Phase Behaviors of Aerosol-OT Analogue Fluorinated Surfactants in 1,1,1,2-Tetrafluoroethane and Supercritical CO₂

Abstract

A series of Aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulfosuccinate) analogue fluorinated surfactants, i.e., the sodium salt of bis(2,2,3,3,3-pentafluoropropyl) 2-sulfosuccinate (di-CF2), the sodium salt of bis(2,2,3,4,4,4-hexafluorobutyl)2-sulfosuccinate (di-HCF3), the sodium salt of bis(3,3,4,4,5,5,6,6,6-nonafluorohexyl)2-sulfosuccinate (di-HCF4), and the sodium salt of bis(2,2,3,3-tetrafluoropropyl) 2-sulfosuccinate (di-HCF2), were synthesized and characterized by 1 H NMR, 13 C NMR, 19 F NMR, melting point, and elemental analysis. The pressure-temperature (P-T) phase diagrams for water-in-CO 2 (W/CO 2 ) and water-in-1,1,1,2-tetrafluoroethane (W/HFC-134a) microemulsions stabilized by the surfactants were determined. In this work, the phase behaviors for different surfactants are obtained in supercritical CO 2 (scCO 2 ) and 1,1,1,2-tetrafluoroethane (HFC-134a) as a function of temperature, pressure, and water-to-surfactant ratio. At a fixed temperature, the cloud-point pressures increased with the increase of water-to-surfactant ratio (W o ) and the concentration of the surfactants. The cloud-point pressures for the surfactants in HFC-134a decrease with an increase in temperature at a fixed W o and a surfactant concentration, which is in opposition to the results obtained in scCO 2 .

Amphiphile self-assemblies in supercritical CO2 and ionic liquids

“…Fluorosurfactants have been designed for compatibility with scCO 2 . [16][17][18][19][20] The uorinated chains represent low cohesive energy density groups, thereby promoting low solubility parameters and low polarizability. For example, Sawada 18 prepared reverse micelles of peruoro-2,5,8,11-tetramethyl-3,6,9,12-tetraoxapentadecanoic acid ammonium salt in CO 2 , which had high potential to solubilize conventional acid dyes and to dye wool fabrics.…”

“…For example, Sawada 18 prepared reverse micelles of peruoro-2,5,8,11-tetramethyl-3,6,9,12-tetraoxapentadecanoic acid ammonium salt in CO 2 , which had high potential to solubilize conventional acid dyes and to dye wool fabrics. Liu and coworkers 19 synthesized a series of uorinated AOT analogue surfactants for reverse micelle formation in scCO 2 . Berkowitz et al 16 and Senapati et al 20 used the molecular dynamics simulation to study the formation of reverse micelles of uorosurfactants in scCO 2 .…”

Selective Dehydrofluorination of 1,1,1,3,3‐Pentafluoropropane to Synthesize Tetrafluoropropylene and Trifluoropropyne over the ZnO/Cr2O3 Catalysts

“…Hydrofluorolefins (HFOs), such as the typical 2,3,3,3‐tetrafluoropropylene (CH 2 =CFCF 3 ), [1] are considered as an ideal alternative refrigerant for 1,1,1,2‐tetrafluoroethane (CF 3 CH 2 F) due to their low life cycle climate performance (LCCP), zero ozone depletion potential and extremely low GWP [2,3] . 2,3,3,3‐tetrafluoropropylene (CH 2 =CFCF 3 , HFO‐1234yf) has excellent environment parameters (ODP=0, GWP=4) and short atmospheric life time.…”

“…Hydrofluorolefins (HFOs), such as the typical 2,3,3,3-tetrafluoropropylene (CH 2 = CFCF 3 ), [1] are considered as an ideal alternative refrigerant for 1,1,1,2-tetrafluoroethane (CF 3 CH 2 F) due to their low life cycle climate performance (LCCP), zero ozone depletion potential and extremely low GWP. [2,3] 2,3,3,3-tetrafluoropropylene (CH 2 = CFCF 3 , HFO-1234yf) has excellent environment parameters (ODP = 0, GWP = 4) and short atmospheric life time. Moreover, its molecular weight, lower boiling point (À 28.3°C), density and critical point both are all similar to those of CF 3 CH 2 F. Thus, 2,3,3,3-tetrafluoropropylene (CH 2 C = CFCF 3 ) is regarded as a "direct and economic substitution" for 1,1,1,2tetrafluorethane (CF 3 CH 2 F) and could be a promising candidate for the four-generation of refrigerants.…”

A Novel Ni/NiF2‐AlF3 Catalyst with Mild‐Strength Lewis Acid Sites for Dehydrofluorination of 1, 1, 1, 2‐Tetrafluoroethane to Synthesize Trifluoroethylene

“…1, 1, 1, 2‐tetrafluoroethane (HFC‐134a) once regarded as the ideal substitute of CFCs (ODS) has been widely used in the fields of refrigeration, but its high global warming potentials (GWP) results in constrained reduction of production according to the European Union's new F‐gas ,. Therefore, it is urgent and necessary to transformation of excess HFC‐134a to the high value‐added HFOs products such as trifluoroethylene.…”