Note: Descriptions are shown in the official language in which they were submitted.
"~ WO 93/09060 2 ~ ~ 9 3 6 ~ PCT/US92/09052
METHOD FOR THE PRODUCTION OF H2O2
USING FULLERENES
RELATED APPLICATION
This application is a continuation-in-part of Ser. No.
07/906,305, filed June 26, 1992, entitled "Method for the
Production of H202 Using Fullerenes" by danis Vasilevskis, which in
turn is a continuation-in-part of Ser. No. 07/874,349, filed April
24, 1992, entitled "Method for the Production of H2O2 Using
Fullerenes" by Janis Vasilevskis, which application in turn is a
continuation of Ser. No. 07/842,871, filed February 26, 1992,
entitled "Method for the Production of H202 Using Fullerenes" by
Janis Vasilevskis, which application is in turn a continuation of Ser.
No. 07/814,384, filed December 26, 1991, entitled "Method for
the Production of H2O2 Using Fullerenes" by Janis Vasilevskis,
which application is in turn a continuation-in-part of Ser. No.
07/782,254, filed October 26, 1991, entitled "Method for the
Production of H202 Using Buckminster-Fullerenes" by Janis
Vasilevskis, the entirety of which are incorporated by notice.
FIELD OF THE INVENTION
This invention is a process for the production of H2O2 using
fullerenes, including buckminster-fullerene. The process involves
the hydrogenation of the fullerenes and the reaction of the
hydrogenated fullerenes with 2 to produce H2O2. The process
utilizes a hydrogenation catalyst and may involve a single phase
reaction medium either aqueous or solvent-laden or a two-phase
reaction mixture of a solvent and water. The solvent solvates the
fullerenes and may solvate the hydrogenation catalyst. The H2C)2
enters the water phase for removal from the process.
BACKGROUND OF THE INVENTION
H2O2 is a weakly acidic, clear, colorless liquid miscible in all
proportions with water. It is widely used in bleaching operations,
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wo 93/09~6~ 2 0 9 S 3 6 0 PCI/US92/09052~,
in the preparation of other peroxygen compounds, and as an
oxidizing agent.
Most H202 is currently made using a process involving an
anthraquinone compound as the hydrogen carrier. This process
was first operated in Germany during World War ll. In the process,
an alkyl-anthraquinone such as a 2-alkyl-anthraquinone is dissolved -
in a in a solvent system such as a mixture of benzene and C7-Cg
alcohols, trialkylphosphates, tetraalkyl-substituted ureas,
dialkylcarboxylic acid amides, 1,3,5-tritetraalkylazene, 2,6-
dialkylcyclohexane, pivalic esters, mono- and
diacetylbenzoquinone, and diacetylbenzene. The dissolved
anthraquinone or "working so!ution" is mixed with with hydrogen
and a hydrogenation catalyst such as palladium-black, Raney
nickel, or nickel boride. The anthraquinone is reduced to the
corresponding anthraquinol (or anthrahydroquinone). The working
solution is separated from the catalyst and contacted with air to
again produce the anthraquinone. Simultaneously H202 is formed
and is then extracted with H20 to form an H2O2 solution. The 1-1202
solution is purified and concentrated if needed. The working
solution is recycled.
This process suffers form a wide variety of maladies. Many
involve secondary "over-reduction" reactions or degradation
reactions of the anthraquinone during the process cycle. The
solvents are often degraded through oxidation. Many of the
resulting byproducts end up in the aqueous H202 solution and must
be subsequently removed thereby adding to the cost of the
process.
The inventive process does not involve the use of
anthraquinone but instead uses fullerenes as the hydrogen carrier.
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SUMMARY OF THE INVENTION
This invention is a process for the production of H2O2 using
fullerenes. The process involves the catalytic hydrogenation of the
fullerenes and the reaction of the hydrogenated fullerenes with 2
to produce H202. Although the process may utilize a two-phase
reaction mixture of a solvent and water, a single aqueous or
solvent phase is also applicable. The H202 is extracted into the
water phase for removal from the process.
DETAILED DESCRIPTION OF THE INVENTION
This invention is a process for the production of H2O2 using
fullerenes. The process involves the catalytic hydrogenation of the
fullerenes and the reaction of the hydrogenated fullerenes with 2
to produce H2O2. The process may utilize a two-phase reaction
mixture of a solvent and water or an aqueous or sotvent single
phase. In the two-phase or solvent reaction mixture, the solvent
solvates the fullerenes and any applicable hydrogenation catalyst.
The H2O2 is extracted into the water phase for removal from the
process.
Fullerene hvdrogen carrier
Fullerenes, recently discovered by Smalley, Curl, Kroto,
Heath and O'Brien rNature, 318, 162 (1985)], are representative of
a set of carbon molecules which hava been shown to have both
aromatic and olefinic character. The simplest of the fullerene
molecules is a sperical C60 molecule, called buckminster-fullerene, -`~ -
with the geometry of a truncated icosahedron - a polygon with 60
vertices and 32 facles, 12 of which are pentagons and 20 are
hexagons. Other fullerene molecules have been identified and
include C70~ C7B~ C7B~ C84, C90, C94, and others up to C286. See,
Parker et al, J.Am. Chem. Soc. 1991, 113, 7499-7503.
Methods for the production of fullerenes have been
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WO 93/09060 2 ~ 9 ~ 3 6 0 PCI/US92/0~052
described in a number of journals. For instance, in J. Phys. Chem.
1990, 94, 8634-8636, Haufler et al describe an apparatus and a
process for producing fullerenes in which a graphite rod is
vaporized in an arc using a 100-200A current in a heliùm
atmosphere held near 100 Torr. The resulting soot is extracted
with boiling toluene to form a dark red-brown liquid of the C60 and
which typically contains about 10% of the original soot.
Haufler et al also shows that the CBO buckminster-fullerene
may be hydrogenated to form a CBoH3a molecule and subsequently
dehydrogenated to C50 without substantial alteration of the
molecule.
Additionally, Hawkins et al have shown [J. Org. Chem.
1990, 55, 6250-6252 and Science 1991, 252, 312-313] that C60
buckminster-fullerene may be functionalized. Hawkins et al utilizes
osmium tetraoxide and pyridine to produce an ester.
Cioslowski has reported [J. Am. Chem. Soc. 1991, 113,
4139-4141] that C~O buclcminster-fullerene could form cages about
several ions including F, Ne, Na+, Mg2~, and Al3~.
Fagan et al lScience 1991, 252, 1160-1162] have shown
that buckminster-fullerene C60 may be easily formed into
cyclopentadienyl platinum group metal complexes.
Selig et al lJ. Am. Chem. Soc. 1991, 113, 5475-5476]
shows that C60 and C70 fullerenes may be readily fluorinated using
a low pressure (at several hundred Torr) fluorine gas to form
neutral fluorinated compounds of up to about C60F46. Holloway et
al [J. Chem. Soc., Chem. Commun., 1991, 14, 966-969] similarly
shows the production of C60F60 buckminster-fullerene without the
apparent degradation of the buckminster-fullerene core molecule.
Krusic et al lJ. Am. Soc. 1991, 113, 627~6275] shows
that fullerenes may be easily alkylated using known techniques.
The fullerene molecule has been shown to be quite stable to
oxidation in a 25% 2 atmosphere at temperatures lower than
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about 500~C. [Vassallo et al, J. Am. Chem. Soc. 1991, 113, ~ -
7820-7821 ]
The production of solid fullerene/metal containing materials
is shown [H. Nagashima, J. Chem. Soc. - Chem. Con., 1992, 377-
79]. Polymeric materials of C60 fullerene, palladium, and
dibenzylidene acetone are described.
The fullerene molecule used in the inventive process may be
any of the molecules listed above or others of the genre and, as
required by the choice of solvent and hydrogenation catalyst, may
be alkylated, fluorinated, modified to contain a metal or molecule
within the fullerene molecule or to contain a metal on the fullerene
surface or in the fullerene cage. The fullerene molecule may be
complexed with a metal-containing ligand which may act as a
hydrogenation component integrated with the fullerene. The
fullerene molecule may be converted into a heterogeneous form by
the proceses noted above. These modifications to the fullerene
molecule are a matter of technical choice to tailor the solubility of
the fullerene molecule to the chosen solvent, to form a
heterogeneous fullerene material which is not soluble, or to modify
the reaction rate of the fullerene molecule or to enhance the
stability of the fullerene molecule. -~
The molecule used in the process and containing the
fullerene core may desirably be converted to one having a metal-
containing hydrogenation catalyst, e.g., platinum group metals
such as Pd, Pt, Ru, etc., complexed to the fullerene molecule (e.g.,
C~ol(MLn)m] where "M" is one or more of the noted hydrogenation
metals and "L" represents one or more ligands as needed to
stabilize the metals) or adsorbed on the surface or substituted for
one or more carbon atoms in the fullerene core. In this way the
hydrogenation catalyst need not necessarily be separately added to
the process.
WO 93/09060 P~T/US92/09052
2099~0
Process
This invention is a process for the production of H202 using
a molecule containing the fullerene core. The process involves the
hydrogenation of the fullerene and the re;action of the
hydrogenated fullerene with 2 to produce H202.
The process may utilize a two-phase reaction mixture of a
solvent and water. The solvent may solvate the fullerenes and any
applicable hydrogenation catalyst. If the fullerenes have been
modified to a heterogeneous form, the solvent need not solvate the
catalyst and fullerene. The H202 is extracted into the water phase
for removal from the process. As noted below, the process may
also be operated in a single liquid phase and either in continuous or
in batch mode.
The process is straightforward. In one variation of the
process, one or more of the fullerene core carbons is replaced with
a hydrogenation metal, e.g., Pd, so that the hydrogenation catalyst
is a part of the fullerene structure. These structures are soluble in
hydrocarbon solvents which are not miscible with water and which
would not oxidize under the peroxide synthesis conditions. The
solvents should be substantially insoluble in water or in aqueous
solutions containing H202, e.g., aromatics or chlorinated aliphatics.
In the process of the present invention, an organic solution
of CZ~xpdx ~where "z" represents the number of carbons necessary
to form a determinate fullerene structure) is contacted with a water
phase and then reacted with a mixture of H2/02 (outside of
explosive limits~ to produce hydrogen peroxide. The relative rates
of hydrogenation/oxidation determine the various structures Cz.x.
yPdXHy which are present in solution. The peroxide which is formed
is not soluble in the hydrocarbon and therefore is continuously
extracted into the aqueous phase. As a result, it does not displace
oxygen as the oxidant in the hydrocarbon phase thus avoiding
reduction to water and giving high selectivity to hydrogen peroxide.
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VO 93/09060 2 ~ 9 9 ~ ti U PCI~US92/090~2
The fullerene cores are stable under the reac~ion conditions which
make it possible to attain high le.g., >20%) concentrations of
H202 without peroxide contamination or catalyst/reaction carrier
degradation. The fullerene containing molecule is desirably usr d in
as high a concentration as is possible to provide the highest
production rates but obviously lower conc:entrations would be
acceptable. The reaction should be operated at as low a
temperature and pressure as is convenient so to simplify the
cooling of the reaction mixture and obviate the need for expensive
pressure vessels. Preferably, the reaction is operated at room
ternperature and at atmospheric pressure although temperatures
from below room temperature to about 100C and pressures from
about atmospheric to about 500 psig are appropriate.
The process may also be operated in a continuous fashion, ~-
e.g., contact of the hydrocarbon/fullerene/hydrogenationcatalyst
mixture with hydrogen, followed by contact of the hydrogenated
fullerenes with oxygen and water to form an H2O2 solution, and
recycle of the fullerenes. The process may also be be operated
semi-continuously with the cycling of H2/02 mixtures and water.
Other variations of the process include:
1. The fullerene-containing hydrogen carrier may be
alkylated, fluorinated, or made to contain a metal or
molecule within the fullerene molecule. These
modi~ications to the fullerene containing core molecule
are a matter of technical choice to tailor the solubility
of the fullerene molecule to the chosen solvent or to
modify the reaction rate of the fullerene molecule or to
enhance the stability of the fullerene molecule.
2. The manner by which the fullerene-containing
molecule is reduced may be changed in a number of
ways. The molecule containing the fullerene core may
desirably be converted to one having a hydrogenation
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WO 93/0906~ 2 0 9 9 3 ~ ~ PCI-/US92/09052~
metal, e.g., Pd, Pt, Ru, etc., complexed to the
fullerene molecule ~e.g., C~o[(MLn)m] where "M" is one
or more of the noted hydroge~nation metals and "L"
represents one or more ligands as needed to stabilize
the metals) or adsorbed on the surface or substituted
for one or more carbon atom~s in the fullerene core.
Attachment of the catalytic rnetal to the surface of
the fullerene core likely provides added stabilization of
the metal complex.
The hydrogenation catalyst may be homogeneous and
dissolved in the hydrocarbon layer. Salts or complexes of the
hydrogenation catalysts, e.g., Pd, Pt, Ni (using ligands such as
phosphines or aryl groups which stabilize the metal and allow it to
be solubilized in the hydrocarbon phase) are appropriate. The
dissolved catalyst should be selected also using the criteria that it
not degrade by oxidation.
A heterogeneous hydrogenation catalyst comptising, e.g.,
platinum group metals such as Pd, Pt, Ru, etc., is useful so long as
the catalyst is preferentially wet by the hydrocarbon phase. An
example of such a catalyst is palladium on partially fluorinated
carbon. The catalyst in this example also produces H202
independently of the fullerene.
Since the fullereness will support a negative charge, they
can be used to stabilize metal colloids of, e.g., Pdo, to provide
PdO/fullerenes colloid H202 reaction systems for inclusion in the
hydrocarbon phase.
Another variation involves a one-liquid-phase ~hydrocarbon or
aqueous) system having a catalyst system which repels H202 so
that it does not return to the active catalyst site. Partially alkylated
or fluorinated fullerenes hydrogen carrier systems (such as C~oPdF~
in a heterogeneous catalys~ or C ~oF~ with adsorbed Pd) have the
desired properties.
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WO 93/09060 2 ~ 9 9 3 ~ ~ PCI~/US92/09052
Another variation includes the concept of forming the
fullerene into a heterogeneous form.
Still another variation is the use of an electrode of fullerene
which would then be reduced with electrons. The surface would
be protonated by protons in solution. Reaction with oxygen would
then produce H202. The protons would be replenished by oxidation
of hydrogen at the other electrode made of a conductive material.
A proton conducting between the electrodes would have the
advantage of not allowing 2 and 2 in the same compartment.
Finally, the process may be operated in a batch mode; the
oxygen and the hydrogen are alternated over the fullerene
containing solution.
EXAMPLE
This Example demonstrates the use of fullerene as a
hydrogen carrier in a process of producing H202.
A C60 fullerene solution containing a Pd catalyst was
contacted with H2 at temperatures between 45-65C. The
solution was then contacted with 2 A white silky precipitate
formed. Testing of the solution with KMnO4 indicated the presence
of H202.
In another series of experiments, the hydrogenated solution
was contacted with a solution of eAQ and extracted. The amount
of H202 formed was equal to about 30% of hydrogen under the
assumption that the hydrogenated fullerene had the formula C~oH3~.
The white precipitate was also formed.
It should be clear that one having ordinary skill in this art
would envision equivalents to the processes found in the claims
that follow and that those equivalents would be within the scope
and spirit of the claimed invention.
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