Measurement and Thermodynamic Models for Ternary Liquid–Liquid Equilibrium Systems {Water + Polyoxymethylene Dimethyl Ethers +4-Methyl-2-pentanol} at Different Temperatures

Abstract

Polyoxymethylene dimethyl ethers (DMM n ) have attracted particular attention in industry as excellent oxygenated fuel additives. This study aims to reveal the liquid−liquid equilibrium (LLE) values regarding ternary mixtures {water + methylal (DMM 1 ) + 4-methyl-2-pentanol (MIBC)}, {water + DMM 2 + MIBC}, {water + DMM 3 + MIBC}, and {water + DMM 4 + MIBC} at 298.2 and 308.2 K under 101.3 kPa. Distribution factor and selectivity were utilized to assess the extracting capabilities of the selected extractant. The well known Hand equation and Othmer− Tobias equation were utilized to test the consistency of the LLE values. In addition, the experimental results were correlated by the UNIQUAC and NRTL thermodynamic models with all of the root-mean-square deviation values less than 0.0127,which indicated that both models agree well with the experimental tieline data.

Experimental and Correlated Liquid–Liquid Equilibrium Data for Ternary Systems (Water + Poly(oxymethylene) Dimethyl Ethers + Toluene) at T = 293.15 and 303.15 K and p = 101.3 kPa

“…As shown in Table , the distribution coefficients and separation factor values for the studied systems are all greater than 1, which indicates the extraction capability of toluene to extract PODE n from aqueous phase and toluene as an ideal solvent. As shown in Figure , the distribution coefficient for the ternary LLE equilibrium systems are not constant, which is consistent with the reported research. ,, The distribution coefficient at 303.15 K is higher than at 293.15 K, indicating that the extraction capacity of the extractant increases with increasing temperature. ,, As can be seen in Figure , the separation factors decreased with the increase of the mass fraction of PODE n in aqueous phase and hence as a result of the mass fraction of water in organic phase was also increased . Meanwhile, the separation factor of four studied systems decreased with the increasing temperature and the influence of temperature on the separation factor was slight. ,− As the ratio of feed (water + PODE n ) to toluene increases, the separation capacity of the solvent decreases.…”

“…21−25 Due to low vapor pressure, density, viscosity, and capability to form two phases, 26,27 toluene can be used as an appropriate solvent for extracting the PODE n from aqueous solution. Shi et al 28 20 studied the LLE in binary and ternary mixtures containing water, formaldehyde, methanol, and PODE n in the temperature range of 280−240 K. Wang et al 29 investigated the LLE for ternary systems of water + PODE n + 4-methyl-2-pentanol at 298.2 and 308.2 K. By comparing their experimental data of distribution coefficient (D) and separation factor (S), it can be found that the extraction ability of aromatic extractants (pxylene and toluene, etc.) is better than 4-methyl-2-pentanol (MIBC), since the excellent hydrophobicity of aromatic hydrocarbons is better than MIBC.…”

Liquid–Liquid Equilibria for Ternary Systems n-Hexane + 1-Hexene + Furfural (or N,N-Dimethylformamide) at 298.2, 308.2, and 318.2 K

“…The partition coefficient, D , and the separation factor, S , are used to assess the separation efficiency about furfural and DMF, and the formula for calculating D and S : where w 1 II and w 1 I are the concentrations of n -hexane in the solvent phase and n -hexane phase, respectively. w 2 II and w 2 I indicate the mass fractions of 1-hexene in the two phases, respectively.…”

Measurement and Thermodynamic Modeling of Ternary (Liquid + Liquid) Equilibrium for Extraction of Phenols from Alkane with Furfural

“…The operations were done in a specific laboratory setup, and the details are dispensed below. , First, the mixture of a certain concentration is added to a 50 mL impenetrable glass equilibrium cell. After the stationary phase, equilibrated kettle and circulating water were vigorously stirred for 4 h, and the composite system was maintained for at least 6 h to achieve system stability.…”