Chemistry Reference
In-Depth Information
tAbLe 4.39
Distribution Ratios
a
and selectivity for the extraction of Am and eu from
Aqueous solutions [Hno
3
] into a nPHe solution of Picolinamide CMPo
Calixarenes (10
−
3
M)
Hno
3
Concentration
1 M
2 M
3 M
4 M
Ligands
10
−
3
M
10
−
2
M
10
−
1
M
CPw29
D
Eu
0.03
0.03
0.14
0.24
0.29
0.36
<0.01
D
Am
0.03
0.2
0.5
0.8
0.8
0.7
<0.01
S
Am/Eu
1.1
-
-
3.3
3.3
2.7
1.9
CPw29 BrCosan
3 × 10
−3
M
D
Eu
42.3
7.6
11.1
3.3
0.7
0.7
0.7
D
Am
0.03
7.2
8.8
1.0
1.2
1.0
<0.01
S
Am/Eu
1.3
5.4
0.6
2.7
1.6
1.7
1.5
CPn16
D
Eu
0.49
0.18
0.35
2.5
2.3
2.9
3.7
D
Am
0.77
0.3
0.97
6.9
4.9
5.3
5.9
S
Am/Eu
1.6
1.7
2.8
2.8
2.1
1.9
1.6
CPn17
D
Eu
0.85
0.44
0.58
0.39
<0.01
D
Am
<0.01
1.52
1.02
1.4
0.8
S
Am/Eu
-
1.8
2.3
2.4
2.1
CPn18
D
Eu
0.1
D
Am
0.2
S
Am/Eu
2.2
CPn18 BrCosan
3 × 10
−3
M
D
Eu
7.8
D
Am
12.5
S
Am/Eu
1.6
arene, but higher than that observed for OΦCMPO, particularly for Cv2. It has to be
pointed out that, in contrast to CMPO calixarenes, selectivity between lanthanides
is not marked.
Important works were devoted to the synthesis of calixarenes bearing differ-
ent groups (malonamide, glycolamide, pyrazolone, thiopyrazolone, terpyridine,
TTFA). Unfortunately, none of these compounds displayed a sufficient extracting
ability.
4.5.4.4 Dicarbollide (Cosan) and Calixarenes
In certain cases, cosan derivatives were used to improve the distribution ratios. In
particular, it was interesting to know if linking a calixarene and cosan could lead
to a synergistic effect in comparison to a mixture of these compounds. For the first
time, very sophisticated synthesis led to mixed compounds with cosan linked to the
wide rim or narrow rim of calixarenes or cavitands, Cos1 and Cos2, precursors of
new extractants.
18
