USOO6254845B1

(12) United States Patent (10) Patent No.: US 6,254,845 B1

Ohashi et al. (45) Date of Patent: *Jul. 3, 2001

(54) SYNTHESIS METHOD OF SPHERICAL (56) References Cited

HOLLOW ALUMNOSILICATE CLUSTER U.S. PATENT DOCUMENTS
(75) Inventors: Fumihiko Ohashi, Aichi; Shin-Ichiro 4.217.240 8/1980 Bergra ............................... 423/328.1
Wada; Yasuko Kakuto, both of 4.252,779 2/1981 Farmer ................................. 423/327
Fukuoka, all of (JP) FOREIGN PATENT DOCUMENTS
(73) Assignee: Agency of Industrial Science and 1574954 3/1977 (GB).
Technology, Tokyo (JP) OTHER PUBLICATIONS
Wada, “Synthesis of Allophane and Imogolite-Reactions
(*) Notice: This patent issued on a continued pros between Silicic Acid and Aluminum Ions in Dilute Aqueous
ecution application filed under 37 CFR Solutions”, Nendo Kagaku, Feb. 25, 1985, pp. 53-60.
1.53(d), and is subject to the twenty year
patent term provisions of 35 U.S.C. * cited by examiner
154(a)(2). Primary Examiner Stuart Hendrickson
(74) Attorney, Agent, or Firm-Oblon, Spivak, McClelland,
Subject to any disclaimer, the term of this Maier & Neustadt, P.C.
patent is extended or adjusted under 35 (57) ABSTRACT
U.S.C. 154(b) by 0 days.
The present invention provides a method for the homog
(21) Appl. No.: 09/021,819 enous and highly efficient Synthesis of an aluminosilicate
material that can be used for adsorbents, deodorants, catalyst
(22) Filed: Feb. 11, 1998 carriers, humidity adjustors, and the like, and relates to a
(30) Foreign Application Priority Data method for manufacturing Spherical hollow Silicate clusters,
comprising Steps of mixing a Solution of a Silicon compound
Feb. 25, 1997 (JP) ................................................... 9-058460 and a Solution of an aluminum compound or transition metal
(51) Int. Cl." ................................................. C01B33/26 compound, each with a solution concentration of 10-1000
(52) U.S. Cl. ................... 423/328.1; 423/326; 423/330.1; mmol, rapidly or simultaneously at a rate of 1-10,000
502/263 mL/min, removing a Salt formed as a by-product, and then
subjecting the mixture to hydrothermal synthesis to yield the
(58) Field of Search .............................. 423/328.1, 330.1, Silicate clusters.
423/326, 329.1; 516/110; 502/263, 241,
242, 243, 246, 250, 254, 258 9 Claims, 6 Drawing Sheets
U.S. Patent Jul. 3, 2001 Sheet 1 of 6 US 6,254,845 B1
U.S. Patent Jul. 3, 2001 Sheet 2 of 6 US 6,254,845 B1

i
O 20 40 60 80
26 (Cu-Ka)

F ig. 2
U.S. Patent Jul. 3, 2001 Sheet 3 of 6 US 6,254,845 B1

3: 38:
U.S. Patent Jul. 3, 2001 Sheet 4 of 6 US 6,254,845 B1

10mM

s
t
8 30mM
s
re
9.o
<C

50mM

100mM

5000 4000 3000 2000 1000

Wavenumber (cm)

Fig. 4
U.S. Patent Jul. 3, 2001 Sheet 5 of 6 US 6,254,845 B1

i
O 20 40 60
26 (Cu-Ka)

Fig. 5
U.S. Patent Jul. 3, 2001 Sheet 6 of 6 US 6,254,845 B1

5000 4000 3000 2000 1000

Wavenumber (cm)

F i g. 6
 US 6,254,845 B1
1 2
SYNTHESIS METHOD OF SPHERICAL SUMMARY OF THE INVENTION
HOLLOW ALUMNOSILICATE CLUSTER The present invention provides a method for the homog
DISCLOSURE OF THE INVENTION enous and highly efficient Synthesis of an aluminosilicate
material that can be used for adsorbents, deodorants, catalyst
The present invention relates to a novel method for carriers, humidity adjustors, and the like.
manufacturing spherical hollow Silicate clusters that can be The present invention relates to a method for manufac
used as adsorbents of hazardous Substances, deodorants, turing spherical hollow Silicate clusters, comprising Steps of
catalyst carriers, humidity adjustors for automatically con mixing a Solution of a Silicon compound and a Solution of an
trolling the humidity of living rooms, car interiors, and other aluminum compound or transition metal compound, each
living environments, drug microcapsules, and other appli with a solution concentration of 10-1000 mmol, rapidly or
cations in which high Specific Surface is utilized and which simultaneously at a rate of 1-10,000 mL/min, removing a
have excellent water resistance, heat resistance, corrosion Salt formed as a by-product, and then Subjecting the mixture
resistance, ion-exchange capacity, and adsorption capabili to hydrothermal Synthesis to yield the Silicate clusters.
ties.
15 DETAILED DESCRIPTION OF THE
BACKGROUND OF THE INVENTION INVENTION
Nanometric fine particles are being Studied in electronics, It is an object of the present invention to provide a method
chemistry, machine metal industry, and other fields. Of in which high-concentration Starting materials are used to
particular interest for these industries are clusters represent manufacture, with high efficiency, purity, and yield, homo
ing aggregates of Several thousand molecules, and Superfine geneous and highly pure hollow spherical Silicate clusters
clusters comprising anywhere from Several to Several hun that can be used as adsorbents of hazardous Substances,
dred atoms. The issue of controlling the Synthesis, Surface deodorants, catalyst carriers, humidity adjustors for auto
improvement, and fine Structure of Such nanometric fine matically controlling the humidity of living rooms, car
particles occupies an important position in the aforemen 25 interiors, and other living environments, drug microcap
tioned fields. There are, however, no reports on established Sules, and other applications having excellent water
methods for Synthesizing hollow Spherical particles of nano resistance, heat resistance, and corrosion resistance.
metric size capable of being used for microcapsules and the Aimed at attaining the Stated object, the present invention
like.
resides in a method for producing spherical hollow Silicate
Naturally occurring aluminosilicates shaped as hollow cluster characterized in the Steps comprising of mixing a
Spheres are known as weathered volcanic glass, but preci Solution of a Silicon compound and a Solution of an alumi
Sion techniques Such as high-efficiency, high-purity num compound or transition metal compound, each with a
Separation/extraction have not yet been established for solution concentration of 10-1000 mmol, rapidly or simul
obtaining Such fine particles, and additional research is taneously at a rate of 1-10,000 mL/min, removing a salt
being conducted. 35 formed as a by-product, and then Subjecting the mixture to
An attempt has also been made to artificially Synthesize hydrothermal Synthesis to yield the Silicate cluster.
amorphous aluminosilicate clusters shaped as Such hollow In addition, the following methods are preferred embodi
spheres (Wada, S., Nendo Kagaku, Vol. 25, No. 2, pp. 53–60, ments of the present invention: a method for producing the
1985), but successful results can only be obtained when the aforementioned spherical hollow Silicate cluster in which the
Starting material is a Solution diluted to about 2–4 mmol, 40 composition of Superfine particles shaped as hollow spheres
which is disadvantageous because the resulting yield is very and Synthesized by using Silicon compounds, aluminum
low, the purity of the product is also low due to the formation compounds, or transition metal compounds as Starting mate
of by-products, and the like. A Synthesis method has also rials consists of one or more components Selected from the
been proposed for raising the concentration of nanotubular group composed of Silicates, aluminum, and transition metal
Silicates called imogolite to 60 mmol by making use of 45 elements, a method for producing the aforementioned
organosilicon and aluminum compounds (GB Patent 1,574, Spherical hollow Silicate cluster in which the mean particle
954 and U.S. Pat. No. 4,252,779), but there are no examples diameter of the Spherical Silicate particles constituting the
in which hollow spherical particles are Synthesized in high clusterS falls within a range of 1-10 nm, and the Specific
concentrations. Surface thereof, as measured by nitrogen adsorption, is
The concentration of Starting materials and the acidity or 50 50m/g or greater; and a method for producing the afore
basicity of Solutions must be taken into account in order to mentioned spherical hollow Silicate cluster in which the
Synthesize hollow spherical Silicate clusters having Such Silicon/aluminum or transition metal compound molar ratio
compositions or structures. is 0.5-5.0.
According to a conventional technique, a Sodium hydrox In the past, a Solution of a Silicate cluster and a Solution
ide Solution is added to a mixture of a monomer Silicic acid 55 of an aluminum compound or transition metal compound
compound Solution (2 mmol or lower) and an aluminum were slowly mixed in low concentrations. The present
compound solution (0.5–4 mmol) such that the NaOH/Al invention, however, adopts Steps in which a Solution of an
ratio is 3.0 in order to control the rate of polymerization, and alkali Silicon compound and a Solution of an aluminum
the system is kept at 100° C. for about 5 days, yielding a compound or transition metal compound, each with a Solu
hollow Spherical Silicate. 60 tion concentration of 10-1000 mmol, are mixed rapidly or
The aforementioned Synthesis techniques are incapable of Simultaneously and a Salt formed as a by-product is removed
yielding Such materials with high efficiency because of the in order to (1) mix the Silicon, aluminum, and transition
conventional notion that amorphous Silica or a hydroxide metal compounds while neutralizing the System with the aid
(boehmite, gypsite, or the like) precipitates first unless the of the alkali Silicon compound, and (2) use high
Starting materials are gradually mixed in a low concentration 65 concentration Starting Solutions while preventing amorphous
under near-equilibrium conditions, and the pH is slowly Silica from precipitating by rapidly mixing these compo
neutralized with an alkali. nents. The corresponding Silicon/aluminum or transition
 US 6,254,845 B1
3 4
metal compound ratio should be about 0.5-5.0. The system organic Solvent after the System has been dried, or a heat
is Subsequently heated and aged, yielding a material in treatment is performed in air at 300-600 C. over a holding
which the particle diameter is adjusted to 1-10 nm and in period of 1-8 hours, yielding the proposed hollow Spherical
which the composition of the Silicate material shaped as Silicate clusters.
hollow spheres consists of one or more components Selected The compound obtained by the above-described tech
from the group composed of aluminosilicates and transition nique has a specific surface area of about 50-500 m/g (as
metal elements. measured by a nitrogen adsorption technique), a mean
In the present invention, Silicon compounds, aluminum particle diameter of 3–5 nm, and a mean pore diameter of
compounds, and transition metal compounds may be used in 1-5 nm. An infrared absorption spectrum reveals a Single
order to obtain a homogeneous Silicate materials shaped as absorption due to silicate compounds. Powder X-ray dif
hollow Spheres. Examples of reagents that can be used as fraction reveals two broad peaks close to 27 and 40, which
Silicon Sources include Sodium orthosilicate, alkyl correspond to a noncrystalline Structure. In addition, obser
orthosilicates, Sodium metasilicate, and Silicon dioxides in Vations under a transmission electron microscope reveal a
the form of amorphous colloids (Such as aerogels and the state in which hollow spherical particles with diameters of
like). These Silicate compounds may be used individually or 15 3-5 nm are evenly distributed.
as combinations of two or more compounds. Thus, a noncrystalline aluminosilicate porous material
Examples of inorganic compounds linked to the afore shaped as hollow Spheres can be obtained by a method in
mentioned Silicate molecular aggregates in accordance with which an aqueous Solution of a Silicon compound and an
the present invention include aluminum chloride, Sodium aqueous Solution of an aluminum or transition metal com
aluminate, aluminum hydroxide, and other aluminum com pound are mixed simultaneously at a high rate, reaction
pounds, organometallic compounds, and chloride, Sulfide, by-products are then removed, and the System is treated at
hydroxide, nitrate, and other compounds of Vanadium, iron, its boiling point.
tungsten, titanium, cobalt, nickel, copper, Zirconium, and
other transition metals. These inorganic compounds may be BRIEF DESCRIPTION OF THE DRAWINGS
25
used individually or as combinations of two or more com FIG. 1 is a Schematic depicting the Structure of a Silicate
pounds. cluster shaped as a hollow sphere.
To obtain the proposed hollow spherical Silicate clusters, FIG. 2 is an X-ray diffraction pattern of a spherical hollow
a mixed Solution of an aluminum compound or a compound aluminosilicate cluster pertaining to an example of the
of Vanadium, iron, tungsten, titanium, cobalt, nickel, copper, present invention Synthesized by varying the initial Solution
Zirconium, or another transition metal or other element with concentration.
a concentration of 10-1000 mmol, and an aqueous Solution FIG. 3 is an electronic photomicrograph of a spherical
of an alkali Silicate compound with a concentration of hollow aluminosilicate cluster (particle structure) pertaining
10-1000 mmol are mixed rapidly or simultaneously at a rate to an example of the present invention.
of 1-10,000 mL/min, yielding a precursor. The correspond 35
ing Silicon/aluminum or transition metal compound ratio FIG. 4 is an infrared absorption spectrum of the spherical
molar should be about 0.5-5.0. Boehmite or gypsite forms hollow aluminosilicate cluster pertaining to an example of
as a by-product when the molar ratio is below 0.5, and a the present invention.
large amount of noncrystalline Silica forms as a by-product FIG. 5 is an X-ray diffraction pattern of a spherical hollow
when the ratio exceeds 5.0. 40
aluminosilicate cluster pertaining to Comparative Example
When the precursor Suspension has Solution properties 1.
that are not neutral, it is effective to neutralize the System by FIG. 6 is an infrared absorption spectrum of the spherical
adding hydrochloric acid, nitric acid, or Sulfuric acid as an hollow aluminosilicate cluster pertaining to Comparative
acid component after calculating its amount for the transi Example 1.
tion metal compound Solution, or by adding Sodium 45
EXAMPLES
hydroxide, potassium hydroxide, calcium hydroxide, or the
like as an alkali component after calculating its amount for The present invention will now be described in further
the Silicon compound Solution. In this case, polyethylene detail through examples and comparative examples.
glycol, polyvinyl alcohol, a Surfactant, or other water
Soluble or water-insoluble reagent may also be added as an 50
Example 1
anticoagulant. Sodium orthosilicate was dissolved in purified water,
The resulting precursor Suspension is Shaken for 1-24 yielding 50 mL of a 100-mmol aqueous solution. In a
hours at room temperature, and Salts, which are the Separate operation, aluminum chloride was dissolved in
by-products of the reaction, are then removed. The removal purified water, yielding 67.15 mL of a 100-mmol aqueous
method is not Subject to any particular limitations and may 55 Solution. The aluminum chloride Solution was mixed at a
involve ultrafiltration, Separation in a centrifugal Separator, high rate with the aqueous Solution of Sodium orthosilicate,
or the like. Desalting is followed by the addition of purified and the System was Shaken for 1 hour at room temperature.
water in the same amount as the amount removed, the The corresponding silicon/aluminum ratio was 0.75. After
system is aged for 3-5 days at 80–120° C., and the resulting the shaking had been completed, the Suspension was filtered
product is used to Synthesize the hollow Spherical Silicate 60 using a membrane filter in order to remove the Sodium
material of the present invention, either directly or after chloride formed as a by-product. The precursor that had
being washed Several times with purified water and dried. adhered to the filter was transferred into a conical flask,
The drying is accomplished at normal pressure and a tem about 120 mL of purified water was then added, and the
perature of 40-100° C. If an anticoagulant has been added, System was dispersed by ultraSonic waves for 1 hour. The
the component is extracted off for at last one hour at a 65 dispersed Suspension was aged for 5 days at 80 C., washed
temperature of 200 C. or lower with the aid of methanol, with purified water, and dried at normal temperature and
ethanol, acetone, toluene, Xylene, benzene, or another preSSure.
 US 6,254,845 B1
S 6
It follows from the X-ray diffraction pattern in FIG. 2 that it was evident that the product had an inhomogeneous phase.
the Spherical hollow aluminosilicate cluster thus obtained The formation of boehmite was also confirmed by the results
has broad peaks near 20=25-26 and near 38-42 on the of infrared absorption spectroScopy.
Cu-K line, which is characteristic of Spherical particles AS described in detail above, conventional Synthesis
referred to as allophane. techniques are incapable of yielding nanometric hollow
The fact that the product was hollow and spherical and Spherical particles with high efficiency and in a high
had a diameter of 3-5 nm was also confirmed based on the
results of observations under an electronic microScope. In concentration, whereas the present invention allows high
addition, an infrared absorption Spectrum revealed only an purity, homogeneous spherical hollow Silicate clusters to be
absorption due to aluminosilicates. The Specific Surface was manufactured with high efficiency, purity, and yield by using
about 500 m/g (as measured by nitrogen adsorption), and high-concentration starting materials. The Spherical hollow
the mean pore diameter was about 3 mm. The yield was 90% Silicate clusters prepared by the new Synthesis method of the
or higher, and the purity was nearly 100%, irrespective of the present invention have the excellent water resistance, heat
type of compound formed as a by-product. resistance, and corrosion resistance of inorganic compounds
15 and can thus be used as adsorbents of hazardous Substances,
Example 2 detergents, deodorants, catalyst carriers, humidity adjustors
for automatically controlling the humidity of living rooms,
A 50-mmol aqueous solution (25 mL) and a 100-mmol car interiors, and other living environments, drug microcap
aqueous solution of sodium hydroxide (26.82 mL) were Sules utilizing the irregular shape thereof, and a wide variety
prepared and mixed. In a separate operation, 84.15 mL of an of other commercial applications.
aqueous Solution of aluminum chloride (50 mmol) was What is clamed is:
prepared and quickly added to the aforementioned mixed 1. A method for producing hollow Silicate clusters, the
Solution. The corresponding Silicon/aluminum ratio was 0.6. method comprising
The product was thoroughly agitated at room temperature,
and the resultant Sodium chloride by-product was then 25
mixing at a rate of 1-10,000 mL/min a 10-1000 milli
removed by a technique involving the removal of a Super molar solution of a silicon compound and a 10-1000
natant by centrifugation. The reaction precursor was millimolar Solution of an aluminum compound or a
recovered, 130 mL of purified water was added, and a transition metal compound to form a Suspension
reaction was then conducted for 5 days at 80 C. including a Salt in Solution and precursor particles,
It was learned based on a morphological Study of spheri removing at least a portion of the Salt in Solution from the
cal particles under an electron microScope, on broad peaks precursor particles, and
and other peaks obtained by X-ray diffraction and ascribed then Subjecting the precursor particles to hydrothermal
to noncrystalline substances, and on Si-OH, Si-O-Si(Al), Synthesis to yield the hollow Silicate clusters, wherein
and other broad adsorption bands obtained by infrared each of the hollow Silicate clusters comprises hollow
absorption spectroscopy and ascribed to aluminosilicates 35 Silicate particles, and
that the reagent that had been dried in a 50° C. electric drier each of the hollow Silicate particles comprises a Silicate.
was an aggregate of hollow spherical particles with diam and aluminum or a transition metal element.
eters of 4-5 nm and that this aggregate had a specific Surface 2. The method as defined in claim 1, wherein
area of about 500 m/g (as measured by nitrogen adsorption) the hollow Silicate particles form at least one pore in the
and a mean pore diameter of 5 nm, and formed an alumi 40
hollow Silicate clusters, and
nosilicate cluster. The yield was about 95%, and the purity
was about 100%. the mean pore diameter of the at least one pore is in a
Similar results were obtained by performing the same range of from 1-5 nm.
procedures using other Silicon compounds, aluminum 3. The method as defined in claim 1, wherein
compounds, or transition metal compounds. 45 the mean particle diameter of the hollow Silicate particles
is from 1-10 nm, and
Comparative Example 1 the Specific Surface area of the hollow Silicate particles, as
measured by nitrogen adsorption, is 50 m/g or greater.
An ethanol solution of ethyl orthosilicate was diluted with 4. The method as defined in claim 1, wherein a molar ratio
purified water Such that the Silicon concentration was 2 50 of the Silicon compound to the aluminum compound or the
mmol, yielding a total of 4000 mL of aqueous solutions transition metal compound is 0.5-5.0.
(1000 mL each). Aqueous solutions of aluminum chloride 5. The method as defined in claim 1, wherein the Solution
(0.5, 1.0, 2.0, and 4.0 mmol) were prepared in an amount of of a Silicon compound is an aqueous Solution.
1000 mL each, and these Solutions were mixed with the 6. The method as defined in claim 1, wherein the Solution
above, yielding 2000 mL in each case. An aqueous Solution 55 of an aluminum compound or a transition metal compound
of sodium hydroxide (1000 mmol) was then slowly added at is an aqueous Solution.
a rate of 0.5 mL/min under agitation Such that the Sodium 7. The method as defined in claim 1, wherein the hydro
hydroxide/aluminum ratio was 3.0. A Saturated aqueous thermal Synthesis comprises heating the precursor particles
Solution of Sodium chloride was added in order to aggregate in an aqueous Suspension at a boiling point of the aqueous
and precipitate the resulting aluminosilicate. 60 Suspension.
After the aggregation had been completed, the final prod 8. The method as defined in claim 7, wherein the boiling
uct was washed with purified water, dried at room point of the aqueous suspension is from 80 C-120° C.
temperature, and Submitted to various measurements. 9. The method as defined in claim 1, wherein each of the
X-ray diffraction revealed that, of the Samples obtained, hollow Silicate clusters comprises an empty core larger than
the product in which 4 mmol of the aqueous Solution of 65 each of the hollow Silicate particles.
aluminum chloride was used had a peak that could be
ascribed to boehmite, which is an aluminum compound, and k k k k k
 UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION

PATENT NO. : 6.254,845 B1 Page 1 of 1

DATED : July 3, 2001
INVENTOR(S) : Ohashi et al.

It is certified that error appears in the above-identified patent and that said Letters Patent is
hereby corrected as shown below:

Title page,
Item 75, the inventor's information should read:
-- (75) Inventors: Fumihiko Ohashi, Nagoya, Shin-Ichiro Wada, Ogoori;
Yasuko Kakuto, Fukuoka, all of (JP) --.
-- (73) Assignee: Japan as represented by Director General of Agency of
Industrial Science and Technology, Tokyo (JP) --

Signed and Sealed this

Eleventh Day of June, 2002

Attest.

JAMES E. ROGAN
Attesting Officer Director of the United States Patent and Trademark Office