U.S. patent application number 11/159384 was filed with the patent office on 2006-12-28 for mesostructured aluminosilicate material.
Invention is credited to Cedric Boissiere, Alexandra Chaumonnot, Aurelie Coupe, Patrick Euzen, David Grosso, Clement Sanchez.
Application Number | 20060292054 11/159384 |
Document ID | / |
Family ID | 34942335 |
Filed Date | 2006-12-28 |
United States Patent
Application |
20060292054 |
Kind Code |
A1 |
Chaumonnot; Alexandra ; et
al. |
December 28, 2006 |
Mesostructured aluminosilicate material
Abstract
A mesostructured aluminosilicate material is described,
constituted by at least two spherical elementary particles, each of
said spherical particles being constituted by a matrix based on
silicon oxide and aluminium oxide, having a pore size in the range
1.5 to 30 nm, a Si/Al molar ratio of at least 1, having amorphous
walls with a thickness in the range 1 to 20 nm, said spherical
elementary particles having a maximum diameter of 10 .mu.m. A
process for preparing said material and its application in the
fields of refining and petrochemistry are also described.
Inventors: |
Chaumonnot; Alexandra;
(Lyon, FR) ; Coupe; Aurelie; (Noisiel, FR)
; Sanchez; Clement; (Gif-Sur-Yvette, FR) ; Euzen;
Patrick; (Paris, FR) ; Boissiere; Cedric;
(Paris, FR) ; Grosso; David; (Rueil Malmaison,
FR) |
Correspondence
Address: |
MILLEN, WHITE, ZELANO & BRANIGAN, P.C.
2200 CLARENDON BLVD.
SUITE 1400
ARLINGTON
VA
22201
US
|
Family ID: |
34942335 |
Appl. No.: |
11/159384 |
Filed: |
June 23, 2005 |
Current U.S.
Class: |
423/328.1 ;
423/328.2 |
Current CPC
Class: |
B01J 35/1023 20130101;
B01J 37/0045 20130101; B01J 35/10 20130101; C01B 39/02 20130101;
B01J 35/023 20130101; B01J 29/041 20130101; B01J 35/0013
20130101 |
Class at
Publication: |
423/328.1 ;
423/328.2 |
International
Class: |
C01B 33/26 20060101
C01B033/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2004 |
FR |
04/06.938 |
Claims
1. A mesostructured aluminosilicate material constituted by at
least two spherical elementary particles, each of said spherical
particles being constituted by a mesostructured matrix based on
silicon oxide and aluminium oxide, having a pore size in the range
1.5 to 30 nm, a Si/Al molar ratio of at least 1, having amorphous
walls with a thickness in the range 1 to 20 nm, said spherical
elementary particles having a maximum diameter of 10 .mu.m.
2. A material according to claim 1, in which the Si/Al molar ratio
is in the range 1 to 10.
3. A material according to claim 1, in which the Si/Al molar ratio
is in the range 1 to 5.
4. A material according to claim 1, in which the pore size of said
matrix is in the range 1.5 to 10 nm.
5. A material according to claim 1, in which the diameter of said
spherical elementary particles is in the range 50 to 300 nm.
6. A material according to claim 1, having a specific surface area
in the range 100 to 1200 m.sup.2/g.
7. A material according to claim 1, having a specific surface area
in the range 300 to 1000 m.sup.2/g.
8. A material according to claim 1, in which said matrix based on
silicon oxide and aluminium oxide has a hexagonal, vemmicular or
cubic structure.
9. A process for preparing a mesostructured aluminosilicate
material according to claim 1, comprising a) mixing, in solution,
at least one surfactant, at least one aluminic precursor and at
least one silicic precursor; b) atomizing by aerosol the solution
obtained in a) to produce spherical droplets with a diameter of
less than 200 .mu.m; c) drying said droplets and d) eliminating
said surfactant to obtain a material with a mesostructured
porosity.
10. A process according to claim 9, in which the silicic precursor
is an organometallic precursor with formula Si(OR).sub.4 in which
R.dbd.H, methyl or ethyl.
11. A process according to claim 9, in which the aluminic precursor
is an inorganic aluminium salt with formula AlX.sub.3, X being a
halogen or an NO.sub.3 group.
12. A process according to claim 9, in which the surfactant is an
ionic surfactant selected from phoshonium and ammonium ions.
13. A process according to claim 9, in which the surfactant is a
non ionic surfactant in the form of a copolymer having at least two
portions with differing polarities.
14. A process according to claim 13, in which said block copolymer
contains two, three or four blocks, each block being constituted by
a poly(alkylene oxide) chain.
15. A process according to claim 14, in which the non ionic
surfactant is poly(ethylene oxide).sub.20-poly(propylene
oxide).sub.70-poly(ethylene oxide).sub.20.
16. A process according to claim 9, in which said solution is a
water-alcohol mixture.
17. A process according to claim 9, in which said solution is
acidic.
18. An adsorbant comprising a mesostructured aluminosilicate
material according to claim 1.
19. A catalyst comprising a mesostructured aluminosilicate material
according to claim 1.
20. An adsorbant comprising a mesostructured aluminosilicate
material prepared according to claim 9.
21. A catalyst comprising a mesostructured aluminosilicate material
prepared according to claim 9.
Description
[0001] The present invention relates to the field of mesostructured
aluminosilicate materials with a high aluminium content. It also
relates to the preparation of said materials which are obtained
using the "aerosol" synthesis technique. The structural and
textural properties of the materials of the invention and their
acid-base properties render them particularly suitable for
applications in the refining and petrochemicals fields.
PRIOR ART
[0002] Novel synthesis strategies for producing materials with a
porosity which is well defined over a very broad range, from
microporous materials to macroporous materials via materials with a
hierarchical porosity, i.e. with pores of various sizes, have been
under development in the scientific community since the middle of
the 1990s (G J de A A Soler-Illia, C Sanchez, B Lebeau, J Patarin,
Chem Rev 2002, 102, 4093). Materials are obtained in which the pore
size is controlled. In particular, the development of syntheses
using "mild chemistry" methods has led to the production of
mesostructured materials at low temperature by the co-existence in
aqueous solution or in highly polar solvents of inorganic
precursors with templates, generally ionic or neutral molecular or
supramolecular surfactants. Controlling the electrostatic
interactions or hydrogen bonding between the inorganic precursors
and the template jointly with hydrolysis/condensation reactions of
the inorganic precursor has led to a cooperative organization of
organic and inorganic phases generating micellar aggregates of
surfactants of controlled uniform size in an inorganic matrix. This
cooperative self-organization phenomenon governed, inter alia, by
the concentration of the template, may be induced by progressive
evaporation of a solution of reagents in which the concentration of
the template is lower than the critical micellar concentration,
which leads either to the formation of mesostructured films in the
case of deposition onto a substrate (dip-coating) or to the
formation of a mesostructured powder when the solution is atomized
(aerosol technique). As an example, U.S. Pat. No. 6,387,453
discloses the formation of mesostructured organic-inorganic hybrid
films using the dip coating technique, the same authors having also
used the aerosol technique to produce purely silicic mesostructured
materials (C J Brinker, Y Lu, A Sellinger, H Fan, Adv Mater 1999,
11, 7). The pores are then released by eliminating the surfactant,
this being carried out conventionally by chemical extraction or by
heat treatment. Several classes of mesostructured materials have
been developed using the different natures of the inorganic
precursors and the template employed as well as the operating
conditions imposed. As an example, the M41S class initially
developed by Mobil (J S Beck, J C Vartuli, W J Roth, M E Leonowicz,
C T Kresge, K D Schmitt, C T-W Chu, D H Olson, E W Sheppard, S B
McCullen, J B Higgins, J L Schlenker, J Am Chem Soc, 1992, 114, 27,
10834) constituted by mesoporous materials obtained using ionic
surfactants such as quaternary ammonium salts, having a generally
hexagonal, cubic or lamellar structure, pores of uniform size in
the range 1.5 to 10 nm and amorphous walls with a thickness of the
order of 1 to 2 nm, has been widely studied. Subsequently, to
increase the hydrothermal stability while developing the acid-basic
properties relative to said materials, incorporation of elemental
aluminium into the amorphous silicic framework by direct synthesis
or by post-synthesis processes have been particularly regarded, the
aluminosilicate materials obtained having a Si/Al molar ratio in
the range 1 to 1000 (S Kawi, S C Chen, Stud Surf Sci Catal 2000,
129, 227; S Kawi, S C Shen, Stud Surf Sci Catal 2000, 129, 219; R
Mokaya, W Jones, Chem Commun 1997, 2185). The hydrothermal
stability and acid-basic properties developed by such
aluminosilicates, however, did not allow them to be used on an
industrial scale in refining processes or in petrochemistry, which
has steadily led to the use of novel templates such as block
copolymer type amphiphilic macromolecules, these latter producing
mesostructured materials having a generally hexagonal, cubic or
lamellar structure, with uniform sized pores in the range 4 to 50
nm and amorphous walls with a thickness in the range 3 to 7 nm. In
contrast to dip-coating or aerosol techniques described above, the
materials thus defined are not obtained by progressive
concentration of inorganic precursors and the template in an
aqueous solution in which they are present, but are conventionally
obtained by direct precipitation in an aqueous solvent or in high
polarity solvents by adjusting the value of the critical micellar
concentration of the template. Further, synthesis of such materials
obtained by precipitation necessitates a step for autoclave ageing
and not all of the reagents are integrated into the products in
stoichiometric quantities as they can be found in the supernatant.
Depending on the structure and desired degree of organization for
the final mesostructured material, such synthesis methods may take
place in an acidic medium (pH approx 1) (International patent
application WO-A-99/37705) or in a neutral medium (WO-A-96/39357),
the nature of the template used also playing a major role. The
elementary particles obtained do not have a regular form and are
generally characterized by dimensions of over 500 nm. The
mesostructured aluminosilicate materials obtained have enhanced
hydrothermal stability properties compared with their homologues
synthesized using other templates, their acid-basic properties
remaining very similar (1<Si/Al<1000). Low values for the
molar ratio Si/Al are, however, difficult to obtain as it is
difficult to incorporate large quantities of aluminium into the
material using such particular operating procedures (D Zaho, J
Feng, Q Huo, N Melosh, G H Fredrickson, B F Chmelke, G D Stucky,
Science, 1998, 279, 548; Y-H Yue, A Gedeon, J-L Bonardet, J B
d'Espinose, N Melosh, J Fraissard, Stud Surf Sci Catal 2000, 129,
209).
SUMMARY OF THE INVENTION
[0003] The invention concerns a mesostructured aluminosilicate
material constituted by at least two spherical elementary
particles, each of said spherical particles being constituted by a
matrix based on silicon oxide and aluminium oxide, having a pore
size in the range 1.5 to 30 nm, a Si/Al molar ratio of at least 1,
having amorphous walls with a thickness in the range 1 to 20 nm,
said spherical elementary particles having a maximum diameter of 10
.mu.m. The material of the invention has a high aluminium content
and the Si/Al molar ratio is preferably in the range 1 to 10. The
present invention also concerns a process for preparing the
material of the invention: it is obtained by interacting at least
one ionic or non ionic surfactant with at least one aluminic
precursor and at least one silicic precursor, preferably in an
acidic medium, the ordered structure of the material following on
from micellization or self-organization by evaporation induced by
the aerosol technique.
APPLICATION OF THE INVENTION
[0004] The aluminosilicate material of the invention is a
mesostructured material constituted by spherical elementary
particles, each of said particles being constituted by a matrix
based on silicon oxide and aluminium oxide. Said matrix is
mesostructured and has amorphous walls with a thickness in the
range 1 to 20 nm, a uniform pore size in the range 1.5 to 30 nm and
with a molar ratio Si/Al of at least 1. Said spherical elementary
particles advantageously have a diameter in the range 50 nm to 10
.mu.m, preferably in the range 50 to 300 nm, the limited size of
said particles and their perfectly spherical form allowing better
diffusion of compounds when using the material of the invention as
a catalyst or adsorbant for applications in the field of refining
and petrochemistry, compared with known prior art materials in the
form of elementary particles with a non homogeneous shape, i.e.
irregular particles, and with a dimension which is generally over
500 nm. The matrix constituting each of said particles of the
material of the invention advantageously has a Si/Al molar ratio in
the range 1 to 10, more advantageously in the range 1 to 5: the
material of the invention has a high aluminium content, which
endows the material of the invention with advantageous acid-base
properties for catalysis applications. The material of the
invention is also particularly advantageous for the organized
porosity it has on the mesopore scale.
DESCRIPTION OF THE INVENTION
[0005] The present invention provides a mesostructured
aluminosilicate material constituted by at least two spherical
elementary particles, each of said spherical particles being
constituted by a matrix based on silicon oxide and aluminium oxide,
having a pore size in the range 1.5 to 30 nm, a Si/Al molar ratio
of at least 1, having amorphous walls with a thickness in the range
1 to 20 nm, said spherical elementary particles having a maximum
diameter of 10 .mu.m.
[0006] In accordance with the invention, the matrix based on
silicon oxide and aluminium oxide constituting each of said
spherical particles of the aluminosilicate material of the
invention advantageously has a high aluminium content: the Si/Al
molar ratio is preferably in the range 1 to 10, and more preferably
in the range 1 to 5.
[0007] The term "mesostructured material" as used in the present
invention means a material having organized porosity on the
mesopore scale in each of said spherical particles, i.e. an
organized porosity on the scale of pores having a uniform dimension
in the range 1.5 to 30 nm, preferably in the range 1.5 to 10 nm,
distributed homogeneously and in a regular manner in each of said
particles (mesostructure of material).
[0008] The material located between the mesopores of each of said
spherical particles of the material of the invention is amorphous
and in the form of walls the thickness of which is in the range 1
to 20 nm. The thickness of the walls corresponds to the distance
separating one pore from another pore. The organization of the
mesoporosity described above results in structuring of the matrix
based on silicon oxide and aluminium oxide, which may be hexagonal,
two-dimensionally hexagonal, vermicular or cubic, preferably
vermicular.
[0009] In accordance with the invention, the maximum diameter of
said spherical elementary particles constituting the material of
the invention is 10 .mu.m, preferably in the range 50 nm to 10
.mu.m, and more advantageously in the range 50 to 300 nm. More
precisely, said particles are present in the material of the
invention in the form of aggregates.
[0010] The material of the invention advantageously has a specific
surface area in the range 100 to 1200 m.sup.2/g, more
advantageously in the range 300 to 1000 m.sup.2/g.
[0011] The present invention also concerns the preparation of the
material of the invention. Said process comprises a) mixing, in
solution, at least one surfactant, at least one aluminic precursor
and at least one silicic precursor; b) atomizing by aerosol the
solution obtained in a) to produce spherical droplets with a
diameter of less than 200 .mu.m; c) drying said droplets and d)
eliminating said surfactant to obtain a material with a
mesostructured porosity.
[0012] The silicic and aluminic precursors used in step a) of the
process of the invention are inorganic oxide precursors that are
well known to the skilled person. The silicic precursor is obtained
from any source of silicon and advantageously from a sodium
silicate precursor with formula SiO.sub.2, NaOH, from a
chlorine-containing precursor with formula SiCl.sub.4, from an
organometallic precursor with formula Si(OR).sub.4 in which
R.dbd.H, methyl, ethyl or from a chloroalkoxide precursor with
formula Si(OR).sub.4-xCl.sub.x in which R.dbd.H, methyl, ethyl, x
being in the range 0 to 4. The silicic precursor may also
advantageously be an organometallic precursor with formula
Si(OR).sub.4-xR'.sub.x in which R.dbd.H, methyl, ethyl and R' is an
alkyl chain or a functionalized alkyl chain, for example a thiol,
amino, .beta.-diketone or sulphonic acid group, x being in the
range 0 to 4. The aluminic precursor is advantageously an inorganic
aluminium salt with formula ALX.sub.3, X being a halogen or the
NO.sub.3 group. Preferably, X is chlorine. The aluminic precursor
may also be an organometallic precursor with formula Al(OR'').sub.3
in which R''=ethyl, isopropyl, b-butyl, s-butyl or t-butyl or a
chelated precursor such as aluminium acetylacetonate
(Al(CH.sub.7O.sub.2).sub.3). The aluminic precursor may also be an
aluminium oxide or hydroxide.
[0013] The surfactant used to prepare the mixture of step b) of the
preparation process of the invention is an ionic or non ionic
surfactant or a mixture of the two. Preferably, the ionic
surfactant is selected from phosphonium or ammonium ions, and more
preferably from quaternary ammonium salts such as cetyltrimethyl
ammonium bromide (CTAB). Preferably, the non ionic surfactant may
be any copolymer having at least two portions with different
polarities endowing them with amphiphilic macromolecular
properties. Said copolymers may be included in the following non
exhaustive list of copolymer classes: fluorinated copolymers
(--[CH.sub.2--CH.sub.2--CH.sub.2--CH.sub.2O--CO--R1- in which
R1=C.sub.4F.sub.9, C.sub.8F.sub.17, etc), biological copolymers
such as poly amino acids (polylysine, alginates, etc), dendrimers,
block copolymers constituted by chains of poly(alkylene oxide) and
any other copolymer with an amphiphilic nature which is known to
the skilled person (S Forster, M Antionnetti, Adv Mater, 1998, 10,
195-217, S Forster, T Plantenberg, Angew Chem Int Ed, 2002, 41,
688-714, H Colfen, Macromol Rapid Commun, 2001, 22, 219-252).
Preferably, in the context of the present invention, a block
copolymer constituted by poly (alkylene oxide) chains is used. Said
block copolymer is preferably a block copolymer having two, three
of four blocks, each block being constituted by one poly(alkylene
oxide) chain. For a two-block copolymer, one of the blocks is
constituted by a poly(alkylene oxide) chain which is hydrophilic in
nature and the other block is constituted by a poly(alkylene oxide)
chain which is hydrophobic in nature. For a three-block copolymer,
two of the blocks are constituted by a poly(alkylene oxide) chain
which is hydrophilic in nature while the other block, located
between two blocks with hydrophilic portions, is constituted by a
poly(alkylene oxide) chain which is hydrophobic in nature.
Preferably, in the case of a three-block copolymer, the chains of
poly(alkylene oxide) of hydrophilic nature are chains of
poly(ethylene oxide), (PEO).sub.x and (PEO).sub.z, and the
poly(alkylene oxide) chains which are hydrophobic in nature are
chains of poly (propylene oxide), (PPO).sub.y, chains of
poly(butylene oxide) or mixed chains, each chain of which is a
mixture of several alkylene oxide monomers. More preferably, in the
case of a three-block copolymer, a compound with formula
(PEO).sub.x(PPO).sub.y(PEO).sub.z is used in which x is in the
range 5 to 106, y is in the range 33 to 70 and z is in the range 5
to 106. Preferably, the values of x and z are identical. Highly
advantageously, a compound in which x=20, y=70 and z=20 (P123) is
used and a compound in which x=106, y=70 and z=106 (F127) is used.
Commercially available non ionic surfactants known as Pluronic
(BASF), Tetronic (BASF), Triton (Sigma), Tergitol (UnionCarbide),
Brij (Aldrich) can be used as non ionic surfactants in step a) of
the preparation process of the invention. For a four-block
copolymer, two of the blocks are constituted by a poly(alkylene
oxide) chain which is hydrophilic in nature and the two other
blocks are constituted by a poly(alkylene oxide) chain which is
hydrophobic in nature.
[0014] The solution into which the following are mixed: at least
one silicic precursor, at least one aluminic precursor and at least
one surfactant in accordance with step a) of the preparation
process of the invention, may be acidic, neutral or basic.
Preferably, said solution is acidic and has a maximum pH of 2, more
preferably in the range 0 to 2. Non limiting examples of acids used
to obtain an acidic solution with a maximum pH of 2 are
hydrochloric acid, sulphuric acid and nitric acid. Said solution
may be aqueous or it may be a water-organic solvent mixture, the
organic solvent preferably being a polar solvent, in particular an
alcohol, preferably ethanol. Said solution may also be practically
organic, preferably practically alcoholic, the quantity of water
being such that hydrolysis of the inorganic precursors is ensured
(stoichiometric quantity). More preferably, said solution in which
the following are mixed: at least one silicic precursor, at least
one aluminic precursor and at least one surfactant is a
hydro-organic acid mixture, more preferably an acidic water-alcohol
mixture.
[0015] The concentrations of silicic and aluminic precursors are
defined by the molar ratio Si/Al, this being at least equal to 1,
preferably in the range 1 to 1000, and more preferably in the range
1 to 10 and highly preferably in the range 1 to 5. The initial
concentration of surfactant introduced into the mixture of step a)
of the preparation process of the invention is defined by c.sub.0
which is defined with respect to the critical micellar
concentration (c.sub.mc) which is well known to the skilled person.
The c.sub.mc is the limiting concentration beyond which
self-arrangement of the molecules of surfactant in the solution
occurs. The concentration c.sub.0 may be less than, equal to or
more than c.sub.mc, preferably less than c.sub.mc. In a preferred
implementation of the process of the invention, the concentration
c.sub.0 is less than the c.sub.mc and said solution in step a) of
the preparation process of the invention is an acidic water-alcohol
acidic mixture.
[0016] The step for atomizing a mixture in step b) of the
preparation process of the invention produces spherical droplets
with a diameter which is preferably in the range 2 to 200 .mu.m.
The size distribution of said droplets is of the log normal type.
The aerosol generator used is a commercial model 3078 apparatus
supplied by TSI. The solution is atomized into a chamber into which
a vector gas is sent, an O.sub.2/N.sub.2 mixture (dry air), at a
pressure P of 1.5 bars. In step c) of the preparation process of
the invention, said droplets are dried. Drying is carried out by
transporting said droplets via the vector gas, the O.sub.2/N.sub.2
mixture, in glass tubes, which results in progressive evaporation
of the solution, for example of the hydro-organic acid solution,
and the production of spherical elementary particles. Drying is
completed by passing said particles into an oven the temperature of
which can be adjusted, usually between temperatures of 50.degree.
C. to 600.degree. C. and preferably 80.degree. C. to 400.degree.
C., the residence time for said particles in the oven being of the
order of 3 to 4 seconds. The particles are then harvested in a
filter and constitute the material of the invention. A pump placed
at the end of the circuit routes the species into the experimental
aerosol device.
[0017] In the case in which the solution in step a) of the
preparation process of the invention is a water-organic solvent
mixture, preferably acidic, it is preferable during step a) of the
preparation process of the invention that the concentration of
surfactant at the start of mesostructuring of the matrix is less
than the critical micellar concentration so that evaporation of
said hydro-organic solution, preferably acidic, during step b) of
the preparation process of the invention using the aerosol
technique induces a phenomenon of micellization or
self-organization leading to mesostructuring of the matrix of
material of the invention. When c.sub.0<c.sub.mc,
mesostructuring of the matrix of the material of the invention
prepared using the process described above follows progressive
concentration of the silicic precursor in each droplet, of the
aluminic precursor, and of the surfactant, until a concentration of
surfactant c>c.sub.mc results from evaporation of the
hydro-organic solution, preferably acidic.
[0018] In general, increasing the joint concentration of the
silicic precursor and an aluminic precursor and the surfactant
causes precipitation of the silicic and aluminic precursors around
the self-organized surfactant and as a consequence, structuration
of the matrix of the material of the invention. The
inorganic/inorganic phase, organic/organic phase and
organic/inorganic phase interactions result in a self-organization
mechanism which is cooperative with hydrolysis/condensation of the
silicic and aluminic precursors around the surfactant. The aerosol
technique is particularly advantageous for carrying out step b) of
the preparation process of the invention to constrain the reagents
present in the initial solution to interact together, with no
possible loss of material apart from the solvents, the totality of
the aluminium and silicon elements initially present then being
perfectly preserved throughout the process of the invention instead
of being eliminated during the filtering steps and washes
encountered in conventional synthesis processes known to the
skilled person.
[0019] Elimination of the surfactant in step d) of the preparation
process of the invention to obtain the material of the invention
with a mesostructured porosity is advantageously carried out by
chemical extraction or heat treatment, preferably by calcining in
air within a temperature range of 300.degree. C. to 1000.degree. C.
and more precisely in a range of 500.degree. C. to 600.degree. C.
for a period of 1 to 24 hours, preferably for a period of 2 to 6
hours.
[0020] The mesostructured aluminosilicate material with a high
aluminium content of the present invention may be obtained in the
form of powder, beads, pellets, granules or extrudates, the forming
operations being carried out using conventional techniques which
are known to the skilled person. Preferably, the mesostructured
aluminosilicate material of the invention is obtained in the form
of a powder which is constituted by spherical elementary particles
having a maximum diameter of 10 .mu.m, preferably in the range 50
to 300 nm, which facilitates any diffusion of the compounds in the
case of the use of a material of the invention as a catalyst or
adsorbant in refining or petrochemicals applications.
[0021] The mesostructured aluminosilicate material of the invention
is characterized using several analytical techniques, in particular
by small angle X ray diffraction (small angle XRD), the nitrogen
adsorption isotherm, transmission electron microscopy (TEM) and X
ray fluorescence elementary analysis. Small angle X ray diffraction
(values of 2.theta. in the range 0.5.degree. to 3.degree.) can be
used to characterize the periodicity on a nanometric scale
generated by the organized mesoporosity of the mesostructured
matrix of the material of the invention. In the description below,
X ray analysis is carried out on powder with a diffractometer
operating in reflection equipped with a back monochromator using
the copper radiation line (wavelength 1.5406 .ANG.). The peaks
normally observed on diffractograms corresponding to a given value
for the angle 2.theta. are associated with the interplanar spacings
d.sub.hkl which are characteristic of the structural symmetry of
the material, (hkl being the Miller indices of the reciprocal
lattice) by the Bragg relationship: 2d.sub.hkl*sin
(.theta.)=n*.lamda.. This indexation allows the lattice parameters
(a, b, c) of the framework to be determined directly, the lattice
parameters being a function of the hexagonal, cubic or vermicular
structure obtained. As an example, the small angle X ray
diffractogram of a mesostructured aluminosilicate material obtained
using the process of the invention with a particular block
copolymer, poly(ethylene oxide).sub.20-poly(propylene
oxide).sub.70-poly(ethylene oxide).sub.20
(PEO.sub.20--PPO.sub.70--PEO.sub.20 or Pluronic 123) has a
correlation-peak which is perfectly resolved which corresponds to a
correlation distance d between pores characteristic of a vermicular
structure and defined using the Bragg relationship:
2d*sin(.theta.)=n*.lamda..
[0022] Nitrogen adsorption isothermal analysis corresponding to the
physical adsorption of nitrogen molecules in the pores of the
material on progressively increasing the pressure at constant
temperature provides information regarding the textural
characteristics which are peculiar to the material of the
invention. In particular, it provides access to the specific
surface area and to the mesoporous distribution of the material.
The term "specific surface area" means the BET specific surface
area (S.sub.BET in m.sup.2/g) determined by nitrogen adsorption in
accordance with American standard ASTM D 3663-78 established using
the BRUNAUER-EMMETT-TELLER method described in the periodical "The
Journal of the American Society", 60, 309, (1938). The pore
distribution representative of a population of mesopores centered
in a range of 1.5 to 50 nm is determined using the
Barrett-Joyner-Halenda (BJH) model. The nitrogen
adsorption-desorption isotherm using the BJH model is described in
the periodical "The Journal of the American Society", 73, 373
(1951) written by E P Barrett, L G Joyner and P P Halenda. In the
description below, the mesopore diameter .phi. in a given
mesostructured matrix corresponds to the mean diameter for nitrogen
desorption defined as a diameter such that all pores with less than
that diameter constitute 50% of the pore volume (Vp) measured on
the desorption arm of the nitrogen isotherm. Further, the shape of
the nitrogen adsorption isotherm and the hysteresis loop provides
information regarding the nature of the microporosity. As an
example, the nitrogen adsorption isotherm of a mesostructured
aluminosilicate material of the invention using a particular block
copolymer, poly(ethylene oxide).sub.20-poly(propylene
oxide).sub.70-poly(ethylene oxide).sub.20
(PEO.sub.20-PPO.sub.70-PEO.sub.20 or Pluronic 123, P123) has a type
IV isotherm and a type H1 hysteresis loop, the associated pore
distribution curve being representative of a population of
mesopores with a uniform size centered in a range of 1.5 to 30 nm.
The difference between the value for the pore diameter .phi. and
the correlation distance between pores d defined by small angle XRD
as described above provides access to the dimension e in which
e=d-.phi. and is characteristic of the thickness of the amorphous
walls of the mesostructured matrix of the invention.
[0023] Transmission electron microscope analysis (TEM) is a
technique which is also widely used to characterize the structure
of these materials. This allows the formation of an image of the
solid being studied, the contrasts observed being characteristic of
the structural organization, texture or morphology of the particles
observed, the resolution reaching a maximum of 0.2 nm. In the
description below, TEM images were produced from microtomed
sections of the sample to visualize a section of a spherical
elementary particle of the material of the invention. As an
example, TEM images obtained for a mesostructured aluminosilicate
material of the invention obtained using the process of the
invention with a copolymer as described above, namely a particular
block copolymer, Pluronic 123, had spherical elementary particles
with a vermicular mesostructure, the material being defined by the
dark zones. Analysis of the image also provides access to the
parameters d, .phi. and e, characteristic of the mesostructured
matrix defined above.
[0024] The morphology and dimensional distribution of the
elementary particles were established from analysis of the images
obtained by SEM (scanning electron microscopy).
[0025] The structure of the mesostructured matrix constituting each
of the particles of the material of the invention may be cubic,
vermicular or hexagonal depending on the nature of the support
selected as the template. As an example, a mesostructured
aluminosilicate material obtained as described above using a
particular block copolymer, poly(ethylene
oxide).sub.20-poly(propylene oxide).sub.70-poly(ethylene
oxide).sub.20 (PEO.sub.20-PPO.sub.70-PEO.sub.20 or Pluronic 123,
P123) has a vermicular structure.
[0026] The present invention concerns the use of a mesostructured
aluminosilicate material of the invention as an adsorbant for
controlling pollution or as a molecular sieve for separation. The
present invention thus provides an adsorbant comprising the
mesostructured aluminosilicate material of the invention. It is
also advantageously used as an acidic solid to catalyze reactions,
for example those occurring in the refining and petrochemistry
fields.
[0027] When the mesostructured aluminosilicate material of the
invention is used as a catalyst, said material may be associated
with an inorganic matrix, which may be inert or catalytically
active, and a metallic phase. The inorganic matrix may simply be
present as a binder to keep together the particles of said material
in the various known forms for catalysts (extrudates, pellets,
beads, powder) or it may be added as a diluent to impose a degree
of conversion on the process which would otherwise run away,
leading to clogging of the catalyst due to the formation of too
large an amount of coke. Typical inorganic matrices are support
materials for catalysts such as the various forms of silica,
alumina, silica-alumina, magnesia, zirconia, titanium and boron
oxides, aluminium, titanium or zirconium phosphates, clays such as
kaolin, bentonite, montmorillonite, sepiolite, attapulgite,
Fuller's earth, synthetic porous materials such as
SiO.sub.2--Al.sub.2O.sub.3, SiO.sub.2--ZrO.sub.2,
SiO.sub.2--ThO.sub.2, SiO.sub.2--BeO, SiO.sub.2--TiO.sub.2 or any
combination of these compounds. The inorganic matrix may be a
mixture of different compounds, in particular of an inert phase and
an active phase. Said material of the present invention may also be
associated with at least one zeolite and may act as the principal
active phase or as an additive. The metallic phase may be
introduced integrally onto said material of the invention. It may
also be introduced integrally into the inorganic matrix or onto the
inorganic matrix--mesostructured solid ensemble by ion exchange or
impregnation with cations or oxides selected from the following
elements: Cu, Ag, Ga, Mg, Ca, Sr, Zn, Cd, B, Al, Sn, Pb, V, P, Sb,
Cr, Mo, W, Mn, Re, Fe, Co, Ni, Pt, Pd, Ru, Rh, Os, Ir and any other
element from the periodic table.
[0028] The catalytic compositions comprising the material of the
present invention are generally suitable for carrying out the
principal processes for hydrocarbon transformation and organic
compound synthesis reactions.
[0029] The catalytic compositions comprising the material of the
invention advantageously have applications in the reactions of
isomerization, transalkylation and dismutation, alkylation and
dealkylation, hydration and dehydration, oligomerization and
polymerization, cyclization, aromatization, cracking, reforming,
hydrogenation and dehydrogenation, oxidation, halogenation,
hydrocracking, hydroconversion, hydrotreatment,
hydrodesulphurization and hydrodenitrogenation, catalytic
elimination of oxides of nitrogen, said reaction involving feeds
comprising saturated and unsaturated aliphatic hydrocarbons,
aromatic hydrocarbons, organic oxygen-containing compounds and
organic compounds containing nitrogen and/or sulphur as well as
organic compounds containing other functional groups.
[0030] The invention will now be illustrated in the following
examples.
EXAMPLES
[0031] In the examples below, the aerosol technique used is that
described above in the description of the invention.
Example 1 (Invention)
Preparation of an aluminosilicate material with a Si/Al ratio of
5
[0032] 1.03 g of aluminium trichloride was added to a solution
containing 30 g of ethanol, 14.5 g of water, 0.036 ml of HCl and
1.4 g of the surfactant CTAB. The ensemble was left at ambient
temperature, with stirring, until the aluminic precursor had
completely dissolved. 3.59 g of tetraethylorthosilicate (TEOS) was
then added. After stirring for 10 min at ambient temperature, the
ensemble was sent to the atomization chamber of an aerosol
generator as described above and the solution was atomized in the
form of fine droplets under the action of the vector gas (dry air)
introduced under pressure (P=1.5 bars) as described above. The
droplets were dried using the protocol described in the invention
described above. The temperature of the drying oven was fixed at
350.degree. C. The harvested powder was then calcined in air for 5
h at T=550.degree. C. The solid was characterized by small angle
XRD (FIG. 1), by the nitrogen adsorption isotherm (FIG. 2: the
indication P0 shown along the abscissa is the saturated vapour
pressure), by TEM (FIG. 3) and by X ray fluorescence. TEM analysis
showed that the final material had an organized mesoporosity
characterized by a vermicular structure. The nitrogen adsorption
isothermal analysis produced a specific surface area in the final
material of S.sub.BET=800 m.sup.2/g and a mesopore diameter of
.phi.=2.4 nm. Small angle XRD showed a correlation peak at an angle
20 of 2.4. The Bragg relationship, 2d*sin(1.2)=1.5406, allowed the
correlation distance d between the pores of the mesostructured
matrix to be calculated, namely d=3.7 nm. The thickness of the
walls of the mesostructured material defined by e=d-.phi. was thus
e=1.3 nm. A SEM image of the spherical elementary particles
obtained indicated that the particle size was characterized by a
diameter of 50 to 700 nm, with a particle size distribution being
centred around 300 nm.
Example 2 (Invention)
Preparation of an aluminosilicate material with a Si/Al ratio
of
[0033] 0.52 g of aluminium trichloride was added to a solution
containing 30 g of ethanol, 14.7 g of water, 0.036 ml of HCl and
1.4 g of the surfactant P123. The ensemble was left at ambient
temperature, with stirring, until the aluminic precursor had
completely dissolved. 4.09 g of tetraethylorthosilicate (TEOS) was
then added. After stirring for 18 hours at ambient temperature, the
ensemble was sent to the atomization chamber of an aerosol
generator and the solution was atomized in the form of fine
droplets under the action of the vector gas (dry air) introduced
under pressure (P=1.5 bars). The droplets were dried using the
protocol described in the invention described above. The
temperature of the drying oven was fixed at 350.degree. C. The
harvested powder was then calcined in air for 5 h at T=550.degree.
C. The solid was characterized by small angle XRD (FIG. 4), by the
nitrogen adsorption isotherm (FIG. 5: the indication P0 shown along
the abscissa is the saturated vapour pressure), by TEM (FIG. 6) and
by X ray fluorescence. TEM analysis showed that the final material
had an organized mesoporosity characterized by a vermicular
structure. The nitrogen adsorption isothermal analysis produced a
specific surface area in the final material of S.sub.BET=320
m.sup.2/g and a mesopore diameter of +=5.3 nm. Small angle XRD
showed a correlation peak at an angle 2.theta. of 0.72. The Bragg
relationship, 2d*sin(0.36)=1.5406 allowed the correlation distance
d between the pores of the mesostructured matrix to be calculated,
namely d=12.2 nm. The thickness of the walls of the mesostructured
material defined by e=d-.phi. was thus e=6.9 nm. A SEM image of the
spherical elementary particles obtained indicated that the particle
size was characterized by a diameter of 50 to 700 nm, with a
particle size distribution being centred around 300 nm.
Example 3 (Invention)
Preparation of an aluminosilicate material with a Si/Al ratio of
3
[0034] 1.56 g of aluminium trichloride was added to a solution
containing 30 g of ethanol, 14.2 g of water, 0.036 ml of HCl and
1.4 g of the surfactant P123. The ensemble was left at ambient
temperature, with stirring, until the aluminic precursor had
completely dissolved. 3.14 g of tetraethylorthosilicate (TEOS) was
then added. After stirring for 18 hours at ambient temperature, the
ensemble was sent to the atomization chamber of an aerosol
generator as described above and the solution was atomized in the
form of fine droplets under the action of the vector gas (dry air)
introduced under pressure (P=1.5 bars). The droplets were dried
using the protocol described in the invention described above. The
temperature of the drying oven was fixed at 350.degree. C. The
harvested powder was then calcined in air for 5 h at T=550.degree.
C. The solid was characterized by small angle XRD (FIG. 7), by the
nitrogen adsorption isotherm (FIG. 8: the indication P0 shown along
the abscissa is the saturated vapour pressure), by TEM and by X ray
fluorescence. TEM analysis showed that the final material had an
organized mesoporosity characterized by a vermicular structure. The
nitrogen adsorption isothermal analysis produced a specific surface
area in the final material of S.sub.BET=220 m.sup.2/g and a
mesopore diameter of .phi.=5.9 nm. Small angle XRD showed a
correlation peak at an angle 2.theta. of 0.72. The Bragg
relationship, 2d*sin(0.36)=1.5406 allowed the correlation distance
d between the pores of the mesostructured matrix to be calculated,
namely d=12.2 nm. The thickness of the walls of the mesostructured
material defined by e=d-.phi. was thus e=6.3 nm. A SEM image of the
spherical elementary particles obtained indicated that the particle
size was characterized by a diameter of 50 to 700 nm, with a
particle size distribution being centred around 300 nm.
[0035] Without further elaboration, it is believed that one skilled
in the art can, using the preceding description, utilize the
present invention to its fullest extent. The preceding preferred
specific embodiments are, therefore, to be construed as merely
illustrative, and not limitative of the remainder of the disclosure
in any way whatsoever.
[0036] In the foregoing and in the examples, all temperatures are
set forth uncorrected in degrees Celsius and, all parts and
percentages are by weight, unless otherwise indicated.
[0037] The entire disclosures of all applications, patents and
publications, cited herein and of corresponding French application
No. 0406938, filed Jun. 24, 2004 are incorporated by reference
herein.
[0038] The preceding examples can be repeated with similar success
by substituting the generically or specifically described reactants
and/or operating conditions of this invention for those used in the
preceding examples.
[0039] From the foregoing description, one skilled in the art can
easily ascertain the essential characteristics of this invention
and, without departing from the spirit and scope thereof, can make
various changes and modifications of the invention to adapt it to
various usages and conditions.
* * * * *