Note: Descriptions are shown in the official language in which they were submitted.
1
Hydrophobic, functionalised particles
Description
The present invention relates to a stable mixture comprising surface-modified
particles which are
obtained by reacting metal oxide or semimetal oxide particles with at least
one compound selected
from among silicon-comprising compounds bearing at least one metaloxy radical
and optionally
further alkoxy and/or hydroxy radical(s) and at least one solvent, at least
one surface-active
substance or a mixture thereof, a process for producing the mixture, the use
of these particles in
systems in which they are brought into contact with at least one solvent,
where the mass ratio of
solvent to modified particle is greater than 500, and also the use of these
particles in
agglomeration-deagglomeration cycles.
Metal oxide and/or semimetal oxide particles which are functionalized on the
surface by means of
silicon-comprising compounds are known from the prior art.
WO 2009/059382 Al discloses, for example, hydrophobic modification of mineral
fillers and mixed
polymer systems. According to this document, hydrophobic modification is
effected by reaction of
the corresponding mineral particles with silanes, for example C3-C12-
alkyltrialkoxy silanes. That the
correspondingly hydrophobically modified particles according to WO 2009/059382
Al are
particularly stable in large amounts of solvents, optionally in the presence
of surface-active
substances, is not disclosed in this document.
In the light of the prior art, it is thus an object of the present invention
to provide particles which are
hydrophobicized on the surface and have a particularly high stability toward
large amounts of
solvents and/or surface-active substances.
This object is achieved by a stable mixture comprising surface-modified
particles which are
obtained by reacting metal oxide or semimetal oxide particles of metals of the
transition groups of
the Periodic Table of the Elements selected from Sc, Y, the lanthanides, the
actinides, Zr, Hf, Mn,
Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au and Cd, with at least one
compound of the
general formula (I)
R1n-Si(OR2)4-n (I)
where R1, R2 and n have the following meanings:
the radicals R1 are each, independently of one another, hydrogen, linear or
branched, optionally
CA 2832814 2018-06-07
2
functionalized C1-C30-alkyl, linear or branched, optionally functionalized C2-
C30-
alkenyl, linear or branched, optionally functionalized C2-C30-alkynyl,
optionally
functionalized C3-C20-cycloalkyl, optionally functionalized C3-C20-
cycloalkenyl,
optionally functionalized Ci-C20-heteroalkyl, optionally functionalized Cs-C22-
aryl,
optionally functionalized C6-C23-alkylaryl, optionally functionalized C6-C23-
arylalkyl,
optionally functionalized C5-C22-heteroaryl,
the radicals R2 are each, independently of one another, hydrogen, linear or
branched, optionally
functionalized C1-C30-alkyl, linear or branched, optionally functionalized C2-
C30-
alkenyl, linear or branched, optionally functionalized C2-C30-alkynyl,
optionally
functionalized C3-C20-cycloalkyl, optionally functionalized C3-C20-
cycloalkenyl,
optionally functionalized C1-C2o-heteroalkyl, optionally functionalized C5-022-
aryl,
optionally functionalized C6-C23-alkylaryl, optionally functionalized C6-C23-
arylalkyl,
optionally functionalized C5-C22-heteroaryl,
NR14+, where the radicals R1 can, independently of one another, have the
abovementioned
meanings,
a group of the general formula 1/(p-x*y) MP+Xx-y, where M is a metal atom
selected from the
group consisting of metals of the main and transition groups of the Periodic
Table of the
Elements, X is an anion, p is the oxidation number of the metal atom M, x is
1, 2 or 3 and y is
0,1 or 2,
and/or
a group of the general formula (11a)
-SiR1m(0R2)3-rn (11a),
where R1 and R2 have, independently of one another, the abovementioned
meanings and the
indices m can be, independently of one another, 0, 1, 2 or 3,
is 1, 2 or 3,
and contacting with CO2 in the same step or a separate step
and at least one solvent, at least one surface-active substance or a mixture
thereof, where at least
one radical R2 in the compound of the general formula (1) or in the group of
the general formula
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2a
(11a) is NR14* or a group of the general formula 1/(p-x*y) MP+Xx-y with the
abovementioned meanings
of RI, p, x, y, M and X.
In another aspect, this object is achieved by a stable mixture comprising
surface-modified particles
which are obtained by reacting metal oxide particles of metals of the
transition groups of the
Periodic Table of the Elements selected from Sc, Y, the lanthanides, the
actinides, Zr, Hf, Mn, Re,
Fe, Ru, Os, Co, Rh, 1r, Ni, Pd, Pt, Cu, Ag, Au and Cd, with at least one
compound of the general
formula (I)
R1n-Si(OR2)4-n (I)
where R1, R2 and n have the following meanings:
the radicals R1 are each, independently of one another, hydrogen, linear or
branched, C1-
C30-alkyl, linear or branched, optionally functionalized C2-C30-alkenyl,
linear
or branched, optionally functionalized C2-C30-alkynyl, optionally
functionalized C3-C20-cycloalkyl, optionally functionalized C3-C20-
cycloalkenyl, optionally functionalized Cl-C20-heteroalkyl, optionally
functionalized C5-C22-aryl, optionally functionalized C6-C23-alkylaryl,
optionally functionalized C6-C23-arylalkyl, optionally functionalized C5-C22-
heteroaryl,
the radicals R2 are each, independently of one another, hydrogen, linear or
branched,
optionally functionalized CI-Cm-alkyl, linear or branched, optionally
functionalized C2-C30-alkenyl, linear or branched, optionally functionalized
C2-C30-alkynyl, optionally functionalized C3-C20-cycloalkyl, optionally
functionalized C3-C20-cycloalkenyl, optionally functionalized Cl-C20-
heteroalkyl, optionally functionalized C5-C22-aryl, optionally functionalized
0e-C23-alkylaryl, optionally functionalized C6-C23-arylalkyl, optionally
functionalized C5-C22-heteroaryl,
NR14+, where the radicals R' can, independently of one another, have the
abovementioned meanings,
a group of the general formula 1/(p-x.y) MP+Xx-y, where M is a metal atom
selected from the group consisting of metals of the main and transition
groups of the Periodic Table of the Elements, X is an anion, p is the
oxidation number of the metal atom M, x is 1, 2 or 3 and y is 0, 1 or 2,
and/or
a group of the general formula (11a)
CA 2832814 2018-08-22
.= =
2b
-SiR1rn(OR2)3.m (11a),
where R1 and R2 have, independently of one another, the abovementioned
meanings and the indices m can, independently of one another, be 0, 1, 2
or 3,
is 1, 2 or 3,
and contacting with CO2 in the same step or a separate step
and at least one solvent, at least one surface-active substance or a mixture
thereof, wherein at
least one radical R2 in the compound of the general formula (I) or in the
group of the general
formula (11a) is NR14+ or a group of the general formula 1/(p-x*y) MP+Xx-y
with the abovementioned
meanings of R1, p, x, y, M and X.
If R2 is a group of the general formula (11a) a plurality of times, for
example more than once, in the
compound of the general formula (I), the corresponding compounds bear two,
three, four or more
units having Si atoms. Thus, when R2 is a group of the general formula (11a) a
plurality of times,
polysiloxanes are present.
In another aspect, there is provided a process for producing a surface-
modified particle as defined
herein by bringing the metal oxide particle to be modified and a compound of
the general formula (I)
as defined herein into contact with one another, and contacting with CO2 in
the same step or a
separate step.
In a further aspect, there is provided a process for treating surface-modified
particles as defined
herein with at least one solvent, wherein the mass ratio of solvent to
modified particle is greater
than 500.
Furthermore, the object is achieved by the use of the surface-modified
particle according to the
invention in systems in which the modified particles are brought into contact
with at least one
solvent, where the mass ratio of solvent to modified particle is greater than
500.
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3
The object of the invention is also achieved by the use of surface-modified
particles according
to the invention in agglomeration-deagglomeration cycles.
The stable mixture of the invention comprises surface-modified particles which
are obtained by
reacting metal oxide or semimetal oxide particles with at least one compound
of the general
formula (I) or a polysiloxane of the general formula (I) comprising groups of
the general formula
(11a).
For the purposes of the present invention, it is generally possible to use all
metal oxide or
semimetal oxide particles, in particular metal oxide particles, known to those
skilled in the art.
Examples of metal oxides which are particularly suitable for the purposes of
the invention are
the oxides of the metals of the main groups and transition groups of the
Periodic Table of the
Elements, in particular the transition groups of the Periodic Table of the
Elements.
According to the invention, silicon oxide is not preferred as semimetal oxide
and is therefore not
comprised in a preferred embodiment of the present invention.
In a preferred embodiment, the present invention therefore provides the
mixture according to
the invention, with silicon dioxide being excepted as semimetal oxide.
Examples of suitable metals of the main groups of the Periodic Table of the
Elements are the
alkali metals, for example Li, Na, K, Rb, Cs, alkaline earth metals, for
example Be, Mg, Ca, Ba,
Sr, the third main group of the Periodic Table of the Elements, for example
Al, Ga, In, TI, the
fourth main group of the Periodic Table of the Elements, for example Sn, Pb,
or the fifth main
group of the Periodic Table of the Elements, for example Sb, Bi.
Examples of suitable metals of the transition groups of the Periodic Table of
the Elements are
Sc, Y, the lanthanides, the actinides, Ti, Zr, Hf, Mn, Re, Fe, Ru, Os, Co, Rh,
Ir, Ni, Pd, Pt, Cu,
Ag, Au, Zn and Cd.
In a preferred embodiment, the metal oxide used according to the invention is
an oxide of the
metals selected from the group consisting of Li, Na, K, Rb, Cs, Be, Mg, Ca,
Ba, Sr, Al, Ga, In,
TI, Sn, Pb, Sb, Bi, Sc, Y, the lanthanides, the actinides, Ti, Zr, Hf, Mn, Re,
Fe, Ru, Os, Co, Rh,
Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd and mixtures thereof, very particularly
preferably selected from
the group consisting of Mn, Fe, Co, Ni, Cu and combinations thereof.
Furthermore, mixed
oxides of these metals, in particular Mn, Fe, Co, Ni or Cu, with at least one
alkaline earth metal,
for example Mg, Ca, Sr and/or Ba, are also suitable for the purposes of the
invention.
The present invention therefore preferably provides the mixture of the
invention in which the
metal oxide used is an oxide of a metal selected from the group consisting of
Mn, Fe, Co, Ni,
Cu, combinations thereof and mixed oxides of these metals with at least one
alkaline earth
metal, for example Mg, Ca, Sr and/or Ba.
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4
In a particularly preferred embodiment, the present invention provides the
mixture of the
invention in which the metal oxide or semimetal oxide particles are magnetic.
Very particularly preferably preferred metal oxides are iron oxides, for
example Fe2O3, magnetic
iron oxides, for example magnetite, maghemite, hematite, cubic ferrites of the
general formula
(III)
M2+),Fe2+1,Fe3+204 (III)
where
M is selected from among Co, Ni, Mn, Zn and mixtures thereof and
x is s 1,
hexagonal ferrites, for example calcium, barium or strontium ferrite MFesOls
where M = Ca, Sr,
Ba, and combinations thereof.
In a preferred embodiment, the metal oxide used according to the invention is
a magnetic iron
oxide selected from the abovementioned group. In a very particularly preferred
embodiment, the
at least one metal oxide used according to the invention is magnetite.
Magnetite has the formula
Fe304, in particular FeuFe",204, and is known to those skilled in the art.
Magnetite can be
prepared by known processes and is commercially available.
The metal oxide particles used according to the invention can optionally
comprise dopants, for
example further metals in oxidic or elemental form, for example noble metals
such as platinum.
The particles which are present according to the invention generally have a
particle size of from
50 nm to 500 pm, preferably from 200 nm to 100 pm, particularly preferably
from 500 nm to
10 pm.
The particles which are present according to the invention can generally have
any shape, for
example spherical, cylindrical, acicular or cuboidal.
Surface-modified particles which are obtained by reacting metal oxide or
semimetal oxide
particles with at least one compound of the general formula (I)
Rln-Si(OR2)4-n (I)
where R', R2 and n have the abovementioned meaning, where it is important for
the purposes of
the invention that at least one radical R2 in the compound of the general
formula (I) or in the
group of the general formula (11a) is NR14+ or a group of the general formula
1/(p-x*y) MP*Xx-y
with the abovementioned meanings of R1, p, x, y, M and X, are present in the
stable mixture of
CA 02832814 2013-10-09
PF 71797
the invention.
Furthermore, the present invention provides a stable mixture comprising
surface-modified
particles which are obtained by reacting a metal oxide or semimetal oxide
particles with at least
5 one compound of the general formula (I)
R1n-Si(OR2)4-n (I)
where R', R2 and n have the abovementioned meanings, where it is important for
the purposes
of the invention that at least one radical R2 in the compound of the general
formula (I) or in the
group of the general formula (11a) is NR14+ or a group of the general formula
1/(p-x*y) MP+Xx-y
with the abovementioned meanings of R1, p, x, y, M and X.
Preference is given to the radicals R1 each being, independently of one
another, linear or
branched, optionally functionalized Ci-C30-alkyl, particularly preferably C1-
C20-alkyl, very
particularly preferably C4-C12-alkyl. In a preferred embodiment, R1 is linear
or branched,
unfunctionalized Cl-C30-alkyl, particularly preferably C1-C20-alkyl, very
particularly preferably C4-
C12-alkyl. Examples of linear or branched C4-C12-alkyl radicals are butyl, in
particular, n-butyl,
isobutyl, tert-butyl, pentyl, in particular n-pentyl, isopentyl, tert-pentyl,
hexyl, in particular n-
hexyl, isohexyl, tert-hexyl, heptyl, in particular n-heptyl, isoheptyl, tert-
heptyl, octyl, in particular
n-octyl, isooctyl, tert-octyl, nonyl, in particular n-nonyl, isononyl, tert-
nonyl, decyl, in particular n-
decyl, isodecyl, tert-decyl, undecyl, in particular n-undecyl, isoundecyl,
tert-undecyl, or dodecyl,
in particular n-dodecyl, isododecyl, tert-dodecyl.
Further preference is given to the radicals R1 each being, independently of
one another, linear
or branched, optionally functionalized C2-C30-alkenyl, particularly preferably
C2-C20-alkenyl, very
particularly preferably C2-, C3- or C4-C12-alkenyl. Examples of alkenyl
radicals which are
particularly preferred according to the invention are ethenyl (vinyl),
propenyl, in particular n-
propenyl, isopropenyl, butenyl, in particular n-butenyl, isobutenyl, tert-
butenyl, pentenyl, in
particular n-pentenyl, isopentenyl, tert-pentenyl, hexenyl, in particular n-
hexenyl, isohexenyl,
tert-hexenyl, heptenyl, in particular n-heptenyl, isoheptenyl, tert-heptenyl,
octenyl, in particular
n-octenyl, isooctenyl, tert-octenyl, nonenyl, in particular n-nonenyl,
isononenyl, tert-nonenyl,
decenyl, in particular n-decenyl, isodecenyl, tert-decenyl, undecenyl, in
particular n-undecenyl,
isoundecenyl, tert-undecenyl, or dodecenyl, in particular n-dodecenyl,
isododecenyl, tert-
dodecenyl.
Further preference is given to the radicals R1 each being, independently of
one another, linear
or branched, optionally functionalized C2-C30-alkynyl, particularly preferably
C2-C20-alkynyl, very
particularly preferably C2-, C3- or C4-C12-alkynyl. Examples of alkynyl
radicals which are
particularly preferred according to the invention are ethynyl, propynyl, in
particular n-propynyl,
isopropynyl, butynyl, in particular n-butynyl, isobutynyl, tert-butynyl,
pentynyl, in particular n-
pentynyl, isopentynyl, tert-pentynyl, hexynyl, in particular n-hexynyl,
isohexynyl, tert-hexynyl,
,
CA 02832814 2013-10-09
,
PF 71797
6
heptynyl, in particular n-heptynyl, isoheptynyl, tert-heptynyl, octynyl, in
particular n-octynyl,
isooctynyl, tert-octynyl, nonynyl, in particular n-nonynyl, isononynyl, tert-
nonynyl, decynyl, in
particular n-decynyl, isodecynyl, tert-decynyl, undecynyl, in particular n-
undecynyl,
isoundecynyl, tert-undecynyl, or dodecynyl, in particular n-dodecynyl,
isododecynyl, tert-
dodecynyl.
Further preference is given to the radicals R1 each being, independently of
one another,
optionally functionalized C3-C20-cycloalkyl, particularly preferably C3-C12-
cycloalkyl, very
particularly preferably C3-C6-cycloalkyl, for example cyclopropyl, cyclobutyl,
cyclopentyl,
cyclohexyl.
Further preference is given to the radicals R1 each being, independently of
one another,
optionally functionalized C3-C20-cycloalkenyl, particularly preferably C3-C12-
cycloalkenyl, very
particularly preferably 03-C6-cycloalkenyl, for example cyclopropenyl,
cyclobutenyl,
cyclopentenyl, cyclohexenyl.
Further preference is given to the radicals R1 each being, independently of
one another,
optionally functionalized Cl-C20-heteroalkyl, particularly preferably Ci-C12-
heteroalkyl. The
heteroalkyl radicals present according to the invention are derived from the
abovementioned
alkyl radicals, with at least one carbon atom being replaced by a heteroatom
selected from
among N, 0, P and S.
Further preference is given to the radicals R1 each being, independently of
one another,
optionally functionalized C5-C22-aryl, particularly preferably C5-C12-aryl.
Examples of aryl
radicals which are preferred according to the invention are phenyl, naphthyl
or biaryls.
Further preference is given to the radicals R1 each being, independently of
one another,
optionally functionalized C6-C23-alkylaryl, particularly preferably C6-C13-
alkylaryl. An example of
an alklaryl radical which is preferred according to the invention is benzyl.
Further preference is given to the radicals R' each being, independently of
one another,
optionally functionalized 06-C23-arylalkyl, particularly preferably 06-C13-
arylalkyl. Examples of
arylalkyl radicals which are preferred according to the invention are tolyl,
xylyl, propylbenzyl,
hexylbenzyl.
Further preference is given to the radicals R1 each being, independently of
one another,
optionally functionalized C5-C22-heteroaryl, particularly preferably C5-C12-
heteroaryl.
The abovementioned radicals R1 can optionally be functionalized. Suitable
functional groups
are, for example, selected from among amino, amido, imido, hydroxyl, ether,
aldehyde, keto,
carboxylic acid, thiol, thioether, hydroxamate and carbamate groups. The
abovementioned
radicals R" can be singly or multiply functionalized. In the case of multiple
functionalization, one
,
CA 02832814 2013-10-09
,
PF 71797
7
functional group can be present a plurality of times or various functional
groups are
simultaneously present. The radicals mentioned for R1 can also be
monosubstituted or
polysubstituted by the abovementioned alkyl, alkenyl, alkynyl, aryl,
alkylaryl, arylalkyl,
heteroalkyl or heteroaryl radicals.
Very particularly preferred radicals R1 are octyl, in particular n-octyl,
hexyl, in particular n-hexyl
and/or butyl, in particular n-butyl, decyl, in particular n-decyl, or dodecyl,
in particular n-dodecyl.
For the purposes of the present invention, "independently of one another"
means that if a
plurality of radicals Ril are present in the compound of the general formula
(1) or the group of the
general formula (11a), these can be identical or different.
Preference is given to the radicals R2 each being, independently of one
another, hydrogen,
linear or branched, optionally functionalized C1-C30-alkyl, particularly
preferably C1-C20-alkyl,
very particularly preferably C1-C12-alkyl, In a preferred embodiment, R2 is
linear or branched,
unfunctionalized CI-Cu-alkyl, particularly preferably Cy-Car-alkyl, very
particularly preferably C1-
C12-alkyl. Examples of linear or branched C1-C12-alkyl radicals are methyl,
ethyl, propyl, in
particular n-propyl, isopropyl, butyl, in particular n-butyl, isobutyl, tert-
butyl, pentyl, in particular
n-pentyl, isopentyl, tert-pentyl, hexyl, in particular n-hexyl, isohexyl, tert-
hexyl, heptyl, in
particular n-heptyl, isoheptyl, tert-heptyl, octyl, in particular n-octyl,
isooctyl, tert-octyl, nonyl, in
particular n-nonyl, isononyl, tert-nonyl, decyl, in particular n-decyl,
isodecyl, tert-decyl, undecyl,
in particular n-undecyl, isoundecyl, tert-undecyl, or dodecyl, in particular n-
dodecyl, isododecyl,
tert-dodecyl.
Further preference is given to the radicals R2 each being, independently of
one another, linear
or branched, optionally functional ized 02-C30-alkenyl, particularly
preferably C2-C20-alkenyl, very
particularly preferably C2-C12-alkenyl. Examples of alkynyl radicals which are
particularly
preferred according to the invention are ethenyl (vinyl), propenyl, in
particular n-propenyl,
isopropenyl, butenyl, in particular n-butenyl, isobutenyl, tert-butenyl,
pentenyl, in particular n-
pentenyl, isopentenyl, tert-pentenyl, hexenyl, in particular n-hexenyl,
isohexenyl, tert-hexenyl,
heptenyl, in particular n-heptenyl, isoheptenyl, tert-heptenyl, octenyl, in
particular n-octenyl,
isooctenyl, tert-octenyl, nonenyl, in particular n-nonenyl, isononenyl, tert-
nonenyl, decenyl, in
particular n-decenyl, isodecenyl, tert-decenyl, undecenyl, in particular n-
undecenyl,
isoundecenyl, tert-undecenyl, or dodecenyl, in particular n-dodecenyl,
isododecenyl, tert-
dodecenyl.
Further preference is given to the radicals R2 each being, independently of
one another, linear
or branched, optionally functionalized C2-C30-alkynyl, particularly preferably
C2-C20-alkynyl, very
particularly preferably C2-C12-alkynyl. Examples of alkynyl radicals which are
particularly
preferred according to the invention are ethynyl, propynyl, in particular n-
propynyl, isopropynyl,
butynyl, in particular n-butynyl, isobutynyl, tert-butynyl, pentynyl, in
particular n-pentynyl,
isopentynyl, tert-pentynyl, hexynyl, in particular n-hexynyl, isohexynyl, tert-
hexynyl, heptynyl, in
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8
particular n-heptynyl, isoheptynyl, tert-heptynyl, octynyl, in particular n-
octynyl, isooctynyl, tert-
octynyl, nonynyl, in particular n-nonynyl, isononynyl, tert-nonynyl, decynyl,
in particular n-
decynyl, isodecynyl, tert-decynyl, undecynyl, in particular n-undecynyl,
isoundecynyl, tert-
undecynyl, or dodecynyl, in particular n-dodecynyl, isododecynyl, tert-
dodecynyl.
Further preference is given to the radicals R2 each being, independently of
one another,
optionally functionalized C3-C20-cycloalkyl, particularly preferably C3-C12-
cycloalkyl, particularly
preferably C3-C6-cycloalkyl, for example cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl.
Further preference is given to the radicals R2 each being, independently of
one another,
optionally functionalized C3-C20-cycloalkenyl, particularly preferably C3-C12-
cycloalkenyl, very
particularly preferably C3-C6-cycloalkenyl, for example cyclopropenyl,
cyclobutenyl,
cyclopentenyl, cyclohexenyl.
Further preference is given to the radicals R2 each being, independently of
one another,
optionally functionalized C1-C20-heteroalkyl, particularly preferably C4-C12-
heteroalkyl. The
heteroalkyl radicals which are present according to the invention are derived
from the
abovementioned alkyl radicals, with at least one carbon atom being replaced by
a heteroatom
selected from among N, 0, P and S.
Further preference is given to the radicals R2 each being, independently of
one another,
optionally functionalized C5-C22-aryl, particularly preferably C5-C12-aryl.
Examples of aryl
radicals which are preferred according to the invention are phenyl, naphthyl
or biaryls.
Further preference is given to the radicals R2 each being, independently of
one another,
optionally functionalized C6-C23-alkylaryl, particularly preferably 06-C13-
alkylaryl. An example of
an alkylaryl radical which is preferred according to the invention is benzyl.
Further preference is given to the radicals R2 each being, independently of
one another,
optionally functionalized 06-C23-arylalkyl, particularly preferably C5-C13-
arylalkyl. Examples of
arylalkyl radicals which are preferred according to the invention are tolyl,
xylyl, propylbenzyl,
hexylbenzyl.
Further preference is given to the radicals R2 each being, independently of
one another,
optionally functionalized C5-C22-heteroaryl, particularly preferably C5-C12-
heteroaryl.
The abovementioned radicals R2 can optionally be functionalized. Suitable
functional groups
are, for example, selected from among amino, amido, imido, hydroxy, ether,
aldehyde, keto,
carboxylic acid, thiol, thioether, hydroxamate and carbamate groups. The
abovementioned
radicals R1 can be singly or multiply functionalized. In the case of multiple
functionalization, one
functional group can be present a plurality of times or various functional
groups are
simultaneously present. The radicals mentioned for R2 can also be
monosubstituted or
CA 02832814 2013-10-09
PF 71797
9
polysubstituted by the abovementioned alkyl, alkenyl, alkynyl, aryl,
alkylaryl, arylalkyl,
heteroalkyl or heteroaryl radicals.
It is important for the purposes of the invention that at least one radical R2
in the compound of
the general formula (I) or in the group of the general formula (11a) is NR14+
or a group of the
general formula 1/(p-x*y) MP+Xx-y with the abovementioned meanings of R1, p,
x, y, M and X.
In one embodiment, at least one radical R2 is NR14*. In this case, the
radicals R1 can,
independently of one another, have the abovementioned meanings, with
particular preference
being given in this case to R1 being hydrogen, methyl, ethyl, propyl, in
particular n-propyl, octyl,
in particular n-octyl, hexyl, in particular n-hexyl, and/or butyl, in
particular n-butyl, decyl, in
particular n-decyl, or dodecyl, in particular n-dodecyl.
In a further preferred embodiment, at least one radical R2 is a group of the
general formula
1/(p-x*y) MP+Xx-y, where M is a metal atom selected from the group consisting
of metals of the
main and transition groups of the Periodic Table of the Elements, X is an
anion, p is the
oxidation number of the metal atom M, x is 1, 2 or 3 and y is 0, 1 or 2.
X in the abovementioned general formula is generally an anion, for example an
anion selected
from the group consisting of Cl-, NO3-, S042- or P042-. In these preferred
embodiments, x is 1, 2
or 3 and thus corresponds to the negative formal charge on the anions.
The number of anions present in the abovementioned group is described by y. y
is therefore
particularly preferably 0, 1 or 2, i.e. it is possible for no, one or two
further anion(s) to be present
in the abovementioned group.
In a preferred embodiment, p is 1, 2, 3, 4, 5, 6 or 7, with particular
preference being given to p
being 1, 2 or 3.
Since at least one radical R2 in the compound of the general formula (I),
optionally comprising at
least one group of the general formula (Ha), is NR14* or a group of the
general formula
1/(p-x.y) MP*Xx-y, this means that, according to the invention, a salt is used
as compound of the
general formula (I). The positive formal charge(s) on the ammonium cation
NR14+ or the group
1/(p-x*y) MR+Xx-y, is/are, in this embodiment, compensated by the negative
formal charge on the
oxygen atom. Compounds of the general formula (I) in which at least one
radical R2 is NR14+ or
a group of the general formula 1/(p-x*y) MP+Xx-y which are used according to
the invention are
uncharged in a particularly preferred embodiment.
The factor 1/(p-x*y) is important for the purposes of the invention since the
molar amount of
metal is dependent on the valence of the metal present and the number and
valence of any
anions present. For example, if metal atoms present in the oxidation state +3,
i.e. p is equal to
3, are used, the molar amount of compound of the general formula (I) is, in
the absence of
,
CA 02832814 2013-10-09
PF 71797
further anions X, three times the molar amount of metal in order to obtain an
uncharged Si-
comprising salt. If, for example, metal atoms which are present in the
oxidation state +2, i.e. p is
equal to 2, are used, the molar amount of compound of the general formula (1)
is, in the
absence of further anions X, twice the molar amount of metal in order to
obtain an uncharged
5 Si-comprising salt. If, for example, metal atoms which are present in the
oxidation state +1, i.e.
p is equal to 1, are used, the molar amount of compound of the general formula
(I) is, in the
absence of further anions X, equal to the molar amount of metal in order to
obtain an uncharged
Si-comprising salt. In the case of mixtures of metal atoms having different
valences or when
particular amounts of anions having particular charges are present, the ratio
is calculated
10 correspondingly.
According to the invention, a number of embodiments are possible:
If a monovalent cation such as Nat, Kt, etc., is used as cation MP, such a
cation is present in
each group of the general formula 1/(p-x`y) MP+Xx-y.
If a divalent cation such as Ca2+, etc., is used as cation MP+, the factor
1/(p-x*y) has, in the
absence of further anions, i.e. y is equal to zero, the value 0.5, i.e. 0.5
equivalents of Ca2* are
mathematically present per group R2. According to the invention, this can be
realized either by
two negatively charged oxygen atoms whose two negative charges are neutralized
by a Ca2+
cation being present in a compound of the general formula (1) or (11a), so
that each oxygen
anion is neutralized mathematically by 0.5 Ca2+. It is also possible according
to the invention for
one negatively charged oxygen atom to be present in each of two compounds of
the general
formula (I) or (11a), whose two negative charges in total are neutralized by a
Ca2+ cation, so that
each oxygen anion is mathematically neutralized by 0.5 Ca2+. Mixed forms of
these
embodiments are also possible according to the invention.
In the case of polyvalent cations or mixtures of various cations, optionally
with different
oxidation numbers, analogous considerations apply.
In general, M is selected from among metals of the main and transition groups
of the Periodic
Table of the Elements, preferably from groups 1,2 and 13 (IUPAC nomenclature).
M is
preferably selected from the group of the alkali metals, for example Li, Na,
K, Rb, Cs, Fr,
preferably Lit, Nat, Kt, Rbt, Cs, Fr, where p is in each case equal to 1, from
the group of the
alkaline earth metals, for example Be, Mg, Ca, Sr, Ba, Ra, preferably Be24,
Mg2+, Ca2+, Sr2+,
Ba2+, Ra2+, where p is in each case equal to 2, and/or from group 13 of the
Periodic Table of the
Elements, for example B, Al, Ga, In, T1, preferably B34, Al3+, Ga3+, In3+,
TI3+, where p is in each
case equal to 3.
The present invention therefore preferably provides the mixture of the
invention in which MP* is
selected from group 1, 2 or 13 of the Periodic Table of the Elements (IUPAC
nomenclature).
CA 02832814 2013-10-09
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11
In a particularly preferred embodiment, at least one radical R2 in the
compound of the general
formula (1) or in the group of the general formula (11a) is independently a
group of the general
formula 1/(p-x*y) MP'Xx-y where p is 1, y is 0 and M is Na and/or K.
The present invention therefore preferably provides the mixture of the
invention in which at least
one radical R2 in the compound of the general formula (I) or in the group of
the general formula
(11a) is independently a group of the general formula 1/(p-x*y) MP+Xx-y where
p is 1, y is 0 and M
is Na and/or K.
In a further preferred embodiment, R2 is a group of the general formula (11a)
(11a)
where Rl and R2 have, independently of one another, the abovementioned
meanings and the
indices m can, independently of one another, each be 0, 1, 2 or 3, preferably
1 or 2. The
bonding of this group of the general formula (11a) to the compound of the
general formula (I) is
via the free bond on the Si atom.
In a particularly preferred embodiment, the radicals R1 in the group of the
general formula (11a)
are each, independently of one another, hydrogen, methyl, ethyl, octyl, in
particular n-octyl,
hexyl, in particular n-hexyl, and/or butyl, in particular n-butyl, decyl, in
particular n-decyl, or
dodecyl, in particular n-dodecyl.
In a particularly preferred embodiment, the radicals R2 in the group of the
general formula (11a)
are each, independently of one another, methyl or ethyl.
In a particularly preferred embodiment, at least one radical R2 in the group
of the general
formula (11a) is independently a group of the general formula 1/(p-x*y) MP*Xx-
y where p is 1, y is 0
and M is Na and/or K.
The present invention therefore preferably provides the mixture of the
invention in which at least
one radical R2 in the group of the general formula (11a) is independently a
group of the general
formula 1/(p-x*y) MP*Xx-y where p is 1, y is 0 and M is Na and/or K.
If groups of the general formula (11a) are repeatedly present in the compound
of the general
formula (1), polysiloxanes are used according to the invention as compounds of
the general
formula (I). If polysiloxanes comprising groups of the general formula (11a)
are used for the
purposes of the invention, these can be linear or branched. Polysiloxanes
comprising groups of
the general formula (11a) which are used according to the invention generally
have a molecular
weight of from 250 to 200 000 g/mol, preferably from 250 to 20 000 g/mol,
particularly preferably
from 300 to 5000 g/mol.
CA 02832814 2013-10-09
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12
For the purposes of the present invention, "independently of one another"
means that if a
plurality of radicals R2 are present in the compound of the general formula
(1) or (11a), these can
be identical or different.
In the compound of the general formula (1), n is generally 1, 2 or 3. n in the
compound of the
general formula (I) is preferably 1 or 2. n in the compound of the general
formula (I) is
particularly preferably 1.
The present invention therefore preferably provides the mixture of the
invention in which n in the
compound of the general formula (1) is 1 0r2, particularly preferably 1.
In the polysiloxanes of the general formula (1) comprising groups of the
general formula (11a) the
indices m are generally each independently 0, 1, 2 or 3, preferably 1 or 2.
Compounds of the general formula (I) which are particularly preferred
according to the invention
are selected from the group of salts consisting of
Rin-Si(OR2)4.,, where R1 is methyl, ethyl, butyl, pentyl, hexyl, octyl, decyl
and/or dodecyl, R2 is
Na, K and/or NH4 and n is 1, 2 or 3,
Or
IR1n-Si(OR2)4_,, where R1 is methyl, ethyl, butyl, pentyl, hexyl, octyl, decyl
and/or dodecyl, R2 is
0.5 Ca and/or 0.5 Mg and n is 1, 2 or 3, with what has been said above
applying in respect of
the divalent cations. In these particularly preferred embodiments, no further
anions Xx- are
present, i.e. y in the formula 1/(p-x*y) is equal to zero.
Very particularly preferred compounds of the general formula (1) are selected
from the group
consisting of (Na0)(CH3)Si(OH)2, (Na0)(C2H5)Si(OH)2, (Na0)(C5H11)Si(OH)2,
(Na0)(C81--117)Si(OH)2, (K0)(CH3)Si(OH)2, (K0)(C2H5)Si(OH)2, (K0)(C5H11)
Si(OH)2,
(K0)(C8H17)Si(OH)2, (NH40)(CH3)Si(OH)2, (NH.40)(C2H5)Si(OH)2, (NH40)(C51-111)
Si(OH)2,
(NH40)(C81-117)Si(OH)2, (Na0)2(CH3)Si(OH), (Na0)2(C2H5)Si(OH),
(Na0)2(C5F111)Si(OH),
(Na0)2(C81-117)Si(OH), (K0)2(CH3)Si(OH), (K0)2(C2H5)Si(OH),
(K0)2(C5H11)Si(OH),
(K0)2(C8F117)Si(OH), (NH40)2(CH3)Si(OH), (NH40)2(C2H5)Si(OH), (N1-140)2(C51-
111)Si(OH),
(NH40)2(C8H17)Si(OH), (Na0)3(CH3)Si, (Na0)3(C2H5)Si, (Na0)3(C5F111)Si,
(Na0)3(C81-117)Si,
(K0)3(CH3)Si, (K0)3(C2H5)Si, (K0)3(C51-111)Si, (K0)3(C81-117)Si,
(NH40)3(CH3)Si, (NH40)3(C2H5)Si,
(NH.40)3(C51-111)Si, (NH40)3(Ce1-117)Si, (Na0)(CH3)2Si(OH),
(Na0)(C2H5)2Si(OH),
(K0)(CH3)2Si(OH), (K0)(C2H5)2Si(OH), (Na0)2(CH3)2Si, (Na0)2(C2H5)2Si,
(K0)2(CH3)2Si,
(K0)2(C2H5)2Si, Ca+[(0-)(CH3)Si(OH)2]2, Ca4[(0-)(C2H5)Si(OH)2]2, Cal(0-
)(C5Hii)Si(OH)2]2,
Cal(0-)(C81-117)Si(OH)2]2, Cal(0-)(CH3)2Si(OH)12, Cal(0-)(C2H5)2Si(OH)]2,
Call(0-)2(CH3)Si(OH)], Cal(0-)2(C2H5)Si(OH)], Cal(0-)2(C5F111)Si(OH)],
Ca+[(0-)2(C8H17)Si(OH)1, Ca+[(0-)2(CH3)2Si], Cal(0-)2(C2H5)2Si].
ine present invention also provioes a process Tor proaucing a surface-mom-leo
particle as
defined above by bringing the metal oxide or semimetal oxide particle to be
modified and a
compound of the general formula (I) as defined above into contact with one
another.
A"
CA 02832814 2013-10-09
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13
A class of polysiliconates of the general formula (1) comprising groups of the
general formula
(11a) which is preferred for the purposes of the invention is that of
polymethylsiliconates and
polydimethylsiliconates having sodium, potassium, magnesium, calcium or
ammonium as
cation.
The present invention also provides a process for producing a surface-modified
particle as
defined above by bringing the metal oxide or semimetal oxide particle to be
modified and a
compound of the general formula (I) as defined above into contact with one
another.
The reaction of the abovementioned metal oxide or semimetal oxide particles
with the
compounds of the general formula (1) or the polysiloxanes of the general
formula (1) comprising
groups of the general formula (11a) can be carried out by processes known to
those skilled in the
art, for example by contacting of the substrates in a solvent, for example
toluene or water, at a
temperature in the range from room temperature to the boiling point of the
solvent. In addition,
the substrates may be contacted with further reactants or reaction
accelerators, for example
acids, CO2, etc., in the same step or a separate step. After conventional work-
up, the reaction
product of metal oxide or semimetal oxide particles and compounds of the
general formula (1) or
polysiloxanes of the general formula (1) comprising groups of the general
formula (11a) can be
obtained.
The silicon compounds are preferably fixed to the metal oxide or semimetal
oxide surface by
condensation of the surface hydroxyl groups of the oxide M-OH with silanol
groups of the silicon
compound (Si-OH + M-OH Si-O-M + H20). The silanol groups can be originally
comprised in
the starting silicon compound of the formula (I) or a subunit (11a) or be
formed in situ. This can
be effected, for example, by hydrolysis of the silicon ether (Si¨OR + H20) to
the silanol (Si¨OH
+ ROH). SiOR2 can be hydrolyzed, R and all further radicals mentioned cannot
be hydrolyzed.
The process of the invention can, for example, be carried out by spraying a
reagent solution
comprising the compound of the general formula (I) onto the metal oxide or
semimetal oxide
particles. A further method of bringing the metal oxide or semimetal oxide
particles to be
modified and a compound of the general formula (1) as defined above into
contact with one
another comprises, for example, suspending the metal oxide or semimetal oxide
particles in a
compound of the general formula (I) or in a solution of a compound of the
general formula (1) in
a suitable solvent. Corresponding processes are known per se to those skilled
in the art.
After the compound of the formula (1) has been brought into contact with the
metal oxide or
semimetal oxide particles, a further treatment step may be necessary in order
to complete the
fixing reaction. This can be carried out, for example, by adjusting the pH,
heat treatment,
treatment with various gas atmospheres, e.g. CO2 or SO2, or a combination of
such steps.
The stable mixture of the invention comprises at least one solvent, at least
one surface-active
. CA 02832814 2013-10-09
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14
substance or a mixture thereof in addition to the abovementioned
functionalized metal oxide or
semimetal oxide particles.
It has surprisingly been found that the reaction products according to the
invention, i.e. the
surface-functionalized metal oxide or semimetal oxide particles, are
particularly stable in
mixtures with solvents and/or surface-active compounds, i.e. no detachment of
the silicon
compounds bound to the surface occurs.
The at least one solvent present in the mixture of the invention is preferably
selected from the
group consisting of aromatic hydrocarbons, for example benzene, toluene,
xylene, alcohols, for
example methanol, ethanol, propanols such as n-propanol, isopropanol, butanols
such as n-
butanol, isobutanol, tert-butanol, ethers such as diethyl ether, methyl tert-
butyl ether, isobutyl
tert-butyl ether, cyclic ethers such as tetrahydrofuran, dioxane, esters,
cyclic esters, alkanes
such as hexane, cycloalkanes such as cyclohexane, olefins, cycloolefins, water
and mixtures
thereof. If mixtures of solvents are used according to the invention,
preference is given to using
solvents which are completely miscible with one another, i.e. form a single
phase on mixing.
The present invention therefore preferably provides the mixture of the
invention in which the at
least one solvent is selected from the group consisting of aromatic
hydrocarbons, preferably
benzene, toluene, xylene, alcohols, for example methanol, ethanol, propanols
such as n-
propanol, isopropanol, butanols such as n-butanol, isobutanol, tert-butanol,
ethers such as
diethyl ether, methyl tert-butyl ether, isobutyl-tert-butyl ether, cyclic
ethers such as
tetrahydrofuran, dioxane, esters, cyclic esters, alkanes such as hexane,
cycloalkanes such as
cyclohexane, olefins, cycloolefins, water and mixtures thereof.
In a preferred embodiment, the mixture of the invention is used in processes
in which the
surface-modified particles are brought into contact with particularly large
amounts of solvents.
The mixture of the invention generally has a solids content of up to 70% by
weight, preferably
up to 60% by weight. The content of at least one solvent in the mixture of the
invention is
therefore generally at least 30% by weight, preferably at least 40% by weight,
i.e. in general
from 30 to 99.9% by weight, preferably from 40 to 99.9% by weight, of solvent.
According to the
invention, the solids content is the content of particles which have been
modified on the surface
according to the invention and any further solids present.
The at least one surface-active substance present in the mixture of the
invention is preferably
selected from the group consisting of nonionic, anionic, cationic or
zwitterionic surfactants and
mixtures thereof.
Preferred examples of nonionic surfactants are fatty alcohol polyglycol
ethers, in particular fatty
alcohol polyethylene glycol ethers.
= CA 02832814 2013-10-09
PF 71797
Preferred examples of anionic surfactants are alkylbenzenesulfonates,
secondary
alkanesulfonates, a-olefinsulfonates, fatty alcohol sulfates or fatty alcohol
ether sulfates.
Preferred examples of cationic surfactants are stearyltrimethylammonium salts.
5
Preferred examples of zwitterionic surfactants are sultaines, fatty acid
amidoalkylhydroxysultaine or alkyl betaines.
Particularly preferred surface-active substances are sodium alkylphenol ether
sulfates.
The at least one surface-active substance is generally present in the mixture
of the invention in
an amount of from 0.001 to 20% by weight, preferably from 0.01 to 15% by
weight, particularly
preferably from 0.1 to 10% by weight, in each case based on the total mixture.
If at least one
surface-active substance is present according to the invention, the
abovementioned amount of
at least one solvent is modified accordingly.
The surface-functionalized metal oxide or semimetal oxide particles are
generally present in the
mixture of the invention in an amount of from 0.1 to 70% by weight, preferably
from 0.1 to 60%
by weight.
If further solids are optionally present in the mixture of the invention, the
abovementioned
amount of surface-functionalized metal oxide or semimetal oxide particles is
modified
accordingly.
In all possible embodiments, the amounts of surface-functionalized metal oxide
or semimetal
oxide particles, at least one solvent, optionally present surface-active
substances and optionally
present further solids add up to 100% by weight.
Apart from the functionalized particles, the at least one solvent and/or the
at least one surface-
active substance, the mixture of the invention can comprise further
components, for example
oxidic or metallic solids and further hydrophobic components. The sum of the
amounts of the
components present in the mixture of the invention in each case add up to 100%
by weight.
The mass ratio of solvent to modified particles in the mixture of the
invention is generally greater
than 500, preferably 1000, particularly preferably greater than 5000, very
particularly preferably
greater than 10 000.
For the purposes of the present invention, the term "stable mixture" means
that the surface-
functionalized metal oxide or semimetal oxide particles present in the mixture
of the invention
are not changed in the mixture, i.e. the silyl groups present on the surface
are not detached
from the surface of the metal oxide or semimetal oxide particles, for example
by hydrolysis, so
that the mixture of the invention as a whole does not change or changes only
slightly. That a
CA 02832814 2013-10-09
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16
mixture comprising surface-modified particles is stable for the purposes of
the present invention
can be demonstrated, for example, by the fact that such particles which are in
contact with
solvents and/or surface-active substance in a mixture according to the
invention remain
chemically and/or physically unchanged. This can, for example, be determined
by elemental
analysis or determination of the hydrophobic properties, for example by
determination of the
ability to float or the contact angle.
The present invention also provides a process for treating surface-modified
particles according
to the invention with at least one solvent, wherein the mass ratio of solvent
to modified particle
is greater than 500.
As regards the surface-modified particles and the solvents, what has been said
above in
respect of the mixture according to the invention applies to the process of
the invention.
In the process of the invention, the mass ratio of surface-modified particle
and the at least one
solvent is generally greater than 500, preferably greater than 1000,
particularly preferably
greater than 5000, very particularly preferably greater than 10000.
In this process of the invention, the surface-modified particles according to
the invention are
brought into contact, i.e. treated, with a relatively large amount of solvent.
Corresponding
systems according to the invention in which this treatment can be carried out
are, for example,
flowing systems in which the surface-modified particles of the invention are
brought into contact
in, for example, continuous processes with further substances, particles,
materials, etc., for
example continuous processes for agglomeration with further substances,
particles, materials,
etc., in solution or dispersion. The process of the invention also relates to
deagglomeration of
agglomerates of the surface-modified particles of the invention and further
substances, particles
or materials, or of agglomerates of the surface-modified particles with
themselves, for example
likewise in flowing systems.
.. The present invention also provides for the use of surface-modified
particles according to the
invention in systems in which the modified particles are brought into contact
with at least one
solvent, wherein the mass ratio of solvent to modified particles is greater
than 500.
As regards the surface-modified particles and the solvents, what has been said
above in
respect of the mixture of the invention applies.
The mass ratio of surface-modified particle and the at least one solvent is
generally greater than
500, preferably greater than 1000, particularly preferably greater than 5000,
very particularly
preferably greater than 10 000.
In this use according to the invention, the surface-modified particles of the
invention are brought
into contact with a relatively large amount of solvent. Corresponding systems
according to the
= CA 02832814 2013-10-09
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17
invention in which this contacting can be carried out are, for example,
flowing systems in which
the surface-modified particles of the invention are brought into contact in,
for example,
continuous processes with further substances, particles, materials, etc., for
example continuous
processes for agglomeration with further substances, particles, materials,
etc., in solution or
dispersion. The use according to the invention also relates to deagglomeration
of agglomerates
of the surface-modified particles of the invention and further substances,
particles or materials,
or of agglomerates of surface-modified particles with themselves, for example
likewise in
flowing systems.
The present invention also provides for the use of surface-modified particles
according to the
invention, in particular magnetic particles, in agglomeration-deagglomeration
cycles.
In this use too, what has been said in respect of the mixture of the invention
applies to the
surface-modified particles and the solvents.
According to the invention, an agglomeration-deagglomeration cycle is a
process in which the
surface-functionalized particles of the invention, in particular magnetic
particles, are brought into
contact with themselves or other particles, substances, materials, etc., in
solution or dispersion
and agglomerate as a result of hydrophobic interaction, ionic forces, van der
Waals interactions
and/or other attractive forces. These agglomerates are then processed in
further processes, for
example separated from other components and/or the solution or dispersion.
After this
treatment, the agglomerates are then separated again, i.e. deagglomerated, so
that the surface-
functionalized particles and the other particles, substances, materials, etc.,
are again present
separately (deagglomeration). Examples of agglomeration-deagglomeration cycles
which are
preferred according to the invention are chemical, physical or biological test
methods or
separation processes, decontamination of contaminated, for example heavy metal-
contaminated earth, water purification, recycling of electrical/electronic
scrap or gravity
separation.
In chemical, physical or biological test methods or separation processes, use
is made of, for
example, specifically modified magnetic nanoparticles which have anchor groups
for a specific
antigen or virus, e.g. borrelia, HIV, hepatitis, on their surface. These
specific anchor groups
correspond, in particular, to the abovementioned group R1 which has a
structure corresponding
to the respective separation or test task, for example as a result of the
presence of the
abovementioned functional groups. Bonding of these antigens/viruses to the
modified particle
surface (agglomeration) enables these constituents to be separated off from a
solution by
means of magnetic separation and thus detected. The functionalized magnetic
particles are
then recycled by means of surfactants which again release the electrostatic,
adhesive or van
der Weals interaction between functionalized magnetic particle and
antigen/virus
(deagglomeration). In this way, the functionalized magnetite particles can be
reused.
The modified particles of the invention, in particular magnetic particles, can
be used in water
. CA 02832814 2013-10-09
PF 71797
18
purification. Here, for example, it is possible to use functionalized
magnetite particles which
remove organic constituents, suspended materials or fat droplets from the
water by effecting
hydrophobic agglomeration between the functionalized magnetite particle and
the hydrophobic
contaminant. These hydrophobic agglomerates can be separated off by magnetic
separation. In
order that water purification is economical, it is useful to "unload" the
hydrophobic magnetite
particles from the contaminant again and return them to the circuit. This
"unloading" can once
again be effected by deagglomeration using a specific surface-active substance
(surfactant)
and/or by means of a specific solvent or solvent mixture.
Recycling of electrical/electronic scrap can, for example, be carried out by
magnetic recovery of
materials of value (Ir, Pt, Ru) from electrical/electronic scrap, once again
preferably using
modified magnetite particles which, after hydrophobicization of the materials
of value to be
separated, can agglomerate with these and be separated off. After the
agglomerates have been
separated off, they are deagglomerated again so that the modified magnetic
particles can be
reused.
A further example is gravity separation, e.g. by means of cyclones known to
those skilled in the
art. In this way, relatively dense constituents can be separated off from less
dense constituents
by means of a gravity separation. If the densities of the individual
components differ only
slightly, e.g. Pt-doped hematite and undoped hematite, the density of the
component to be
separated off can be increased by agglomeration with a further component.
Here, for example,
the Pt-doped hematite component is hydrophobicized according to the invention
to give
modified particles, so that addition of hydrophobicized barium sulfate gives
an agglomerate of
the modified hematite and barium sulfate which has a greater density
difference from the
undoped hematite. After the agglomerate has been separated off, it can be
deagglomerated
again.
The present invention therefore also preferably provides for the use according
to the invention
in which the agglomeration-deagglomeration cycle is a chemical, physical or
biological test
method or separation process, water purification, purification of
contaminated, for example
heavy metal-polluted earth, recycling of electrical/electronic scrap or
gravity separation.
An advantage of the invention is that the particles which have been surface-
modified according
to the invention are stable under the conditions prevailing in agglomeration
and especially
deagglomeration and can therefore preferably be reused.
,
Examples
Example 1: General methods
Example 1.1: Preparation of the alkali metal alkylsiliconates used
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The preparation of the alkali metal alkylsiliconates is carried out by the
method in R. Murugavel
etal., Solid State Sciences 2001, 3 (1-2), 169-182. As an alternative, the
procedure in the
examples in GB675188A can be employed.
For example, nOctSi(ONa)3 is prepared by introducing 1 mol of nOctSi(OMe)3
from ABCR (97%
pure) into a solution of 10 mol of NaOH in 400 g of water over a period of 30
minutes. The
reaction is then completed under reflux within 4 hours. Distilling off the
solvent gives a
concentrated solution or complete drying gives the product as a solid.
Example 1.2: Repeated treatment of the solid with surfactant solution
10 g of solid to be examined are stirred in 1 I of a 0.2% strength by weight
solution of Lutensit A-
ES from BASF SE (mixture of sodium alkylphenol ether sulfates) in water for 2
hours at room
temperature. The solid is subsequently filtered off and washed with 1 I of
water, 100 ml of
ethanol and 100 ml of acetone. The filter cake is dried at 120 C under reduced
pressure for
4 hours. Samples are subsequently taken for analysis. The remaining product is
used for the
renewed washing tests.
Example 1.3: Rapid test for ability to float on water
3 ml of water are placed in a 5 ml test tube. The solid to be examined is
subsequently carefully
placed on the surface of the water by means of a spatula. The solid in the
test tube is
subsequently observed to see whether the solid sinks or remains afloat. In the
case of floating
solids, the closed vessel is shaken for 10 s. The solid in the test tube is
subsequently observed
to see whether the solid floats again or remains under water.
Example 1.4: Contact angle measurement
Contact angle measurement on powders:
Contact angles are measured using a standard instrument (Dropshape Analysis
Instrument,
Kruss DAS 10). A silhouette of the drop is recorded by means of a CCD camera
and the drop
shape is determined by computer-aided image analysis. The measurements are,
unless
indicated otherwise, carried out as described in DIN 5560-2.
a) Production of a homogeneous powder layer
The magnetite powder is applied as an appropriately 1 mm thick layer onto a
100 pm thick
BASF Acronal V215 adhesive dispersion on a PET film. Using a spatula, the
powder is pressed
into the adhesive and excess material which does not adhere is removed by
shaking. Finally,
remaining loose material is removed by blowing purified nitrogen under
pressure over the
specimen. This method gives a clean, homogeneous powder surface over the total
area of the
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substrate of 75 mm x 25 mm.
Powder surfaces normally display a certain roughness and contact angle or the
measurement
thereof are sensitive to this roughness. A direct comparison of the
hydrophobicity can therefore
5 be carried out only on powders having the same particle size distribution
and particle shape.
Careful surfaces analyses using ToF-SIMS have shown that the surface of the
powder layer
produced by this method has no traces of adhesive and is representative of the
powder.
b) Dynamic, progressive contact angle measurement
One milliliter of water is placed as a drop on the surface and 2 pl/min of
water are continuously
added. 20 pl of liquid volume are added continuously in this way. Starting
from a minimal
volume of about 3 pl, contact angles are measured while the needle of the
syringe used for
introduction remains in the drop. Contour measurements are carried out at a
rate of about
0.5 Hz and are evaluated by means of a tangent method in order to determine
the contact angle
directly at the three-phase contact line. These contact angles are averaged
over time, and five
progressive drops are measured at various positions for each sample and the
average value
together with a standard deviation is determined.
Example 1.5: Recycling experiments
An experiment is carried out on the use of magnetite hydrophobicized according
to the
respective example as reusable carrier for the decontamination of (heavy metal-
) contaminated
earth. For this purpose, 3 g of magnetite were dispersed in a system
comprising 100 g of a sand
mixture (solids content: 1% by weight). This sand mixture comprises 99% by
weight of inorganic
siliceous constituents (e.g. feltspars, mica, iron pyrites) and 1% by weight
of a specific
hydrophobicized inorganic As-comprising contaminant (Enargite).
Hydrophobicization of this
inorganic contaminant is carried out using butylxanthate. After vigorous
mixing of the
hydrophobicized magnetite with this sand mixture, the arsenic component is
separated off by
means of hydrophobic flocculation with the magnetite. The hydrophobic
constituents are
collected and treated with a 0.1% strength by weight solution of a surfactant
(Lutensit A-ES from
BASF SE). In a subsequent magnetic separation step, the magnetic constituents
are separated
from the nonmagnetic As-comprising impurities. The hydrophobic magnetite is
washed with a
1:1 mixture of water and Et0H, filtered off and remixed with a freshly
produced sand mixture.
The process is repeated a total of ten times.
Example 2: Production of hydrophobicized magnetite
Example 2.1: Magnetic pigment 345 from BASF SE silanized with nOctS1(0K)3
(according to the
invention)
Synthesis: 10 g of magnet pigment 345 (magnetite FeD(Fe9204) from BASF SE are
added to a
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solution of 370 mg of nOctS i(OK)3 in 30 ml of water. The solution is stirred
for 30 min at room
temperature. The product is dried at 40 C under reduced pressure. Then the
product is stored
at 40 C in air for 7 days. The resulting solid is washed with water until the
pH of the washing
water does not change any more. Then it is dried overnight in air at 40 C. The
dried product is,
after preliminary comminution, brushed through an analytical sieve (400 pm)
and thus
deagglomerated and homogenized.
Analysis:
Floatation test: fresh solid and solid which has been washed ten times float
equally well on
water (also after shaking under);
Contact angle: fresh 146 , washed ten times 139';
Recycling test: When the yield of the As component is detected, the yield of
92% in the first
cycle drops to only 90% in the tenth cycle when using the nOctSi(OK)3-
silanized magnetic
pigment 345 from BASF SE.
Example 2.2: nBuSi(OH)2(0Na)-silanized magnetic pigment 345 from BASF SE
(according to
the invention)
Synthesis: The synthesis is carried out according to the scheme described in
example 2.1.
However, 350 mg of nBuSi(OH)2(0Na) are used and the product is stored at 120 C
in a CO2
atmosphere.
Analysis:
Floatation test: fresh solid and solid which has been washed ten times float
equally well on
water (also after shaking under);
Contact angle: fresh 154 , washed ten times 152";
Recycling test: When the yield of the As component is detected, the yield of
95% in the first
cycle drops to only 91% in the tenth cycle when using the nB uSi(0 H)2(0Na)-si
la nized magnetic
pigment 345 from BASF SE.
Example 2.3: (Ca2)pPr(Me)Si(OH)(0-)b-silanized magnetic pigment 345 from BASF
SE
(according to the invention)
Synthesis: The synthesis is carried out according to the scheme described in
example 2.1.
However, 340 mg of (Ca21-)[nPr(Me)Si(OH)(0-)}2are used as silanization
reagent.
Analysis:
Floatation test: fresh solid and solid which has been washed ten times float
equally well on
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water (also after shaking under);
Contact angle: fresh 142 , washed ten times 136';
Recycling test: When the yield of the As component is detected, the yield of
89% in the first
cycle drops to only 87% in the tenth cycle when using the (Ca2+)[nPr(Me)Si(OH)
(0-)k-silanized
magnetic pigment 345 from BASF SE.
Example 3: Comparative examples
Comparative example 3.1: commercial, hydrophobic magnetite Bayoxide E8707 H
from
Lanxess (not according to the invention)
Analysis:
Floatation test: fresh solid floats on water even after shaking under, while
solid which has been
washed twice no longer floats;
Contact angle: fresh 158 , washed ten times 116
Recycling: Comparative tests using a previously hydrophobicized magnetite from
Lanxess
(product: Bayoxide E8707 H) display a dramatic loss in yield of over 40% after
only the fourth
cycle. The experiments using this product are then stopped.
Comparative example 3.2: nOctMe2SiCI-silanized magnetic pigment 345 from BASF
SE (not
according to the invention)
Synthesis: Under a protective atmosphere, 10 g of magnetic pigment 345 from
BASF SE are
suspended in 20 ml of toluene. The suspension is heated to 70 C, and 0.3 g of
nOctMe2SiCI
(97% strength, from ABCR) are then added. The reaction mixture is subsequently
maintained at
70 C for 4 hours while stirring. The solid is subsequently filtered off,
washed firstly with 50 ml of
toluene, then 50 ml of methanol and finally water until the washings are free
of chloride. The
product is dried at 120 C under reduced pressure for 4 hours. The dried
product is, after
preliminary comminution, brushed through an analytical sieve (400 pm) and thus
deagglomerated and homogenized.
Analysis:
Floatation test: solid floats on water (even after shaking under), while solid
washed once no
longer floats on water;
Contact angle: fresh 148 , washed once 120 , washed ten times 98
Comparative example 3.3: nBuMe2SICI-silanized magnetic pigment 345 from BASF
SE (not
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according to the invention)
Synthesis: The synthesis is carried out according to the scheme described in
example 2.1.
However, 0.3 g of nBuMe2SiCI (97% strength from ABCR) is used as silanization
reagent.
Analysis:
Floatation test: solid floats on water (not after shaking under), while solid
washed once no
longer floats on water;
Contact angle: fresh 103 , washed ten times 89
Comparative example 3.4: magnetic pigment 345 from BASF SE hydrophobicized
with
octylphosphonic acid (not according to the invention)
Synthesis: 8.0 kg of water are placed in an apparatus comprising a 12 I
plastic bucket with
spout as stirred vessel and a metal stirrer. 2 kg of magnetic pigment 345 from
BASF SE are
subsequently introduced and the stirring speed of the metal stirrer is
selected so that the
pigment does not sediment and air is also not drawn in (no head of foam is
formed). 12.59 of
n-octylphosphonic acid (OPA, 80% strength) from Albright & Wilson are
subsequently added all
at once and all the starting materials are mixed in air at room temperature
for 1.5 hours. After
the end of the stirring time, the suspension is poured on to a porcelain
filter (d = 24 cm with an
MN 85/90 paper filter from Macherey-Nagel). Cracks formed in the filter cake
are wiped shut to
improve the washing action. The solid is dried overnight at 110 C in a
convection drying oven.
The dried product is, after preliminary comminution, brushed through an
analytical sieve
(400 pm) and thus deagglomerated and homogenized.
Analysis:
Elemental analysis: 0.06% of P in the end product;
Recycling test: Even after the third cycle, only an unsatisfactory yield of
the As-comprising
impurity of less than 50% is detected. The experiments are subsequently
stopped.
