Multimetallic pillared interlayered clay products and processes of making them

This invention is a composition of matter made up of an expanded smectite clay having multimetallic pillars separating the clay layers. The expanded clay may be used as a shape selective catalyst, catalyst support, or as an adsorbent material. More particularly, this invention relates to expanded smectite clays wherein the pillars are made up of aluminum and one or more transition metals.

FIELD OF THE INVENTION 
This invention is a composition of matter made up of an expanded smectite 
clay having multimetallic pillars separating the clay layers. The expanded 
clay may be used as a shape selective catalyst, catalyst support, or as an 
adsorbent material. More particularly, this invention relates to expanded 
smectite clays wherein the pillars are made up of aluminum atoms and one 
or more transition metals. 
The invention also relates to a method for producing such a composition of 
matter by the steps of introducing a transition metal ion into aluminum 
chlorohydrol, i.e., Al.sub.13 O.sub.4 (OH).sub.24 Cl.sub.17 ; 
intercalating the aluminum-transition metal modified chlorohydrol into a 
smectite clay; drying the clay; and thermally treating it in an inert gas 
atmosphere to produce the expanded product. 
BACKGROUND OF THE INVENTION 
Layered naturally occurring and synthetic smectites such as bentonite, 
montmorillonites and chlorites may be visualized as a sandwich comprising 
two outer layers of silcon tetrahedra and an inner layer of aluminum 
octahedra. These clays are generally representable by the general formula: 
EQU (Si.sub.8).sup.iv (Al.sub.4).sup.vi O.sub.20 (OH).sub.4 
where the iv designation indicates an ion coordinated to four other ions, 
and the vi designates an ion coordinated to six other ions. The iv 
coordinated ion is commonly Si.sup.4+, Al.sup.3+, or Fe.sup.3+, but could 
also include several other four-coordinate ions, e.g., p.sup.5+, B.sup.3+, 
Ga.sup.3+, Cr.sup.3+, Ge.sup.4+, Be.sup.2+, etc. The vi coordinated ion is 
typically Al.sup.3+ or Mg.sup.2+, but could also include many other 
possible hexacoordinate ions, e.g., Fe.sup.3+, Fe.sup.2+, Ni.sup.2+, 
Co.sup.2+, Li.sup.+, Cr.sup.3+, V.sup.2+, etc. The charge deficiencies 
created by substitutions into these cation positions are balanced by one 
or more cations located between the structure's platelets. Water may be 
occluded between the layers and either bonded to the structure itself or 
to the cations as a hydration shell. Commercially available clays of this 
type include the above mentioned montmorillonite, bentonite, hectorite, 
beidellite, nontronite, and a host of other smectite materials from 
hundreds of localities, often having local names and specific 
compositions. 
Normally the clay structure yields repeating plate every 9 .ANG. or 
thereabouts. Much work has been done to demonstrate that these platelets 
may be separated further, i.e., interlayered, by insertion of various 
polar molecules such as water, ethylene glycol, various amines, etc., and 
that the platelets can be separated by as much as 30 to 40 .ANG.. 
Some prior workers have prepared phosphated interlayered clays for use as 
low temperature traps for slow release fertilizers. 
U.S. Pat. Nos. 3,803,026; 3,844,979; 3,887,454; and 3,892,655 describe 
layered clay-like materials and the process for using these materials. The 
layered materials are prepared from synthetic solutions of silica, alumina 
and magnesia salts. The final product has non-exchangeable alumina between 
the layers and an interlayer spacing greater than about 6 .ANG.. Such a 
spacing is characteristic of an anhydrous product. 
U.S Pat. No. 3,275,757 also discloses synthetic layered type silicate 
materials as does U.S. Pat. No. 3,252,889. U.S. Pat. No. 3,586,478 
discloses a method of producing synthetic swelling clays of the hectorite 
type by forming an aqueous slurry from a water soluble magnesium salt, 
sodium silicate, sodium carbonate, or sodium hydroxide and materials 
containing lithium and fluoride ions. The slurry is hydrothermally treated 
to crystallize a synthetic clay-like material. 
U.S. Pat. Nos. 3,666,407 and 3,671,190 describe other methods of preparing 
clay-like materials. All of these synthetic clays are acceptable raw 
materials for use in the instant invention in place of naturally occurring 
clays. However, by virtue of the ready availability of large quantities of 
the natural clays at low prices, natural clays will generally be used in 
the practice of the present invention. 
U.S. Pat. Nos. 3,798,177 and 4,060,480 disclose the preparation of hydroxy- 
aluminum modified smectite clays wherein a gibbsite-like layer is formed 
between the crystalline layers of the clay. The gibbsite-like layer is 
characterized by 14 .ANG. spacing, is continuous and does not 
substantially increase the internal pore volume of the modified clay 
material. 
U.S. Pat. No. 4,060,480 discloses a process for the preparation of a 
crystalline catalyst support via the steps of treating montmorillonite 
clay with a hydroxy-aluminum solution. Clay, after contact with such 
solution, flucculation, removal from the solution by filtration, is then 
suspended in fresh water and allowed to age. The aged hydroxy-aluminum 
treated clay slurry is refiltered and impregnated with catalytic materials 
such as palladium or other metals. 
U.S. Pat. Nos. 4,176,090; 4,248,739; and 4,271,043 all discuss pillared 
interlayered clays which are prepared by reacting smectite clays with high 
molecular weight cationic metal complexes containing metals such as 
aluminum, zirconium, titanium and various alkaline earth metals. The high 
molecular weight complexes are prepared by hydrolysis or copolymerization 
of a metal complex such as aluminum chlorohydrol. 
U.S. Pat. No. 4,216,188 teaches the production of montmorillonites 
cross-linked with aluminum hydroxide or with chromium hydroxide and a 
process for the production of those clays by the interaction of a 
colloidal suspension of montmorillonite and a buffered and aged colloidal 
solution of the aluminum or chromium hydroxide. 
U.S. Pat. No. 4,367,163 discloses a method for intercalating smectite clays 
with various ionic silicon complexes such as silicon (acetylacetonato) 
cation. The imbibed clays are then subjected to heating to form silica 
pillars between the various sheets of the clay. Similar iron complexes 
have been introduced into clays to yield expanded structures. See, 
Yamanaka et al, Materials Res. Bull., 19 (1984), p. 161. 
U.S. Pat. No. 4,410,751 discloses the production of a smectite host 
material having zirconium oxide intercalated therebetween. The zirconium 
oxide is said to be in the form of pillars. Other smallspacing, metal 
intercalated clays have been described by Brindley et al, infra. 
U.S. Pat. No. 4,452,910 discloses expanded layer smectite clay having a 
regular pore structure suitable for catalytic uses. The patent also 
discloses a process for preparing that expanded clay by treating a 
suspension of the clay with a chromiumoligomer solution and then 
subjecting the thus-treated clay to a stabilization heat treatment in an 
inert gas atmosphere. 
The present invention is substantially different than each of the 
disclosures cited above in that it is concerned with a composition of 
matter having multimetallic pillars intercalated between layers of 
smectite clay. It is also concerned with a method for modifying smectite 
type materials in such a way as to produce a substantial micropore 
structure in the materials and yield novel catalytic and sorbent products 
having utility in the petroleum, chemical and related industries. The 
resulting properties may be viewed as being more characteristic of 
crystalline zeolites than of clays. 
BRIEF DESCRIPTION OF THE INVENTION 
The present invention relates to the preparation of pillared interlayered 
clays which may be obtained by reacting smectite type clays with polymeric 
cationic multimetal complexes. The pillared interlayered clays of the 
invention possess an internal microstructure which may be established by 
introducing discrete and non-continuous inorganic oxide particles or 
pillars having a length between about 6 and 16 .ANG., between the clay 
layers. These pillars serve to hold the space between the clay layers open 
after removal of included water and serve to form an internal 
interconnected micropore structure throughout the inner layer in which the 
majority of the pores are less than about 30 .ANG. in diameter. 
Typically, the invention relates to thermally stable interlayered clays 
having interlayer spacings up to about 16 .ANG. and whose pillars contain 
more than one type of metal atom. The product interlayered clay may be 
produced by reacting a naturally occurring or synthetic smectite type clay 
with a polymeric cationic hydroxy multimetal complex, the complex being 
produced by reacting certain metal-containing compounds with materials 
such as aluminum chlorohydroxide complexes ("chlorohydrol"), and heating 
to convert the hydrolyzed polymer complex into an inorganic multimetal 
oxide. The polymeric cationic hydroxy multimetal complex may be, of 
course, produced in a variety of other ways including introduction of the 
additional metals into the initial acidic aluminum solutions used in 
polymer synthesis.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
To obtain the novel pillared interlayered clay products of the invention, 
the following general procedure may be used: 
(1) a cationic polymer of the type believed to be (Al.sub.13 O.sub.4 
(OH).sub.24).sup.7+, having a globular structure as first described by 
Johansen, Acta. Chem. Scand., v. 14 (1960), p. 771, is reacted in aqueous 
solution with a fourth, fifth or sixth period transition metal. These will 
primarily be from Groups 5B, 6B, 7B and 8 of the Periodic Table. The base 
multiatomic complex is thought to be of the type: 
EQU Al.sup.iv Al.sub.12.sup.vi O.sub.4 (OH).sub.24).sup.7+. 
One or more of the noted elements may be substituted into either or both of 
the iv or vi coordinate sites. The general formula for the substituted 
molecule may be represented as: 
EQU N.sup.iv (Al.sub.12-x M.sub.x).sup.iv O.sub.4 (OH).sub.24.sup.+a 
where N may be Al.sup.3+, Si.sup.4+, Ga.sup.3+, Ge.sup.4+, As.sup.5+, 
p.sup.5+, Cr.sup.3+, Fe.sup.3+, V.sup.5+, Ru.sup.3+, Ru.sup.4+, Ni.sup.3+ 
; M may be one or more of the elements of Groups 5B, 6B, 7B and 8 of the 
4th, 5th or 6th Periods of the Periodic Table. The value for "x" may be 
from about 1 to about 6. The value for "a" depends upon the nature of the 
metal substitutions. Representative multimetal cationic polymer complexes 
include: 
EQU (Fe.sup.iv (Al.sub.10 Cr.sub.2).sup.vi O.sub.4 (OH).sub.24).sup.7+ 
EQU (Al.sup.iv (Al.sub.9 Fe.sub.3).sup.vi O.sub.4 (OH).sub.24).sup.7+ 
EQU (Al.sup.iv (Al.sub.10 Ni.sub.2).sup.vi O.sub.4 (OH).sub.24).sup.5+. 
Obviously, such substitutions may change the charge on the polymer 
molecules. Depending upon the solution pH, such multimetallic molecules 
may be hydrolyzed to produce lower charged species as indicated by Vaughan 
et al, Proc. 5th Intl. Zeolite Conf., (1980), p. 94. 
Other methods for producing (Al.sub.13).sup.7+ are discussed below and may 
be used as an alternative to beginning with a commercial solution of lower 
aluminum chlorohydrol. 
(2) A smectite clay is mixed with the aqueous solution of polymeric 
cationic hydroxy multimetal complex formed in step (1), in amounts so that 
the weight ratio of clay to metal complex solution is from 1:2 to 1000. 
The metal complex solution will preferably contain from about 1 to about 
40% by weight solids in a suitable liquid medium such as water. 
(3) The mixture of clay and metal complex is maintained at a temperature of 
about 5.degree. to about 200.degree. C. for a period of 0.1 to 4.0 hours. 
(4) The reacted clay solids are recovered and heated at a temperature of 
from about 200.degree. to about 700.degree. C. to decompose the hydrolyzed 
metal complex to a pillar believed to be of multiple metallic oxides or 
hydroxides. 
The clays which are suitable for use as starting materials in the present 
invention are the group of minerals known as smectites and are generally 
described above in the Background of the Invention. An extensive 
discussion of these materials is given in "Crystal Structures of Clay 
Materials and Their X-Ray Identification", edited by G. W. Brindley et al, 
(Mineralogical Soc.), 1980. 
The inorganic metal polymers that are used as starting material for 
production of the multimetal polymers are generally known as basic 
aluminum complexes which are formed by the hydrolysis of aluminum salts. 
While there is inevitably some disagreement on the nature of the species 
present in hydrolyzed metal complex solutions (or suspensions), it is 
generally believed that these mixtures contain highly charged cationic 
complexes with several metal ions being complexed. 
The hydrolysis of cations brings about polymers through a process called 
olation. For aluminum this process is described by C. L. Rollinson in 
Chemistry of the Coordination Compounds, edited by J. C. Bailar, Reinhold 
Publishing Corp., New York, 1956 as follows: 
##STR1## 
In this process, single or double OH.sup.- bridges can be formed between 
Al ions. In less acidic solution, larger polymers are formed by the 
process and the bridging OH.sup.- can be converted to a bridging O.sup.-2, 
a process called oxolation. Note that a doubly OH bridged complex is a 
pair of edged-sharing octahedra, and this is the same type of structure 
found in boehmite, AlOOH, where the OH.sup.- groups at the surface of the 
layers are each shared by two AlO.sub.6 octahedra. In hydrargillite, 
Al(OH).sub.3, all oxygen are also shared between two AlO.sub.6 octahedra. 
Various methods that have been used to produce Al polymers are discussed 
in U.S. Pat. No. 4,176,090, supra. 
However, for the purposes of making the novel substituted clays of the 
invention, mixtures of aluminum salts and transition metal salts are used. 
The metal ions may either be added to a solution already containing 
(Al.sub.13).sup.7+ polymers or may be added to a solution in which those 
polymers are being formed. Either method appears to produce similar mixed 
metal polymers. The present work is concerned only with the transition 
metal cationic substituted forms of (Al.sub.13).sup.7+ having the general 
formula: 
EQU N.sup.iv (Al.sub.12-x M.sub.x).sup.vi O.sub.4 (OH).sub.24 +a 
where N may be Al.sup.3+, Si.sup.4+, Ga.sup.3+, Ge.sup.4+, As.sup.5+, 
P.sup.5+, Cr.sup.3+, Fe.sup.3+, V.sup.5+, Ru.sup.3+, Ru.sup.4+, Ni.sup.3+ 
or a mixture; M may be one or more of the elements selected from Groups 
5B, 6B, 7B and 8 of the 4th, 5th or 6th Periods of the Periodic Table. 
These metals include V, Cr, Mn, Fe, Co, Ni, Nb, Mo, Tc, Ru, Rh, Pd, Ta, W, 
Re, Os, Ir and Pt. The value for "x" may be from about 1 to 6. The value 
for "a" depends upon the metal substitutions. 
The preferred material is that when N is Al or Al and Ru and M is selected 
from V, Cr, Mn, Fe, Co, Ni or a mixture of these metals. 
The polymers described above may be exchanged into smectite-type clays by 
cation exchange or other methods of imbibition to form expanded clays. 
Typically the clay will be finely ground and slurried in an excess of 
water. The multimetallic polymer is also added in a large amount to the 
clay slurry. The mixture is then aged for a period of time sufficient to 
allow introduction of the polymer to a position between platelets of the 
host clay. 
Referring to the drawing, FIG. 1 represents a typical smectite which has 
been treated with the multimetal complex polymers in accordance with the 
teachings of this invention and have a repeat distance A of about 16 to 
about 24 .ANG.. The distance B between layers ranges between 6 and 16 
.ANG.. The height of the pillar b is established when the pillared 
multimetal complex polymer which is inserted between the clay platelets is 
decomposed by calcination at temperatures between about 200.degree. and 
700.degree. . The distance as shown in the drawing may readily be obtained 
from X-ray diffraction pattern for the various products and represent the 
first-order basal reflection parameter, i.e., 001. 
It should be understood that within a given clay structure, the layers are 
not uniform but instead form a heterogeneous chemical mixture in which the 
exact composition of one layer may be somewhat different from that 
adjacent layer. This would be expected to result in slight variations in 
charge between layers, and therefore, slight differences in the amount of 
polymer exchange in different layers. Since the size of the multimetal 
polymer is the controlling factor in setting the inner layer distance, 
charge heterogeneity on the layers would only affect the number of polymer 
species between the layers, that is to say, the number of pillars but not 
their size. 
In general, the calcined products of the invention will have interlayer 
spacing of about 6 to about 16 .ANG., a nitrogen BET surface area of about 
150 to 600 m.sup.2 /gram, and a nitrogen pore volume of from about 0.1 to 
about 0.6 cc/g. Furthermore, the novel pillared multimetal interlayered 
clay composition possess a substantial internal micropore structure, 
reflected by the nitrogen pore size distribution analyses which show a 
major fraction of pores in the range of less than 25 .ANG.. The pillars 
themselves, in that they are produced by heating the multimetallic 
polymers discussed above, must contain some aluminum. A portion of the 
aluminum may be replaced by a number of semi metals or metals, as 
discussed above, i.e., N.sup.1.sup.v may be one or more of Al, Si, Ga, Ge, 
As, P, Cr, Fe, V, Ru, or Ni in the cationic multimetal polymer. 
Furthermore, a substantial portion of the metal compound in the pillar 
must be at least one or more of V, Cr, Mn, Fe, Co, Ni, Nb, Mo, Tc, Ru, Rh, 
Pd, Ta, W, Re, Os, Ir or Pt. The Mx component of the polymer intermediate 
is the source of these metals. The compound in the pillars is believed to 
be, after calcination, mostly an oxide of a simple or complex type. Some 
hydroxide may remain, however, 
These interlayered products are useful as adsorbents, catalytic supports 
and in many instances as catalysts. Furthermore, it is contemplated that 
the interlayered clay products may be combined with other inorganic oxide 
adsorbents and catalysts, such as silica, alumina, silica-magnesia, 
silica-alumina, hydrogel, natural or synthetic zeolites, and clays. These 
compositions may be useful in the preparation of catalysts which contain 
other active or stabilizing metals such as platinum, palladium, cobalt, 
molybdenum, nickel, tungsten, rare-earths and so forth, as well as matrix 
components, such as silica, alumina, and silica-alumina hydrogel. The 
resulting catalysts may be used in conventional petroleum conversion 
processes, such as catalytic cracking, hydrocracking, hydrotreating, 
isomerization, reforming, in polymerization and other petrochemical 
processes, as well as in molecular sieve separations. It is contemplated 
that these compositions may be especially useful in preparing bifunctional 
catalysts wherein a primary metallic catalyst is introduced into the clay 
by ion exchange and a secondary functional catalytic material is 
incorporated in the pillars as a portion of the multimetal pillars. 
Having described the basic aspects of the invention, the following specific 
examples are given to illustrate the preferred specific embodiments. 
EXAMPLE 1 
In this example, sufficient Cr.sup.3+ was added to an aluminum 
chlorohydrol Al.sub.13 O.sub.4 (OH).sub.24 Cl.sub.7 ("chlorohydrol") 
solution to give a resulting theoretical pillar having a composition of 
Al.sub.11 Cr.sub.2 O.sub.4 (OH).sub.24 Cl.sub.7. 
A 0.5 gm. CrCl.sub.3. 6H.sub.2 O sample was dissolved, at room temperature, 
in 20 gm. of a 50 wt. % aqueous chlorohydrol solution (Reheis Chemical 
Co.). The solution was stirred for 16 hours at 22.degree. C., then heated 
for two hours at 100.degree. C. A 10 gm. sample of Bentolite L smectite 
(Georgia Kaolin Co.) was added and the slurry stirred at 95.degree. C. for 
75 minutes. The mixture was filtered, and the blue-grey filter cake dried 
for 16 hours in a freeze dryer. X-ray diffraction analysis showed that 
about 30% of the clay had expanded to give an (001) layer spacing of 18.8 
.ANG.. In contrast, a similar sample of the clay exchanged only with a 
solution of CrCl.sub.3, gave a green grey product that had an (001) 
reflection 15.1 .ANG.. After calcination at 550.degree. C. the polymer 
treated clay was a light tan-cream color, whereas the Cr.sup.3+ exchanged 
clay was a grey-brown color. 
EXAMPLE 2 
A 0.5 gm. sample of CrCl.sub.3. 6H.sub.2 O was dissolved in 10 gm. H.sub.2 
O and mixed with a 20 gm. sample of chlorohydrol (as in Example 1). After 
aging for 16 hours at 22.degree. C., the polymer solution was hot-aged for 
75 minutes at 95.degree. C. A 10 gm. sample of Bentolite L smectite was 
added and the slurry agitated at 95.degree. C. for 90 minutes. The clay 
was filtered, yielding a blue grey filter cake and a similarly colored 
filtrate. After freeze drying, the exchanged clay for 16 hours, the clay 
powder gave an x-ray diffraction (001) spacing of 18.2 .ANG. (60%) and a 
spacing at 15.1 .ANG. (25% indicating only H.sub.2 O intercalation and 9.8 
.ANG. indicating no expansion). After calcination, the sample turned a 
light tan-cream color. 
EXAMPLE 3 
In this example, Ni.sup.2+ is substituted into the pillar. 
A 0.5 gm. sample of NiCl.sub.2 6.6H.sub.2 O was dissolved in 20 gm. H.sub.2 
O, and added to 20 gm. of a 50% wt. solution of chlorohydrol (Reheis 
Chemical Co.). The resulting mixture was stirred for ten minutes at room 
temperature. A 10 gm. sample of Bentolite L montmorillonite was added and 
the whole was stirred for 16 hours at 23.degree. C. After filtration, the 
filter cake was freeze dried. X-ray diffraction showed the sample to have 
strong reflections at 21.7 .ANG. and 11.8 .ANG.. After calcination of the 
material at 450.degree. C. for one hour, the sample was equilibrated at 
88% RH. over a saturated solution of CaCl.sub.2. Thermogravimetric 
analysis of this sample showed a total weight loss of 26 wt. %, 23 wt. % 
being lost below a temperature of 450.degree. C. X-ray diffraction showed 
the sample to have a strong (001) reflection at 18.2 .ANG.. Sorption of 
n-hexane showed a weight gain of 3.8 wt. %. After calcining in air for 2 
hours at 650.degree. C. and re-equilibrating with water at 88% RH for 2 
hours, the sample sorbed 9 wt. % H.sub.2 O. If two Ni.sup.2+ have 
replaced two Al.sup.3+ in this experiment, the intercalated polymer will 
have a formula [Al.sub.11 Ni.sub.2 O.sub.4 (OH).sub.24 ].sup.5+. 
Having thus described the invention and giving several examples in its 
practice, it should be apparent that various equivalents will be obvious 
to one having ordinary skill in this art and yet be within the purview of 
the claims appended hereon.