Transcript The influence of the magnetic field on the chemical reaction kinetic

October 9th-12th, 2014
Pamporovo, BULGARIA
The influence of the magnetic field on the
kinetic of the chemical reaction
Antonella De Ninno
ENEA – Italian National Agency for New Technologies, Energy
and Sustainable Economic Development
October 9th -12th, 2014
Pamporovo, BULGARIA
Summary
1.
The supra-molecular structure of liquid water
2.
Non-isolated systems out of equilibrium
3.
The effect of weak magnetic field on hydration of molecules
4.
Low Energy/matter exchanges in aqueous systems
Models of liquid water





Röngten: floating low density clusters in high density matrix

Robinson: domains of different density. The mixture model provides for the specific
volume the simple expression:
Bernal and Fowler : the revenge of the thermodynamics
Linus Pauling: the idea of hydrogen bond
Stanley and Teixeira the concept of infinite connected network or gel
In the last decades a great number of Molecular Dynamics (MD) simulations have been
carried on these bases.
V ( p, T )  f ( p, T )VI ( p, T )  1  f ( p, T )VII ( p, T )

Philippa Wiggins and Martin Chaplin extended this two phase liquid concept to room
temperature water in terms of: Low Density Water LDW is the hydrating water around
cell membranes and DNA double helix and High Density Water HDW is the “bulk” water.
Electrodynamic coherence
Later on, the existence of water in two different populations made up by
molecules having different degree of mutual correlation has been demonstrated
according to first principles: it can be proved that when
 the temperature T is lower than a critical T crit and the density N is higher
than a critical Ncrit
an ensemble of particles is subjected to a collective coherent oscillation
between a couple of internal levels of its components, thus generating a
 collective behaviour.
These collective behaviour is responsible for the long-range forces which
account for the actual existence of the condensed state.
Water represents a remarkable example of such a general
principle:
at room temperature a dynamical superposition of two populations, Fc , Fnc of
coherent and non-coherent molecules is thereby established, depending
on temperature.
According to this view, each atom or molecule belongs to one of the two fractions in
a dynamical sense, i.e. it fluctuates between a coherent and a non-coherent state
with a characteristic
time life ~ 5·10-15 sec. The coherent fraction represents
the lowest energy, ordered state while the non coherent fraction is populated by
monomers and dimers such as the gas phase.
The vibrational spectra of liquid water can be easily interpreted in agreement with
this theory .
Very recent time-resolved optical Kerr effect investigation (pub, on Nature Comm.)
have shown the evidence of the coexistence of two local configuration, interpreted
as high density and low density water form from ambient to supercooled conditions
Non-isolated systems out of equilibrium





Nanoaggregates – Alexander Konovalov
EZ water – Jerry Pollack
Aquaphotomics – Roumiana Tsenkova
Stable aggregates of water at room temperature – Vittorio Elia
…
Actually, we know that the Temperature is not the only parameter
influencing the fraction of coherent population:
 Temperature (“ab initio” calculations)
 Contact with surfaces (Pollack, Konovalov, Tsenkova)
 Exchange of low amount of mechanical energy with the environment
(Elia)
 Electromagnetic fields (will see in the following)
Water
•
•
•
Gases are fully non coherent systems
Liquids are systems where electron clouds are coherent
Solids are systems where nuclei, too, are coherent
•
Liquid water is peculiar, since the coherent oscillation connects
two electronic configurations that have extreme features:
F (T )  F (T )  1
1) The ground configuration where all electrons are tightly bound
(the ionization potential is 12.60 eV, corresponding to soft X-rays and to an
excitation temperature ofc145.000 °C !) nc
2) The excited configuration has an energy E=12.06 eV, only 0.54 eV below the
ionization threshold. So for each molecule there is an almost free electron!
Ө Ө Ө Ө Ө Ө Ө Ө Ө Ө Ө Ө
 ( )   r ( )  i i ( )
Let’s have a look on the
surface of solutes in water,
or, what is the same on a
wet surface.
Negatively charged surface
 ( )   r ( )  i i ( )
Positively charged surface
The general theory of the Van der Waals Forces (1961)
 The basic idea of the theory is that the interactions between nonpolar bodies is considered to take place through a fluctuating electro
magnetic field.
 These fluctuations are all the spectral components which have
wavelengths large compared to the atomic dimensions.
 All the properties of these long wavelength fluctuations, are
completely specified through the complex dielectric permeability of the
body.
 The only limitation is that all the characteristic dimensions of the
bodies must be large compared to the inter-atomic distances. Thus it
applies to the macromolecules involved in the biological reactions.
Forces between two bodies separated by a medium depend on the dielectric
constant of 1, 2
of the two bodies and 3 of the medium which fills the gap
d<l
l ~ 1-2 mm
l
1
2
l characterize the absorption
spectrum of the body
F (d ) 

8 d
2
3
d
1 (i )   3 (i )  2 (i )   3 (i ) 

 
d
 (i )   3 (i )  2 (i )   3 (i ) 
0  1

Suppose that both bodies are sufficiently rarefied.
From the point of view of macroscopic electrodynamics this means
that their dielectric permeability are close to 1.
We obtain the classical London formula (1930)
3  1
3 e4
U (d )   2 6
2m d
f1 (1 ) f 2 2 
0 0 12 1  2 d1d2

Attraction and repulsion depend on the medium which
fills the gap
It has to be noted that if the two bodies differ and the medium
between them is water the interaction can be either an attraction
or a repulsion:
If
1   3
and
 2  3
have opposite sign
then F < 0 and the bodies will repel each other.
If
1   3
and
 2  3
have the same sign
then F > 0 and the bodies will attract
for “large” separation, the forces are determined by the
electrostatic values of the dielectric constants.
Two atoms in water (Pitaevskii, 1959)
 Weak solution of N1 and N2 atoms in the same solvent
 Gap filled with pure water
 For small concentrations the dielectric permeabilities ε1 and ε2 differ
little from that of pure solvent ε3= ε
 1  i  
  2  i  
1
N
N
d



1 2
2 3
2
32 R
N1  N 10  N 2  N 20   i 
0

F ( R) 
This force corresponds to an interaction energy of the dissolved atoms equal to:
 1  i  
  2  i  
1
U ( R)  
d



3 6 
2
16 R 0  N1  N 10  N 2  N 20   i 
3

We see that when the dissolved molecules interact strongly
with the solvent the interaction forces between them are no
longer determined by their polarizability
but depend on the dielectric constant of the solvent !
Static dielectric constant
Dielectric properties of water
 (T )  Fcoh (T ) coh (T )  Fnoncoh (T ) noncoh (T )
 exp T 298 K  79
experimental value
 calc T 298 K  12
non interacting dipoles
 coh T 0 K  160
coherent domains
* with respect to the wavelength of the em fluctuation
large
distances
*
Aqueous solutions used by Prof. Konovalov ‘s group have typical
absorption line in their spectrum in the range of 200-600 nm.
Hence, whenever the average distance among particles exceed such a
length the following formula holds
23 c 1 1  N 0 2
U (d )  
(
) N 0
3
3
7
64 R  2 N
0
Energy is decreased by the formation of aggregates of
coherent water having a higher static dielectric constant
(Konovalov nanoaggregates)
The magnetic field may protect the pile-up of the energy
aligning the magnetic dipoles associated to the CDs thus
stabilizing the aggregates.
Average distance less than l 200/400 nm
depending on the substances
Average distance greater than l 200/400 nm
depending on the substances
The observed stable nano objects have a size of hundreds of
nanometers which is in the same range of the wavelength
characteristic of the spectrum of the solute.
We suggest that whenever the dilution exceed a certain threshold
where the average distance among solutes d ≫ l water Coherent
Domains gather to form a mesoscopic region in order to decrease
the free energy of the system.
Stable water cluster may have a permanent electric charge
(ζpotential) due to the quasi-free electrons at the border of the
CDs. In bulk water such a feature cannot be observed because the
lifetime of a CD is too short (10-15 sec)
We are talking about the arrangement of extended structures formed by the
water coherent domains and the solutes.
It is also possible that their collective vibrations could become coherent due
to the principle of minimization of energy, this implies that water shift its
oscillation frequency or (what is the same) its energy gap.
Experimental hints:
Blu shift of the IR spectrum of EZ water
aquaphotomics
Water permittivity
short
distances
Hic sunt leones !
(here are the lions!)
* with respect to the wavelength of the em fluctuation
*
A film of water on the surface of a solid body (EZ water)
The chemical potential of the film per unit volume of the liquid is:
m

8 R
2
  F (i w ( ), i s ( ))
3
For “large” thickness
m ( R)
is proportional to R-4 with a coefficient
depending on the electrostatic dielectric constants of the film
and of the solid surface
 solid
 water
The function may change sign and be non-monotonic according to the sign
of the difference
( w   s )
Open the way for a theory for EZ water
Permittivity vs frequency at
25°C for Nafion 117
( coh   Nafion )
( noncoh   Nafion )
The collective vibration of dangling charges (SO 3- sulfonic groups)
of the surface and of the coherent water molecules could become
coherent (blue shift) in order to further reduce the energy of the
system water + Nafion
0
0
Dielectric constant 160
Nafion
Dielectric constant 12
Non coherent molecules can enter into
the Nafion structure.
After a threshold of hydration they are
attracted toward the surface
Nafion
Nafion acts as a phase separator
EZ water
The effect of weak magnetic field on hydration
of molecules
FTIR spectra of aqueous solution of L-phe
Phenylalanine
Exposure to a static magnetic field 1 Gauss – 30 minutes
pH  pK a  log
unprotonatedform(base)
 protonatedform(acid )
pKa1 = 2.88± 0.03 MAGNETIC FIELD pKa1 = 3.31± 0.04
TheDexposure
of L-Phe to the magnetic field has an effect similar
=+0.43
to the exposure to NIR radiation, which is known to cause
significant changes in the hydration properties of such molecules.
1
pKa2= 9.51±0.04
MAGNETIC FIELD pKa2= 9.41±0.04
D2=-0.1
H 2O
modifications
aggregation
pKa shift
The unusual property of EDTA is its ability to chelate or
complex metal ions in 1:1 metal-to-EDTA complexes
C
r
(
H
O
)

E
D
T
A

C
r
(
E
D
T
A
)

6
H
O




3
 4

2
6
a
q
.
a
q
.
Classic form (H4y) EDTA

l
i
q
.
a
q
. 2
Cr-EDTA
Following the formation of the complex
via the UV-vis spectroscopy
Two cuvettes C1 and C2.
To the C2 cuvette have been applied
two permanent, rare earth oxides,
magnets having dimensions 52 x 13x 7
mm. The magnitude of the field is
2800±100 Gauss inside the cuvette.
Absorbance at l = 540.0 nm of the EDTA-Cr(III)
complex.
Kinetic of formation of EDTA-Cr (III)
complex: difference in the absorbance of
exposed – not exposed samples.
Kinetic data, available in the literature, show that the rate constant
for the reaction is accelerated with increasing the EDTA:
 concentration,
 pH,
 temperature,
 decreasing ionic strength and dielectric constant of the reaction
medium
These results point towards an associative mechanism supported by
the decrease of enthalpy and a large negative entropy for substitution
of water by ligand compared to water exchange.
Substitution of water by a ligand

1
D
H

5
7
.
2

3
K
J
m
o
l

1
D
S


1
2
8

8
J
K
m
o
l
Water exchange

1
D
H

1
0
9
.
6
K
J
m
o
l

1
D
S


1
2
J
K
m
o
l
The much higher entropy gain of the reaction implies a larger scale ordering
realized in the construction of the complex
The magnetic field increases the kinetic constant affecting the ordered
structures of water molecules surrounding the hydrophobic chains.
It increases the fraction of non coherent molecules available for the
substitution of water by a ligand.
The energy of the system water + solute is decreased.
Other experimental reports
1.
Very High field: 10T
1.
2.
High field: 6T
1.
3.
Refraction index increases of 0.1% (Hosoda et al.- J. of Phys Cem A,
2004, 108, 1461)
Modifications when O2 is dissolved: Raman bands, contact angle,
electrolytic potential (Otsuka and Ozeki – J. of Phys Chem B Lett
2006,110,1509-1512)
Low field: 45-65 mT
1.
Vaporization enthalpy increases
2.
Viscosity increases
3.
Surface tension increases (Toledo et al. – J. of Mol Struct 2008, 888,
409-425)
Energy/matter exchanges in aqueous systems
 The spontaneous evolution of the system is influenced by the
environment (temperature, energy exchange, magnetic field).
 In general it can be said that a system doesn’t reach the
thermodynamic equilibrium unless the system is isolated. This principle
is valid not only for the living matter but also for the inanimate one.
 These considerations have been the basis of the experimental work of
an Italian chemist, Giorgio Piccardi, in the ‘50s.
we suggest that water is the
medium in which these exchanges
at very low energy occur.
Thank you for your attention