Solubilities of dialkylhydrogen phosphonates in supercritical carbon dioxide and their correlation using semi-empirical equations

ABSTRACT

The solubilities of dibutylhydrogen phosphonate (DBHP) and dihexylhydrogen phosphonate (DHHP) in supercritical carbon dioxide were determined at 313–333 K and 10–20 MPa. The mole fraction solubility of DBHP and DHHP are in the range of 3.4 × 10⁻⁴ to 66.4 × 10⁻⁴ and 4.5 × 10⁻⁴ to 806.6 × 10^−4, respectively. The solubility data are self-consistent with Mendez–Teja model. The experimental solubilities were correlated using Chrastil, Hezave–Lashkarbolooki and three models based on activity coefficient models. Hezave–Lashkarbolooki model resulted in better solubility predictions for DBHP with an AARD of 5%. Chrastil and van Laar activity coefficient based model correlated the solubility of DHHP with a lowest AARD of 11%.

KEYWORDS:

• Solubility
• supercritical carbon dioxide
• phosphonates
• semi-empirical equations

Supplementary material

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