Yongtao Zhang,Zaizheng Jiang,Zhihe Xin,Qingqi Dong,Fei Wang
Traditional coal burning emits a large amount of pollutants, including sulfur dioxide (SO2), nitrogen oxides, and carbon dioxide (CO2), severely contaminating the environment and exacerbating global warming. In contrast, integrated gasification combined cycle (IGCC) technology, with highly efficient and clean characteristics, significantly reduces pollutant emissions and has a positive impact on environmental protection. It is a simple and effective method to obtain hydrogen (H2) by purifying IGCC fuel gas with the main components of H2 and CO2. Thermodynamic promoter tetra-n-butyl ammonium bromide (TBAB) is widely used in gas separation of IGCC fuel gas by the hydrate method. In this work, polystyrene nanoparticles grafted by –SO3– groups (−SO3–@PSNS) and grafted by –SO3– groups and Ag particles (Ag&–SO3–@PSNS) are used together with TBAB, respectively, to promote the formation of hydrate. The gas separation effect and growth morphology are studied. The experimental results demonstrate that the incorporation of nanopolymer can significantly enhance the separation efficiency (SFr) of a mixture of H2 and CO2. Notably, compared to the reaction solution without nanopolymer, 2 mmol/L –SO3–@PSNS exhibits the most pronounced effect on gas separation, resulting in an impressive gas consumption of 0.755 ± 0.323 mmol/L and a remarkable increase in the separation factor (SF) by 106%. After loading silver nanoparticles, the promoting effect of Ag&–SO3–@PSNS is further strengthened. Under Ag&–SO3–@PSNS-20%, the gas consumption reaches the maximum of 0.775 ± 0.003. Under Ag&–SO3–@PSNS-30%, the SF rises from 32.79 ± 6.27 to 37.92 ± 7.19, indicating an impressive increment of 15.80%. The visualized droplet experiment shows that Ag&–SO3–@PSNS significantly promotes the nucleation of hydrate and the growth rate of hydrate.
The cycloaddition of CO 2 with epoxides is regarded as one of the most efficient methods to synthesize cyclic carbonate because of the 100% atom utilization. Therefore, it is necessary to develop efficient catalysts for the synthesis of cyclic carbonates. Hydrogen bond donors (HBDs) have been widely investigated due to their ability to activate epoxides and dramatically enhance the cycloaddition process. In this study, boric acid as a cheap HBD combined with TBAB as an effective co-catalysis system for cyclic carbonates synthesis through cycloaddition of CO 2 to epoxidized soybean biodiesel. 92.3% yield of cyclic carbonates product was achieved at 100 °C with 10 bar pressure of CO 2 for 10 h under solvent-free conditions. To further evaluate the catalyst activity, preliminary kinetic investigations were conducted and the results showed that activation energies (Ea) of cyclic carbonate formation were different (58.5 kJ/mol for TBAB, 44.22 kJ/mol for TBAB-boric acid). The results show that boric acid as HBD can efficiently improve the yield of cyclic carbonates. Thus, the developed catalyst system provides an efficient and economical approach for the industrial production of bio-based cyclic carbonates.