Xuezhi Dai,Jinhang Li,Yuzhi Ma,Xianqiu Lan,Hang Song
The application of guanidinium-based ionic liquids (ILs) is a newly emerging area in the fields of extraction desulfurization. Herein, four novel pentaalkylguanidinium-based magnetic room temperature ionic liquids (MRTILs) [C n TMG][FeCl 3 Br] (n = 2, 4, 6, 8) were synthesized and characterized by FT-IR, Raman and HRMS (ESI) spectra. The physical properties including thermal stability, density, viscosity, conductivity and magnetic properties were determined and revealed that the MRTILs were liquids at room temperature and have good thermal stability ( T d > 250 °C), high magnetic susceptibility (>3.8 × 10 5 emu·g −1 ) and low viscosities (<160 mPa·s, 25 °C). Moreover, the mutual solubility behaviors for binary systems of MRTILs with representative non-polar organic solvents (cyclohexane, n -octane) were measured at temperatures from 5 to 65 °C, showed a low miscibility between MRTILs and organic solvents and a typical lower critical solution temperature (LCST) phenomenon. The results are supposed to provide useful information for further application as “green” liquid desulfurization extractants or others potential dispersive liquid-liquid microextraction applications.
In this study, mineral oil–water fluid miscibility without and with the addition of surfactant-decorated nanoparticles is experimentally and theoretically studied. First, three series of interfacial tension (IFT) tests are conducted using a spinning drop tensiometer (SDT) with the addition of hexadecyltrimethylammonium bromide (CTAB) surfactant-decorated SiO2 nanoparticles at different concentrations. Second, a new comprehensive thermodynamic model is developed to describe the fluid miscibility without and with the addition of these surfactant-decorated nanoparticles, which is also applied theoretically to reveal how the surfactant-decorated nanoparticles contribute to the thermodynamic miscibility state. The thermodynamic model developed is proven to be accurate and physically meaningful by comparing its calculated free energy of mixing with the experimental results and examples from the literature. A series of optimum conditions for the improvement of fluid miscibility by the addition of such surfactant-decorated nanoparticles are determined: a lower temperature, a higher pressure, more wetting conditions, a smaller nanoparticle radius (rNP < 40 nm), a larger surfactant concentration, and a nanoparticle concentration in the range of 0.5–0.6 wt.%. It should be noted that a higher nanoparticle concentration is required with the addition of more CTAB surfactants in order to reach the most miscible state. Moreover, the effect of surfactant concentration on the miscibility development is found to be independent of the nanoparticle radius, whereas the optimum nanoparticle concentration is reduced with increasing particle size.
To realize the goal of energy-saving SO 2 capture process, a series of novel SO 2 phase change absorbents (SPCAs) composed of 2-[2-(Dimethylamino)ethoxy]ethanol (DMEE)/long-chain alcohols/hexadecane were investigated in this work. The long-chain alcohols had dual effects in SPCAs, i.e., increasing mutual solubility of DMEE and hexadecane , and decreasing viscosity of the absorption products. Three alcohols, including butyl, hexyl and decyl alcohol, could turn the immiscible mixture of DMEE and hexadecane into homogeneous solution to form SPCAs. The decyl alcohol in absorption product could efficiently decrease the viscosity from 2338.1 mPa·s to 362.02 mPa·s, which is beneficial to gas-liquid mass transfer and fluid transport process. Meanwhile, the NMR and FTIR results indicated that DMEE chemically absorbed SO 2 , forming a zwitterionic alkyl sulfite compound. The long-chain alcohol formed hydrogen bonds with the alkyl sulfite and it didn't change the reaction mechanism. Noteworthy, the SPCA can absorb 0.823 mol SO 2 /mol DMEE (0.396 g SO 2 /g DMEE) at 293.15 K and 0.002 atm, which was exceptionally attractive. Furthermore, the absorbed SO 2 could be partly released under vacuum at 110 °C and the net cycle capacity can reach 73% ~ 74% of the maximum capacity, which indicated the SPCAs have a promising application prospect.
危险品化学品经营许可证（带存储）