524
J Chem. Eng Data 1988, 33, 524-527
Effect of Sodium Chloride on the Water-Phosphoric Acid-I-Hexanol-Cyclohexanone Liquid-Liquid Equilibria at 25 C Josh M. Marco," Mafia I. Galin, and Josi Costa Departamento de Ingenieda Qsmica, Universidad de Barcelona, Mart2 i Franqds, 7, 08028 Barcelona, Spain
Llquld-iiquld equiilbria, mutual solublky, and tie-line data have been studled at 25 O C and atmospheric pressure for the quaternary system water-phosphoric acld-1-hexanoi-cyclohexanone In the presence of sodlum chloride at saturation with respect to both conlugated phases. The salt effect increases the distribution coefficient and selectivlty for phosphoric acld in 1-hexanoi and cyclohexanone and for their mixtures. Quantitative results Indicate the salting-out effect due to sodium chloride in aqueous solutlons, both for phosphoric acid and for the solvents.
Table 11. Solubility and Tie-Line Data on a Salt-Free Basis (weight percent) for Water (W)-Phosphoric Acid (P)-1-Hexanol (H)-Cyclohexanone (K) at 25 OC (Ratio of Solvents 4/1) Initial Mixture xw 50.61 44.28 40.91 37.20 33.65
XW
I n the purification of wet process phosphoric acid by liquidliquid extraction, the salt effect has a remarkable importance due to the presence of saline impurities, which are present in great quantity if the attack of phosphate rock is carried out with hydrochloric or nitric acid. There is no doubt that the impurities modify the equilibrium of extraction of water-phosphoric acidsolvents systems. The goal of most studies, mainly patents, is to remove impurities in order to obtain a good qualii phosphoric acid. Information concerning equilibrium data in phosphoric acid extraction systems with salt effects is rather scarce ( 7 ). This paper reports the quantitative study, at 25 OC and atmospheric pressure, of the effect of sodium chloride, at saturation in the two conjugated phases, on the quaternary system water-phosphoric acid- 1-hexanol-cyclohexanone. Equilibrium data for the system without the salt effect were presented in a previous paper (2). The salt effect in the binary water-solvent systems, where the solvents are alcohols and ketones (3-6),has been explained in terms of "salting out", that is, the solubility in water
4.50 6.78 8.78 10.23 11.54 12.48 12.95 14.79 14.50 15.21
x w
49.77 46.81 43.75 40.31 37.22
XP 0.00 7.78 15.29 22.96 30.37
xw
xw
XP
Xn
33.98 30.55 27.10 23.81 18.87
39.93 46.40 54.48 62.41 74.13
26.09 23.05 18.42 13.78 7.00
Solubility Curve and Tie-Line Data organic phase aqueous phase
Xw
XP
Xn
Xs
Xw
XP
XH
XS
3.45 6.17 6.68 7.61 8.52 9.71 10.80 12.00 11.86 13.31
0.00 3.30 7.38 12.04 17.13 23.92 29.82 37.22 45.09 57.71
96.55 90.53 85.94 80.35 74.35 66.37 59.38 50.78 43.05 28.98
0.04 0.88 1.64 2.33 2.84 3.38 3.44 3.45 3.24 2.86
99.51 87.34 76.92 67.54 59.09 49.36 42.81 35.60 29.16 20.70
0.00 12.19 22.93 32.27 40.70 50.46 56.97 64.25 70.67 79.10
0.49 0.47 0.15 0.19 0.21 0.18 0.22 0.15 0.17 0.20
26.44 21.42 17.08 13.21 9.78 6.67 4.64 3.21 2.25 1.63
XP 0.00 6.87 12.43 19.09 25.10 30.81 36.50 40.73 45.08 49.03
XP
x,
44.95 51.06 54.93 59.12 63.00
23.52 19.95 17.71 15.17 12.98
XW
XK
XS
XW
76.39 68.90 63.40 57.53 52.02 47.02 42.14 37.03 33.97 30.34
19.11 17.45 15.39 13.15 11.34 9.69 8.41 7.45 6.45 5.42
0.04 1.33 2.07 2.66 2.98 3.13 3.10 3.07 2.96 2.85
99.42 79.49 69.24 58.48 49.33 44.39 38.71 35.21 31.77 28.86
XP Xn Xu x s 0.00 0.58 0.00 26.45 20.01 0.50 0.00 18.17 30.36 40.82 49.96 54.76 60.26 63.75 66.82 69.73
0.22 0.16 0.16 0.17 0.22 0.22 0.33 0.36
0.18 13.70 0.54 9.48 0.55 6.81 0.68 5.00 0.81 3.75 0.81 3.11 1.08 2.61 1.05 2.29
Initial Mixture
xw 50.32 47.10 44.25 39.56 37.63
XP 0.00 6.95 13.70 25.02 29.41
xhl
xw
XP
xhl
49.68 45.95 42.05 35.42 32.96
34.76 32.78 30.93 29.56 28.16
35.84 40.90 45.08 48.51 51.65
29.40 26.32 23.99 21.93 20.19
Solubility Curve and Tie-Line Data organic phase aqueous phase xW
50.23 45.41 40.96 36.73 32.41
xw 31.52 28.99 27.36 25.71 24.02
Table 111. Solubility and Tie-Line Data on a Salt-Free Basis (weight percent) for Water (W)-Phosphoric Acid (P)-1-Hexanol (H)-Cyclohexanone (K) at 25 "C (Ratio of Solvents 3/2)
Table I. Solubility and Tie-Line Data on a Salt-Free Basis (weight percent) for Water (W)-Phosphoric Acid (P)-1-Hexanol (H) at 25 "C Initial Mixture
13.66 22.17 31.08 39.50
XM 49.39 42.06 36.92 31.72 26.85
Solubility Curve and Tie-Line Data organic phase - - aqueous phase -
Introductlon
XP 0.00
4.66 5.57 7.17 9.61 11.28 12.17 15.64 15.82 16.74 17.24
xP
0.00 2.85 7.09 15.85 19.12 24.59 29.87 34.26 38.13 40.89
XH
57.26 55.56 52.52 47.73 42.94 40.30 34.35 31.81 28.90 27.36
XK
38.08 36.02 33.22 28.81 26.66 22.94 20.14 18.11 16.23 14.51
xS
0.03 0.65 1.26 2.19 2.43 2.77 2.93 2.99 2.96 2.91
XW 99.25 88.04 79.33 65.00 60.73 53.40 47.62 43.70 40.27 37.34
XP XH XU XS 0.00 0.24 0.51 26.40 11.17 20.03 33.88 38.05 45.14 50.71 54.58 57.73 60.43
0.35 0.16 0.13 0.12 0.14 0.16 0.17 0.22 0.26
0.44 0.48 0.99 1.10 1.32 1.51 1.55 1.78 1.97
23.47 18.26 12.07 10.39 7.80 6.04 4.87 4.10 3.46
of the nonelectrolyte decreases in the presence of salt. Salting out of solute was also observed for pyridine ( 7 ) ,acetic acid ( 8 , 9),benzoic acid (70), hydrochloric acid ( 7 7 ) , and phosphoric acid ( 7 ) in ternary systems. A review of the salt effect for polar molecules in aqueous electrolyte solutions was performed by Treiner (72). The influence of sodium chloride upon the system studied in the present work is shown through distribution and selectivity curves, drawn for the systems with salt effect and for the systems in absence of it.
0021-9568/88/1733-0524$01.50/00 1988 American Chemical Society
Journal of Chemical and Engineering Data, Vol. 33,
Table VI. Solubility and Tie-Line Data on a Salt-Free Basis (weight percent) for Water (W)-Phosphoric Acid (P)-Cyclohexanone (K) at 25 "C
Table IV. Solubility and Tie-Line Data on a Salt-Free Basis (weight percent) for Water (W)-Phosphoric Acid (P)-1-Hexanol (H)-Cyclohexanone (K) at 25 "C (Ratio of Solvents 2/3)
Initial Mixture
Initial Mixture
xw
XP
XM
xw
XP
XM
50.18 47.62 45.35 42.60 40.27
0.00 5.95 11.27 17.42 22.88
49.82 46.43 43.38 39.98 36.85
38.57 36.49 34.74 33.50 32.12
27.08 32.33 35.39 37.89 42.18
34.35 31.18 29.87 28.61 25.70
Solubility Curve and Tie-Line Data organic phase - - aqueous phase XP xu x u x s XW XP Xn XK x s XW 4.01 0.00 38.40 57.59 0.01 99.10 0.00 0.20 0.70 26.40 4.92 6.58 8.28 10.00 12.24 14.05 15.15 17.86 18.35
2.02 5.26 9.96 14.33 18.20 23.52 26.70 30.59 34.41
37.78 36.02 33.41 30.86 28.82 26.51 24.94 22.56 20.84
55.28 52.14 48.35 44.81 40.74 35.92 33.21 28.99 26.40
0.45 0.88 1.37 1.82 2.17 2.56 2.73 2.94 3.00
89.20 81.89 73.73 67.86 62.75 56.97 53.60 49.55 46.48
9.74 16.99 24.64 30.51 35.33 40.85 44.03 47.66 50.57
0.22 0.15 0.31 0.11 0.13 0.13 0.15 0.18 0.20
0.84 0.97 1.32 1.52 1.79 2.05 2.22 2.61 2.75
22.77 19.58 16.02 13.37 11.31 8.91 7.32 6.54 5.56
Table V. Solubility and Tie-Line Data on a Salt-Free Basis (weight percent) for Water (W)-Phosphoric Acid (P)-1-Hexanol (H)-Cyclohexanone (K) at 25 O C (Ratio of Solvents 1/4) Initial Mixture
xw
XP
xhl
50.35 47.60 45.09 43.32 41.94
0.00 5.71 11.68 15.92 19.10
49.65 46.69 43.23 40.76 38.96
-
xw
XP
xhl
40.27 38.78 37.89 36.90 36.00 33.80
23.11 26.25 28.64 31.29 33.05 38.11
36.62 34.97 33.47 31.81 30.95 28.09
Solubility Curve and Tie-Line Data aqueous phase organic phase
XW
XP
XH
3.80 6.74 6.62 7.66 9.23 10.80 13.41 14.94 16.35 17.44 22.26
0.00 1.34 4.73 8.04 11.30 15.25 18.68 21.15 24.04 26.10 32.50
19.23 18.77 18.32 17.27 16.51 15.53 14.40 13.72 12.91 12.39 10.02
XK
XS
x w
XP
xu
Xu
No. 4, 1988 525
xW
XP
XK
XW
50.37 48.31 46.75 45.03 43.63
0.00 3.72 8.00 11.74 15.32
49.63 47.97 45.25 43.23 41.05
41.71 40.25 38.57 37.01 35.76
XK
xP
19.60 22.96 27.39 30.20 33.69
solubility Curve and Tie-Line Data organic phase aqueous phase x w
XP
xu
xs
x w
XP
xu
Xf
2.87 3.09 3.71 4.99 7.14 9.73 12.04 16.17 19.20 24.90
0.00 0.23 0.96 2.48 5.46 10.72 14.84 21.15 24.99 30.63
97.13 96.68 95.33 92.53 87.40 79.55 73.12 62.68 55.81 44.47
