Alumina-based aerogel supported transition metal catalyst useful as a Ziegler-Natta olefin polymerization catalyst and process for preparing same

A new polymerization catalyst system comprising an aluminum compound and a transition metal compound on an alumina-based aerogel support, a process for preparing the polymerization catalyst system and use of the catalyst system for polymerization and copolymerization of alpha-olefins are disclosed. A heat-activated alumina-based aerogel useful as a catalyst support and having a morphology by transmission electron microcopy comprising extremely thin folded film-like ribbons or plates and having a high BET surface area, high pore volume, and low bulk density is also disclosed.

BACKGROUND OF THE INVENTION 
This invention relates to a new polymerization catalyst system comprising 
an aluminum compound and a transition metal compound on an alumina-based 
aerogel support, a process for preparing the polymerization catalyst 
system and use of the polymerization catalyst system for polymerization 
and copolymerization of alpha-olefins. Another aspect of this invention 
relates to a heat-activated alumina-based aerogel useful as a catalyst 
support and have a morphology by transmission electron microscopy 
comprising film, platelets and needles and substantially free of spherical 
particles and having a high BET surface area, high pore volume, and low 
bulk density. 
It is well known that alpha-olefins may be polymerized and copolymerized in 
the presence of a Ziegler-Natta type catalyst comprising Group III metal 
compound such as Al(C.sub.2 H.sub.5).sub.3 and a transition metal compound 
such as titanium tetrachloride on an inorganic oxide support such as 
alumina, silica, titania, magnesia, etc. The polymerization reaction may 
be carried out in suspension, in solution or even in the gas phase. (See, 
for example, Professor Natta's article in Encyclopedia of Polymer Science 
and Technology, Volume 4, at pages 137 to 150, (1971) J. Wiley & Sons, 
Inc., and articles in Volume 13, at pages 13 to 122 and Volume 15, at page 
133 ibid. 
U.S. Pat. No. 3,506,633 (Matuura, et al.) discloses a polymerization 
catalyst having a Cl/Ti ratio of 2.5 to 3.5 that is prepared by reacting 
TiCl.sub.4 with a substantially amorphous alumina xerogel having a total 
pore volumn less than 0.7 cm.sup.3 /g. 
U.S. Pat. No. 3,978,031 (Reginato, et al.) discloses a polymerization 
catalyst system containing an organo-metallic compound such as an alkyl 
aluminum compound and a co-catalyst formed by reacting a heat-activated 
halogenated alumina having an atomic ratio of halogen to aluminum of from 
0.1 to 1, such as fluoronated alumina, and a transition metal compound 
such as TiCl.sub.4. 
U.S. Pat. No. 4,088,812 (Matuura, et al.) discloses preparation of an 
olefin polymerization catalyst by impregnating a titanium or a vanadium 
compound such as TiCl.sub.4 onto a solid carrier formed by treatment with 
SO.sub.3 of an oxide or mixture of oxides of Group II-IV metals such as 
alumina. 
U.S. Pat. No. 4,247,669 (Reginato, et al.) discloses an olefin 
polymerization catalyst system containing an organo-metallic compound such 
as trialkyl aluminum and a supported catalyst prepared by reaction of a 
halogen-containing transition metal compound such as TiCl.sub.4 with a 
heat-activated alumina having an internal pore volume greater than 0.8 
cm.sup.3 /g so that the ratio of halogen to transition metal in the 
supported catalyst is greater than that of the halogen-containing 
compound. 
All of the above-mentioned U.S. patents disclose polymerization catalysts 
that are characterized by relatively low productivity in the low pressure 
(&lt;1000 psi) polymerization of ethylene. In commercial production of 
ethylene, the use of catalysts having a high productivity (which is a 
measure of the grams of polymer produced per gram of catalyst per hour) is 
frequently the difference between making an acceptable or a non-acceptable 
product. The higher the catalyst productivity, the lower the concentration 
of catalyst remaining in the polymer. Very low concentrations of catalyst 
residue in the polymer are innocuous and, consequently, need not be 
removed by expensive de-ashing procedures. For this reason, the polyolefin 
industry has ongoing research efforts on developing polymerization 
catalysts having high productivity for the low pressure polymerization of 
ethylene. 
An inorganic hydrated oxide, precipitated from an aqueous solution of the 
corresponding metal cation washed and then dried in an oven (in air or in 
vacuum) is very often obtained in a divided state as a porous gel. The 
general name of xerogel is given to these materials by A. Freundlich 
(Colloid and Capillary Chemistry), Duttom, N.Y. 1923). However, the 
texturial characteristics (pore volume and surface area) of the xerogel is 
considerably poorer than that of the wet gel before the elimination of the 
solvent (water). It is theorized that the evaporation of the solvent 
creates a vapor-liquid interface inside the pores and that the surface 
tension of the solvent is responsible for a partial collapse of the pore 
structure. In order to eliminate the liquid-vapor interface inside the 
pores, Kistler (J. Phys. Chem., 36 (1932) 52) disclosed an efficient 
process of evacuating the solvent from the system under supercritical 
conditions in an autoclave. The general name of aerogel is given to solids 
dried in this way. S. J. Teichner et al. (article entitled "Inorganic 
Oxide Aerogels" in Advances in Colloid and Interface Science, Volume 5, 
1976) 245-273) disclosed a general method for preparation of inorganic 
oxide aerogels such as SiO.sub.2,Al.sub.2 O.sub.3,TiO.sub.2,ZrO.sub.2,MgO 
and mixed inorganic oxides by dissolving in an organic solvent such as 
alcohol or benzene the corresponding alcoholate of the metal, hydrolyzing 
same at room temperature and evacuating the solvent under super-critical 
conditions in an autoclave. The method disclosed by Teichner is simpler 
than the complicated method of Kistler in that the hydrolysis reaction is 
carried out directly in an organic medium such as alcohol or benzene and 
there is no need for the substitution of an organic solvent for the 
initial aqueous medium which was previously used in the preparation of 
aerogels. U.S. Pat. No. 3,963,646 (Teichner et al.) disclosed preparation 
of NiO-Al.sub.2 O.sub.3 aerogels useful as catalysts for the hydrogenation 
or the controlled oxidation of olefins. See also M. Astier et al. in 
Preparation of Catalysts, edited by B. Delmor et al., Elsevier Scientific 
Publishing Company (1976) Amsterdam, at pages 315 to 328. 
U.S. Pat. No. 4,018,672 (Moser) discloses a hydrodesulfurization catalyst 
having an alumina-containing support prepared by a thermal decomposition 
of aluminum alcoholates in a manner analagous to that disclosed by 
Teichner et al. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a process for 
the polymerization and copolymerization of alpha-olefins which comprises 
contacting an alpha-olefin at a temperature and at a pressure sufficient 
to initiate the polymerization and copolymerization with a catalytic 
amount of 
(a) a di(C.sub.1 -C.sub.18 alkyl)aluminum chlorocompound or a tri(C.sub.1 
-C.sub.18 alkyl)aluminum compound; and 
(b) a catalyst produced by the reaction of a transition metal compound 
formed from a member selected from the group consisting of titanium, 
vanadium, hafnium, and zirconium, and members selected from the group 
consisting of chlorides, oxychlorides, alkoxychlorides and 
oxyalkoxychlorides with a heat-activated alumina-based aerogel having a 
bulk density less than about 0.10 g/cm.sup.3, a BET surface area greater 
than about 300.sup.2 m/g and a pore volume greater than about 3 cm.sup.3 
/g and obtained by heating an alumina-based aerogel having a carbon 
content at a temperature of at least about 400.degree. C., in the presence 
of oxygen, for a time sufficient to produce said heat-activated 
alumina-based aerogel substantially free of carbon; said alumina-based 
aerogel being prepared by venting a C.sub.1 -C.sub.5 alcohol or mixture of 
same, under super-critical conditions, from a mixture comprising a 
hydrolyzable aluminum compound, water, and a C.sub.1 -C.sub.5 alcohol or 
mixture of same. This polymerization process may be operated effectively 
to produce polyethylene over a broad range of temperatures and pressures 
and in the presence and in the absence of hydrogen gas. When hydrogen is 
present, the ratio of the pressure of hydrogen to ethylene may be varied 
over the range of about 0.5:1 to 5:1. 
In another aspect of the present invention, there is provided a method of 
preparing a catalyst system for polymerization and copolymerization of 
alpha-olefins which comprises: 
(a) forming a solution or a suspension comprising an alcohol or mixture of 
alcohols selected from C.sub.1 to C.sub.5 alcohols and a hydrolyzable 
aluminum compound and at least about a stoichiometric amount of water 
required to hydrolyze said hydrolyzable aluminum compound; 
(b) heating a suspension comprising the hydrolyzed and hydrolyzable 
aluminum compound in the presence of a solvent comprising methanol to a 
temperature above the critical temperature of the solvent comprising 
methanol; 
(c) removing the solvent comprising methanol under super-critical 
conditions to form an alumina-based aerogel having a carbon content; 
(d) heating the carbon-containing alumina-based aerogel in the presence of 
an oxygen-containing gas stream at a temperature of at least about 
400.degree. C. for a time sufficient to form a heat-activated 
alumina-based aerogel substantially free of carbon; and 
(e) reacting said heat-activated aerogel under substantially anhydrous 
conditions with a transition metal compound formed from a member selected 
from the group consisting of titanium, vanadium, hafnium and zirconium, 
and members selected from the group consisting of chlorides, oxychlorides, 
alkoxychlorides and oxyalkoxychlorides with said heat-activated aerogel to 
form a catalyst system having a BET surface area greater than about 300 
m.sup.2 /g, a pore volume greater than about 3.0 cm.sup.3 /g, a bulk 
density less than about 0.1 g/cm.sup.3. 
In one aspect of this invention, a catalyst system comprising TiCl.sub.4 
impregnated on a heat-activited alumina-based aerogel formed by 
super-critical venting of methanol from a reaction mixture prepared from a 
suspension of aluminum isopropoxide and, at least about a stoichiometric 
amount of water (about 3:1 molar ratio of H.sub.2 O:Al) in methanol is 
provided. A preferred embodiment of the present catalyst system comprising 
TiCl.sub.4 impregnated on heat-activated alumina aerogel in combination 
with an organo-aluminum compound effects polymerization of ethylene at 
hourly productivities of 3000 g of polyethylene/g of catalyst/hr/ and 
produces polyethylene having values of about 8-12 for high load melt index 
(I.sub.22) at H.sub.2 /C.sub.2 H.sub.4 ratios less than 1. 
In still another aspect of the present invention, there is provided a 
catalyst system for the polymerization and the copolymerization of 
alpha-olefins comprising a di(C.sub.1 -C.sub.18 alkyl)chloroaluminum 
compound or tri(C.sub.1 -C.sub.18 alkyl)aluminum compound and a catalyst 
comprising the reaction product of a transition metal compound formed from 
a member selected from the group consisting of titanium, vanadium, hafnium 
and zirconium and members selected from the group of chlorides, 
oxychlorides, alkoxychlorides, and oxyalkoxychlorides with a 
heat-activated alumina-based aerogel having a BET surface area greater 
than about 300 m.sup.2 /g, a pore volume greater than about 3 cm.sup.3 /g, 
a bulk density less than about 0.1 g/cm.sup.3. 
Further, there is provided a heat-activated alumina-based aerogel having a 
morphology by transmission electron microscopy comprising extremely thin, 
film-like ribbons and plates, said ribbons and plates being folded upon 
themselves or twisted around one another and rolled up into scrolls or 
mixtures of spherical particles and said thin, film-like ribbons and 
plates, a BET surface area greater than about 300 m.sup.2 /g, a pore 
volume greater than about 3 cm.sup.3 /g and a bulk density less than about 
0.1 g/cm.sup.3. 
Finally there is provided a process for preparing a heat-activated 
alumina-based aerogel which comprises the steps of: 
(a) forming a solution or a suspension comprising an alcohol or mixture of 
alcohols selected from C.sub.1 to C.sub.5 alcohols and a hydrolyzable 
aluminum compound and at least about a stoichiometric amount of water 
required to hydrolyze said compound; 
(b) heating a suspension comprising the hydrolyzed and hydrolyzable 
aluminum compound in the presence of a solvent comprising methanol to a 
temperature above the critical temperature of the solvent comprising 
methanol; 
(c) removing the solvent comprising methanol under supercritical conditions 
to form an alumina-based aerogel; and 
(d) heating the carbon-containing alumina-based aerogel in the presence of 
an oxygen-containing gas stream at a temperature of at least about 
400.degree. C. for a time sufficient to form a heat-activated 
alumina-based aerogel substantially free of carbon.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention employs a new Ziegler-Natta catalyst system based on 
heat-activated alumina-based aerogel carriers useful for low pressure 
polymerization and copolymerization of alpha-olefins, such as ethylene. 
Hourly productivity rates above about 3,000 grams of polyethylene (PE) per 
gram of catalyst per hour have been obtained using preferred embodiments 
of the alumina-based aerogel supports of the present invention. 
Furthermore, the new alumina-based aerogel catalysts of the present 
invention effect high pressure polymerization of ethylene in the presence 
of hydrogen with a significant cost savings in that the loss of ethylene 
by hydrogen reduction to ethane can be reduced by about one-half compared 
to the ethylene polymerizations effected by certain prior art catalysts. 
These economically advantageous results of higher hourly productivity and 
lower ethylene loss by reduction have been achieved by employing a 
catalyst system comprising an organo-aluminum compound and a catalyst 
produced by impregnating a transition metal compound such as TiCl.sub.4 
onto heat-activated alumina-based aerogel carriers that, unlike prior art 
carriers, do not require pre-treatment of carriers with fluoride or other 
chemical reagents such as SO.sub.3. 
The present invention may be fully understood by a discussion of (1) 
preparation of the catalyst by reaction of a transition metal compound and 
the heat-activated alumina-based aerogel carrier (2) preparation of the 
catalyst system which comprises an organo-aluminum compound and a catalyst 
produced by reaction of a transition metal compound with a heat-activated 
alumina-based aerogel carrier, and (3) the polymerization and 
copolymerization of alpha-olefins by contacting the monomer with a 
catalytic amount of the catalyst system at a temperature and a pressure 
sufficient to initiate polymerization and copolymerization. 
1. Preparation of the Supported Catalyst 
(a) Heat Activated Alumina-Based Aerogel Carriers. By the term 
"alumina-based aerogel" as used herein is meant an aerogel comprising 
mixed metal oxides of at least about 65 weight percent of aluminum oxide 
and up to about 35 weight percent of at least one of the oxides selected 
from the group consisting of calcium oxide, barium oxide, magnesium oxide, 
cerium oxide, lanthanum oxide, titanium oxide, zirconium oxide, chromium 
oxide, zinc oxide, gallium oxide, silica and antimony oxide. 
The present invention relates to catalyst comprising heat-activated 
alumina-based aerogels found useful as carriers for transition metal 
compounds to produce catalyst systems useful for polymerization and 
copolymerization. Hourly productivities above about 3,000 gPE/g-cat-h. 
have been achieved with preferred embodiments of the alumina-based 
aerogels of the present invention. Based on comparative test data, the 
heat-activated alumina-based aerogel carriers of the present invention are 
largely responsible for the desirable results achieved in the 
polymerization and copolymerization of alpha-olefins. The heat-activated 
alumina-based aerogel carriers of the present invention are prepared by 
(a) forming a solution or a suspension comprising a C.sub.1 -C.sub.5 
alcohol or mixture of same and a hydrolyzable aluminum compound and at 
least about a stoichiometric amount of water required to hydrolyze said 
aluminum compound; (b) heating the suspension or solution so formed in the 
presence of a C.sub.1 -C.sub.5 alcohol or mixture of same to a temperature 
above the critical temperature of said alcohol or mixture of same, and (c) 
removing said alcohol or mixture of same under supercritical conditions to 
form an aerogel having a carbon content greater than about 1 weight 
percent carbon. 
The C.sub.1 -C.sub.5 alcohols found useful in the process of forming the 
carriers of the present invention are methanol, ethanol, isopropanol, 
n-propanol, sec-butanol, etc. or mixtures thereof. Methanol is a preferred 
alcohol. 
The hydrolyzable aluminum compounds found useful in the process of forming 
alumina-based aerogel carriers of the present invention are aluminum 
alkoxides, preferably secondary alkoxides having 3 to 5 carbon atoms. 
By the term "stoichiometric amount of water" is meant a molar ratio of 
water to hydrolyzable aluminum compound of at least about 3:1. 
The temperature and pressure for the supercritical venting of the solvent 
alcohol or mixture of alcohols is dependent upon the exact alcohol or 
mixture of alcohols used. 
To insure that super-critical conditions are maintained during the venting 
step, it has been found convenient to heat the autoclave containing 
hydrolyzed aluminum compound and said alcohol or mixture of same to a 
temperature of at least about 20.degree. C. above the supercritical 
temperature. 
FIGS. 4(A-E) graphically illustrate five possible preparations of 
alumina-based aerogel useful as carriers. The five variations may be 
designated as methods 4A, 4B, 4C, 4D and 4E. FIG. 4A illustrates an aspect 
of the preparation of alumina aerogel carriers of the present invention. A 
dispersion of an aluminum alkoxide, such as aluminum isopropoxide in 
methanol is mixed with at least about a stoichiometric amount of water 
required to hydrolyze the aluminum compound, employing mild agitation and 
heated at elevated temperatures, e.g., 50.degree.-70.degree. C., for a 
time sufficient to precipitate the aluminum hydroxide. The mixture is 
heated in an autoclave to a temperature at least about 20.degree. above 
the supercritical temperature of methanol. The methanol is vented while 
the temperature of the contents of the autoclave is maintained above the 
critical temperature of methanol and there is recovered an alumina aerogel 
having a carbon content of at least about 1 weight percent carbon. 
See FIG. 4B wherein another example of a method of preparation of 
alumina-based aerogels is illustrated. A solution of aluminum secondary 
butoxide and secondary butanol in water is formed at ambient temperture 
and heated at elevated temperatures, e.g., 75.degree.-80.degree. C. for a 
time sufficient to precipitate aluminum hydroxide. The precipitate is 
filtered to separate secondary butanol and a wet cake of aluminum 
hydroxide and residual sec-butanol which is dispersed in methanol and 
placed in an autoclave. The methanol dispersion is heated at a temperature 
sufficient to produce the super-critical conditions for 
methanol/secbutanol solvent mixture which is vented and an alumina aerogel 
having a carbon content of at least about 1 weight percent carbon is 
obtained. 
FIG. 4C illustrates still another method of preparation wherein, for 
example, a solution of aluminum isopropoxide is isopropanol is mixed with 
at least about a stoichiometric amount of water at elevated temperatures, 
e.g., 75.degree.-80.degree. C., for a time sufficient to produce a 
precipitate of aluminum hydroxide in isopropanol. The reaction mixture is 
heated in an autoclave to a temperature at least about 20.degree. C. above 
the supercritical temperature for isopropanol. The isopropanol solvent is 
vented at supercritical conditions of temperature and pressure and an 
alumina aerogel is recovered having a carbon content of at least about 1 
weight percent carbon. 
FIG. 4E illustrates a preferred method of preparation of alumina-based 
aerogels of the present invention, wherein aluminum isopropoxide is 
dissolved in sufficient isopropanol to form a completely homogeneous 
solution at elevated temperatures, and at least a stoichiometric amount of 
water is added thereto, with mixing. Heating is continued for a time 
sufficient to produce a precipitate of aluminum hydroxide in isopropanol. 
The heterogeneous reaction mixture is transferred (without filtration) to 
an autoclave. The temperature of the contents of the autoclave is raised 
to a value of at least about 20.degree. C. above the critical temperature 
for the isopropanol-methanol solvent mixture which is then vented and the 
alumina-based aerogel is recovered. The preferred method of FIG. 4E 
operates without the additional step of filtration of the wet cake of 
Al(OH).sub.3 to produce an alumina-based aerogel, even though the aluminum 
isopropoxide may be partially hydrolyzed, i.e., Al(OH)(i-C.sub.3 H.sub.7 
O).sub.2. After the hydrolysis step but before the venting step of FIG. 
4E, methanol may be added. The solvent composition, in weight %, may 
thereby be varied from about 100% isopropanol up to about 80% methanol-20% 
isopropanol, preferably, from about 80% isopropanol-20% methanol to about 
20% isopropanol-80% methanol. 
The alumina-based aerogels prepared in accordance with the procedures 
illustrated in FIGS. 4(A-E) are calcined (heat-activated) at a temperature 
of at least about 400.degree. C., in the presence of an oxygen-containing 
gas, such as air or oxygen gas, for a time sufficient to produce a 
heat-activated alumina-based aerogel substantially free of carbon, i.e., 
having a carbon content of less than about 0.2 weight percent carbon. The 
calcination temperature found useful to accomplish preparing the 
alumina-based aerogels of the present invention is in the range of about 
400.degree. to no more than 700.degree. C.; a temperature of about 
700.degree. C. has been found convenient to produce the heat-activated 
alumina-based aerogel useful as a catalyst in the present invention. 
Surprisingly, the presence of methanol in the heterogeneous reaction 
mixture in the autoclave during the venting step has been found to have a 
beneficial effect on the hourly productivity of the polymerization 
catalyst derived from alumina-based aerogel supports produced in 
accordance with the preferred embodiments of the method illustrated in 
FIG. 4E. The Table below illustrates that the hourly productivity of 
preferred ethylene polymerization catalysts of the present invention 
(TiCl.sub.4 impregnated on heat activated alumina-based aerogels) was 
increased as the weight percent of methanol in the solvent added to the 
heterogeneous reaction mixture in the autoclave prior to venting was 
increased from zero to 20 percent. 
______________________________________ 
Solvent Composition 
of Autoclave Prior to 
Hourly 
Venting (wgt. %) 
Productivity 
Example No. 
i-propanol 
methanol (g PE/g cat-h) 
______________________________________ 
11 100 0 1751 
14d 92 8 2327 
14a 80 20 2994 
______________________________________ 
The carbon content of the alumina-based aerogel prior to calcination is 
preferably at least about 1 weight percent carbon, more preferably in the 
range of about 1 to about 8 weight percent carbon. While the preferred 
carbon content of the alumina-based aerogel prior to calcination is at 
least about 1 weight percent, and more preferably in the range of about 1 
to about 8 percent carbon, in a preferred embodiment of the present 
invention, a surprisingly high hourly productivity of 2327 g PE/g cat-h 
was obtained in ethylene polymerization reaction wherein the catalyst was 
derived from an alumina-based aerogel having a carbon content of 0.61 
weight percent prior to calcination (See Examples 5d and 14d). While 
alumina-based aerogels are calcined at a temperature of at least about 
400.degree. C., in the presence of an oxygen-containing gas, for a time 
sufficient to produce a heat-activated alumina-based aerogel substantially 
free of carbon, a carbon content of at least about 1 weight percent in the 
aluminabased aerogel prior to calcination has been found to be critical 
for production of a heat-activated aluminabased aerogel that is useful in 
the present invention, i.e., as a carrier for a transition metal compound 
such as TiCl.sub.4. 
The heat-activated alumina-based aerogel carriers found useful in the 
present invention are characterized as having bulk densities less than 
about 0.10 g/cm.sup.3, BET surface areas greater than about 300 m.sup.2 /g 
and X-ray diffraction patterns indicating the presence of amorphous phases 
or crystalline phases and pore volumes greater than about 3 cm.sup.3 /g. 
Alumina-based aerogels having properties outside these limits, for 
example, those alumina-based aerogels having pore volumes less than 3 
cm.sup.3 /g were found to be less effective carriers for TiCl.sub.4 and 
are to be avoided. 
The catalyst systems which operated with superior productivity in the 
polymerization of ethylene were derived from heat-activated alumina-based 
aerogels wherein methanol is employed for the supercritical venting 
operation of the procedure of FIGS. 4A, 4B, 4C and 4E. The highest hourly 
productivities in the polymerization of ethylene were obtained with a 
catalyst systems based on alumina-based aerogels prepared in accordance 
with the procedures of FIGS. 4A, 4B and 4E. 
The preferred heat-activated alumina-based aerogels of the present 
invention prepared in accordance with the preferred embodiments of the 
methods illustrated in FIGS. 4A-4C and 4E have a morphology by 
transmission electron microscopy comprising extremely thin film-like 
ribbons and plates, some of said ribbons and plates being folded upon 
themselves and twisted around one another and others of said ribbons and 
plates being rolled up into scrolls or mixtures of spherical particles and 
said ribbons and plates, BET surface areas greater than about 300 cm.sup.2 
/g, pore volumes greater than about 3 cm.sup.3 /g and bulk densities less 
than about 0.10 g/mL. While these unique aerogels have been prepared by 
the methods of the present invention, illustrated in FIGS. 4A-4C and 4E, 
it is believed that other methods may be employed to achieve these 
distinctive characteristics which are responsible for the high hourly 
productivity of the catalyst systems used to polymerize and copolymerize 
alpha-olefins. 
FIGS. 5 to 12 illustrate transmission electron mirographs of the aerogels 
prepared in accordance with the preferred embodiments of the process of 
the present invention, the prior art, and nonvented materials called 
xerogels, i.e., materials prepared without removal of solvent under 
supercritical conditions. 
FIG. 5 shows that the morphology of KETJEN.RTM. NFF, a fluorinated alumina, 
prepared as described in Example 6 hereinbelow, contains predominately 
spherical particles having a particle size (diameter) in the 40-70 .ANG. 
range. 
FIGS. 6a and 6b are electron micrographs (planar views) of a heat-activated 
alumina aerogel prepared exactly as described in Example 2 hereinbelow and 
illustrated in FIG. 4B. The samples shown in FIGS. 6a and b were vacuum 
embedded in MARAGLAS.RTM. epoxy and sectioned with an ultramicrotome and 
have a morphology consisting of a mixture of spherical particles (having a 
particle size in the 40-60 .ANG. range) and thin, film-like ribbons and 
thin plates which as such have folded upon themselves and twisted around 
one another. FIG. 7 is an electron micrograph of the catalyst prepared by 
impregnating TiCl.sub.4 on the heat-activated alumina aerogel illustrated 
in FIGS. 6a and 6b. The sample of the catalyst of FIG. 7 was prepared as 
described for FIGS. 6a and b and has essentially the same morphology as 
the alumina aerogel supports shown in FIGS. 6a and 6b. FIGS. 8a and 8b are 
electron micrographs of a heat-activated alumina aerogel prepared exactly 
as described in Example 3b hereinbelow and illustrated in FIG. 4C. The 
aerogel shown in FIGS. 8a and 8b was ground between glass plates and 
dusted onto holey carbon coated grids and has a morphology that consists 
essentially of thin, film-like platelets having a salt and pepper texture, 
some of which are folded upon one another and others rolled up in the form 
of scrolls and is substantially free of spherical particles. 
FIGS. 9a and 9b are electron micrographs of a heat-activated alumina 
prepared exactly as described in Example 4 hereinbelow. The aerogel shown 
in FIGS. 9a and 9b were prepared for examination by the transmission 
electron microscope in the manner as described for FIGS. 8a and 8b and 
have a morphology consisting essentially of spherical clusters of 
spherical particles having a particle diameter in the 20-40 .ANG. range, 
substantially free of thin film-like structures. FIGS. 10a and 10b are 
transmission electron micrographs of an alumina aerogel prepared exactly 
as described in Example 1 and prepared for examination in exactly the same 
manner as described for FIGS. 8a and 8b and 9a and 9b. The morphology of 
the heat-activated alumina aerogel shown in FIGS. 10a and 10b is 
significantly different than those of FIGS. 5 and 9a and 9b and consists 
predominately of extremely thin film-like ribbons and plates which as such 
have folded upon themselves and twisted around one another and some of 
which are rolled up into scrolls. 
FIGS. 11a, 11b, 11c and 11d are electron micrographs of an uncalcined (11a, 
11b) and heat-activated alumina aerogels (11c and 11d) prepared as 
described in Example 5 hereinbelow and illustrated in FIG. 4E. The 
aerogels shown in FIGS. 11a, 11b, 11c and 11d were prepared for 
examination by the transmission electron microscope in a manner exactly as 
described for FIGS. 8a and 8b. No significant difference could be found 
between the morphology of the uncalcined alumina aerogel shown in FIGS. 
11a and 11b and the morphology of the calcined or heat-activated alumina 
aerogel shown in FIGS. 11c and 11d. The morphologies of the uncalcined 
alumina-based aerogel shown in FIGS. 11a and 11b and of the heat-activated 
alumina-based aerogel shown in FIGS. 11c and 11d are almost exactly the 
same as the morphology of the aerogels shown in FIGS. 8a and 8b and 
consist essentially of thin film-like textured platelets, some of which 
are folded upon one another and others of which are rolled up into 
scrolllike structures and is substantially free of spherical particles. 
Only the texture of the plates shown in FIGS. 11a to 11d are different 
from the salt and pepper texture of the plates of FIGS. 8a and 8b. 
FIGS. 12a and 12b are electron micrographs of a heat-activated co-aerogel 
of calcium oxide and alumina prepared as described in Example 21 
hereinbelow. The aerogels shown in FIGS. 12a and 12b were prepared for 
examination by the transmission electron microscope in a manner exactly 
the same as that described for FIGS. 8a and 8b. The morphology of the 
heat-activated co-aerogel of calcium oxide and alumina oxide is similar to 
the morphologies of the aerogels illustrated in FIGS. 8a and 8b and 11a to 
11d and consists of a mixture of mainly very thin sheets or plates having 
a line or fibrous texture and some thin film-like ribbons some of which 
are folded upon one another and others of which are rolled up into scrolls 
and is substantially free of spherical particles. Thus, the morphology of 
the heat-activated co-aerogel of clacium oxide and alumina illustrated in 
FIGS. 12a and 12b is similar to the morphologies of the heat-activated 
aerogels illustrated in FIGS. 8a and 8b and in FIGS. 11a, 11b, 11c and 
11d, but contains a greater quantity of very thin sheets or plates and 
less thin film-like ribbons than the morphologies illustrated in FIGS. 8a 
and 8b and in FIGS. 11a to 11d. 
In another aspect of the present invention, the heat-activated 
alumina-based aerogel comprises mixed metal oxides of at least about 65 
wgt % aluminum oxide and up to about 35 wgt %, preferably about 1 to about 
15 wgt % of one or more of the aerogels selected from the group consisting 
of calcium oxide (CaO), barium oxide (BaO), magnesium oxide (MgO), cerium 
oxide (CeO.sub.2), lanthanum oxide (La.sub.2 O.sub.3) titanium oxide 
(TiO.sub.2), zirconium oxide (ZrO.sub.2), chromium oxide (Cr.sub.2 
O.sub.3), zinc oxide (ZnO), gallium oxide (Ga.sub.2 O.sub.3) silica 
(SiO.sub.2).sub.x antimony oxide (Sb.sub.2 O.sub.3) and mixtures thereof. 
The aerogels considered within the scope of the present invention comprise 
a heat-activated alumina-based aerogel prepared in accordance with the 
procedures described in FIGS. 4A-E by hydrolysis of at least about 65 wgt 
% (basis Al.sub.2 O.sub.3) a hydrolyzable aluminum compound and up to 
about 35, preferably about 1 to about 15 wgt % (basis metal oxide) of at 
least one member selected from the group consisting of hydrolyzable 
non-aluminum compounds of calcium, barium, magnesium, cerium, lanthanum, 
titanium, zirconium, chromium, zinc, gallium, silicon and antimony. 
Among the hydrolyzable non-aluminum compounds found useful in the process 
of the present invention are the primary alkyl groups of one to ten 
carbons, secondary alkyl groups of three to ten carbons and tertiary alkyl 
groups of four to ten carbons, the primary, secondary and tertiary 
alkoxides of one to ten carbons, alkanoates of two to eight carbons, 
nitrates, halides, preferably chloride, and ammonium nitrates of calcium, 
barium, magnesium, cerium, lanthanum, titanium, zirconium, chromium, zinc, 
gallium, silicon, antimony and mixtures thereof. Exemplary hydrolyzable 
non-alumina compounds include Ca(NO.sub.3).sub.2.4H.sub.2 O, Ba(C.sub.9 
H.sub.19 CO.sub.2).sub.2, Mg(CH.sub.3 CO.sub.2).sub.2 MgCl.sub.2, 
Mg(C.sub.2 H.sub.5 O).sub.2, Mg(C.sub.6 H.sub.13).sub.2, (NH.sub.4).sub.2 
Ce(NO.sub.3).sub.6, LaCl.sub.3.6H.sub.2 O, La(NO.sub.3).sub.3.6H.sub.2 O, 
Ti(i-C.sub.3 H.sub.7 O).sub.4, Zr(nC.sub.3 H.sub.7 O).sub.4 Cr(CH.sub.3 
CO.sub.2).sub.3, Zn(C.sub.9 H.sub.19 CO.sub.2).sub.2, Ga(sec-C.sub.4 
H.sub.9 O).sub.4, Si(OCH.sub.3).sub.4 and Sb(sec-C.sub.4 H.sub.9 O).sub.3. 
(b) Impregnation of the Heat-Activated Alumina-Based Aerogel with a 
Transition Metal Compound 
The supported catalyst of the present invention is prepared by contacting 
the heat-activated alumina aerogel or mixed oxide aerogel, under 
substantially anhydrous conditions with an effective amount of a 
transition metal compound formed from a member selected from the group 
consisting of titanium, vanadium, hafnium and zirconium and of members 
selected from the group consisting of chlorides, oxychlorides, 
alkoxychlorides and oxyalkoxychlorides. The catalyst so formed has a BET 
surface area greater than about 300 m.sup.2 /g, a pore volume greater than 
about 3 cm.sup.3 /g, a bulk density and less than about 0.10 g/cm.sup.3 
and a Cl to transition metal ratio of no more than 4:1. 
Illustrative chloro-transition metal compounds include TiCl.sub.3, 
TiCl.sub.4, Cp.sub.2 Ti, Cp.sub.2 TiCl.sub.2, CpTiCl.sub.3, VCl.sub.4, 
VOCl.sub.4, HfCl.sub.4, ZrCl.sub.4, and the like, wherein Cp is C.sub.5 
H.sub.5.sup.-. 
When using transition metal compounds containing alkoxide radicals, they 
are preferably selected from straight and branched chain alkoxide radicals 
of 1 to 20 carbon atoms and more preferably, 1 to 10 carbon atoms such as, 
TiCl.sub.3 (OC.sub.2 H.sub.5),TiCl.sub.2 (OC.sub.2 H.sub.5).sub.2, 
TiCl(OC.sub.2 H.sub.5).sub.3 [Ti(OC.sub.2 H.sub.5).sub.4 is not 
preferred]; TiCl(OC.sub.4 H.sub.9).sub.3, TiCl.sub.3 (O-i-C.sub.3 
H.sub.7), VO(O-i-C.sub.4 H.sub.9).sub.3, VO(OC.sub.7 H.sub.15).sub.3, 
HfCl(O-i-C.sub.3 H.sub.7).sub.3, HfCl.sub.2 (O-i-C.sub.4 H.sub.9).sub.2, 
ZrCl(O-i-C.sub.5 H.sub.11).sub.3. Titanium compounds are preferred. The 
preferred titanium compound is TiCl.sub.4. 
The amount of transition metal compound, preferably TiCl.sub.4, impregnated 
onto the alumina-based aerogel carrier affects productivity and is 
critical. While the polymerization support based on a fluorinated carrier 
such as KETJEN.RTM. NFF, a fluorinated alumina of the prior art, can 
accept no more than about 1.5 weight percent of titanium, the 
alumina-based aerogels of the present invention operate as effective 
carriers without incorporation of fluoride and accordingly may accept and 
retain a greater quantity of transition metal compounds, such as 
TiCl.sub.4 conveniently about 3-5 weight percent transition metal such as 
titanium than the fluorinated carriers presently available. 
The anhydrous conditions required for the reaction of the alumina-based 
aerogel and the transition metal compound are critical because of the 
sensitivity to air and moisture of the transition metal compound. The 
preferred carrier for the catalyst system of the present invention 
consists essentially of a heat-activated alumina-based aerogel or 
co-aerogel that is substantially free of fluorinated alumina. 
2. Preparation of the Catalyst System Comprising an Organo-Aluminum 
Compound and the Catalyst Produced by Reaction of a Transition Metal 
Compound with the Heat-Activated Alumina-Based Aerogel Support 
The polymerization and the copolymerization catalyst system of the present 
invention is formed by the reaction of the transition metal compound on 
the heat-activated alumina-based aerogel support and an organo-aluminum 
compound such as di(C.sub.1 -C.sub.18 alkyl) chloroaluminum compound or a 
tri(C.sub.1 -C.sub.18 alkyl) aluminum compound. The preferred 
polymerization and copolymerization catalyst system of the present 
invention incorporates a catalytic amount of a trialkyl aluminum compound 
preferably a C.sub.1 to C.sub.12 alkyl aluminum compound such as 
tributylaluminum, triisobutylaluminum, trioctylaluminum, tridecylaluminum, 
and more preferably, triisobutylaluminum. 
The amount of the dialkylchloroaluminum compound or the trialkylaluminum 
compound is not critical. The molar ratio of organo aluminum compound to 
the transition metal on the heat-activated aluminabased support is 
conveniently in the range of about 5:1 to 20:1. 
The method of formation of the polymerization and copolymerization catalyst 
system of the invention is not critical so long as the transition metal 
compound, e.g., TiCl.sub.4, is added to alumina-based aerogel support 
prior to the addition of the organo-aluminum compound. The organo-aluminum 
compound and the transition metal compound on the heat-activated 
alumina-based aerogel support may be reacted either in the presence of the 
alpha-olefin to be polymerized or the catalyst system may be prepared 
separately and then introduced into the polymerization reaction medium. 
3. The Polymerization and Copolymerization Reaction 
The process of the present invention is applicable to the polymerization 
and copolymerization of alpha-olefins containing from 2 to 18 carbons and 
preferably containing 2 to 6 carbon atoms such as ethylene, propene, 
butene-1, cis-and trans-butene-2, isoprene, and hexene-1. 
In accordance with the process of the present invention, polymerization and 
copolymerization of alpha-olefins comprises contacting an alpha-olefin at 
a temperature and at a pressure sufficient to initiate polymerization and 
copolymerization with a catalytic amount of an organo-aluminum compound 
(described herein above) and a catalyst produced by the reaction of a 
transition metal compound and the heat-activated alumina-based aerogel 
described hereinabove. 
The preferred catalyst of the present invention is formed by contacting 
TiCl.sub.4 with the heat-activated alumina-based aerogel formed in 
accordance with the preferred embodiments of the preparations described in 
FIGS. 4A, 4B, 4C and 4E. The preferred olefin of the present invention is 
ethylene alone or with about 0 to about 10 weight percent of co-monomers 
of 3-6 carbons such as 1-butene, 1-hexene or the like. The temperature and 
the pressure for the polymerization of ethylene is at least about 
50.degree. C. and a pressure in the convenient range of about 1000 psig. 
In a preferred aspect of the process of the present invention, the 
preferred temperature is in the range of about 50.degree. to 100.degree. 
C. and pressure is in the range of about 450 to 650 psig. The process of 
the polymerization of ethylene in either preferred aspect of the present 
invention is effected in the presence of hydrogen. However, the 
polymerization of ethylene may be effected in the absence of hydrogen. 
When hydrogen is present, the preferred ratio of the pressure of hydrogen 
to the pressure of ethylene is in the range of about 0.5:1 to 5:1. 
FIG. 1 graphically compares the productivities in the ethylene 
polymerization reaction employing a catalyst system comprising 
triisobutyaluminum and TiCl.sub.4 on a heat-activated alumina aerogel of 
the present invention with those of samples of a prior art catalyst based 
on fluorinated alumina carrier. In a preferred aspect of the present 
invention, the polymerization process employing the alumina-based aerogel 
carrier effected polymerization of polyethylene at an hourly productivity 
of over 3,000 G PE/g cat/hour. 
In a preferred aspect of the polymerization process to produce polyethylene 
of a high load melt index (I.sub.22) equal to about 10, the high 
productivity for a catalyst employing an alumina-based aerogel carrier 
produced by the procedure of Example 1 hereinbelow was achieved at a 
hydrogen to ethylene pressure of about 0.5:1 to less than 1.5:1, 
preferably 0.75:1 to less than 1.0:1. As illustrated in FIG. 2, 
polyethylene having a high load melt index of about 10 is produced by 
using preferred alumina-based aerogel carrier of the present invention, 
and a hydrogen to ethylene ratio that is less than 1.0 as opposed to 
ratios of greater than 1.0 required with a prior art catalyst. Operating 
at a lower hydrogen pressure produces two desirable results. Since a 
polymerization plant operates at a constant pressure, the ethylene 
pressure increases as the hydrogen pressure decreases; this results in 
greater productivity of polyethylene. The second advantage is the reduced 
loss of ethylene via hydrogenation of the ethylene to ethane. 
GENERAL EXPERIMENTAL 
A. Apparatus of Polymerization 
A 2L autoclave reactor vessel, manufactured by Precision, Inc., was 
interfaced with an Autoclave Engineers Magna-drive assembly. 
The reactants, solvent and purge gas were first passed through three 
activated treaters in the following order: charcoal, CuO and 4A or 3A 
(ethylene) molecular sieve. After leaving the treaters, each gas passed 
through a valve to a gas manifold and then to the reactor. 
Positioned directly before the reactor and after the gas manifold was a 
loop system that allowed catalyst and co-catalyst additions to the reactor 
vessel. Connected to the loop system by a tee was a stainless steel line 
from the solvent reservoir. The location of the tee enabled the 
catalyst/co-catalyst to be carried to the reactor while the solvent was 
added. To assist solvent delivery, argon pressure was applied to the top 
of the reservoir at 100 psig (689.11 kPa) above the operating solvent 
vapor pressure. 
B. Procedure for Polymerization: Typical Run 
Before the addition of reagents, the atmosphere in the argon purged reactor 
was analyzed by the Lockwood-McLorie trace oxygen analyzer. The oxygen 
content was typically less than 1.5 ppm. Then, approximately 500 cm.sup.3 
of isobutane was transferred to the reactor that was equipped with a water 
jacket maintained at a temperature of 85.degree. C. The reactor was 
stirred for 30-45 minutes. The isobutane was then vented and the reactor 
isolated from the rest of the system. The isobutane venting step was 
employed to help rid the reactor of traces of air and to condition the 
vessel before the reagents were introduced. Argon was then used to purge 
the loop system and the 2.5 cm.sup.3 syringe that would be used to 
introduce the trialkylaluminum compound. With the loop under argon purge, 
triisobutylaluminum (TiBAL) was added with the syringe through the 3/8" 
(9.5 mm) ball valve and carried to the autoclave reactor with 800 cm.sup.3 
of isobutane. The loop was again isolated from the reactor, purged again 
with argon and the catalyst added. The catalyst was carried to the reactor 
by the remaining 200 mL of isobutane. The reactor at 85.degree. C. was 
stirred at 520 RPM. At this point the vapor pressure of the solvent was 
recorded at 1509.4 kPa. The loop was again isolated from the reactor, 
purged with hydrogen and the hydrogen pressure set in the reactor. At 
equilibrium temperature (85.degree. C.) and pressure, ethylene was 
introduced for one hour while maintaining the proper pressure and 
temperature. At the end of the run the reactor was vented and the product 
was removed. The reactor was then cleaned and sealed and purged with argon 
in preparation for the next run. 
Example 1 (Catalyst A) 
1a. Support Preparation 
A suspension consisting of 16.95 g, 0.083 mol aluminum isopropoxide and 95 
g methanol was heated at 50.degree. C. in a beaker while being stirred 
with a magnetic stir bar. Water (4.5 g) was added and the mixture stirred 
while the temperature was maintained between 50.degree.-70.degree. C. for 
67 minutes. The suspension was transferred to a glass test tube and placed 
into a 300 cm.sup.3 stainless steel autoclave. The autoclave was heated 
without stirring. When the temperature reached 255.degree. C., the gases 
at 1275 psig (8888 kPa) were vented to the atmosphere over a period of 25 
minutes. Five and one-half grams of solid product were recovered. The 
solid had a BET surface area of 656 m.sup.2 /g. pore volume (Hg 
porosimetry) of 5.42 cm.sup.3 /g, bulk density of 0.057 g/cm.sup.3, carbon 
content of 7.92 wt % and gave an amorphous (with possible Iota and Kappa 
phases) X-ray pattern. See Tables I an II for a summary of the results. 
1b. Calcination or Heat-Activation 
Alumina aerogel (1.3 g) prepared as described in 1a was placed in a 
vertical quartz tube and heated to 700.+-.20.degree. C., over a period of 
4 hours and then held at this temperature for an additional 11 hours while 
85 cm.sup.3 /min of oxygen was flowed upwards through the solid. One gram 
of solid was recovered from the calcination treatment. 
1c. Impregnation 
The calcined alumina aerogel (0.747 g) of 1b was transferred in a glove box 
to a 150 mL glass H-reactor for impregnation with TiCl.sub.4. The solid in 
one leg of the H-reactor was contacted with 0.5 mL of a heptane solution 
containing 0.31 g/cm.sup.3 of TiCl.sub.4. The mixture was diluted with 
additional heptane so that the suspension could be easily stirred with a 
magnetic stir bar. The suspension was stirred for 1.5 hours at ambient 
temperature, after which time the solid was filtered within the H-reactor. 
The solid catalyst was washed once with pure heptane, filtered and 
maintained under vacuum (10.sup.-3 mmHg) until dry. A catalyst prepared by 
the above-described procedures was found by elemental analysis to contain 
3.84 wgt% Ti and 11.05 wgt% Cl. 
Example 2 (Catalyst B) 
The procedures of Example 1 were followed except that a solution was formed 
from 21.5 g, 0.0874 mol aluminum s-butoxide and 300 g of s-butanol. 
Precipitation was effected at room temperature using 4.5 g, 0.25 mol of 
H.sub.2 O. The mixture was warmed to 75.degree.-80.degree. C. with 
stirring and then filtered to give 75 g of wet cake. The wet cake was 
dispersed in 60 g of methanol. Venting, calcination, and impregnation were 
carried out in accordance with the procedures outlined in Example 1. The 
physical properties of the alumina aerogel were similar to those of the 
object of Example 1: 650 m.sup.2 /g surface area, 5.76 cm.sup.3 /g pore 
volume (Hg porosimetry), 0.043 g/cm.sup.3 bulk density, 5.8 wt % carbon 
and an X-ray pattern suggesting mixed amorphous and crystalline phases. 
After calcination and impregnation (TiCl.sub.4) in accordance with the 
procedure of Example 1, the catalyst was found by elemental analysis to 
contain 4.10 wgt% Ti and 11.48 wgt% Cl. 
The results are summarized in Tables I and II. 
Example 3a (Catalyst C) 
Aluminum i-propoxide (16.94 g, 0.083 mol) was heated in 95 g i-propanol. At 
70.degree. C. most of the solid dissolved, the solution appearing only 
slightly cloudy. Addition of 2.25 g H.sub.2 O (0.125 mol) caused formation 
of a milky white precipitate. After about 2 minutes additional stirring, 
the hot mixture was transferred to the autoclave for venting as described 
in Example 1 above. The solid, totalling 4.7 g, had a BET surface area of 
674 m.sup.2 /g, pore volume of 4.18 cm.sup.3 /g, bulk density of 0.07 
g/cm.sup.3 and carbon content of 1.42 wt % by elemental analysis. Its 
X-ray diffraction pattern was typical of gamma alumina. 
The solid was calcined and impregnated as described in Example 1. The 
catalyst was analyzed to contain 3.65 wt % Ti and 10.89 wt % Cl. 
Example 3b (Catalyst C) 
The procedure of 3a was exactly followed except that 4.5 g of H.sub.2 O was 
used in the hydrolysis step. The solid had the following physical 
properties: a BET surface area of 289 m.sup.2 /g, a pore volume of 4.3 
cm.sup.3 g, a bulk density of 0.036 g/cm.sup.3 and a carbon content of 1.3 
wt. % by elemental analysis. Its X-ray diffraction pattern was typical of 
Boehmite and unidentified material. 
The solid was calcined and impregnated as described in Example 1. The 
catalyst was used in ethylene polymerization similar to that described in 
Examples 11 and 12a and 12b. Similar results were obtained. 
Example 4 (Catalyst D) 
This alumina aerogel was prepared by adding 1.1 g H.sub.2 O (0.0611 mol) to 
a solution of 10 g (0.0406 mol) aluminum s-butoxide in 90 g of s-butanol 
at ambient temperature. The mixture was vented in accordance with the 
procedure of Example 1 over a period of 57 minutes while the temperature 
was maintained between 273.degree.-290.degree. C. The yield amounted to 
2.22 g. The alumina had a BET surface area of 404.4 m.sup.2 /g, pore 
volume of 4.35 cm.sup.3 /g (Hg porosimetry) and 0.3 wt % carbon. Its X-ray 
pattern suggested the presence of a major boehmite phase and a minor 
amorphous phase. 
Calcination and impregnation with TiCl.sub.4 were carried out as described 
in Example 1 above. Elemental analysis indicated that the catalyst 
contained 3.2 wt % titanium and 6.1 wt % chlorine. 
Example 5(a) (Catalyst E) 
This example shows that incorporation of methanol has a beneficial effect 
on the physical properties of the alumina aerogel and improves the 
activity of the TiCl.sub.4 impregnated catalyst (compare with catalysts C 
of Example 3 and E of Example 5(d)). 
Aluminum isopropoxide (16.94 g, 0.083 mol) was heated to 70.degree. C., 
with stirring in 95 g i-proponal in a beaker. When almost all of the solid 
dissolved, the solution appeared hazy and 4.5 g H.sub.2 O was added. The 
milky white suspension was stirred for two minutes and the hot mixture was 
transferred to a glass test tube liner with 24 g of methanol and placed 
into a 300 cm.sup.3 SS autoclave for heating and venting in accordance 
with the procedures as described in Example 1. 
The yield of alumina aerogel amounted to 5.12 g. The solid contained 6.48 
w% C and 2.97 w% H by elemental analysis and had a BET surface area of 
675.4 m.sup.2 /g, a bulk density of 0.061 g/cm.sup.3 and a pore volume of 
5.38 cm.sup.3 g. The X-ray diffraction pattern indicated the presence of 
amorphous and possibly iota and kappa phases. After calcination as 
described in Example 1, the calcined aerogel had a surface area of 466 
m.sup.2 /g and a pore volume of 4.26 cm.sup.3 /g. See FIGS. 11c and 11d 
and Table I. The support was impregnated with TiCl.sub.4 as described in 
Example 1 and used in ethylene polymerization. See Example 14(a) and Table 
II. 
EXAMPLE 5(b) (Catalyst E) 
Catalyst Support E was prepared in accordance with procedure of 5(a) on a 
larger scale using the following procedures. Three hundred twenty-eight 
grams of i-propanol and 66.2 g (0.325 mol) of aluminum isopropoxide were 
added directly to a 1 L SS autoclave. After the mixture was stirred for 30 
minutes at 70.degree. C. 17.6 g of H.sub.2 O was added, causing formation 
of a thick white precipitate. The mixture was stirred at 70.degree. C. for 
an additional 15 minutes. The temperature was raised after the addition of 
82 g of methanol. When the temperature reached 255.degree. C. (2 h, 5 min) 
the gases at 1780 psig were super-critically vented down to 1 atm over a 
period of 1 hour. The product was recovered as a white powder and had a 
bulk density of 0.031 g/cm.sup.3, BET surface area of 456 m.sup.2 /g and 
pore volume of 5.38 cm.sup.3 /g. See FIGS. 11a and 11b and Table II. The 
catalyst (E) formed after calcination and impregnation with TiCl.sub.4 as 
described in Example 1 was used for ethylene polymerization. See Example 
14(b) and Table II. 
Example 5(c) (Catalyst E) 
In a procedure completely analagous to Example 5(b) there was obtained 18.2 
g of an alumina aerogel in the form of a white powder having the following 
physical properties: bulk density, 0.030 g/cm.sup.3, BET surface area, 495 
m.sup.2 /g and a pore volume of 6.31 cm.sup.3 /g. (See Table I). After 
calcination and impregnation with TiCl.sub.4 in accordance with Example 1, 
Catalyst E was used in ethylene polymerization described in Example 14(c) 
and Table II. 
Comparative Example 5(d) (Catalyst E) 
The procedure completely analgous to Example 5(a) was followed except that 
the solvent composition, in weight percent, was 92% i-propanol and 8% 
methanol. 
Example 6 (KETJEN.RTM.NFF alumina support) 
"KETJEN.RTM.NFF" fluorinated alumina (fluoride concentration 2.3 wgt %) was 
prepared as described in Example 1 of U.S. Pat. No. 3,978,031 and was 
calcined in nitrogen at 700.degree. C. and impregnated as described in 
Example 1b and 1c above. An elemental analysis indicated that the catalyst 
contained 1.33 wt % titanium and 3.69 wt % chlorine. 
TABLE I 
______________________________________ 
Physical Properties of Alumina Aerogels 
______________________________________ 
Pore 
Example # Surface Volume.sup.2 
(Catalyst Area (M.sup.2 /g) 
(cm.sup.2 /g) 
Designation) 
Before.sup.1 
After.sup.1,3 
Before.sup.1 
After.sup.1,3 
______________________________________ 
Example 1 (A.sup.a) 
656 417 5.42 5.52 
Example 2 (B.sup.b) 
650 498 (501).sup.3 
6.83 5.38 (6.69).sup.3 
Example 3a (C.sup.c) 
674 340 4.18 3.52 
Example 4 (D.sup.d) 
404 289 (287).sup.3 
4.35 3.59 (3.12).sup.3 
Example 5a (E.sup.e) 
675 466 5.38 4.26 
Example 5b (E.sup.e) 
456 (389).sup.3 
5.38 (4.44).sup.3 
Example 5c (E.sup.e) 
495 364 (348).sup.3 
6.31 4.17 (4.53).sup.3 
Example 5d (E.sup.d) 
388 341 5.62 5.79 
Example 6 250 220 (220).sup.3 
1.9 1.85 (1.85).sup.3 
KETJEN .RTM. NFF 
alumina.sup.f 
______________________________________ 
Example # Bulk Density Carbon Content 
(Catalyst (g/cm.sup.3) (wgt %) 
Designation) Before.sup.4 
After.sup.4 
Before.sup.5 
______________________________________ 
Example 1 (A.sup.a) 
0.057 .095 7.92 
Example 2 (B.sup.b) 
0.05 .073 5.56 
Example 3a (C.sup.c) 
0.07 .128 1.42 
Example 4 (D.sup.d) 
0.04 0.14 0.3.sup.11 
Example 5a (E.sup.e) 
0.061 0.104 6.48 
Example 5b (E.sup.e) 
0.031 0.093 1.74 
Example 5c (E.sup.e) 
0.030 0.083 1.27 
Example 5d (E.sup.d) 
0.037 0.08 0.61 
KETJEN .RTM. NFF 
0.23 0.23 0.2 
alumina.sup.f 
______________________________________ 
Footnotes for Table I 
.sup.a Support A: Suspension of Al(OC(CH.sub.3).sub.2 H).sub.3 /H.sub.2 O 
Methanol; Hydrolysis/supercritical Venting of Methanol and isopropanol 
(Prepared as described in Example 1) 
##STR1## 
filtration; addition of Methanol; supercritical Venting of Methanol and 
secbutanol. 
.sup.c Support C: Solution of Al[OC(CH.sub.3).sub.2 H].sub.3 H.sub.2 
O/ipropanol; Hydrolysis; supercritical venting of ipropanol. 
.sup.d Support D: Solution of Al(OC(CH.sub.3 (H)C.sub.2 H.sub.5).sub.3 
/H.sub.2 O/ secbutanol; Hydrolysis; supercritical Venting of secbutanol. 
.sup.e Support E: Solution of Al[OC(CH.sub.3).sub.2 H].sub.3 in ipropanol 
Hydrolysis methanol added to slurry; supercritical venting of 
ipropanol/MeOH. 
.sup.f Fluoride content of 2.3 wgt % 
.sup.1 Before and after calcination at 700.degree. C. 
.sup.2 Pore volume was measured by Hg Porosimetry. 
.sup.3 While S.A. and P.V. have not been measured on all heatactivated or 
calcined aerogels after impregnation with TiCl.sub.4, the values of S.A. 
and P.V. listed in Table I, based on limited data available for calcined, 
alumina aerogels impregnated with TiCl.sub.4 in an exact analogous matter 
to those listed in Table I, are expected to undergo little or no change 
after impregnation with TiCl.sub.4. 
.sup.4 Before calcination and after calcination (700.degree. C.) and 
impregnation with TiCl.sub.4. 
.sup.5 One alumina aerogel, calcined at 700.degree. C. in O.sub.2, was 
found to contain 0.21 wgt % carbon by elemental analysis. Similar values 
are to be expected for all alumina aerogels listed in Table I. 
Example 7 
Ethylene Polymerization with Catalyst A 
Ethylene polymerization with catalyst A (prepared as described in Example 
1) was carried out in a 2 L SS autoclave in 1 L of isobutane containing 
129 mg, 0.65 mmol (6.5.times.10.sup.-4 mol) of triisobutylaluminum. The 
polymerization was carried out at 85.degree. C. and 550 psia, 3790 kPa 
total pressure, using 121.3 mg. of catalyst A and 11.1 atm of hydrogen. 
Ethylene was admitted on demand at a constant pressure of 13.0 atm. After 
1 hour, the polymerization was stopped and 356.7 g of polyethylene powder 
were recovered. The hourly productivity was 2941 g.PE/g cat-h and the 
activity (productivity/atm C.sub.2 H.sub.4) was 226. The polymer had melt 
index values of I.sub.22 =11.79 and I.sub.5 =0.82 (See Table II for a 
summary of the results of this and similar runs.) 
Example 8 
Ethylene Polymerization with Catalyst A 
A catalyst prepared as described in Example 1 above was also tested for 
polymerization activity at low pressure. Into a 450 mL glass reactor was 
charged 41 mg of the solid catalyst A, 225 cm.sup.3 of heptane, 71 mg of 
triisobutylaluminum and 35.4 psia, 244 kPa of hydrogen. Sufficient 
ethylene at 23.6 psia, 163 kPa was fed on demand to maintain a constant 
pressure of 465 kPa. The reaction mixture was stirred at 950 rpm and the 
temperature controlled at 83.+-.3.degree. C. After 1 hour, the run was 
stopped and the polyethylene was separated and dried; 17.83 g were 
recovered. The polyethylene had an I.sub.22 melt index of 0.5 and I.sub.5 
of 0.02. The activity of catalyst A (g.PE/g cat-hr-atm C.sub.2 H.sub.4) 
was 264. (See Table III for a summary of the results of this and similar 
runs.) 
Example 9 
Ethylene Polymerization with Catalyst B 
The polymerization procedures of Example 7 were followed. A 1 hour run at 
11.42 atm pressure of ethylene and 11.30 atm of hydrogen produced 207 g of 
polyethylene at 85.degree. C. from 68 mg. of the solid catalyst B 
(preferred as described in Example 2) and 129 mg, 0.65 mmol of 
triisobutylaluminum. The melt index values of the polymer were I.sub.22 
=10.4 and I.sub.5 =0.70. (See Table II) 
Example 10 
Ethylene Polymerization with Catalyst B 
A low pressure test with a catalyst B, prepared as described in Example 2, 
gave 27.58 g of polyethylene in 1 hour at 87.+-.3.degree. C. from 73 mg. 
of solid catalyst B in 225 mL heptane containing 109 mg, 0.55 mmol of 
triisobutylaluminum. The pressures of ethylene and hydrogen were 22.5 
psia, 155 kPa and 33.75 psia, 233 kPa, respectively. The polymer had an 
I.sub.22 melt index of 0.12. The activity of catalyst B was 247 g PE/g 
cat/h/atm C.sub.2 H.sub.4. (see Table III for a summary of the results. 
Example 11 
Ethylene Polymerization with Catalyst C 
In the 2 L autoclave described above, operating at 85.degree. C., 10.35 atm 
H.sub.2 and 13.8 atm C.sub.2 H.sub.4, 184 g of polyethylene were obtained 
in 1 hour from 105.3 mg. of the solid catalyst C (prepared as described in 
Example 3(a)) with 129 mg, 0.65 mmol of triisobutylaluminum. The polymer 
had an I.sub.22 melt index of 7.39 and I.sub.5 of 0.46. 
Example 12a 
Ethylene Polymerization with Catalyst C 
The catalyst (C) of Example 3a was tested also at low pressure. The 
catalyst (43 mg) in conjunction with 64.5 mg, 0.32 mmol of 
triisobutylaluminum in 255 mL heptane gave 9.78 g of polyethylene in 1 
hour at 85.+-.1.degree. C. The pressures of hydrogen and ethylene were 
33.75 psia, 232 kPa and 22.5 psia, 155 kPa, respectively. The I22 melt 
index of the polymer was 2.6 and the I5 value was 0.12. 
Example 12b 
Ethylene Polymerization with Catalyst C 
In a second, low-pressure run with 40 mg. of the same catalyst (C) and 58 
mg, 0.29 mmol of triisobutylaluminum, 12.27 g of polyethylene were 
obtained in 1 hour at 86.+-.1.degree. C., 23.5 psia, 162 kPa of ethylene 
and 33.25 psia, 229 kPa of hydrogen. 
Example 13 
Ethylene Polymerization with Catalyst D 
Catalyst D, prepared in accordance with Example 4, was tested only at low 
pressure, 64.7 psia 446 kPa, using 225 mL of heptane, 22.5 psia, 155 kPa 
of ethylene and 33.75 psia, 233 kPa of hydrogen. Following a 1 hour run at 
86.+-.2.degree. C., 9.09 g of polyethylene were obtained from 70 mg. of 
the solid catalyst (D) and 97 mg, 0.49 mmol of triisobutylaluminum. The 
I.sub.22 melt index of the polymer was 3.1 and I.sub.5 was 0.10. (See 
Table III). 
Example 14a 
Ethylene Polymerization with Catalyst E of Example 5a 
Polymerization of ethylene with the TiCl.sub.4 impregnated catalyst E 
prepared as described in Example 5a gave the following results. A 
productivity of 2994 g PE/g cat-h was obtained in the 2 L autoclave 
reactor using 126 mg of the catalyst E (Example 5a) 129 mg, 
6.5.times.10.sup.-4 mol of trisobutylaluminum, 12.4 atm C.sub.2 H.sub.4 
and 10.4 atm of H.sub.2 in 1 L of isolutane at 85.degree. C. The polymer 
had an I.sub.22 melt index of 1.73 and I.sub.5 of 0.19. See Table II. 
Example 14b 
Ethylene Polymerization with Catalyst E of Example 5b 
Ethylene polymerization with the TiCl.sub.4 impregnated catalyst E of 
Example 5b yield a productivity of 3160 g PE/g cat-h in the 2 L autoclave 
reactor using conditions of 12.8 atm C.sub.2 H.sub.4, 10.2 atm H.sub.2 and 
1 L of isobutane at 85.degree. C. In this run 108.3 mg of the catalyst E 
(Example 5b) was used in conjunction with 129 mg (6.5.times.10.sup.-4 mol) 
of triisobutylaluminum. The I.sub.22 melt index of the polymer was 12.1. 
Example 14c 
Ethylene Polymerization with Catalyst E of Example 5c 
The procedure and apparatus of Example 7 were used. Ninety-nine mg of the 
TiCl.sub.4 impregnated catalyst E prepared as described in Example 5c 
produced 314 g of polyethylene in 1 hour at 85.degree. C. in 1 L of 
isobutane in the 2 L autoclave reactor using 129 gm (6.5.times.10.sup.-4 
mol) of triisobutylaluminum, 12.6 atm C.sub.2 H.sub.4 and 10.1 atm 
H.sub.2. The polymer had an I.sub.22 melt index of 8.82. The productivity 
of the catalyst was 3176 g PE/g cat-h. 
Example 14d 
Ethylene Polymerization with Catalyst E of Example 5d 
The procedure and apparatus of Example 7 were used. A productivity of 2327 
g PE/g cat-h was obtained in the 2 L autoclave reactor using 119 mg. of 
the catalyst E (Example 5d), 129 mg., 6.5.times.10.sup.-4 mol 
triisobutylaluminum, 12.3 atm C.sub.2 H.sub.4 and 10.4 atm of H.sub.2 in 1 
L of isobutane at 85.degree. C. See Table II. 
Example 15a 
The polymerization was carried out in the 2 L autoclave described above 
using 126.8 mg. of the solid KETJEN.RTM. catalyst, prepared as described 
in Example 6, 1 L of isobutane, 129 mg, 0.65 mmol of triisobutylaluminum, 
13.7 atm H.sub.2 and 9.82 atm C.sub.2 H.sub.4. After 1 hour at 85.degree. 
C., 127.6 g of polyethylene were obtained having an I.sub.22 melt index of 
11.4 and an I.sub.5 of 0.616. 
Example 15b 
In another run with the same KETJEN.RTM. catalyst of Example 14a, 143 g of 
polyethylene were produced in 1 hour at 85.degree. C. from 124.6 mg of the 
solid KETJEN.RTM. catalyst, 129 mg of triisobutylaluminum, 9.7 atm, 67 kPa 
of C.sub.2 H.sub.4 and 14.45 atm, 100 kPa of H.sub.2. The melt indexes of 
the polymer were I.sub.22 =12.7 and I.sub.5 =0.67. 
Example 16a 
Ethylene Polymerization with KETJEN.RTM.NFF 
The KETJEN.RTM. catalyst of Example 6 was also tested at low pressure. 
Using 52 mg. of the solid KETJEN.RTM. catalyst and 33.5 mg, 0.17 mmol of 
triisobutylaluminum in 225 mL of heptane, a 1-hour run at 86.+-.1.degree. 
C. produced 10.94 g of polyethylene having an I.sub.22 melt index of 1.4 
and I.sub.5 of 0.06. The pressures of hydrogen and ethylene during the run 
were 19.7 psia, 136 kPa and 39.05 psia, 269 kPa, respectively. 
Example 16b 
In a run similar to that described in 16a, (except that the pressures of 
ethylene and hydrogen were 22.5 psia, 155 kPa and 33.75 psia, 232 kPa, 
respectively) 10.60 g of polyethylene were produced from 39 mg of the 
solid KETJEN.RTM. catalyst and 25.8 mg of triisobutylaluminum. The 
I.sub.22 melt index of the polymer was 0.8 and the I.sub.5, 0.04. (See 
Table III). 
TABLE II 
______________________________________ 
Ethylene Polymerization at 85.degree. C. Data 
for TiCl.sub.4 -Impregnated Aluminas.sup.a 
______________________________________ 
Pressure 
(absolute) 
Catalyst.sup.c 
atm Melt Index.sup.d 
Support.sup.b 
mg H.sub.2 
C.sub.2 H.sub.4 
I.sub.22 
I.sub.5 
______________________________________ 
A 75.5 8.20 16.70 2.60 0.17 
A 73.8 10.79 14.21 7.91 0.52 
.sup. A.sup.1 
121.3 11.1 13.0 11.79 
0.82 
A 74.6 11.23 13.86 11.8 0.77 
A 76.5 14.04 9.30 64.1 3.91 
.sup. B.sup.2 
68.0 11.30 11.42 10.4 0.70 
B 128.0 8.71 13.07 34.5 2.0 
B 130.0 14.88 10.71 8.0 0.48 
C 129.6 14.30 9.65 60.2 3.27 
C 134.5 11.54 11.54 16.55 
1.09 
.sup. C.sup.3 
105.3 10.35 13.80 7.39 0.46 
E.sup.4a 126 10.4 12.4 1.73 0.19 
E.sup.4b 108.3 10.2 12.8 12.1 
E.sup.4c 99 10.2 12.6 8.82 
E.sup.4d 119 10.4 12.3 14.34 
0.94 
KETJEN .RTM. NFF.sup.5 
124.6 14.45 9.70 12.70 
0.67 
KETJEN .RTM. NFF.sup.6 
126.8 13.70 9.82 11.4 0.62 
KETJEN .RTM. NFF.sup.7 
140.4 11.2 11.0 2.76 0.14 
______________________________________ 
Activity 
PE Productivity 
(Productivity 
Support.sup.b 
(g) (g PE/g-cat-h) 
.div. atm C.sub.2 H.sub.4) 
______________________________________ 
A 246 3260 195 
A 219 2976 209 
.sup. A.sup.1 
356.7 2941 226 
A 215 2883 208 
A 140 1841 185 
.sup. B.sup.2 
207 3044 267 
B 243 1898 218 
B 252 1937 130 
C 165 1275 132 
C 218 1626 141 
.sup. C.sup.3 
184 1751 127 
E.sup.4a 377 2994 241 
E.sup.4b 342 3160 247 
E.sup.4c 314 3176 252 
E.sup.4d 277 2327 189 
KETJEN .RTM. NFF.sup.5 
143 1148 118 
KETJEN .RTM. NFF.sup.6 
128 1006 103 
KETJEN .RTM. NFF.sup.7 
180 1282 117 
______________________________________ 
Footnotes for Table II 
.sup.a Supports calcined at 700.degree. C. for 11 hours prior to 
impregnation. 
.sup.b See Table I for explanation. 
.sup.c 129 mg triisobutylaluminum used. 
.sup.d For I.sub.22, procedure of ASTM D1238, condition F was used. For 
I.sub.5, procedure of ASTM D1238, condition p was used. 
.sup.1 Example 7 
.sup.2 Example 9 
.sup.3 Example 11 
.sup.4a-d Examples 14a, b, c and d, 
.sup.5 Example 15b 
.sup.6 Example 15a 
.sup.7 97 mg triisobutylaluminum used. 
TABLE III 
______________________________________ 
Low Pressure Ethylene Polymerization 
______________________________________ 
Cata- Triisobutyl- Activity 
lyst aluminum PE g PE/g cat-h/ 
Support mg mg g .div. atm C.sub.2 H.sub.4 
______________________________________ 
A.sup.a 41.sup.1 
71 17.83 
264 
B.sup.b 73.sup.2 
109 27.6 247 
C.sup.c 43.sup.3 
64.5 9.78 149 
C.sup.c 40.sup.4 
58 12.3 192 
D.sup.d 70.sup.5 
97 9.1 85 
KETJEN .RTM. NFF.sup.e 
41.sup.6 
26 10.6 169 
______________________________________ 
Pressure 
psia Temp. 
Support H.sub.2 C.sub.2 H.sub.4 
.degree.C. 
______________________________________ 
A.sup.a 35.40 23.6 84 .+-. 3 
B.sup.b 33.75 22.5 88 .+-. 3 
C.sup.c 33.75 22.5 85 .+-. 1 
C.sup.c 33.25 23.5 86 .+-. 1 
D.sup.d 33.75 22.5 85 .+-. 2 
KETJEN .RTM. NFF.sup.e 
33.75 23.0 86 .+-. 1 
______________________________________ 
Footnotes for Table III 
.sup.a Support was prepared as described in Example 1. 
.sup.b Support was prepared as described in Example 2. 
.sup.c Support was prepared as described in Example 3a. 
.sup.d Support was prepared as described in Example 4. 
.sup.e Support was prepared as described in Example 6. 
.sup.1 Example 8. 
.sup.2 Example 10 
.sup.3 Example 12a. 
.sup.4 Example 12b. 
.sup.5 Example 13. 
.sup.6 Example 16b 
TABLE IV 
______________________________________ 
Morphology of Alumina Aerogels 
of Examples 1-5 and KETJEN .RTM. NFF 
Example X-Ray Transmission 
(Catalyst Diffraction Electron 
Designation) 
Analysis.sup.1 
Microscopy.sup.3 
______________________________________ 
1 Amorphous Thin Film-like 
(A) Ribbons and 
Plates Folded 
and Rolled into 
Scrolls. (See 
FIGS. 10a and 
10b) 
2 Amorphous Mixtures of Thin 
(B) & Film-like Struc- 
Crystalline tures and Thin 
Plates and Spher- 
ical Particles 
See FIGS. 6a 
and 6b) 
3b Poorly Folded Thin 
(C) Developed Textured Sheets 
Gamma Alumina and Platelets (See 
FIGS. 8a & 8b) 
4 Boehmite Spherical clusters 
(D) and Amorphous.sup.2 
of spherical par- 
ticles (See FIGS. 
9a and 9b) 
5 Gamma Alumina Thin Film-like 
(E) structures and 
Plates Folded and 
Rolled into 
Scrolls (See 
FIGS. 11c and 
11d) 
6 Gamma Alumina Spherical Parti- 
KETJEN .RTM. cles (See FIG. 
5) 
______________________________________ 
.sup.1 After heatactivation at 700.degree. C. in oxygen. 
.sup.2 Before heat activation. 
.sup.3 See description of FIGS. 5-11 for details. pcl Example 17 
Effects of H.sub.2 SO.sub.4 addition on the Hydrolysis of Aluminum 
Isopropoxide in Methanol 
The procedure described in Example 1 was followed with the following 
modification. Water (4.05 g) containing 0.41 g conc (98%) H.sub.2 SO.sub.4 
was added to the suspension of aluminum isopropoxide in methanol. All 
other aspects of support preparation, calcination and impregnation with 
TiCl.sub.4 were the same as described in Example 1. 
The following physical properties were measured before calcination: BET 
surface area=761 m.sup.2 /g; pore volume=6.14 cm.sup.3 /g; and bulk 
density=0.04 g/cm.sup.3. Elemental analysis of catalyst (after calcination 
and impregnation with TiCl.sub.4): 1.79 wgt% S; 3.81 wgt% Ti; 10.48 wgt% 
Cl. It is believed that the use of H.sub.2 SO.sub.4 in the hydrolysis step 
favorably affects the gel structure. 
EXAMPLE 18 
Ethylene polymerization with a catalyst prepared as described in Example 17 
was carried out in the apparatus described in Example 7 at 85.degree. C., 
550 psia, 3790 kPa total pressure and in the presence of 129 mg 
triisobutylaluminum. Results are listed in Table V. 
TABLE V 
______________________________________ 
Polymerization Data for TiCl.sub.4 - 
Impregnated Alumina of Example 17 
______________________________________ 
Pressure Activity 
Absolute Hourly (Hourly Pro- 
Catalyst.sup.a 
(atm) PE Productivity 
ductivity 
(mg) H.sub.2 
C.sub.2 H.sub.4 
(g) (g PE/g cat-h) 
.div. atm C.sub.2 H.sub.4) 
______________________________________ 
123 10.1 12.08 438.2 3560 295 
125 11.1 11.03 394.7 3158 286 
______________________________________ 
Catalyst.sup.a Melt Index 
(mg) I.sub.22 
I.sub.5 
______________________________________ 
123 5.73 .322 
125 9.61 .543 
______________________________________ 
.sup.a TiCl.sub.4 impregnated alumina prepared as described in Example 17 
 
Comparative Examples 19 
Low pressure polymerizations of ethylene were conducted in 450 mL glass 
reactors in accordance with the procedure described in Example 8, with 
various aluminas impregnated with TiCl.sub.4 : The non-fluorinated 
aluminas were prepared by hydrolysis of aluminum secbutoxide in the 
solvents indicated, followed by removal of solvent under non-supercritical 
(non-vented) or supercritical (vented) conditions. The fluorinated 
aluminas were prepared by inclusion of an appropriate quantity of HF or 
NH.sub.4 F in the reaction mixture in the autoclave prior to supercritical 
venting of the solvents. The results are summarized in Table VI. 
TABLE VI 
______________________________________ 
Low Pressure Ethylene Polymerization Data for 
Various TiCl.sub.4 - Impregnated Alumina Catalysts 
______________________________________ 
Bulk 
Support.sup.b,d 
Activity.sup.c 
Activity.sup.c 
Density.sup.d 
Type Per g cat Per g Ti (g/cm.sup.3) 
______________________________________ 
KETJEN .RTM. NFF.sup.1 
84.0 4000 .23 
Aerogel (V-B-M).sup.2 
236.0 5900 .073 
Aerogel (V-B-M-F).sup.3 
161.0 5031 .10 
Aerogel (V-B-B).sup.4 
84.8 2650 .14 
Xerogel (NV-B-B-F).sup.5 
37.8 1189 .48 
Aerogel (V-B-B).sup.6 
34.3 1319 .25 
Hybrid.sup.7 15.5 686 .32 
Aerogel (V-M-M-F).sup.8 
13.8 750 .69 
Aerogel (V-B-B).sup.9 
8.69 -- .39 
Fumed.sup.10 1.40 98 .40 
CATA SB.sup.11 
1.00 42 -- 
______________________________________ 
Support.sup.b,d 
Pore Volume.sup.dc 
Surface Area.sup.df 
Type (cm.sup.3 /g) 
(m.sup.2 /g) 
______________________________________ 
KETJEN .RTM. NFF.sup.1 
1.85 220 
Aerogel (V-B-M).sup.2 
6.69 501 
Aerogel (V-B-M-F).sup.3 
4.54 335 
Aerogel (V-B-B).sup.4 
3.12 287 
Xerogel (NV-B-B-F).sup.5 
2.13 367 
Aerogel (V-B-B).sup.6 
2.67 228 
Hybrid.sup.7 -- -- 
Aerogel (V-M-M-F).sup.8 
1.73 171 
Aerogel (V-B-B).sup.9 
1.83 277 
Fumed.sup.10 3.23 103 
CATA SB.sup.11 
-- -- 
______________________________________ 
Footnotes for Table VI 
.sup.a Low Pressure Ethylene Polymerization in 450 mL glass reactor at 
standard conditions: 85.degree. C.; 22.5 psia C.sub.2 H.sub.4 ; 33.75 psi 
H.sub.2. 
.sup.b Catalyst support prepared as described below impregnated with 
TiCl.sub.4. 
.sup.c Activity in g of PE/h/atm of C.sub.2 
.sup.d Quantity measured on calcined (700.degree. C.) catalyst after 
impregnation with TiCl.sub.4. 
.sup.e Hg Porosimetry. 
.sup.f BET Surface Area. 
.sup.g The abbrevation: V = Vented; NVNonvented; B = secbutanol; 
MMethanol; F = Fluoride. The sequence, e.g., VB-M or NVB-B-F refers to 
conditions of solvent removal: V(supercritical venting of solvent), 
NV(hypocritical venting of solvent). The second letter, e.g., B is the 
first letter of the name of the solvent, e.g., butanol used in hydrolysis 
step; The third letter, e.g., M is the first letter of the solvent, e.g., 
methanol used in venting or nonventing step; The presence of fluorine 
indicated by F. Nonvented materials are materials prepared without remova 
of the solvent under supercritical conditions. 
.sup.1 KETJEN .RTM. NFF fluorinated alumina (2.3 wgt % F) prepared as 
described in Example 1 of U.S. Pat. No. 3,978,031 and treated as describe 
in instant Example 6. 
.sup.2 Al(O--secBu).sub.3 /sec BuOH/H.sub.2 O; filter; methanol added to 
wet filter cake supercritical venting of methanol. (See Example 
.sup.3 Same as in Footnote 2 except that aerogel was fluorinated (2.7 wgt 
% F). 
.sup.4 Al(O--secBu).sub.3 /sec BuOH/H.sub.2 O; supercritical venting of 
sec BuOH. (See Example 4) 
.sup.5 Al(O--secBu).sub.3 /sec-BuOH/H.sub.2 O/nonsupercritical removal of 
secBuOH; xerogel fluorinated with NH.sub.4 F (2.0 wgt % F). 
.sup.6 Prepared as described in Footnote 4. 
.sup.7 Al(O secBu).sub.3 /H.sub.2 O; filter; methanol added to wet filter 
cake; supercritical venting of methanol Pore Volume = 2.95 cm.sup.3 /g 
(before impregnation); SA = 282 m.sup.2 /g (before impregnation). 
.sup.8 Al(Osec Bu).sub.3 /MeOH/NH.sub.4 F/H.sub.2 O: supercritical ventin 
of methanol; fluorinated aerogel contained 3.2 wgt % F. 
.sup.9 Prepared as described in Footnote 4. No impregnation with 
TiCl.sub.4. 
.sup.10 Fumed alumina obtained from Degussa Corp. 
.sup.11 Obtained from Conoco; before impregnation with TiCl.sub.4, Bulk 
Density = 0.70 g/cm.sup.3 ; Pore Volume = 0.57 cm.sup.3 /g; Surface Area 
= 227 m.sup.2 /g. 
Data selected from Table VI is graphically displayed in FIGS. 3A, 3B and 3C 
for the following TiCl.sub.4 -impregnated alumina catalysts: the open 
circles represent data for alumina-based aerogel catalysts, and the filled 
circles represent data for the following non-aerogel alumina-based 
catalysts: C represents data for CATA SB; F represents data for fumed 
alumina; H represents data for the hybrid alumina catalyst prepared as 
described in Footnote 7 of Table VI; and K represents data for KETJEN.RTM. 
NFF. The activity data illustrated in FIGS. 3A, 3B and 3C pertains to 
ethylene polymerization data obtained in the apparatus of Example 19 at a 
nominal total pressure of 65 psia with the various above-identified 
TiCl.sub.4 -impregnated alumina catalysts. The physical properties plotted 
versus activity in FIGS. 3A, 3B and 3C were determined as follows: bulk 
densities were measured after TiCl.sub.4 impregnation; pore volumes were 
measured before calcination; and BET surface areas were measured before 
calcination. Based on the increase (by a factor of about 10) in the bulk 
density for fumed alumina after TiCl.sub.4 impregnation, it is believed 
that the pore volume for fumed alumina after calcination and TiCl.sub.4 
impregnation would be less than about 3 cm.sup.3 /g. 
Example 20 
Preparation of a Sb/Al co-aerogel was conducted, as described in Example 2, 
with the following modification. A solution was formed from 0.42 g, 1.23 
mmol of antimony tri(sec-butoxide), 18.31 g, 0.0744 mol of aluminum 
tri(sec-butoxide), 400 g of sec-butanol, and 8.3 g of H.sub.2 O was added, 
with stirring, to effect precipitation and the mixture so formed was 
heated to 75.degree. C. The mixture was allowed to cool to room 
temperature and filtered to give a wet cake that was dispersed in about 85 
g of methanol. Super-critical venting of solvent from the co-aerogel was 
conducted as described in Example 1. The following physical properties of 
the recovered co-aerogel (4.54 g) were measured: bulk density was 0.05 
g/cm.sup.3 ; BET surface area was 485.4 m.sup.2 /g; pore volume (Hg) was 
4.74 cm.sup.3 /g; elemental analysis: 30.8% Al; 2.89% Sb; 6.78%C; 2.96%H. 
x-ray analysis showed the following morphology: amorphous phase plus 
aluminum hydroxide methoxide. The physical properties after calcination at 
700.degree. C. (O.sub.2) and impregnation with TiCl.sub.4 are listed in 
Table VII. 
Example 21 
The preparation of a Ca/Al co-aerogel was conducted as described in Example 
20 with the following modifications. A solution was formed from 18.32 g, 
0.0745 mol of aluminum tri(sec-butoxide) and 400 g of sec-butanol. 
Precipitation was effected, with stirring, at room temperature by addition 
of 8 mL of an aqueous solution containing 0.89 g, 3.77 mmol of Ca 
(NO.sub.3).sub.2 4H.sub.2 O and 0.7 g (NH.sub.4).sub.2 CO.sub.3. 
The wet cake was filtered, dispersed in about 85 g of methanol, and the 
methanol was super-critically vented as described in Example 20. The 
following physical properties of the Ca/Al co-aerogel were measured: bulk 
density 0.045 g/cm.sup.3 ; BET surface area 389 m.sup.2 /g; pore volume 
(Hg) 5.8 cm.sup.3 /g elemental analysis 32.45% Al; 1.62% Ca; 6.57%C; 
2.6%H. The X-ray pattern suggested the presence of an amorphous phase plus 
aluminum hydroxide methoxide. The physical properties after calcination at 
700.degree. C. (O.sub.2) and impregnation with TiCl.sub.4 are listed in 
Table VII. 
Example 22 
The procedures of Example 21 were followed except that 0.54 g of gallium 
tri(sec-butoxide) was dissolved in the 8 g of deionized water that was 
used for hydrolysis of the aluminum tri(sec-butoxide). Solid amounting to 
4.58 g, having a bulk density of 0.03 g/cm.sup.3 was isolated. The X-ray 
pattern indicated the presence of amorphous and aluminum hydroxide 
methoxide components. The surface area and pore volume were 7/8 cm.sup.2 
/g (BET) and 5.14 cm.sup.3 /g (Hg porosimetry), respectively, Elemental 
Anal: (w%): 1.49 Ga, 30.25 Al, 7.8C, 2.84H. 
TABLE VII 
______________________________________ 
Activity in Low Pressure Ethylene Polymerization 
Physical Properties for Alumina Cogel 
Catalysts Impregnated with TiCl.sub.4 
______________________________________ 
Catalyst.sup.a 
Bulk Density.sup.b 
Pore Volume.sup.c 
Support (g/cm.sup.3) 
(cm.sup.3 /g) 
______________________________________ 
Al.sub.2 O.sub.3 aerogel 
.05 5.38 
of Example 2 
Sb.sub.2 O.sub.3 /Al.sub.2 O.sub.3 
Aerogel of Ex. 20 
.052 6.08 
CaO/Al.sub.2 O.sub.3 
Aerogel of Ex. 21 
.045 7.8 
Ga.sub.2 O.sub.3 /Al.sub.2 O.sub.3 
Aerogel of Ex. 22 
.03 4.85 
______________________________________ 
Catalyst.sup.a 
Surface Area Activity 
Support (m.sup.2 /g) (g PE/g cat/h/atm C.sub.2 H.sub.4) 
______________________________________ 
Al.sub.2 O.sub.3 aerogel 
498 236.sup.d 
of Example 2 
Sb.sub.2 O.sub.3 /Al.sub.2 O.sub.3 
Aerogel of Ex. 20 
440 289.5.sup.e 
CaO/Al.sub.2 O.sub.3 
Aerogel of Ex. 21 
409 250.sup. 
Ga.sub.2 O.sub.3 /Al.sub.2 O.sub.3 
Aerogel of Ex. 22 
472 235.sup.f 
______________________________________ 
Footnotes for Table VII 
.sup.a Low Pressure Ethylene Polymerization at 85.degree. C., 22.5 psia, 
155 kPa of C.sub.2 H.sub.4 and 33.75 psia, 232 kPa of H.sub.2 in 225 mL 
heptane and with triisobutylaluminum. 
.sup.b Bulk Density measured before calcination at 700.degree. C. in 
O.sub.2. 
.sup.c Valves for Pore Volume and BET Surface Area measured after 
calcination at 700.degree. C. in 
.sup.d Average of two runs having activities of 224 and 247 conditions: 
85.degree. C., 22.5 psia, 155 kPa C.sub.2 H.sub.4 and 33.75 psia, 232 kPa 
H.sub.2. 
.sup.e Average of two runs having activity = 284 and 295. 
.sup.f Average of two runs having activities of 248 and 222 conditions: 
85.degree. C., 22.5 psia, 155 kPa C.sub.2 H.sub.4 and 33.75 psia, 232 kPa 
H.sub.2. 
Example 23 
The following aerogels are prepared in accordance with the procedures of 
Examples 20-22, excepting that 5 mole percent of the hydrolyzable 
non-alumina compound listed in Column B is added to 95 mole percent of the 
hydrolyzable aluminum compound listed in Column A in the solvent 
indicated. Supercritical venting is from methanol. 
______________________________________ 
Column A Column B Solvent 
______________________________________ 
Al(iC.sub.3 H.sub.7 O).sub.3 
Mg(CH.sub.3 CO.sub.2).sub.2 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Mg Cl.sub.2 isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Mg(C.sub.2 H.sub.5 O).sub.2 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Mg(C.sub.6 H.sub.13).sub.2 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Si(OCH.sub.3).sub.4 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Zn(C.sub.9 H.sub.19 CO.sub.2).sub.2 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Zr(n-C.sub.3 H.sub.7 O).sub.4 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Cr(CH.sub.3 CO.sub.2).sub.3 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Ba(C.sub.9 H.sub.19 CO.sub.2).sub.2 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
(NH.sub.4).sub.2 Ce(NO.sub.3).sub.6 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
La(NO.sub.3).sub.3 6H.sub.2 O 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
LaCl.sub.3 6H.sub.2 O 
isopropanol 
Al(iC.sub.3 H.sub.7 O).sub.3 
Ti(i-C.sub.3 H.sub.7 O).sub.4 
isopropanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Mg(CH.sub.3 CO.sub.2).sub.2 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Mg Cl.sub.2 sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Mg(C.sub.2 H.sub.5 O).sub.2 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Mg(C.sub.6 H.sub.13).sub.2 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Si(OCH.sub.3).sub.4 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Zn(C.sub.9 H.sub.19 CO.sub.2).sub.2 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Zr(n-C.sub.3 H.sub.7 O).sub.4 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Cr(CH.sub.3 CO.sub.2).sub.3 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Ba(C.sub.9 H.sub.19 CO.sub.2).sub.2 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
(NH.sub.4).sub.2 Ce(NO.sub.3).sub.6 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
La(NO.sub.3).sub.3 6H.sub.2 O 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
LaCl.sub.3 6H.sub.2 O 
sec-butanol 
Al(sec-C.sub.4 H.sub.9 O).sub.3 
Ti(i-C.sub.3 H.sub.7 O).sub.4 
sec-butanol 
______________________________________ 
The aerogels so formed are calcined and impregnated with TiCl.sub.4 as 
described in Example 2 to form catalysts useful for polymerization of 
ethylene. Physical properties and activities of these catalysts are 
expected to be similar to those listed in Table VII. 
Example 24 
The procedure of Example 23 is followed excepting that 15 weight percent 
(based on metal oxide) of materials listed in Column B and 85 weight 
percent (based on Al.sub.2 O.sub.3) of materials listed in Column A are 
used. Similar results are expected. 
Example 25 
The procedure of Example 23 is followed excepting that 35 weight percent 
(based on metal oxide) of materials listed in Column B and 65 weight 
percent (based on Al.sub.2 O.sub.3) of materials listed in Column A are 
used. Similar results are expected.