar: a comparable CO2 absorption capacity of the 30 vol% aqueous MEA and a higher CO2 absorption rate at the later absorption stage. Moreover, with the increase of temperature, CO2 absorption capacity and rate decreased, while CO2 desorption efficiency and rate increased. 393 K was chosen as the optimum desorption temperature with the desorption efficiency of 99.31%. The introducing of IL contributed to CO2 desorption performance of the absorbents significantly. The properties (CO2 absorption capacity, mass loss, density and viscosity) of the I/M2:8 during the cycles suggested that the IL-MEA mixture had an excellent stability performance.