Solubilities of sulfuryl fluoride in propylene carbonate, tributyl phosphate and N-methylpyrrolidone
Introduction
As the methyl bromide was phased out under the Montreal Protocol, sulfuryl fluoride (SO2F2) is used increasingly as a replacement to fumigate the timber, construction materials, soils, buildings, foods, etc.[1], [2], [3], [4], owing to its striking characteristics including zero ozone depletion, rapid penetration, and easy dispersal [5]. However, SO2F2 gas emitted from fumigation can intensify the greenhouse effect and cause health problems [6], [7], [8]. Therefore, it is increasingly important to find a reasonable way to effectively remove SO2F2 after fumigation.
Up to date, several methods have been proposed for the treatment of SO2F2 after fumigation, such as plasma, chemical absorption, and plasma coupled with chemical absorption [9], [10], [11]. However, there still exist some obvious disadvantages including complex process, secondary pollution and intensive energy consumption. Additionally, these methods are also inconsistent with the sustainable development because of wasting the valuable S and F resources. Thus, developing green, economical and reversible absorbent for SO2F2 is highly desirable.
Many physical solvents are now in commercial use, among which propylene carbonate (PC), N-methylpyrrolidone (NMP) and tributyl phosphate (TBP) were reported as absorbents for acid exhaust gases such as CO2, H2S and SO2 [12], [13], [14], [15]. Murrieta-Guevara et al. presented experimental data on the solubilities of CO2 and H2S in PC and NMP [16]. Chen et al. provided thermodynamic parameters of SO2 dissolution in TBP at 295–323 K [17]. Huang et al. compared the solubilities of SO2 in PC and NMP with those in other three solvents including sulfolane, ethylene glycol and n-methylimidazole [18]. Similar to acid gases, the central atom of SO2F2 molecule is lacking of electrons. Therefore, PC, TBP and NMP could be extended to remove SO2F2. However, there are no reports on SO2F2 removal by PC, TBP and NMP. Meanwhile, the data on SO2F2 solubility in physical solvents is lacked.
In this work, we used PC, TBP and NMP as the physical solvents for SO2F2 removal. Therefore, new solubility data of SO2F2 in PC, TBP and NMP were determined at temperatures ranging from (293.15 to 313.15) K and pressures ranging from (0 to 600) kPa. Henry’s law constants were obtained by experimental data regression. The thermodynamic properties including standard dissolution Gibbs free energy, dissolution enthalpy and dissolution entropy were further determined.
Section snippets
Chemicals
CO2. (124-38-9: carbon dioxide) was supplied by Jingong Special Gas Co., Ltd. (Hangzhou, China). SO2F2 (2699-79-8: sulfuryl fluoride) was supplied by Maoyu Co., Ltd. (Hangzhou, China). Propylene carbonate (108-32-7: 1,2-propanediol carbonate), Tributyl phosphate (126-73-8: n-butyl phosphate) and N-methylpyrrolidone (872-50-4: 1-Methyl-2-pyrrolidinone) were obtained from Aladdin Industrial Co., Ltd. (Shanghai, China). SO2F2 is almost insoluble in water [19]. Furthermore, experimental results
Solubilities
Solubility experiments were carried out with PC, TBP and NMP at the pressure of up to 600 kPa and temperatures ranging from (293.15 to 313.15) K. The solubility data of SO2F2 are listed in Table 4, Table 5, Table 6.
Moreover, the SO2F2 solubility profiles (expressed as mole fraction) in PC, TBP and NMP at various temperatures are shown in Fig. 3, Fig. 4, Fig. 5, respectively. It can be seen from Fig. 3, Fig. 4, Fig. 5 that SO2F2 solubility increased with increasing pressure and decreased with
Conclusion
In the present study, solubilities of SO2F2 in PC, TBP and NMP were measured at temperatures of (293.15–313.15) K and pressures of (0–600) kPa using an isochoric saturation method. Meanwhile, Henry’s law constants and thermodynamic properties were calculated based on the solubility data. The solubilities in the three solvents followed the order of TBP > PC > NMP. The dissolution enthalpies were negative at all conditions. Compared with water, PC, TBP and NMP showed potential application for SO2F
Acknowledgments
The financial support from the National Natural Science Foundation of China (NSFC) [Grant No. 51107118], the Science and Technology Plan of General Administration of Quality Supervision of the P.R.C. [Grant No. 201010256651.9], and the Excellent Postdoctoral Science Foundation of Zhejiang Province are gratefully acknowledged.
Author disclosure statement
No competing financial interest exists.
References (23)
- et al.
J. Supercrit. Fluids
(2004) - et al.
Int. J. Greenouse Gas Control
(2017) - et al.
Fluid Phase Equilib.
(1988) - et al.
J. Chem. Thermodyn.
(2016) - et al.
J. Chem. Thermodyn.
(2006) - et al.
J. Chem. Thermodyn.
(2009) - et al.
Pest Manage. Sci.
(2016) - et al.
Acta Hortic.
(2016) - et al.
J. Econ. Entomol.
(2016) - et al.
Pest Manage. Sci.
(2014)