Catalytic utilization of CO2 addition into chemicals has potential as a strategy for removing CO2 from the atmosphere. In this context the additive‐free catalytic conversion of CO2 into cyclic carbonates in the absence of metal and solvents under mild conditions is a major challenge. Herein, a series of hydroxylamino‐tethered polymeric ionic liquids bearing adjustable alkyl length substitutes are constructed from copolymerization of divinyl benzene and vicinal hydroxyl and amino base monomeric ionic liquids synthesized from 1‐glycidyl‐3‐vinylimidazolium bromide with alkyl amine. The polymeric ionic liquids are used in CO2‐epoxide cycloaddition reactions to prepare cyclic carbonates and demonstrate high efficiency and stable reusability without a co‐catalyst under atmospheric pressure and under solvent‐free conditions. The introduction of alkyl groups on an ionic polymer host backbone can accelerate the reaction process. A preliminary kinetic study is performed using [PDVB‐HAVIM‐C18]Br and the activation energy is calculated as 53.2 kJ mol−1. A hydrogen bonding and Br– ion synergistic catalytic mechanism is proposed to account for the excellent catalytic activity of the synthesized ionic polymer. 相似文献
The Sanjiang Plain, the largest inland freshwater marshland in China, was extensive reclaimed into agricultural land. To assess the effects of marshland reclamation on Collembola, we investigated collembolan communities in a chronosequence of soybean plantations (2, 15, and 25 years) in Sanjiang marshland, Northeastern China. We found that: 1) the densities and species richness of Collembola were promoted after short-term (2 years) cultivation of soybean, but significantly decreased after medium-term cultivation (15 years); 2) the densities of epi-edaphic Collembola increased while the densities of hemi-edaphic Collembola decreased as the elongation of soybean cultivation; 3) compared with S0, two species of Collembola appeared while five species disappeared in S25. The changes of plant communities and the soil traits were supposed to be the key factors affecting the composition of soil Collembola. We thus suggest that original marshland should be saved for preserving high diversity and densities of Collembola in the Sanjiang Plain.