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Some quantitative remarks on extraction Equilibria. II
ANALY'TICACHIMICAACTA
VOL..21 (rgsg)
SOME
397
QWANTITATSVE REMARKS ON EQUILIBRIA. fI
EXTRACTION
M. OOSTING AnaIyticuC Researclr Insiitutc
In a pqevious as a chelatc :
paper1 we derived
T.N.O.,
Rijswijk
two expressions
(TJje Neilrevlaqrds)
for the estraction
of a metal ion
and
+nfn res . a
f‘%sR -
MRno sst.(R-)”
n
+ f . LMlbn
(W
WC shall now prove the validity of these expressions and show that they correctly predict the behaviour of metal ions in extraction procedures. Calcwlation
of R-
It has proved very helpful to work out the value of R- in the foim.of a table. From equation A we see that -the value of R- depends on the choice of the system and on the conditions used (B, f, I-X+). W&t K.&e E& Initially, only the system oxine - water - chloroform will be considered. Of the conditions, f is taken as 5, hence only extractions in which the volume of the chloroform phase is one-fifth of that of the aqueous phase will be dealt with. The relationship between B and R- is linear; accordingly, the R--table is calculated for a value B--I, and the value of R- found in the table need only be multiplied by the actual value of B. Thus the tabular values of R- represent the concentration of oxinate anions in the aqueous phase of a system which contains I me; mole of oxine per ml of aqueous phase, and which is in equilibrium with a quantity of chloroform equal to one fifth of the volume of the aqueous phase. The H-+-concentration is considered as the auto-variant. The values of Ku), are required. The value of Km is well-known ; the figure 1.0'10-14 K& and E,, K&v willbe used. Many data have been published regarding the dissociation constants_ of oxine. Fox8 found the value K”,, = 3.68 - IO -11 from hydrolysis measurements. STONE AND FRIEDMAN~, using.the solubility method of DAVIDSON~, found values between References
p. 406
M. OOSTING
398
VOL. 21 (1959)
P~IILIIJS AND MERRITG, using _thc optical method of 4.20. 10-1~ and 4.28 * IO-*‘. STENSTHOM ANI) CIOLDSMITI?~,found pKiR = g.70 (K”,, = x,&j+’ IO-*“) and pKLlt = 9.08 (I<“,, = 8.32 - IO -1”). From potentiometric titrations BARREL AKD PARIS’ found PI<;,,, = 9.85 and p”K:,,, “= 5.05. This I’Ktrn” is not the same as “our” KkR, but is related to it by the simple equation: Kb (our definition) = Ktu/“KLIL”, and accord= 8.95. BOCQUET AND P/%&J, comparing potentiometric and optical ingly PI& methods, found pK& = 9.82 and P~‘I<:~~” = 5.10. In good agreement are also the values pKt%,, = 9.82 and pK&, = 5.09 found by LACROIX 0. .U.MI_ANL)AND PUCIIELT~O found pK&, = g.Go and p”K&” = 5.33, by extracting oxine with benzene at various pr,r-values. These values are based on the determination of the partition coefficient and therefore are as inaccurate as the bromatometrjc determination of II pg of oxine in 50 ml of aqueous solution. The values KT,,, = 1.3 IO-“J and Z”:X,, = 1.2 * IO-“, will be used here; thcsc are based on earlier work’-0. For the partition coefficient of oxinc between water and chloroform values of 7200 and 350 11 have been given. These values disagree, hence the detct-mination of the value of E_ was repeated. A quantity of oxinc was weighed exactly and shaken for 20 h with chloroform and an aqueous buffer solution. The volumes of both phases were clctermincrl. In the aqueous phase the prl was measured and the sum of undissociatcd oxinc and o_xinatc ion was determined by bromatometric titration. With the known value of KzIC, the concentration of undissociated oxine was calculated. The term lCLrL was neglected, which is allowed at the prr valuer; considered. The quantity of oxine in the chloroform phase was obtained from the difference between the amount of oxinc taken and the amount of oxinc + oxinate found in the aqueous phase. In the first experiment, 346.2 mg of oxine (2.387 mg moles) were shaken in a glassstopmred measuring cylinder with aqueous buffer and chloroform and the layers were’&llowcd to separate; the volumes of aqueous and chloroform phases were 33.5 and 25 ml rcspectivcly. The ~1.1of the aqueous phase, measurecl with a glass electrode, was 8.71, thus H+ = 2 ’ 10’~. To 20 ml of the aqueous phase 3.18 ml of 0.1004 N bromate solution, 250 mg of potassium bromide and 5 ml of G N HCl were added. ‘The excess of bromate was backtitrated with 2.81 ml of o.xooo N thiosulphate. The aqueous phase thus contained 0.644 mg equivs. or o.orGr mg moles of oxine + oxinrrte. l
ox&L
=
-I-
1-10x -
O.OlGX
.
*
.
.
.
.
.
.
.
.
.
.
.
.
.
(I)
H+ * Ox= 1.3*10-l”, HOX
3.10-O* ox- = 1.3’10~10l-lox or
Rejcrerrcesp. 406
ox- = 0.065 HOx
. . . . . .
. . . . . . .
. .
(2)
2.9 . 10-26 * 10-26
- 1045
7.3 1.8
4.2 . 10-2~ 1.2 . 10-94 2.9 * 10-34
I.7 * 10-13
2.7 - 10-13 4.3 - x0-13
6.5 . 10-13
1.l * IO-la
1.7 . IO-ls
I.1
I.4
I-5
1.6
I-7
3.4 - 10-30 1.2. IO-=
5.1 * 10-a 1.7 5.8
1.6 - 10-25
2.3 - 10-a 5.3,10-m I.2 * 10-13 2.5
6.4 - 10-19 1.4 - 10-l*
3.2 . 10-18
1.5 . 10-10
2.3 - 10-10
3.4 * IO_‘0
5.0 - 10-13
8.0 - 10-10
I.2 . 10-3
1.8 - 10-3
2.6
2-7
2.8
2.9
3.0
j.0. 9.6 1.7 - 10-1~
3.2 - 10-16
7.x - 10-g
9.8.
1.3. 10-3
1.8 - 10-3
3.5
3.7
3.8
3.9
3.6 10-3
2.5
5.0 * 10-B
3.4
- 10-1~
10-l’
’ 10-n
6.3 - 10-18 1.3 - IO-If
3-3
2.5 - 10-g
- 10-13
3.6 - IO-~
3.2
3.1
6.1
9.4 * 10-31
9.6 * x0-2l
9.8 . IO-II
2.5
-
6.0
2.1 . 10-31
3.5 - x0-31
5.9 a 10-11
2.4
- ,o-er
* 10-35 5.8. 10-24
2.2
9.4
3.6.10-25
I.3 . 10-3s
4.7 - IQ‘-03
- 10-3~
1o-27
.I_3 * 10-33
3.9 * 10-9-g
5.3
6_g . Io-33
I.7 . x0-31
4.1 - x0-11
2’3
6.9
6.7 6.8
6.6
6.4 6.5
6.3
6.2
5.9
5.8
5.7
5.6
5.5
5.4
5’ 5.2
1.8. 10-35
l
6.8 - 10-23
x0-11
2.6. 10-11
l
1.0. 10-33
5-o
4.9
4.1 * 10-33
2.7 a 10-~~
4.8
4*7
10-21
.
’ IO-s5
I .o . 10-33
2.2
2.0
6.9 . IO-~~
4.6
4.5
4.9 ’ 10-36
4.4
1.3 ’ 10-36
4.3
4-2
4.1
4.0
2.7 - IO-~’
8.0 - 10-38
2.0 * 10-a
4.9. 10-33
1.3 - 10-33
2.6
1.0 * 10-11
1.6
4.2 - 10-23
6.5 - IO-I3
1.9
2.0
1.7 - 10-33
2.1
7.3 ’ 10-24
2.7.10-18
4.1 . 10-13
I.8
‘-3
I.2
1.2. 10-26
I.1 - 10-13
I.0
TABLE I
2.4 -
JO-~
* 10-8
* IO-’
- 10-7
* 10-14
- 10-13
2.5 * 10-s
2.0 * 10-S
1.5 . IO-~
1.2 . 10-S
9.8. 10-3
7.7 . IO-”
6.0 . 10-3
5.0 - 10-3
- x0-33
* 10-19
6.3 - 10-10
’ 10-10
1.6 - 10-14
8.0 . 10-15
3.4 * 10-15 4.0
2.3 - 10-10
‘g.4 - 10-16
4.6 - 10-1”
2.2 a IO-l3
I.3 - IO-16
5.5 - 10-17
3.0 * 10-17
1.6 - IO-”
8.0 - IO-**
3.4 . 10-l
1.7. 10-l*
9.1
4.4 * 10-19
2.2 * 10-19
1.3 * 10-19
5. j . IOe20
2.7 . IO-20
1.4 . 10-a
6.9 * 10-21
3_$ . Jo-21
1.3 * 10-21
7.3 - 10-3-n
3.3 * 10-33
I.3
8.0. 10-s
1.7. lo-l5
- IO-11
- 10-11
1.4 * 1o-23 3.0 . 10-23
1.4 e 10-10
9.6
5.9
3.6. IO-‘l
2.5 - 10-l’
1.4 * IO-l*
9.6. IO-~*
3.1 - 10-6 3.8 - 10-3
6.3 - 10-12
4.0 * IO_‘3
.*’ 2.j . IO_‘3
1.4 - 10-13
9.4 * 10-13
5.8 - 10-13
3.6 - 10-13
2.5 . 10-13
I.4 * 1043
9.0 * IO”4
5.8 - 10-14
3.6 O10-14
2.3 - 10-14
I.2
8.1
4.8 - 10-13
2.5 . 10-1~
1.8 . 10-13
10-13
5.8 . 10-16 9.6.
2.5 * 10-3
2.0 * x0-6
I.5 * x0-6
1.2. 10-6
9.7
7.6 - 10-7
6.0. 10-7
j.0
3.8 - 10-7
3.0 . IO-~
2.4 - 10-f
x.9. 10-7
I.5 - 10-y
1.1 * 10-T
9.0
6.9. 10-8
5.5 * 10-8
4.3 e 10-3
3.1 - 10-8
1.6.
3.0 - 10-11
6.3 - IO-* 9.6. IO-*
2.j .10-d
. 10-5 - 10-3
2.5 3.6
5.0 - to-3
6.0.
3.0
9.6. 10-6 * 10-T
* IO-*
- 10-s
. 10-8
2.3
9.9
9.8
- 10-s
1.4
5.8 * x0-4
2.4
- 10-3
6.9 . 10-6
3.4 * 10-e
3.6. 10-4
. ~0-4
I.9 * 10-2
. 10-z
I.5
9-7
- 10-e
1.7
I.4
I.2 a 10-3
9.6
- 10-4
9.1 . 10-7
9.4 * 10-s
9.7 * 10-3
9.5
- IO-’
4.4
9.4
j.8 * 10-3
2.2 * x0-7
I.3
j.j
1.6
6.3 . IO-~
8.0 - x0-9
7.6. 10-3
9.3
9.1 9 .2
10-3
- x0-3
I.4
. 10-s
* x0-3
3.1
3.S
9.0
- 10-3
2.5
10-6
8.9
4.0 -
x0-3
2.3 . 10-a
. 10-S
I.5
2.0.
* 10-9
i.7 * 10-9 3.4
9.4 * 10-19
- 10-3
I.4
8.7 8.8
8-5 8.6
8.4
4.6. x0-10
’ IO-‘I
5.9 9.6. IO-’
. 10-a
7.7
2.2
3.6.10-7
* x0-10
1.3 - 10-19
j. j * IO-l1
- 10-3
- 10-4
6.0
2.5 . 10-7
I.2
* IOs4
8.2
10-11
- 10-13
9.8 - 10-4
- 10-4
3.8
j.0
8.1
8.3
. 10-d
3.1
8.0
7-9
7.8
7.7
7.6
7-3
I.4 * IO-’
3.4 - IO-= 8.0 * IO-lo-
2.3 - 10-9 4.0 * 10-9
IO4
* 10-a
1.j.
2.0
7.9 a IO-~
I_7 - 10-13
1.4 - 10-B
I.2 - 10-d
7.5
s.g a x0-3
4.6 4.9 . 10-13
j.g * IOdg 9.6. IO-9
7.7 * 10-s
IO.4
9.8 * 10-j
5.0 * 10-3
7.1 - 10-3
10.3
74
2.9 . 10-3
5.4 - IO-3
10.2
- x0-13
1.3 2.2 - 10-13
13.0
12.9
12.S
12.7
12.6
12.j
12.4
12.3
13.2
12.1
12.0
II.9
9.7. 10-l
9.6. 10-l
9.6. 10-l
9.4. 10-l
7.6 e 10-l 7.9. 10-I 8.3 * 10-l S.6 * x0-1 s.g * 10-l 9.0 * 10-l 9.3 . 10-l
- 10-l 7.1 - 10-l
* 10-l
5.9 6.6
Il.7 1I.S
5.4 * 10-l
j.0 - 10-l
4.3 * 10-l
3.6 - 10-1
3.3 * 10-l
2.7 * x0-1
2.3 * 10-l
11.6
1I.j
II.)
11.3
II.2
II.1
11.0
4.0 * 10-3
2.0 * 10-l
10.9
-
x0-5
- IO-~
. 10-3
3.j * 10-l
9.4 * 10-l
9.3 * 10-l
9.2 * 10-l
s.s * 10-l
5.6 - 10-l
s.1 * 10-l
7.9 * 10-1
7.4 - 10-l
6.9 * 10-l
9.1 * 10-l
9.0. 10-l
8.5 * 10-l
6.4. 10-l 7.0 * 10-l 7.3 * 10-l 8.0 * 10-l 5.3 * 10-1
5.7 * 10-l
4.9. 10-I
. 10-l
4.4 * 10-l
- 10-l j.S * IO-1
3.6
2.9 e 10-l
“.I * 10-l
10-1
6.2
j-0 * 10-l
4.4 * 10-l
1.6.
I.3 - 10-l
- .10-l 1.3 1.9 e 10-l
s.0
* IO-9-
4.7 - 10-Z
3.6 - 10-3
2-o. IO4
1.2
s.0. 10-3
4.1 . x0-3
2.2 * 10-s
1.3 * 10-s
7.0
3.6 - 10-4
1.6 - 10-4
9.7 * x0-5
4.7 * 10-s
2.7
W-J’
1.S * 10-l
1.3 - 10-1
I.1 e 10-l
7.3 - 10-Z
5.3: IO-3
- 10-3
1.7.10-3 2.6
1.3 * 10-L 1.6. 10-l
- 10-3
1o.s
I.2
2.1 - 10-3
10.7
I.1 . 10-l
10.6
1O.j
1.3
- 10-3
9.0 - 10--I
3.0 - 10-p 3.6 - 10-3 4.6 - 10-2
3.6 - IO-9
10-5
6.0.
IO.1
10.0
- . IO-9 2.3
IOe5
7-I
7.2
- IOml‘l
j.O-
* 10-14
- IO-~
5.5
VW’
3.0
- x0-5
3.1
7.0
R-
I.4 - x0-9
iW
PH
9.6 - IO-lo
(R)=
3.8
PH
R-
TABLE I (continued) . 1. P 00
VOL.
21 (1959)
EXTIlACTION
EQUILIBRIA.
401
II.
From (I) and (2)) 1.065
HOx
= 0.016~
or
HOx
=
o.orgr
mg moles.
and the concentration is therefore 0.00045 mg mole/ml. = 2.371 The chloroform phase contained 2.387 - 0.016 so its concentration was 0.0948 mg moles/ml. From these data, 1: =
concn. HOx
in chloroform
concn. HOx
in water
i
0.0948 0.00045
=
mg moles of oxine and
2x1.
When the experiment was rcpcatcd, the values E = 2x0 and 6 = 194 were found at pri 9.04 and 9.62 respectively. Tn the following calculations the mean value E = 205 is used. It is not clear why three investigators have found such divergent values. The results of the calculations of Ii- as a function of H+ are given in Table I. As metal ions, the this has proved to be useful when dealing with bi- &d trivalent values of (R-) 2 and (R -) 3 are also included. Checking
o/ the cquntions
To check the validity of our equations and the suppositions on which they are based, WC have used the extractions of copper and nickel with oxine and chloroform. Copper-ox&e-clilorofornc For the expression t& ‘1rcs.
-
a
=
lL MI1,, IMIG o sat. (R-1”
+
~LMIL,,
values of L MI& and MR, 0 sat. are still required. The value of L MIC, is given by BORREL AND PARIS 7 as 5 - 110-z”. The value of 7.4 . x0-10 found by TREADWELL AND AMMAN 12 is incorrect. This value was calculated from the solubility of copper oxinate in I :V acetic acid without considering the amphoteric character of oxine; accordingly, it is too large. The value of CuOxa sat. chloroform was determined by shaking chloroform for 24 h with pure copper oxinate, distilling the chloroform, destroying the organic matter with sulphuric-perchloric acids in the presence of ammonium vanadateld, and by final gravimetric determination of copper. The value 3.4 . IO- 3 mg moles/ml was found. the
The ex+erimental
extvactio9t
error
In a separatory funnel were placed 49 ml of water*, I ml of a copper sulphate solution containing I mg Cu/ml, I ml of chloroform containing 56.2 mg of oxine/ml, g ml of chloroform* and a few drops of 2 N hydrochloric acid. The stoppered funnel was shaken for 3 X. 2 min, with 2 min between each shaking period. After final * In order to avoid large changes of volume of the phases, were satuiated with chloroform and water rcspectivcly. References p. 406
the water and the chloroform
used
M.
402
OOSTING
21 (1959)
VOL.
separation of the layers, the p&r of the aqueous layer was determined as well as the copper content of the chloroform layer and in some cases, the copper content of the aqueous layer. Copper was determined in the chloroform layer by measuring the absorbance at 450 m/A. A standard curve was prepared by dissolving a weighed amount of pure copper oxinate in chloroform and measuring the absorbance at 450 rnp of known dilutions of this solution. Copper was determined in the aqueous layer with rubeanic acid13 after destruction of organic matter with sulphuric-perchloric acids in the presence of ammonium vanadatcld. The results are given in Table II. TABLE Bhase
awtws
mg
11 chloroform
o/copper
tubeattic acid
as orhale
x.ijq
<
0.19
2.12
0.14 0.26
2.20
0.61 0.36
2.25
2.36
0.37 0.64
0.21
2.50
The cnhlated
acid
0.04
2.10
3.04
mbeatric
0.01
I .96
2.55 2.85
Pha.w
mg 01 copper
< <
0.28 0.68 0.86
0.09 0.01 0.01
extraction error
In our experiments the value of B (defined as b/V,,) was 56*2/r45 . 1 fso = 8.10-3, hence the values of (R-)2 found in Table I must be multiplied by Bz = 6.4 x0-6. Only l
TABLE W
.
(K-)n- L
(R-):, - 1.10-'
106 X.7 1.8 1.9
2.9 7.3 I.7 ‘1.2
. IO-24 - 10-24 . lo-aa . x0-28
1.8 4.7
2.0
1.0
. IO-22
z:;.
2.1 2.2 2.3 2.4 2.5
2.6 6.8 1:;
. 10-22 * 10-22 * 10-21 * x0-21
I.7 4.4 I.1 2.2 6.1
2.6
2.3 5.3
. 10-23 * 10-20
1.2
* 10-10
;:;
. IO-10
I*;
:
. IO-10
4.1
.
2.7 2.8 2.9 3.0
References
9.6.
p. 406
IO-ai
III
CuOx,sat.(R-)'
jLo.or,
rn+gMs. a
. 10-27
6.x . ‘k-31 1.6 . x0-30 3.7 * 10-2fJ 9.2 . 10-30
IO-27
2.2 * IO-‘JD
0.93
,(yne
5.8 ;:;
* x0-20 ;:I:: : 7.5 - :z-&
0.81 oh3 0.40 0.25
2.x
.
O.II
. 10-33 * 10-28
1.X.
x0-2’
. . . * .
,o-aa 10-25 10’25
10-25
. IO’24
3:; .
2.5 . *o-28
I .oo I .oo 1.oo 0.96
5-I
.
lo-27
0.04
10-a4
I.2
’
10-23
0.02
:z:::
2.6
.
10-23
0.01
0.005 lo-23
0.002
EXTRACTION EQUILIBRIA. II.
VOL. 21 (1959)
the PH range of 1.6 to 3.0 will be considered. values of a
can be calculated
(Table
From the values of (R-)2 obtained, fL
7n+2res.
the
nr lr2
MR2 0 sat. (R-)2
=
403
+ fLMn2
III).
The experimental and the calculated values are shown in Fig. I’, curve I. The experiments were repeated with a smaller amount of oxine (B = 4.3 * 10-q. The results as well as the calculated values are shown in Fig. I, curve II.
PO. 10
.
1.6
1.7
I.6
1.9 2.0
2.1
2.2
2.3
-
2.4
2.Y
26
2.7
2.8
2.0
S.O+S.I
il.2
PH
Fig. f. The extraction of copper WiLh oxinc and chhroform as a fllnCtiOn of pH. Curve I. Calculatccl extraction error B = 8 - roe3. -I- - ~xpcrimcntally found extraction Cure II. Cnlculatcci extraction error R = 4.3 . 10-S. 0 = cxpcrimcntally founcl extraction
error. error.
Nickel - oxine - chloroform The values of f, B, A and n, which depend only on the conditions chosen can be calculated in the same way as in the experiments with copper-oxine-chloroform. The values of K,, K&, KLn and E,, are also the same,,of course. For the solubility product of nickel oxinate, IRVING AND WILLIAMSON found a value of 7.9 . x0 -23. From the experimental data of BORREL AND PARISH, a value of 7 x0-23 can be calculated, and this is used in the following calculations. The solubility of nickel oxinate in chloroform was determined by shaking pure nickel oxinate for 24 h and determining the nickel in the solution. This solubility proved to be nil, hence it would seem that no extraction is possible. Nevertheless, this extraction has been published It-18. Surprisingly, when a nickel solution (PH = 6) is shaken with a solution of oxine in chloroform a definite extraction is obtained. The chloroform solutions, however, are very unstable, nickel oxinate precipitates and ‘after a short time the chloroform is free of nickel. l
References
9. 406
M. OOSTING
404
VOL,
21 (1959)
It can be assumed that the undissociated but not yet precipitated nickel oxinate is extracted from the aqueous phase, and forms chloroform-insoluble NiOxz. 2 aq with the water dissolved in the chloroform. UMMLAND AND HOFPMANN’D found that chloroform
solutions
of
metal
oxinates
were
stabilized
by
the
addition
compounds, n-butylamine being one of the most effective. t&at the ut-butylamine replaces the water in an equilibrium:
organic
NiOx2 - zHz0
f
z IJ.~. -;-t NiOxa * z b.s.
+
of
polar
It is supposed
2I-120
in which b.a. is written for +s-butylamine. The compound NiOxz. z b.a. is soluble in cllloroforni. ‘I’hc solubility of nickel oxinate was the.rcforc dctcrmined in chloroform in presence of +butylamine by shaking an aqueous solution of nickel sulphate containing a large excess of +butylamine with a chloroform solution of oxine for 8 h. At the end of this period, the aqueous phase contained a green precipitate of nickel oxinate which proved to be readily soluble in chloroform, therefore the chloroform phase was considered to bc a saturated solution of nickel oxinate*. The concentration of nickel oxinate in this perfectly stable solution was found to be 5.0 - IO-” mg moles/ml. The oxfierimental
extraction
ewor
50 ml of water containing I mg of nickel as nickel sulphate, I ml of n-butylamine and a few drops of dilute sulphuric acid were shaken with a solution of 49.5 mg df oxine in IO ml of chloroform. After separation of the phases, the prr of the aqueous phase was measured; in the aqueous’and/or chloroform phase, nickel was determined colorimctrically with dimethylglyoxime20 after the destruction of oxine with sulphuric-perchloric acids. The results are given in Table IV. TABLE _-_---_.-
.--_I-.--_fiH
---.-----._--.----__---__-
The calcdatcd
extraction
IV
aqueous phua
.----_I.-.__-_
mg 01 trickcl
.oo
2.91
I
3.10 3.rG 3.40 3.00 3.72, 4.03 4.66 6.47
o.gG o.5G 0.25 0.09 0.03 0.00 0.00
chloroforn, phaac mg 01 nickel _--_ 0.02
0.03 0. IO 0.74 I .oo 1.02
error
From the values LNlora = 7 * 10-23, NiOxa sat. chloroform = 5 - IO-~, R- from Table I, using Z3 = 49.5/r45 * Iso = 6.8. x0-3, the extraction error can be calculated. The calculations are shown in Table V. l
* WC considcr’khe reaction: importance for our purposes. Refevances
p. 406
NiOx2 + z b.n, -+ NiOxa-z
b.a. a scconclary one, which is of no
VOL.
21
EXTRACTION
(1959)
EQUILIBRIA. TABLE
(R-)Y.l -
PH
(R-)
1
2.7 2.8
5.3
* x0-20
2.5
1.2
* 10-12
5.6
3.4 3.5 3.6 ;::
0.99 0.98 0.96
10-24
0.91
10-24
0.82 0.70
. 1043 . 10-22
3.3 7.5
.
K
.
3::
: :“,I:“3
I.2
a 10-2’
5.8
* 10-23
5.0 9.6. 1.7 3.2
IO-”
2.4
.
10-21
I
10-17
.t*s
.
,o-21
* to-22 * 10-22
8.0 ‘05
* 10-2’ . 10-20
2.7
.
IO-20
* md; -
ii:;
.
,o-20
.
1.2
* 10-13
9.6 1.8 2.5 4.8 8.1
4.3 4.4 4.5
g
2.3
I.00
0.54 0.38
4.0
. *o-22 7.5 : ::I:; 1.4
0.02
4.2
* 10-2’ IO-21
0.02
.
0.01
5.8 a IO-~* I.1 * 10-Z” I.9 . ,o-20
. ,o-10 3.8 . xo-lu
- mw:; .
10-23
0.23 0.14 0.08 0.04
.2 2.2
2.2
IO_‘6
-
* 10-28 * x0-25 . 10-24
6.6 I.5
*
3.5
Its.
a
* x0-23
. IO-In * *o-LB G.3 * 10-18 1.3 * x0-*7 2.5 . IO-”
*o-22 10-22
m+’
I LlvWJ‘,
l
I.2
.
4.1 4.2
0.01 0.00 0.00
00
s_ +
. 10-24 - 10-24
(R-)
ml.
* x0-23 10-23
* 10-10 . 10-10 5.8 * x0-10
3.9 4.0
NiOx,
a.~.-
1.2
. xo-lU ’ 10-10
1.4 3.2
;:;
-
3-o
G.4
3.1
II
405
V
2.8 5.8 I.5
2.5
2.9 3.0
s
II.
70
t
i
=O
I
50 40
7
2.8
2.9
3.0
3.1
1.2
3.2
1.4
5.S
3.b
3.7
3.0
3.9
4.0
4.1
42
43
4A
45
46
4.7
-PH
Fig.
2.
The
extraction function of
of nickel PH.
with
Calculated
oxine and chloroform in presence of n-butylaminc and cxperimcntally found extraction errors.
as R
‘The calculated values and the experimentally found extraction errors are shown in Fig. 2. It can be concluded that in both systems the course of the extraction is predicted correctly by the equations given in our previous paperl. References p. 406
VOL.
M. OOSTXNG
406
21
(IQSQ)
SUMMARY ‘Tllc ccluations given in a previous paper are shown to pretlict the course of solvent extraction as well as that of nickel - oxinc - chloroform. correctly in the cast of copper - oxinc - chloroform 130th pn and quantity of reagent prove to have the effect rcquirctl by the equations.
IAS &luations propcisdcs clans le prcmicr article cl’cxtraction par solvant: cuivrc-oxinc-chloroform
da ccttc s&ric ont Gtb appliqu&s et nickel -oxinc-chloroformc.
aux Gas suivants
%USAMMENFASSUNG &lit Jiilfe tlcr in ciner friihcren Vcrtlffcntlichung mitgctciitcn Cleiclrungcn wurdc clcr Vcrlauf rmcl Nickel - Oxin Kupfcr - Oxin -Chlorofor1n verfolgt: clcr Extraktion folgcnclcr Systcmc Chloroform. REFERENCES
’ M. Oosrrluc, Anet. C/&n. /f&z, z I (1959) 301. 2 J. J. Pox. ./. Clron. Sot., 97 (1910) I 1 rg. 3 1C. G. STONE AND L. FRIEDMAN, J. Am. Chcrn. Sue., Gg (1947) zag. 4 13. DAVIDSON, J. Chm. E&M., rg (1942) 22x. 70 (1g48) *lo. & J. P. ~HltIPS AND i_..1~. I~ERRIT. JR,, .I. Anz. Ci&?m.S0c., s W. STfSNsTRonx AND N. GOLIJSMITH, J. PJ~ys. Client., 30 (1926) 1683. 7 M. BORREL AND R, A. /in&. Ckinr. iictu. G (1952) 389. s G. BOCQU~ST AND IX. A. PARIS, AWL Chim. Acta, 11) (rg50) I. IJS. LACROIX, liltal. C/rim. Acta, I (11347) 260. lo F. UMLAND AND tl. ~+XIIIXT, ff8ra!.C/rim. AC/U, 16 (105.7) 334, 11 TH. Morr~~rsa AND P. I,. FUNDSACK, J. /Jm. Clwrt. Sac., 75 (1953) 2258. 1s W. 1). T~sh1.3wrsL~ AND A. ANIMAN,~~&I. Chim. Acfu, 2x (rg38) 1x49. 1s K. QUANDEL, Arcll. ~ise;i~i~t~enw., 14 (x941) 60‘1. 14 M. OosrrNG, Tlresis, Delft, 1953. 1* lI. bl. fHVING AND 13. J. P. WILtthhIS, kf~#h.dyS~, 77 (X952) 813. 1s 0. A. KENYON AND 1.1.A. BILWICK, .&zul. CjteJrt., 24 (1952) 1826. AND D. TV. HAWLEY, /Jml. C/rem., 25 (1953) 1369. I7 iA. SILVISRMAN, L. LMOUDY 1s l’r1. Molz~~an. Irzd. E1tg. Chem.. AIIU!. Ed., I 5 (1943) ~03. 1s L;. UMLAND AND W. HOPFMANN, Ragcru. Ckm., 68 (1956) 704. 20 A. CLAASSEN AND L. UhsTtNGs, &cc. tunv. d&u., 73 (1954) 783.
Received
SEPARATION
OF
COBALT(I1)
ANTIMONY(V) AND
FROM
CADMIUM(I1)
S. S, M. A. l
IRON(III),
BY
February
zoth,
1959
COPPElI(II),
ION-EXCHANGE
AND M, l-1. I;HUNL>KAR Uitivmsity,
Bctccrt (Lhst
Pufristnu)
In view of the clifficultics usually associated with the conventional method of separation of antimony by precipitation as sulphidc 1, a simpler rapid method was desirable. In a previous communication 2, a solvent extraction method for separating macro quantities of antimony(V) from nickel(II), chromium(III), lead(H), tin (IV), mercury(II) and small amounts of copper was described. Iron(III), cobalt(II), References
p. 4x0
VOL..21 (rgsg)
SOME
397
QWANTITATSVE REMARKS ON EQUILIBRIA. fI
EXTRACTION
M. OOSTING AnaIyticuC Researclr Insiitutc
In a pqevious as a chelatc :
paper1 we derived
T.N.O.,
Rijswijk
two expressions
(TJje Neilrevlaqrds)
for the estraction
of a metal ion
and
+nfn res . a
f‘%sR -
MRno sst.(R-)”
n
+ f . LMlbn
(W
WC shall now prove the validity of these expressions and show that they correctly predict the behaviour of metal ions in extraction procedures. Calcwlation
of R-
It has proved very helpful to work out the value of R- in the foim.of a table. From equation A we see that -the value of R- depends on the choice of the system and on the conditions used (B, f, I-X+). W&t K.&e E& Initially, only the system oxine - water - chloroform will be considered. Of the conditions, f is taken as 5, hence only extractions in which the volume of the chloroform phase is one-fifth of that of the aqueous phase will be dealt with. The relationship between B and R- is linear; accordingly, the R--table is calculated for a value B--I, and the value of R- found in the table need only be multiplied by the actual value of B. Thus the tabular values of R- represent the concentration of oxinate anions in the aqueous phase of a system which contains I me; mole of oxine per ml of aqueous phase, and which is in equilibrium with a quantity of chloroform equal to one fifth of the volume of the aqueous phase. The H-+-concentration is considered as the auto-variant. The values of Ku), are required. The value of Km is well-known ; the figure 1.0'10-14 K& and E,, K&v willbe used. Many data have been published regarding the dissociation constants_ of oxine. Fox8 found the value K”,, = 3.68 - IO -11 from hydrolysis measurements. STONE AND FRIEDMAN~, using.the solubility method of DAVIDSON~, found values between References
p. 406
M. OOSTING
398
VOL. 21 (1959)
P~IILIIJS AND MERRITG, using _thc optical method of 4.20. 10-1~ and 4.28 * IO-*‘. STENSTHOM ANI) CIOLDSMITI?~,found pKiR = g.70 (K”,, = x,&j+’ IO-*“) and pKLlt = 9.08 (I<“,, = 8.32 - IO -1”). From potentiometric titrations BARREL AKD PARIS’ found PI<;,,, = 9.85 and p”K:,,, “= 5.05. This I’Ktrn” is not the same as “our” KkR, but is related to it by the simple equation: Kb (our definition) = Ktu/“KLIL”, and accord= 8.95. BOCQUET AND P/%&J, comparing potentiometric and optical ingly PI& methods, found pK& = 9.82 and P~‘I<:~~” = 5.10. In good agreement are also the values pKt%,, = 9.82 and pK&, = 5.09 found by LACROIX 0. .U.MI_ANL)AND PUCIIELT~O found pK&, = g.Go and p”K&” = 5.33, by extracting oxine with benzene at various pr,r-values. These values are based on the determination of the partition coefficient and therefore are as inaccurate as the bromatometrjc determination of II pg of oxine in 50 ml of aqueous solution. The values KT,,, = 1.3 IO-“J and Z”:X,, = 1.2 * IO-“, will be used here; thcsc are based on earlier work’-0. For the partition coefficient of oxinc between water and chloroform values of 7200 and 350 11 have been given. These values disagree, hence the detct-mination of the value of E_ was repeated. A quantity of oxinc was weighed exactly and shaken for 20 h with chloroform and an aqueous buffer solution. The volumes of both phases were clctermincrl. In the aqueous phase the prl was measured and the sum of undissociatcd oxinc and o_xinatc ion was determined by bromatometric titration. With the known value of KzIC, the concentration of undissociated oxine was calculated. The term lCLrL was neglected, which is allowed at the prr valuer; considered. The quantity of oxine in the chloroform phase was obtained from the difference between the amount of oxinc taken and the amount of oxinc + oxinate found in the aqueous phase. In the first experiment, 346.2 mg of oxine (2.387 mg moles) were shaken in a glassstopmred measuring cylinder with aqueous buffer and chloroform and the layers were’&llowcd to separate; the volumes of aqueous and chloroform phases were 33.5 and 25 ml rcspectivcly. The ~1.1of the aqueous phase, measurecl with a glass electrode, was 8.71, thus H+ = 2 ’ 10’~. To 20 ml of the aqueous phase 3.18 ml of 0.1004 N bromate solution, 250 mg of potassium bromide and 5 ml of G N HCl were added. ‘The excess of bromate was backtitrated with 2.81 ml of o.xooo N thiosulphate. The aqueous phase thus contained 0.644 mg equivs. or o.orGr mg moles of oxine + oxinrrte. l
ox&L
=
-I-
1-10x -
O.OlGX
.
*
.
.
.
.
.
.
.
.
.
.
.
.
.
(I)
H+ * Ox= 1.3*10-l”, HOX
3.10-O* ox- = 1.3’10~10l-lox or
Rejcrerrcesp. 406
ox- = 0.065 HOx
. . . . . .
. . . . . . .
. .
(2)
2.9 . 10-26 * 10-26
- 1045
7.3 1.8
4.2 . 10-2~ 1.2 . 10-94 2.9 * 10-34
I.7 * 10-13
2.7 - 10-13 4.3 - x0-13
6.5 . 10-13
1.l * IO-la
1.7 . IO-ls
I.1
I.4
I-5
1.6
I-7
3.4 - 10-30 1.2. IO-=
5.1 * 10-a 1.7 5.8
1.6 - 10-25
2.3 - 10-a 5.3,10-m I.2 * 10-13 2.5
6.4 - 10-19 1.4 - 10-l*
3.2 . 10-18
1.5 . 10-10
2.3 - 10-10
3.4 * IO_‘0
5.0 - 10-13
8.0 - 10-10
I.2 . 10-3
1.8 - 10-3
2.6
2-7
2.8
2.9
3.0
j.0. 9.6 1.7 - 10-1~
3.2 - 10-16
7.x - 10-g
9.8.
1.3. 10-3
1.8 - 10-3
3.5
3.7
3.8
3.9
3.6 10-3
2.5
5.0 * 10-B
3.4
- 10-1~
10-l’
’ 10-n
6.3 - 10-18 1.3 - IO-If
3-3
2.5 - 10-g
- 10-13
3.6 - IO-~
3.2
3.1
6.1
9.4 * 10-31
9.6 * x0-2l
9.8 . IO-II
2.5
-
6.0
2.1 . 10-31
3.5 - x0-31
5.9 a 10-11
2.4
- ,o-er
* 10-35 5.8. 10-24
2.2
9.4
3.6.10-25
I.3 . 10-3s
4.7 - IQ‘-03
- 10-3~
1o-27
.I_3 * 10-33
3.9 * 10-9-g
5.3
6_g . Io-33
I.7 . x0-31
4.1 - x0-11
2’3
6.9
6.7 6.8
6.6
6.4 6.5
6.3
6.2
5.9
5.8
5.7
5.6
5.5
5.4
5’ 5.2
1.8. 10-35
l
6.8 - 10-23
x0-11
2.6. 10-11
l
1.0. 10-33
5-o
4.9
4.1 * 10-33
2.7 a 10-~~
4.8
4*7
10-21
.
’ IO-s5
I .o . 10-33
2.2
2.0
6.9 . IO-~~
4.6
4.5
4.9 ’ 10-36
4.4
1.3 ’ 10-36
4.3
4-2
4.1
4.0
2.7 - IO-~’
8.0 - 10-38
2.0 * 10-a
4.9. 10-33
1.3 - 10-33
2.6
1.0 * 10-11
1.6
4.2 - 10-23
6.5 - IO-I3
1.9
2.0
1.7 - 10-33
2.1
7.3 ’ 10-24
2.7.10-18
4.1 . 10-13
I.8
‘-3
I.2
1.2. 10-26
I.1 - 10-13
I.0
TABLE I
2.4 -
JO-~
* 10-8
* IO-’
- 10-7
* 10-14
- 10-13
2.5 * 10-s
2.0 * 10-S
1.5 . IO-~
1.2 . 10-S
9.8. 10-3
7.7 . IO-”
6.0 . 10-3
5.0 - 10-3
- x0-33
* 10-19
6.3 - 10-10
’ 10-10
1.6 - 10-14
8.0 . 10-15
3.4 * 10-15 4.0
2.3 - 10-10
‘g.4 - 10-16
4.6 - 10-1”
2.2 a IO-l3
I.3 - IO-16
5.5 - 10-17
3.0 * 10-17
1.6 - IO-”
8.0 - IO-**
3.4 . 10-l
1.7. 10-l*
9.1
4.4 * 10-19
2.2 * 10-19
1.3 * 10-19
5. j . IOe20
2.7 . IO-20
1.4 . 10-a
6.9 * 10-21
3_$ . Jo-21
1.3 * 10-21
7.3 - 10-3-n
3.3 * 10-33
I.3
8.0. 10-s
1.7. lo-l5
- IO-11
- 10-11
1.4 * 1o-23 3.0 . 10-23
1.4 e 10-10
9.6
5.9
3.6. IO-‘l
2.5 - 10-l’
1.4 * IO-l*
9.6. IO-~*
3.1 - 10-6 3.8 - 10-3
6.3 - 10-12
4.0 * IO_‘3
.*’ 2.j . IO_‘3
1.4 - 10-13
9.4 * 10-13
5.8 - 10-13
3.6 - 10-13
2.5 . 10-13
I.4 * 1043
9.0 * IO”4
5.8 - 10-14
3.6 O10-14
2.3 - 10-14
I.2
8.1
4.8 - 10-13
2.5 . 10-1~
1.8 . 10-13
10-13
5.8 . 10-16 9.6.
2.5 * 10-3
2.0 * x0-6
I.5 * x0-6
1.2. 10-6
9.7
7.6 - 10-7
6.0. 10-7
j.0
3.8 - 10-7
3.0 . IO-~
2.4 - 10-f
x.9. 10-7
I.5 - 10-y
1.1 * 10-T
9.0
6.9. 10-8
5.5 * 10-8
4.3 e 10-3
3.1 - 10-8
1.6.
3.0 - 10-11
6.3 - IO-* 9.6. IO-*
2.j .10-d
. 10-5 - 10-3
2.5 3.6
5.0 - to-3
6.0.
3.0
9.6. 10-6 * 10-T
* IO-*
- 10-s
. 10-8
2.3
9.9
9.8
- 10-s
1.4
5.8 * x0-4
2.4
- 10-3
6.9 . 10-6
3.4 * 10-e
3.6. 10-4
. ~0-4
I.9 * 10-2
. 10-z
I.5
9-7
- 10-e
1.7
I.4
I.2 a 10-3
9.6
- 10-4
9.1 . 10-7
9.4 * 10-s
9.7 * 10-3
9.5
- IO-’
4.4
9.4
j.8 * 10-3
2.2 * x0-7
I.3
j.j
1.6
6.3 . IO-~
8.0 - x0-9
7.6. 10-3
9.3
9.1 9 .2
10-3
- x0-3
I.4
. 10-s
* x0-3
3.1
3.S
9.0
- 10-3
2.5
10-6
8.9
4.0 -
x0-3
2.3 . 10-a
. 10-S
I.5
2.0.
* 10-9
i.7 * 10-9 3.4
9.4 * 10-19
- 10-3
I.4
8.7 8.8
8-5 8.6
8.4
4.6. x0-10
’ IO-‘I
5.9 9.6. IO-’
. 10-a
7.7
2.2
3.6.10-7
* x0-10
1.3 - 10-19
j. j * IO-l1
- 10-3
- 10-4
6.0
2.5 . 10-7
I.2
* IOs4
8.2
10-11
- 10-13
9.8 - 10-4
- 10-4
3.8
j.0
8.1
8.3
. 10-d
3.1
8.0
7-9
7.8
7.7
7.6
7-3
I.4 * IO-’
3.4 - IO-= 8.0 * IO-lo-
2.3 - 10-9 4.0 * 10-9
IO4
* 10-a
1.j.
2.0
7.9 a IO-~
I_7 - 10-13
1.4 - 10-B
I.2 - 10-d
7.5
s.g a x0-3
4.6 4.9 . 10-13
j.g * IOdg 9.6. IO-9
7.7 * 10-s
IO.4
9.8 * 10-j
5.0 * 10-3
7.1 - 10-3
10.3
74
2.9 . 10-3
5.4 - IO-3
10.2
- x0-13
1.3 2.2 - 10-13
13.0
12.9
12.S
12.7
12.6
12.j
12.4
12.3
13.2
12.1
12.0
II.9
9.7. 10-l
9.6. 10-l
9.6. 10-l
9.4. 10-l
7.6 e 10-l 7.9. 10-I 8.3 * 10-l S.6 * x0-1 s.g * 10-l 9.0 * 10-l 9.3 . 10-l
- 10-l 7.1 - 10-l
* 10-l
5.9 6.6
Il.7 1I.S
5.4 * 10-l
j.0 - 10-l
4.3 * 10-l
3.6 - 10-1
3.3 * 10-l
2.7 * x0-1
2.3 * 10-l
11.6
1I.j
II.)
11.3
II.2
II.1
11.0
4.0 * 10-3
2.0 * 10-l
10.9
-
x0-5
- IO-~
. 10-3
3.j * 10-l
9.4 * 10-l
9.3 * 10-l
9.2 * 10-l
s.s * 10-l
5.6 - 10-l
s.1 * 10-l
7.9 * 10-1
7.4 - 10-l
6.9 * 10-l
9.1 * 10-l
9.0. 10-l
8.5 * 10-l
6.4. 10-l 7.0 * 10-l 7.3 * 10-l 8.0 * 10-l 5.3 * 10-1
5.7 * 10-l
4.9. 10-I
. 10-l
4.4 * 10-l
- 10-l j.S * IO-1
3.6
2.9 e 10-l
“.I * 10-l
10-1
6.2
j-0 * 10-l
4.4 * 10-l
1.6.
I.3 - 10-l
- .10-l 1.3 1.9 e 10-l
s.0
* IO-9-
4.7 - 10-Z
3.6 - 10-3
2-o. IO4
1.2
s.0. 10-3
4.1 . x0-3
2.2 * 10-s
1.3 * 10-s
7.0
3.6 - 10-4
1.6 - 10-4
9.7 * x0-5
4.7 * 10-s
2.7
W-J’
1.S * 10-l
1.3 - 10-1
I.1 e 10-l
7.3 - 10-Z
5.3: IO-3
- 10-3
1.7.10-3 2.6
1.3 * 10-L 1.6. 10-l
- 10-3
1o.s
I.2
2.1 - 10-3
10.7
I.1 . 10-l
10.6
1O.j
1.3
- 10-3
9.0 - 10--I
3.0 - 10-p 3.6 - 10-3 4.6 - 10-2
3.6 - IO-9
10-5
6.0.
IO.1
10.0
- . IO-9 2.3
IOe5
7-I
7.2
- IOml‘l
j.O-
* 10-14
- IO-~
5.5
VW’
3.0
- x0-5
3.1
7.0
R-
I.4 - x0-9
iW
PH
9.6 - IO-lo
(R)=
3.8
PH
R-
TABLE I (continued) . 1. P 00
VOL.
21 (1959)
EXTIlACTION
EQUILIBRIA.
401
II.
From (I) and (2)) 1.065
HOx
= 0.016~
or
HOx
=
o.orgr
mg moles.
and the concentration is therefore 0.00045 mg mole/ml. = 2.371 The chloroform phase contained 2.387 - 0.016 so its concentration was 0.0948 mg moles/ml. From these data, 1: =
concn. HOx
in chloroform
concn. HOx
in water
i
0.0948 0.00045
=
mg moles of oxine and
2x1.
When the experiment was rcpcatcd, the values E = 2x0 and 6 = 194 were found at pri 9.04 and 9.62 respectively. Tn the following calculations the mean value E = 205 is used. It is not clear why three investigators have found such divergent values. The results of the calculations of Ii- as a function of H+ are given in Table I. As metal ions, the this has proved to be useful when dealing with bi- &d trivalent values of (R-) 2 and (R -) 3 are also included. Checking
o/ the cquntions
To check the validity of our equations and the suppositions on which they are based, WC have used the extractions of copper and nickel with oxine and chloroform. Copper-ox&e-clilorofornc For the expression t& ‘1rcs.
-
a
=
lL MI1,, IMIG o sat. (R-1”
+
~LMIL,,
values of L MI& and MR, 0 sat. are still required. The value of L MIC, is given by BORREL AND PARIS 7 as 5 - 110-z”. The value of 7.4 . x0-10 found by TREADWELL AND AMMAN 12 is incorrect. This value was calculated from the solubility of copper oxinate in I :V acetic acid without considering the amphoteric character of oxine; accordingly, it is too large. The value of CuOxa sat. chloroform was determined by shaking chloroform for 24 h with pure copper oxinate, distilling the chloroform, destroying the organic matter with sulphuric-perchloric acids in the presence of ammonium vanadateld, and by final gravimetric determination of copper. The value 3.4 . IO- 3 mg moles/ml was found. the
The ex+erimental
extvactio9t
error
In a separatory funnel were placed 49 ml of water*, I ml of a copper sulphate solution containing I mg Cu/ml, I ml of chloroform containing 56.2 mg of oxine/ml, g ml of chloroform* and a few drops of 2 N hydrochloric acid. The stoppered funnel was shaken for 3 X. 2 min, with 2 min between each shaking period. After final * In order to avoid large changes of volume of the phases, were satuiated with chloroform and water rcspectivcly. References p. 406
the water and the chloroform
used
M.
402
OOSTING
21 (1959)
VOL.
separation of the layers, the p&r of the aqueous layer was determined as well as the copper content of the chloroform layer and in some cases, the copper content of the aqueous layer. Copper was determined in the chloroform layer by measuring the absorbance at 450 m/A. A standard curve was prepared by dissolving a weighed amount of pure copper oxinate in chloroform and measuring the absorbance at 450 rnp of known dilutions of this solution. Copper was determined in the aqueous layer with rubeanic acid13 after destruction of organic matter with sulphuric-perchloric acids in the presence of ammonium vanadatcld. The results are given in Table II. TABLE Bhase
awtws
mg
11 chloroform
o/copper
tubeattic acid
as orhale
x.ijq
<
0.19
2.12
0.14 0.26
2.20
0.61 0.36
2.25
2.36
0.37 0.64
0.21
2.50
The cnhlated
acid
0.04
2.10
3.04
mbeatric
0.01
I .96
2.55 2.85
Pha.w
mg 01 copper
< <
0.28 0.68 0.86
0.09 0.01 0.01
extraction error
In our experiments the value of B (defined as b/V,,) was 56*2/r45 . 1 fso = 8.10-3, hence the values of (R-)2 found in Table I must be multiplied by Bz = 6.4 x0-6. Only l
TABLE W
.
(K-)n- L
(R-):, - 1.10-'
106 X.7 1.8 1.9
2.9 7.3 I.7 ‘1.2
. IO-24 - 10-24 . lo-aa . x0-28
1.8 4.7
2.0
1.0
. IO-22
z:;.
2.1 2.2 2.3 2.4 2.5
2.6 6.8 1:;
. 10-22 * 10-22 * 10-21 * x0-21
I.7 4.4 I.1 2.2 6.1
2.6
2.3 5.3
. 10-23 * 10-20
1.2
* 10-10
;:;
. IO-10
I*;
:
. IO-10
4.1
.
2.7 2.8 2.9 3.0
References
9.6.
p. 406
IO-ai
III
CuOx,sat.(R-)'
jLo.or,
rn+gMs. a
. 10-27
6.x . ‘k-31 1.6 . x0-30 3.7 * 10-2fJ 9.2 . 10-30
IO-27
2.2 * IO-‘JD
0.93
,(yne
5.8 ;:;
* x0-20 ;:I:: : 7.5 - :z-&
0.81 oh3 0.40 0.25
2.x
.
O.II
. 10-33 * 10-28
1.X.
x0-2’
. . . * .
,o-aa 10-25 10’25
10-25
. IO’24
3:; .
2.5 . *o-28
I .oo I .oo 1.oo 0.96
5-I
.
lo-27
0.04
10-a4
I.2
’
10-23
0.02
:z:::
2.6
.
10-23
0.01
0.005 lo-23
0.002
EXTRACTION EQUILIBRIA. II.
VOL. 21 (1959)
the PH range of 1.6 to 3.0 will be considered. values of a
can be calculated
(Table
From the values of (R-)2 obtained, fL
7n+2res.
the
nr lr2
MR2 0 sat. (R-)2
=
403
+ fLMn2
III).
The experimental and the calculated values are shown in Fig. I’, curve I. The experiments were repeated with a smaller amount of oxine (B = 4.3 * 10-q. The results as well as the calculated values are shown in Fig. I, curve II.
PO. 10
.
1.6
1.7
I.6
1.9 2.0
2.1
2.2
2.3
-
2.4
2.Y
26
2.7
2.8
2.0
S.O+S.I
il.2
PH
Fig. f. The extraction of copper WiLh oxinc and chhroform as a fllnCtiOn of pH. Curve I. Calculatccl extraction error B = 8 - roe3. -I- - ~xpcrimcntally found extraction Cure II. Cnlculatcci extraction error R = 4.3 . 10-S. 0 = cxpcrimcntally founcl extraction
error. error.
Nickel - oxine - chloroform The values of f, B, A and n, which depend only on the conditions chosen can be calculated in the same way as in the experiments with copper-oxine-chloroform. The values of K,, K&, KLn and E,, are also the same,,of course. For the solubility product of nickel oxinate, IRVING AND WILLIAMSON found a value of 7.9 . x0 -23. From the experimental data of BORREL AND PARISH, a value of 7 x0-23 can be calculated, and this is used in the following calculations. The solubility of nickel oxinate in chloroform was determined by shaking pure nickel oxinate for 24 h and determining the nickel in the solution. This solubility proved to be nil, hence it would seem that no extraction is possible. Nevertheless, this extraction has been published It-18. Surprisingly, when a nickel solution (PH = 6) is shaken with a solution of oxine in chloroform a definite extraction is obtained. The chloroform solutions, however, are very unstable, nickel oxinate precipitates and ‘after a short time the chloroform is free of nickel. l
References
9. 406
M. OOSTING
404
VOL,
21 (1959)
It can be assumed that the undissociated but not yet precipitated nickel oxinate is extracted from the aqueous phase, and forms chloroform-insoluble NiOxz. 2 aq with the water dissolved in the chloroform. UMMLAND AND HOFPMANN’D found that chloroform
solutions
of
metal
oxinates
were
stabilized
by
the
addition
compounds, n-butylamine being one of the most effective. t&at the ut-butylamine replaces the water in an equilibrium:
organic
NiOx2 - zHz0
f
z IJ.~. -;-t NiOxa * z b.s.
+
of
polar
It is supposed
2I-120
in which b.a. is written for +s-butylamine. The compound NiOxz. z b.a. is soluble in cllloroforni. ‘I’hc solubility of nickel oxinate was the.rcforc dctcrmined in chloroform in presence of +butylamine by shaking an aqueous solution of nickel sulphate containing a large excess of +butylamine with a chloroform solution of oxine for 8 h. At the end of this period, the aqueous phase contained a green precipitate of nickel oxinate which proved to be readily soluble in chloroform, therefore the chloroform phase was considered to bc a saturated solution of nickel oxinate*. The concentration of nickel oxinate in this perfectly stable solution was found to be 5.0 - IO-” mg moles/ml. The oxfierimental
extraction
ewor
50 ml of water containing I mg of nickel as nickel sulphate, I ml of n-butylamine and a few drops of dilute sulphuric acid were shaken with a solution of 49.5 mg df oxine in IO ml of chloroform. After separation of the phases, the prr of the aqueous phase was measured; in the aqueous’and/or chloroform phase, nickel was determined colorimctrically with dimethylglyoxime20 after the destruction of oxine with sulphuric-perchloric acids. The results are given in Table IV. TABLE _-_---_.-
.--_I-.--_fiH
---.-----._--.----__---__-
The calcdatcd
extraction
IV
aqueous phua
.----_I.-.__-_
mg 01 trickcl
.oo
2.91
I
3.10 3.rG 3.40 3.00 3.72, 4.03 4.66 6.47
o.gG o.5G 0.25 0.09 0.03 0.00 0.00
chloroforn, phaac mg 01 nickel _--_ 0.02
0.03 0. IO 0.74 I .oo 1.02
error
From the values LNlora = 7 * 10-23, NiOxa sat. chloroform = 5 - IO-~, R- from Table I, using Z3 = 49.5/r45 * Iso = 6.8. x0-3, the extraction error can be calculated. The calculations are shown in Table V. l
* WC considcr’khe reaction: importance for our purposes. Refevances
p. 406
NiOx2 + z b.n, -+ NiOxa-z
b.a. a scconclary one, which is of no
VOL.
21
EXTRACTION
(1959)
EQUILIBRIA. TABLE
(R-)Y.l -
PH
(R-)
1
2.7 2.8
5.3
* x0-20
2.5
1.2
* 10-12
5.6
3.4 3.5 3.6 ;::
0.99 0.98 0.96
10-24
0.91
10-24
0.82 0.70
. 1043 . 10-22
3.3 7.5
.
K
.
3::
: :“,I:“3
I.2
a 10-2’
5.8
* 10-23
5.0 9.6. 1.7 3.2
IO-”
2.4
.
10-21
I
10-17
.t*s
.
,o-21
* to-22 * 10-22
8.0 ‘05
* 10-2’ . 10-20
2.7
.
IO-20
* md; -
ii:;
.
,o-20
.
1.2
* 10-13
9.6 1.8 2.5 4.8 8.1
4.3 4.4 4.5
g
2.3
I.00
0.54 0.38
4.0
. *o-22 7.5 : ::I:; 1.4
0.02
4.2
* 10-2’ IO-21
0.02
.
0.01
5.8 a IO-~* I.1 * 10-Z” I.9 . ,o-20
. ,o-10 3.8 . xo-lu
- mw:; .
10-23
0.23 0.14 0.08 0.04
.2 2.2
2.2
IO_‘6
-
* 10-28 * x0-25 . 10-24
6.6 I.5
*
3.5
Its.
a
* x0-23
. IO-In * *o-LB G.3 * 10-18 1.3 * x0-*7 2.5 . IO-”
*o-22 10-22
m+’
I LlvWJ‘,
l
I.2
.
4.1 4.2
0.01 0.00 0.00
00
s_ +
. 10-24 - 10-24
(R-)
ml.
* x0-23 10-23
* 10-10 . 10-10 5.8 * x0-10
3.9 4.0
NiOx,
a.~.-
1.2
. xo-lU ’ 10-10
1.4 3.2
;:;
-
3-o
G.4
3.1
II
405
V
2.8 5.8 I.5
2.5
2.9 3.0
s
II.
70
t
i
=O
I
50 40
7
2.8
2.9
3.0
3.1
1.2
3.2
1.4
5.S
3.b
3.7
3.0
3.9
4.0
4.1
42
43
4A
45
46
4.7
-PH
Fig.
2.
The
extraction function of
of nickel PH.
with
Calculated
oxine and chloroform in presence of n-butylaminc and cxperimcntally found extraction errors.
as R
‘The calculated values and the experimentally found extraction errors are shown in Fig. 2. It can be concluded that in both systems the course of the extraction is predicted correctly by the equations given in our previous paperl. References p. 406
VOL.
M. OOSTXNG
406
21
(IQSQ)
SUMMARY ‘Tllc ccluations given in a previous paper are shown to pretlict the course of solvent extraction as well as that of nickel - oxinc - chloroform. correctly in the cast of copper - oxinc - chloroform 130th pn and quantity of reagent prove to have the effect rcquirctl by the equations.
IAS &luations propcisdcs clans le prcmicr article cl’cxtraction par solvant: cuivrc-oxinc-chloroform
da ccttc s&ric ont Gtb appliqu&s et nickel -oxinc-chloroformc.
aux Gas suivants
%USAMMENFASSUNG &lit Jiilfe tlcr in ciner friihcren Vcrtlffcntlichung mitgctciitcn Cleiclrungcn wurdc clcr Vcrlauf rmcl Nickel - Oxin Kupfcr - Oxin -Chlorofor1n verfolgt: clcr Extraktion folgcnclcr Systcmc Chloroform. REFERENCES
’ M. Oosrrluc, Anet. C/&n. /f&z, z I (1959) 301. 2 J. J. Pox. ./. Clron. Sot., 97 (1910) I 1 rg. 3 1C. G. STONE AND L. FRIEDMAN, J. Am. Chcrn. Sue., Gg (1947) zag. 4 13. DAVIDSON, J. Chm. E&M., rg (1942) 22x. 70 (1g48) *lo. & J. P. ~HltIPS AND i_..1~. I~ERRIT. JR,, .I. Anz. Ci&?m.S0c., s W. STfSNsTRonx AND N. GOLIJSMITH, J. PJ~ys. Client., 30 (1926) 1683. 7 M. BORREL AND R, A. /in&. Ckinr. iictu. G (1952) 389. s G. BOCQU~ST AND IX. A. PARIS, AWL Chim. Acta, 11) (rg50) I. IJS. LACROIX, liltal. C/rim. Acta, I (11347) 260. lo F. UMLAND AND tl. ~+XIIIXT, ff8ra!.C/rim. AC/U, 16 (105.7) 334, 11 TH. Morr~~rsa AND P. I,. FUNDSACK, J. /Jm. Clwrt. Sac., 75 (1953) 2258. 1s W. 1). T~sh1.3wrsL~ AND A. ANIMAN,~~&I. Chim. Acfu, 2x (rg38) 1x49. 1s K. QUANDEL, Arcll. ~ise;i~i~t~enw., 14 (x941) 60‘1. 14 M. OosrrNG, Tlresis, Delft, 1953. 1* lI. bl. fHVING AND 13. J. P. WILtthhIS, kf~#h.dyS~, 77 (X952) 813. 1s 0. A. KENYON AND 1.1.A. BILWICK, .&zul. CjteJrt., 24 (1952) 1826. AND D. TV. HAWLEY, /Jml. C/rem., 25 (1953) 1369. I7 iA. SILVISRMAN, L. LMOUDY 1s l’r1. Molz~~an. Irzd. E1tg. Chem.. AIIU!. Ed., I 5 (1943) ~03. 1s L;. UMLAND AND W. HOPFMANN, Ragcru. Ckm., 68 (1956) 704. 20 A. CLAASSEN AND L. UhsTtNGs, &cc. tunv. d&u., 73 (1954) 783.
Received
SEPARATION
OF
COBALT(I1)
ANTIMONY(V) AND
FROM
CADMIUM(I1)
S. S, M. A. l
IRON(III),
BY
February
zoth,
1959
COPPElI(II),
ION-EXCHANGE
AND M, l-1. I;HUNL>KAR Uitivmsity,
Bctccrt (Lhst
Pufristnu)
In view of the clifficultics usually associated with the conventional method of separation of antimony by precipitation as sulphidc 1, a simpler rapid method was desirable. In a previous communication 2, a solvent extraction method for separating macro quantities of antimony(V) from nickel(II), chromium(III), lead(H), tin (IV), mercury(II) and small amounts of copper was described. Iron(III), cobalt(II), References
p. 4x0