Liquid−Liquid Equilibrium of the Water + Citric Acid + Short Chain Alcohol + Tricaprylin System at 298.15 K

Abstract

In the past few years, new processes for citric acid recovery have been studied. Among these processes, liquid-liquid extraction has had special attention. The extraction process is attractive due to the fact that, if a good solvent is used, it presents high selectivity and efficiency, it does not affect the thermal stability of products, and it requires low energy consumption. In this work, experimental data for the liquid-liquid equilibria of water-citric acid-solvent systems were obtained. The following solvents were tested: 2-butanol, 1-butanol, and mixed solvents containing those alcohols and tricaprylin. The parameters for the NRTL and UNIQUAC models were obtained by fitting the thermodynamic models to the experimental data.

Phase stability analysis of liquid-liquid equilibrium with stochastic methods

“…In order to elucidate these results, the ternary experimental diagram for this system is presented in Figure 5. The experimental data were obtained from the literature (Lintomen et al, 2001), and as one can see, the two feed points (a) and (b) lie in a homogeneous region, which is in complete agreement with the results found in this work. Case 5: acetonitrile (1) + benzene (2) + n-heptane (3) system Table 5 contains the results of phase stability analysis for this ternary system at 45ºC and different overall compositions.…”

“…The binary parameters of the NRTL model were taken from Gecegormez and Demirel (2005), which were presented by Lintomen et al (2001). One can see in Table 1 that, for this system, solutions obtained in this work are in perfect agreement with the roots found by Gecegormez and Demirel (2005), which used an interval analysis algorithm.…”

“…The LLE binary parameters of the NRTL model for this system were used as presented by Gecegormez and Demirel (2005), originally reported by Lintomen et al (2001). Table 4 contains the results of phase stability analysis for this ternary system at 25ºC and different overall compositions.…”

Phase stability analysis using interval Newton method with NRTL model

“…The binary parameters of polar-polar mixture water(1)-citric acid(2) are τ 12 = 0.9889317, τ 21 = 13.7521382, G 12 = 0.6887706 and G 21 = 5.6008823 × 10 −3 [17]. As seen in Table 5, the values of D at the stationary points are positive and the feeds are stable.…”

“…The binary parameters of polar-polar mixture citric acid(1)-1-butanol(2) are τ 12 = 2.5479457 × 10 −2 , τ 21 = 11.2949857, G 12 = 0.9948420 and G 21 = 0.1010207 [17]. As Table 6 …”