236
C. De Stefano· C. Foti . A. Gianguzza . D. Piazzese . S. Sammartano
RNlc = (number of aminogroups) / (number of -CHz-groups) = 1, 0.75, 0.67, 0.625, 0.4,
for en, dien, trien, tetren and sper, respectively. By considering the RN/c term we obtain:
10gKi= -1.335 + 0.857i + 0.914 RNlc
(9.12)
By using the parameter R NiO it is also possible to obtain a general equation for apparent protonation constants. Calculations performed using all the protonation data
for i ~ 2 made it possible to formulate the following general relationships for the empirical parameters of Eq. 9.4:
al = 0.0317 + O.Ol77 nN
(9.4d)
a2 = -0.00507 nN+ 0.00379 RNlc
(9.4e)
a3 = 0.000285 nN
(9.4f)
Both apparent protonation constants and BA complex formation constants can be
calculated from protonation constants at different ionic strengths and the formation
constants of (am)ClH i i - 1 , (am)(S04)H i i - 2 , Mg(am)2+ and Ca(am)2+ complexes. This is
certainly possible for 5 ~ 15 (IT~ 0.3 mol rl) and i ~ 3, but for higher salinities and
for amines containing several amino groups, the probability of the formation of
ternary species such as (am)CI(S04)H'i- 3 or MgCa(am)4+ becomes significant. For
purposes of comparison, Table 9.11 shows experimentallogtJl* values and the relative
calculated ones at 5 = 35. Deviation, 0 = logm*(calc) -logm*(exp)' increases consistently with i, and mean deviation, £, can be expressed as a linear function of z*,
£ = 0.03 + 0.026 z*.
On the basis of the above observations, by way of example, Fig. 9.7 shows a speciation diagram for the spermine system in artificial sea water as a single salt (BA). High
yields of complex species of different forms of protonated spermine with the sea water anion component (A) are observed in a wide range of pH values. The most important species in terms of formation percentages is the one with the higher amine charge,
Table 9.11. Differences between experimental and calcuAmine
8' 1
8' 2
8' 3
8' 4
8' 5
lated values of apparent protonation constants of amines
en
0.05
0.11
dien
0.03
0.11
0.19
trien
0.02
0.07
0.14
0.20
tetren
-0.01
0.01
O.OB
0.15
0.21
sper
-0.03
0.01
0.09
0.20
b
0.03
0.06
0.l3
O.lB
(0.21)
e
a
wH~
8; = logf3; (calc) -logf3; (exp).
b e= mean values of 18;1.
C. De Stefano· C. Foti . A. Gianguzza . D. Piazzese . S. Sammartano
RNlc = (number of aminogroups) / (number of -CHz-groups) = 1, 0.75, 0.67, 0.625, 0.4,
for en, dien, trien, tetren and sper, respectively. By considering the RN/c term we obtain:
10gKi= -1.335 + 0.857i + 0.914 RNlc
(9.12)
By using the parameter R NiO it is also possible to obtain a general equation for apparent protonation constants. Calculations performed using all the protonation data
for i ~ 2 made it possible to formulate the following general relationships for the empirical parameters of Eq. 9.4:
al = 0.0317 + O.Ol77 nN
(9.4d)
a2 = -0.00507 nN+ 0.00379 RNlc
(9.4e)
a3 = 0.000285 nN
(9.4f)
Both apparent protonation constants and BA complex formation constants can be
calculated from protonation constants at different ionic strengths and the formation
constants of (am)ClH i i - 1 , (am)(S04)H i i - 2 , Mg(am)2+ and Ca(am)2+ complexes. This is
certainly possible for 5 ~ 15 (IT~ 0.3 mol rl) and i ~ 3, but for higher salinities and
for amines containing several amino groups, the probability of the formation of
ternary species such as (am)CI(S04)H'i- 3 or MgCa(am)4+ becomes significant. For
purposes of comparison, Table 9.11 shows experimentallogtJl* values and the relative
calculated ones at 5 = 35. Deviation, 0 = logm*(calc) -logm*(exp)' increases consistently with i, and mean deviation, £, can be expressed as a linear function of z*,
£ = 0.03 + 0.026 z*.
On the basis of the above observations, by way of example, Fig. 9.7 shows a speciation diagram for the spermine system in artificial sea water as a single salt (BA). High
yields of complex species of different forms of protonated spermine with the sea water anion component (A) are observed in a wide range of pH values. The most important species in terms of formation percentages is the one with the higher amine charge,
Table 9.11. Differences between experimental and calcuAmine
8' 1
8' 2
8' 3
8' 4
8' 5
lated values of apparent protonation constants of amines
en
0.05
0.11
dien
0.03
0.11
0.19
trien
0.02
0.07
0.14
0.20
tetren
-0.01
0.01
O.OB
0.15
0.21
sper
-0.03
0.01
0.09
0.20
b
0.03
0.06
0.l3
O.lB
(0.21)
e
a
wH~
8; = logf3; (calc) -logf3; (exp).
b e= mean values of 18;1.