Supramolecular Catalytic Systems Based on a Cationic Amphiphile and Sodium Polystyrene Sulfonate for Decomposition of Organophosphorus Pollutants

Article abstract of DOI:10.1134/S1070428019010032

A supramolecular catalytic system for hydrolytic decomposition of toxic phosphorus acid esters has been obtained on the basis of a cationic surfactant with a morpholinium head group and sodium polystyrene sulfonate. Self-organization of the new binary catalytic system has been studied by tensiometry, conductometry, pH-metry, spectrophotometry, and dynamic and electrophoretic light scattering, and its aggregation thresholds have been determined. High solubilizing ability of the system with respect to a hydrophobic guest has been revealed. The morpholinium surfactant has been found to accelerate the hydrolysis of phosphonates up to 50 times in comparison to the reaction in water. The apparent hydrolysis rate constant in the presence of the polyelectrolyte decreases threefold due to reduction of the reactant binding constants.

Full text of DOI:10.1134/S1070428019010032

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2019, Vol. 55, No. 1, pp. 11–16. © Pleiades Publishing, Ltd., 2019.
Russian Text © D.A. Kuznetsova, D.R. Gabdrakhmanov, E.A. Vasilieva, S.S. Lukashenko, L.R. Ahtamyanova, I.Sh. Siraev, L.Ya. Zakharova, 2019, published
in Zhurnal Organicheskoi Khimii, 2019, Vol. 55, No. 1, pp. 22–29.
Dedicated to Full Member of the Russian Academy of Sciences
A.I. Konovalov on his 85th anniversary
Supramolecular Catalytic Systems Based on a Cationic
Amphiphile and Sodium Polystyrene Sulfonate for
Decomposition of Organophosphorus Pollutants
a
a
a
a
D. A. Kuznetsova ,* D. R. Gabdrakhmanov , E. A. Vasilieva , S. S. Lukashenko ,
a
a
a
L. R. Ahtamyanova , I. Sh. Siraev , and L. Ya. Zakharova
a
Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center, Russian Academy of Sciences,
ul. Akademika Arbuzova 8, Kazan, 420088 Tatarstan, Russia
*
e-mail: dashyna111@mail.ru
Received November 21, 2018; revised December 2, 2018; accepted December 4, 2018
Abstract—A supramolecular catalytic system for hydrolytic decomposition of toxic phosphorus acid esters has
been obtained on the basis of a cationic surfactant with a morpholinium head group and sodium polystyrene
sulfonate. Self-organization of the new binary catalytic system has been studied by tensiometry, conductom-
etry, pH-metry, spectrophotometry, and dynamic and electrophoretic light scattering, and its aggregation
thresholds have been determined. High solubilizing ability of the system with respect to a hydrophobic guest
has been revealed. The morpholinium surfactant has been found to accelerate the hydrolysis of phosphonates
up to 50 times in comparison to the reaction in water. The apparent hydrolysis rate constant in the presence of
the polyelectrolyte decreases threefold due to reduction of the reactant binding constants.
Keywords: self-organization, phosphorus acid esters, supramolecular catalysis, hydrolysis, kinetics, sodium
polystyrene sulfonate, surfactants.
DOI: 10.1134/S1070428019010032
At present, organophosphorus compounds are used
in various fields, in particular as pesticides and toxic
agents [1–5]. Pollution of the environment with
organophosphorus compounds can pose a serious
problem. For example, instances of poisoning by such
compounds through soil and food have been reported
dextrins [11], and various surfactant-based micellar
systems [12–15]. In addition, the catalytic activity of
supramolecular systems can be considerably enhanced
via introduction of auxiliary components such as high-
molecular-weight compounds [9, 12] and metal ions
[12], so that the efficiency of catalysts could be
changed from inhibition to acceleration by several
orders of magnitude.
The present work continues the series of our studies
aimed at developing supramolecular catalysts for the
decomposition of organophosphorus compounds.
Herein, we report a new supramolecular system based
on a cationic surfactant, 4-hexadecyl-4-methylmorpho-
[6]. Therefore, development of methods for utilization
of organophosphorus pollutants is a topical problem,
and efforts of many research teams are focused on this
field [7, 8]. In particular, Ma et al. [7] have synthesized
a binuclear ligand, (5-vinyl-1,3-phenylene)bis[bis(1H-
imidazol-2-yl)methanol], containing catalytically ac-
tive centers and exhibiting a high activity in the
dephosphorylation of the known organophosphorus
toxicant paraoxon. Supramolecular systems offer
a great potential for controlling the kinetics of decom-
position of pollutants [8]. We previously showed that
proper choice of components for such systems allows
the rate of decomposition of phosphorus acid esters to
be varied over a wide range [9–13]. In particular, the
catalytic agents may be calixarenes [9, 10], cyclo-
n
C H
16 33
N
Me
Br–
O
SO Na
3
1
SPS
1
1

1
2
KUZNETSOVA et al.
Scheme 1.
CH Cl
2
O–
O
CH
2
Cl
HO
P
OR
OH–
+
+
P
OR
O
O
O N
2
O N
2
P1, P2
6 13
P1, R = Et; P2, R = n-C H .
γ, mN/m
linium bromide (1); its catalytic activity was controlled
by adding a polyelectrolyte component, sodium poly-
styrene sulfonate (SPS). The ability of the proposed
system to act as a supramolecular catalyst was tested in
the alkaline hydrolysis of alkyl 4-nitrophenyl chloro-
methylphosphonates P1 and P2 as model reactions
7
0
(
Scheme 1).
Taking into account that the catalytic properties of
6
5
0
0
supramolecular systems are closely related to their
aggregation ability, we initially estimated their
aggregation characteristics at different surfactant con-
centrations and fixed SPS concentrations (1, 3, 5 mM)
by tensiometry and conductometry. The addition of
a small amount of SPS (1 mM) to a solution of 1 led to
the appearance of two critical points on the surface
tension isotherm (Fig. 1). The first critical point
1
2
3
(
inflection point at 0.7 mM) corresponds to the con-
4
0
centration at which polymer–colloid complexes are
formed (critical aggregation concentration, CAC), and
the second inflection point (1.5 mM) corresponds to
the critical micelle concentration (CMC) of an indi-
vidual surfactant. As the concentration of SPS in the
system increased to 3 and 5 mM, the surface tension
isotherms displayed only one critical point correspond-
ing to the CAC. The CAC values are 2.3 and 3.2 mM
at SPS concentrations of 3 and 5 mM, respectively.
Increase of the CAC with rise in the polyelectrolyte
concentration is typical of systems consisting of a ionic
surfactant and an oppositely charged polyelectrolyte,
since the number of anionic fragments increases in
parallel with the SPS concentration, and a larger
number of surfactant molecules are necessary for
binding thereto.
0
.0001
0.001
, M
0.01
c
1
Fig. 1. Surface tension isotherms (25°C) of the binary
systems 1/SPS at SPS concentrations of (1) 1, (2) 3, and
3) 5 mM.
(
6
00
00
00
3
2
4
1
According to the conductometric data (Fig. 2), all
systems display a bend on the dependence of the
specific conductivity on the surfactant concentration at
the same concentration of the latter, which is likely to
reflect formation of free surfactant micelles, since the
given critical concentration coincides with the CMC of
pure surfactant (1 mM).
2
0
.000
0.002
0.004
, M
0.006
0.008
c
1
The size distribution of aggregates formed in the
binary systems 1/SPS was estimated by dynamic light
scattering (Fig. 3). All systems showed the same trend:
Fig. 2. Surfactant concentration dependences of electrical
conductivity of the binary systems 1/SPS at SPS concentra-
tions of (1) 1, (2) 3, and (3) 5 mM; temperature 25°C.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 1 2019

SUPRAMOLECULAR CATALYTIC SYSTEMS
13
3
2
0
0
3
2
0
0
0
1
0
0
0
1
0
0
8
mM
8
mM
5
mM
mM
mM
.5 mM
mM
.5 mM
5
mM
mM
2.5 mM
2 mM
mM
3
3
2
1
1
0
1
1
10
100
, nm
1000
1
10
100
H
D , nm
1000
D
H
Fig. 3. Number-average particle size distribution in aqueous solutions of 1/SPS at SPS concentrations of (a) 1 and (b) 5 mM;
temperature 25°C.
~
10-nm particles corresponding to the size of SPS
tween the components, i.e., attraction of the positively
charged surfactant head groups to the negatively
charged sulfonate groups of the polyelectrolyte.
molecules are formed below the CAC, and the size
increases to 100–120 nm as the SPS concentration
exceeds the CAC; this may be rationalized by the
formation of polymer–colloid complexes (the size of
aggregates in solutions of the pure surfactant is
This assumption was confirmed by the turbidity
measurements, i.e., quantitative spectrophotometric
analysis of the polymer–colloid systems. The obtained
plots of the optical density of the systems 1/SPS versus
surfactant concentration proved the formation of
complexes via electrostatic interactions (Fig. 5). At
an SPS concentration of 1 mM, the system is stable
before and after the isoelectric point, whereas a solid
precipitated at the isoelectric point as a result of
coagulation process. At SPS concentrations of 3 and
5 mM, the turbidity increased as the system ap-
proached the isoelectric point, and precipitate was
formed after a time.
~
4 nm). It should be noted that the size of 1/SPS
complexes changes insignificantly as the surfactant
concentration increases.
The charge of aggregates was estimated by electro-
phoretic light scattering. It was found that the com-
pensation mode of variation of the zeta potential with
rise in the surfactant concentration is typical of such
systems (Fig. 4). In all cases, an isoelectric point was
attained at an equimolar ratio of the components. This
suggests electrostatic mechanism of interaction be-
1
00
3
5
0
0
2
3
2
1
2
3
1
1
0
–
50
–
100
0
.000
0.002
0.004
, M
0.006
0.008
0.0001
0.001
, M
0.01
c
1
c
1
Fig. 4. Surfactant concentration dependences of the zeta
potential of the binary systems 1/SPS at SPS concentrations
of (1) 1, (2) 3, and (3) 5 mM; temperature 25°C.
Fig. 5. Surfactant concentration dependences of the reduced
optical density (λ 400 nm) of the binary systems 1/SPS at
SPS concentrations of (1) 1, (2) 3, and (3) 5 mM; tem-
perature 25°C.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 1 2019

1
4
KUZNETSOVA et al.
0
.10
6
4
2
0
1
2
1
3
4
0
0
.05
.00
2
0
.0001
0.001
0.01
0.000
0.002
0.004
, M
0.006
0.008
c
1
, M
c
1
Fig. 6. Surfactant concentration dependences of the optical
density at λ 495 nm of the binary systems 1/SPS at SPS
concentrations of (1) 0, (2) 1, (3) 3, and (4) 5 mM; tem-
perature 25°C.
Fig. 7. Surfactant concentration dependences of the rate
constant of hydrolysis of phosphonate P1 in the presence
of (1) 1 and (2) 1/PSS (1 mM); 0.001 M NaOH, tempera-
ture 25°C.
The ability of surfactant–polyelectrolyte complexes
due to the fact that a large number of surfactant
aggregates are localized on the polymer chain of the
polyelectrolyte at higher concentration of the latter,
which hinders accessibility of the lipophilic core of
surfactant associates for the hydrophobic dye.
to act as nanocontainers for hydrophobic substrates
was demonstrated by spectrophotometric study of their
solubilizing capacity toward the hydrophobic dye
Orange OT. For this purpose, absorption spectra of the
triple system 1/SPS/Orange OT were recorded at
a fixed concentration of SPS and varied concentration
of 1. All systems displayed a pronounced ability to
solubilize the hydrophobic dye (Fig. 6) at concen-
trations above the CAC. The solubilizing capacities of
the surfactant–polyelectrolyte complexes insignifi-
cantly differed from each other and decreased as the
SPS concentration increased (Table 1). This may be
The ability of surfactant 1 and the system 1/PSS
(
1 mM) to catalyze alkaline hydrolysis of alkyl 4-nitro-
phenyl chloromethylphosphonates (Scheme 1) was
studied by spectrophotometry. Amphiphile 1 showed
pronounced substrate specificity for both phospho-
nates. Morpholinium surfactant 1 accelerated the
hydrolysis of P1 and P2 by factors of 20 and 50,
respectively. The reason is the effect of reactant
concentrating in micelles. Nonpolar substrate resides
in micelles, and hydroxide ions efficiently bind to the
positively charged head groups through electrostatic
forces. In the presence of SPS, the catalytic effect
decreases to 25 times in the reaction with P2 (Fig. 7,
curve 1) and to 6 times in the reaction with less hydro-
phobic substrate P1 (Fig. 8, curve 1). Presumably, the
addition of anionic polyelectrolyte to the organized
system based on surfactant 1 gives rise to a competi-
tion with hydroxide ions for binding to the surfactant
0
0
0
0
.15
.10
.05
.00
1
2
Table 1. Solubilizing capacities of the surfactant–polyelec-
trolyte binary systems
0
.000
0.002
0.004
, M
0.006
0.008
Solubilizing capacity,
System
c
1
mol of dye per mole of 1
1
–SPS (1 mM)
1–SPS (3 mM)
–SPS (5 mM)
0.033
0.025
0.024
Fig. 8. Surfactant concentration dependences of the rate
constant of hydrolysis of phosphonate P2 in the presence
of (1) 1 and (2) 1/PSS (1 mM); 0.001 M NaOH, tempera-
ture 25°C.
1
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 1 2019

SUPRAMOLECULAR CATALYTIC SYSTEMS
15
Table 2. Kinetic data for the hydrolysis of phosphonates P1 and P2 in the presence of surfactant 1 and 1/SPS system
[
processed by Eq. (4)]
3
–1
System
Phosphonate
kap/k
w
S
K′, L/mol
k
cat ×10 , s
P1
P2
P1
P2
20
50
06
25
210
821
082
156
0.051.6
215
1
050
1
/PSS
097
head groups and creates steric hindrances for hy-
droxide ions, so that the concentration of the latter in
the aggregates decreases. The rate constants calculated
by Eq. (4) (Table 2) suggest that the addition of SPS
leads to reduction of the surfactant–phosphonate
binding constants and rate constants for the reaction
in micelles.
The surface tension was measured by the Du Noüy
ring method using a Krüss K06 tensiometer. The
solution volume for tensiometric measurements was no
less than 10 mL. Prior to each measurement, the ring
was treated with ethanol and burned with a burner.
The electrical conductivities were measured with
an Inolab Cond 720 conductometer.
In summary, we have prepared supramolecular
systems on the basis of a cationic morpholinium
surfactant and sodium polystyrene sulfonate, deter-
mined critical aggregation concentrations for these
systems, and revealed their strong solubilization effect
on a hydrophobic dye. The obtained supramolecular
systems showed pronounced substrate specificity in the
alkaline hydrolysis of organophosphorus compounds
with different hydrophobicity. By passing from
micellar systems to polymer–colloid complexes, it
becomes possible to control the concentration region
of the catalytic effect, morphology and size of
aggregates, and the level of catalytic activity.
The dynamic light scattering study was performed
using a Malvern ZetaSizer Nano analyzer (He–Ne gas
laser, 4 mW, λ 633 nm; scattering angle 173°); the data
were processed by the supplied software for frequency
and phase analysis of scattered light. The particle size
was calculated by the Stokes–Einstein equation for
spherical particles [Eq. (2)]:
kT
πηR
D = –––––,
(2)
6
where k is the Boltzmann constant, T is the absolute
temperature, η is the solvent viscosity, and R is the
hydrodynamic radius. To remove dust, all solutions
were filtered through a Millipore filter with a pore
diameter of 450 nm before measurements.
EXPERIMENTAL
4
-Hexadecyl-4-methylmorpholinium bromide (1)
was synthesized according to the procedure described
in [16]. Phosphonates P1 and P2 were prepared as
reported in [17].
The electronic absorption spectra were recorded on
an Analytik Jena Specord PLUS 250 spectrophotom-
eter using cells with a variable cell path length which
was selected so that to ensure the optical density in
the range 0.5–0.8. The solubilizing capacity S was
calculated by Eq. (1):
Spectrophotometric study of the kinetics of hydrol-
ysis of phosphonates P1 and P2 was performed using
an Analytik Jena Specord PLUS 250 spectrophotom-
eter by measuring variation of the optical density at
λ 400 nm (4-nitrophenoxide ion) with time under
pseudo-first-order conditions.
The apparent rate constants k were calculated by
ap
Eq. (3):
ln(A
∞
– A
τ
) = kap τ + const,
(3)
b
S = ––,
(1)
ε
where A and A are, respectively, the optical densities
∞
τ
where b is the slope of the linear part of the depen-
dence of the maximum reduced optical density on the
surfactant concentration above the CMC, and ε is the
molar absorption coefficient of Orange OT which is
of the reaction solution by the end of the reaction and
at a time τ. The calculations were carried out by the
weighted least-squares method; mean values of three
measurements differing by no more than 5% were
taken into consideration.
‒
1
‒1
equal to 17400 L mol cm .
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 1 2019

1
6
KUZNETSOVA et al.
The kinetic data were analyzed using Eq. (4) which
7. Ma, X., Zhang, L., Xia, M., Zhang, X., and Zhang, Y.,
J. Hazard. Mater., 2018, vol. 355, p. 65.
implies formation of a substrate–micelle catalytic
complex [18]:
8
. Sjöblom, J., Lindberg, R., and Friberg, S.E., Micro-
emulsions, 1996, vol. 65, p. 125.
k
w
+ kcat K′
S
c
1
9. Pashirova, T.N., Zhil’tsova, E.P., Lukashenko, S.S.,
Gibadullina, E.M., Burilov, A.R., Zakharova, L.Ya., and
Konovalov, A.I., Russ. Chem. Bull., Int. Ed., 2016,
vol. 65, no. 5, p. 1272.
k
ap = –––––––––––,
(4)
1
S 1
+ K′ c
where k is the apparent pseudo-first-order rate con-
ap
stant, kcat and k are the first-order rate constants for
the reactions in the catalytic complex and in bulk
w
10. Zakharova, L.Ya., Mustafina, A.R., Valeeva, F.G.,
Ibragimova, A.R., Ablakova, Yu.R., Elistratova, Yu.G.,
Syakaev, V.V., Kudryavtseva, L.A., and Konova-
lov, A.I., Kolloid. Zh., 2008, vol. 70, no. 4, p. 485.
water, respectively, K′ (L/mol) is the reduced micelle–
S
substrate binding constant, and c is the concentration
1
of surfactant 1.
11. Kashapov, R.R., Lykova, A.A., and Zakharova, L.Y.,
Macroheterocycles, 2018, vol. 11, no. 2, p. 210.
1
1
2. Gabdrakhmanov, D.R., Valeeva, F.G., Semenov, V.E.,
Samarkina, D.A., Mikhailov, A.S., Reznik, V.S., and
Zakharova, L.Ya., Macroheterocycles, 2016, vol. 9,
no. 1, p. 29.
3. Samarkina, D.A., Gabdrakhmanov, D.R., Seme-
nov, V.E., Valeeva, F.G., Gubaidullina, L.M., Zakha-
rova, L.Ya., Reznik, V.S., and Konovalov, A.I., Russ. J.
Gen. Chem., 2016, vol. 86, no. 3, p. 656.
4. Gaynanova, G.A., Vagapova, G.I., Valeeva, F.G.,
Vasilieva, E.A., Galkina, I.V., Zakharova, L.Y., and
Sinyashin, O.G., Colloids Surf., A, 2016, vol. 489, p. 95.
5. Gabdrakhamanov, D.R., Samarkina, D.A., Seme-
nov, V.E., Saifina, L.F., Valeeva, F.G., Reznik, V.S.,
and Zakharova, L.Y., Phosphorus, Sulfur Silicon Relat.
Elem., 2016, vol. 191, nos. 11‒12, p. 1673.
CONFLICT OF INTERESTS
The authors declare the absence of conflict of
interests.
REFERENCES
1
. Taghani, A., Goudarzi, N., Bagherian, G.A., Arab
Chamjangali, M., and Amin, A.H., J. Sep. Sci., 2018,
vol. 41, no. 10, p. 2245.
1
1
2
3
4
. Raghapriya, R., Dosi, R.V., and Parmar, A., J. Assoc.
Physicians India, 2018, vol. 66, p. 18.
. Li, H., Yan, X., Lu, G., and Su, X., Sens. Actuators, B,
2
018, vol. 260, p. 563.
. Allan, I.J., Garmo, A., Rundberget, J.T., Terentjev, P.,
Christensen, G., and Kashulin, N.A., Environ. Sci. Pollut.
Res., 2018, vol. 25, no. 28, p. 28730.
16. Mirgorodskaya, A.B., Lukashenko, S.S., Yatske-
vich, E.I., Kulik, N.V., Voloshina, A.D., Kudryav-
tsev, D.B., Panteleeva, A.R., Zobov, V.V., Zakharo-
va, L.Ya., and Konovalov, A.I., Prot. Met. Phys. Chem.
Surf., 2014, vol. 50, no. 4, p. 538.
17. Toy, D.F. and Rattinbury, K.H., US Patent
no. 2922810, 1960.
18. Berezin, I.V., Martinek, K., and Yatsimirskii, A.K.,
5
6
. Gorecki, L., Korabecny, J., Musilek, K., Malinak, D.,
Nepovimova, E., Dolezal, R., and Kuca, K., Arch.
Toxicol., 2016, vol. 90, no. 12, p. 2831.
. Thadathil, N., Muralidhara, M., and Rajini, P.S., Comp.
Biochem. Physiol., Part C: Toxicol. Pharmacol., 2018,
vol. 210, p. 15.
Russ. Chem. Rev., 1973, vol. 42, p. 787.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 1 2019