Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1118456
The subject of this invention is a procedure for the
cleavage of ethereal links by the use of chloroiodites of
quaternary ammonic tensioactive compounds having as general
formula (I)
R ~ +
R N - R4 ICI2-
R3
where: Rl and R2 represent Cl-C4 alkyl groups; R3
represents, too, a Cl-C4 alkyl group, or C10-Cl8
alkyl group or a benzyl group; R4 represents a benzyl
group or a 2-benzyloxy-ethyl group or a 2- [2- (p-1,1,3,3-
tetramethylbutylphenoxy)- ethoxy]-ethyl group; or the group
R2R2R3N represents the pyridinium cation and in this
case R4 is an alkyl C10-Cl8.
These compounds are soluble in ethanol or methanol,
from which they may be recrystallized, are slightly
soluble in water, but can be easily solubilized in
solutions of non ionic tensioactive compounds (Tween*,
Span*, etc.) or of the quaternary ammonium salts them-
selves (benzalconium, cetyl-pyridinium, cetrimide), in
which the respective chloroiodites perfectly dissolve
and give rise to thermodynamically stable solutions.
However, under particular conditions which we shall
describe in detail hereunder, the solutions can liberate
hydroiodic acid and thus give rise to particular reactions.
According to the invention, one of these reactions is
unexpectedly constituted by the capacity of hydrolyzing
ethereal links in aqueous solution of cationic tensioactive
* Trade Mark
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1118456
compounds above the critical mycellar concentration (CMC);
it can therefore be assumed as a particular type of
mycellar catalysis.
According to the invention there is provided method
for hydrolysis of ethers, in which ethers are treated with
the chloroiodite of a quaternary ammonic tensioactive
compound having as general formula (I)
R
~ +
R2 - -____________N R4 ICI2
where: Rl and R2 represent Cl-C4 alkyl groups; R3
represents, too, a Cl-C4 alkyl group, or C10-Cl8
alkyl group or a benzyl group; R4 represents a benzyl
group or a 2-benzyloxy-ethyl group or a 2- [2- (p-1,1,3,3-
tetramethylbutylphenoxy1- ethoxy]-ethyl group; or the
group R2R2R3N represents the pyridinium cation and
in this case R4 is an alkyl C10-Cl8, dissolved in an
aqueous solution of a chloride or bromide of the same or
of another quaternary ammonic tensioactive compound.
The importance of the reaction lies in the fact that,
with these chloroiodites, it is possible to easily degrade
molecules even insoluble in water, extremely stable and
hardly degradable by means of other chemical or physical
methods. A typical reaction having obvious extreme
$mportance is the demolition of 2,3,7,8-tetrachloro-
dibenzodioxin (TCDD, "dioxin"), sadly known after the
Seveso ecological catastrophe. The chloroiodites of
quaternary ammonic tensioactive compounds (of which we
already know the strong bactericidal action associated
with a slight toxicity; see U.S. Patent No. 4,192,894
issued on March 11, 1980 to Dr. L. Zambeletti S.p.A.
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.. . .
111~ 6
(may therefore be used in the ecological field for
purifying places or lands polluted by TCDD or by other
toxical ethers (such as chlorinated dibenzofuranes). It
is well known that hydroiodic acid is often used to cleave
ethers, just because the I ion is the strongest nucleo-
philic reagent which can exist in highly acid solutions
such as the solutions necessary to carry out ether
cleavage.
However, the conditions under which hydroiodic acid
hydrolyses ethers (high concentration, very high acidity)
obviously are
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such as to exclude its use in purifying rooms or lands. The
unexpected and unforseeable aspect of the hydrolysis of eth-
ereal links carried out according to the invention lies in
the fact that hydroiodic acid liberated by chloroiodites acts
in conditions of extreme dilution and nonetheless is tremen-
dously effective. This may be attributed (even if the hypothe-
sis is not to be intended as a limitation to the invention)
to a phenomenon of mycellar catalysis.
The fundamental characteristic of cationic mycellae
in comparison with anionic ones is due to the fact that the
presence of the positive charge on the nitrogen atom makes
it less exposed to the action of counter-ions: the result
of it is a closer molecular structure and higher solubil-
izing power of non polar molecules, though with the same
molecular weight, always in comparlson with that of an1onic
mycellae. Moreover, in mycellar catalysis it is very
important to know the disposition of the solubilized molecule
which may be differently placed inside the mycellae, and
namely it may be deep in the mycella, may penetrate in a
radial position of the mycella, remain near to the surface
or finally may be simply adsorbed on its surface.
Now, it is clear that the acceleration or slowing
down of organic reactions at mycellar phase may be strongly
affected not only by the type of mycella but also by the
type of solubilization undergone by certain organic molecule,
and by its possible distribution between mycellar phase and
aqueous phase. Clearly, in the reactions to which the
invention refers, the different factors favourably contribute
to the degradation of the ethereal molecule by the chloro-
iodite.
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According to the invention, the cleavage of ethersis performed by treating the ethers with a solution of
chloroiodite of a quaternary ammonic tensioactive compound
in an aqueous solution of the same (or of another)
tensioactive compound under the form of chloride or ~romide.
The concentration of quaternary ammonic tensioactive
chloride or bromide may be of the order of 0.01-0.5 moles/
liter, while the concentration of the corresponding ~or of
other) chloroiodite in this solution may vary from 0.01 to
10 g/liter. The degradation of the ethereal molecule occurs
at room temperature and is not affected by light.
The following examples illustrate the invention.
EXAMPLE 1
a) A 0.1 M aqueous solution of cetylpyridinium chloride is
prepared; 10 ml are taken to which approx. 50 mg of
cetylpyridinium chloroiodite are added. The solution
is stirred until completely dissolved. The solution
thus obtained is called "solution A".
b) 5 mg of xanthene are added to 10 ml of a 0.1 M
solution of cetylpyridinium chloride and stirred until
complete solution and taking care to operate always in
the dark. Solution A is then added and the resulting
solution is diluted to 80 ml with distilled water.
Then optical density measurements are carried out from
240 to 330 nm at preset time intervals (for instance
at 0 hrs, 30 minutes, 1 hour, 2 hrs, 3 hrs, 4 hrs).
A solution having a concentration of cetylpyridinium
chloride and cetylpyridinium chloroiodite equivalent
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- to the one resulting from the previous dilution is used
as blank.
Results
According to the residence time of xanthene in
the chloroiodite solution a gradual changement in the
absorption spectrum and a decrease in the value of the
optical density rèferring to the peaks characteristic of
xanthene are obtained.
EXAMPLE 2
5 mg of benzofurane are dissolved by stirring in 10 ml
of a 0.1 M solution of cetylpyridinium chloride.
Always operating away from light, 10 ml of solution A
described in Example 1 a) are added. The measurements
of optical density from 600 to 210 nm are performed
at preset time intervals (for instance 0 hrs, 30 minutes,
1 hour, 2 hrs, 3 hrs, 4 hrs). A 0.1 M solution of
cetylpyridinium chloride, to which 5 mg/ml of cetyl-
pyridinium chloroiodite are added, is used as blank.
Results
According to the time the benzofurane solution remains
with the chloroiodite solution, a gradual changement in the
absorption spectrum and a decrease in the value of the
optical density referring to the peaks characteristic of
benzofurane are obtained.
EXAMPLE 3
5 ml of a 0.1 M solution of cetylpyridinium chloride
are added to 20 mcg of 2,3,7,8-tetrachloro-dibenzo-
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p.dioxin (TCDD) and stirred until completely dissolved.
~ To 3 ml of this solution 3 ml of a 0.1 M solution of
cetylpyridinium chloride (in which 6 mg/ml of cetyl-
pyridinium chloroiodite had already been dissolved) are
added, taking care to keep the solution always in the
dark. The blank consists of a 0.1 M solution of cetyl-
pyridinium chloride containing 6 mg/ml of cetylpyridin-
ium chloroiodite. Optical density from 400 to 200 nm
is measured at preset time intervals (for instance
0 hour, 30 minutes, 1 hour, 2 hrs, 3 hrs, 4 hrs, 2
24 hrs, 48 hrs, 72hrs).
Results
According to the time TCDD remains in the Chloro-
iodite solution, in the absence of electromagnetic radiations,
it is possible to notice the gradual decrease in the optical
density characteristic of the absorption peak of TCDD at
290 nm and the subsequent appearance of other peaks around
275 nm, which are typical of some decomposition products of
TCDD (for instance the corresponding 2-phenoxy-phenol), well
known and identified by other authors after photochemical
decomposition of TCDD (see figure 1). Furthermore, portions
of the solution in question have been exhaustively extracted
with methylene chloride,- at different times, namely 7 days
and 20 days after their storage in dark place. The extracts,
evaporated to dryness, have been dissolved with hexane and
submitted to fragmentography by means of the instrument
LKB 9000 S. The sample after 7-days' treatment shows 85~
degradation of originally present TCDD, while degradation
reaches 96~ after 20 days.
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EXAMPLE 4
a) 50 mg of benzalconium chloroiodite are dissolved by
stirring in 10 ml of a 0.1 M aqueous solution of benzal-
conium chloride. The obtained solution is called
"Solution B".
b~ 5 mg of benzofurane are introduced into 10 ml of a
0.1 M solution of benzalconium chloride and stirred
until complete solution; then, away from light,
solution B is added. Optical density from 600 to
210 nm is measured at preset time intervals (0 hrs,
30 minutes, 1 hour, 2 hrs, 3 hrs, 4 hrs), using a 0.1 M
solution of benzalconium chloride plus 5 mg/ml of
benzalconium chloroiodite as blank.
Results are the same as in example 2.
EXAMPLE 5
5 mg of xanthene are added to 10 ml of an aqueous 0.1 M
solution of benzalconium chloride and stirred until
completely dissolved; then, always away from iight,
10 ml of solution B prepared as described in Example
4 a) are added. Optical density measurements from
240 to 330 nm are carried out at preset time intervals
(0 hrs, 30 minutes, 1 hour, 2 hrs, 3 hrs, 4 hrs). A
0.1 M solution of benzalconium chloride, to which
5 mg/ml of benzalconium chloroiodite have been added,
is used as blank.
Results
In proportion to the time the xanthene solution
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remains with the benzalconium chloroidite solution, a grad-
ual changement in the absorption spectrum and a decrease in
the value of the optical densit~ referring to the peaks
characteristic of xanthene are obtained. (Fig. 2).
EXAMPLE 6
a) A 0.1 M solution of cetrimide chloride in water is
prepared; 10 ml are taken and approx. 50 mg of cetrimide
chloroiodite are added to them. The solution is
stirred until complete solution (solution C).
b) 5 mg of benzofurane are added to 10 ml of 0.1 M
solution of cetrimide chloride stirring until complete
solution. Always operating away from light, solution C
is added. Optical density measurements from 600 to
210 nm are carried out at preset time intervals (0 hrs,
30 minutes, 1 hour, 2 hrs, 3 hrs, 4 hrs). A 0.1 M
solution of cetrimide chloride, to which 5 mg/ml of
cetrimide chloroiodite are added, is used
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1~184S6
as blank.
Results
According to the time the benzofurane solution remains
with the cetrimide chloroiodite solution, a gradual change-
ment in the absorption spectrum and a decrease in the value
of the optical density relative to the peaks characteristic
of benzofurane are obtained.
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