Olefin polymerisation uses catalysts based in pi-arene complexes of lanthanide metals in particular such catalysts supported on hydrophobic or hydroxylic surfaces particularly of alumina or silica halide surfaces particularly magnesium chloride. Such catalysts will polymerise ethylene and also propylene to give a largely isotactic polymer without using an electron donor to enhance stereo regularity. They also do not require co-catalysts to activate polymeriscation.

This invention relates to the polymerisation of olefins, in particular 
1-olefins such as ethylene and/or propylene, using as catalysts pi-arene 
complexes of lanthanide metals and to supported pi-arene complexes of 
lanthanide metals which are especially suitable as catalysts in such 
polymerisations. 
Pi-complexes of aromatic compounds (arenes) and lanthanide metals in which 
the atoms of the lanthanides are in the zero valence state are known, for 
example, from published European Patent Specification No. 0295829 A which 
describes a range of such compounds and their use in chemical vapour 
deposition techniques. 
The present invention is based on our discovery that pi-arene complexes of 
lanthanide metals carried on supports, particularly inorganic oxide or 
halide supports, are active as olefin polymerisation catalysts. 
Accordingly, the present invention provides an olefin polymerisation 
catalyst comprising a pi-arene complex of one or more lanthanide metals 
carried on or reacted onto the surface of a solid support. 
The invention includes a method of polymerising at least one olefin monomer 
which comprises bringing the olefin monomer(s) into contact with a 
catalytic amount of an olefin polymerisation catalyst comprising a 
pi-arene complex of one or more lanthanide metals carried on or reacted 
onto the surface of a solid support, thereby bringing about polymerisation 
of the olefin monomer(s). 
The invention further includes the use of an olefin polymerisation catalyst 
comprising a pi-arene complex of one or more lanthanide metals carried on 
or reacted onto the surface of a solid support, as a catalyst in the 
polymerisation or copolymerisation of olefins. 
The pi-arene complexes of lanthanide metals used in this invention are 
materials in which occupied pi-orbitals (bonding or antibonding) of an 
arene molecule interact with the available outer orbitals of a lanthanide 
metal atom. Most usually the arene is a carbocylic, typically a benzenoid, 
arene compound. 
Particularly useful arenes include hydrocarbyl substituted benzenes in 
which there can be one or more, for example two or three, such hydrocarbyl 
substituents. Suitable benzenoid arene compounds can be selected from 
those of the formulae (Ia): 
##STR1## 
where 
R.sub.1 is a hydrocarbyl group; 
R.sub.2 and R.sub.3 are each independently a hydrogen atom or a hydrocarbyl 
group; and 
R.sub.4 is a hydrogen atom or, when R.sub.2 and R.sub.3 are both hydrogen 
atoms, a hydrocarbyl group. 
Thus arenes of the formula I(a) include monohydrocarbyl substituted, 1,3- 
and 1,4-di-hydrocarbyl substituted and 1,3,5-trihydrocarbyl substituted 
benzenes. Further suitable arenes include compounds selected from those of 
the formula (Ib): 
##STR2## 
where 
each R.sub.5 is a hydrocarbyl group; 
n is 0, 1 or 2; and 
A is a group of one of the formulae: 
##STR3## 
where 
R.sub.6 is a hydrocarbyl group; 
m is 0, 1 or 2; and 
l is 0 or 1. 
In particular, arenes of the formula (Ib) include naphthalene and 
hydrocarbyl substituted naphthalenes. 
Hydrocarbyl substituents in the arenes of the pi-complexes, used in this 
invention are particularly alkyl groups typically C.sub.1 to C.sub.10, 
more usually C.sub.1 to C.sub.6, alkyl groups e.g. methyl, ethyl, propyl, 
iso-propyl, butyl, iso-butyl and tert-butyl groups. Particularly suitable 
arenes include toluene and 1,3,5-tri-tert-butyl benzene (TTBB). 
Most usually, the pi-complex will be a 2:1 (molecular) arene:lanthanide 
complex. We believe that such complexes exist primarily as 
arene:lanthanide:arene `sandwich` compounds. In such 2:1 pi-complexes the 
lanthanide metal atom is (formally) in the zeroth valence state. It is 
certain such complexes that form the subject matter of EP 0295829 A 
referred to above. Accordingly, the 2:1 complexes will typically have the 
formula (II): 
EQU (An) (Ld) (An) (II) 
where 
each An is independently a molecule of an arene, particularly one of 
the formula (Ia) or (Ib) set out above; and 
Ld is an atom of a lanthanide metal. 
The lanthanide metal used in the complex can be any lanthanide metal from 
lanthanum (La), Atomic No 57) to Lutetium (Lu, atomic No 71) in the 
Periodic Table. Particularly suitable complexes include those of Neodynium 
(Nd, Atomic No 60), Samarium (Sm, Atomic No 62), Gadolinium (Gd, Atomic No 
64), Erbium (Er, Atomic No 68) and Ytterbium (Yb, Atomic No 70). To date 
we have obtained especially good results using complexes of Gd and Er, in 
particular with toluene and TTBB. 
The pi-arene complexes of lanthanide metals can be synthesized by methods 
generally known in the art. Conveniently they can be made by metal vapour 
synthesis as generally described in J. Chem. Soc. (Dalton), 1981, 1938 as 
referred to in EP 0295829 A, the disclosures of both these documents being 
incorporated herein by reference. The pi-complexes are typically highly 
coloured compounds having strong absorptions in the UV-visible region of 
the spectrum. They are also very reactive and need suitably careful 
handling, keeping them well separated from reactive materials that might 
destroy them e.g. water or air. It may be of benefit to keep them 
relatively cold to reduce the likelihood of undesired reactions. 
According to the invention, particularly good olefin polymerisation 
catalysts can be obtained by supporting the catalytic pi-arene lanthanide 
complexes on a solid support material. The support material will usually 
be particulate and often, but not necessarily porous or spongiform to 
provide a large surface area for absorption or adsorption of the catalyst 
pi-complex and thus a large number of available catalytic sites. The 
support used in the supported catalysts of this invention can be entirely 
inert to the catalytic properties of the complex and polymeric materials 
such as polypropylene, polystyrene and PEEK (polyetheretherkstone). 
However, we have obtained particularly good results by using inorganic 
halides and oxides as supports. Among halides, alkaline earth metal 
halides are useful, especially magnesium chloride which itself may be 
provided as fine crystallites deposited on a base support e.g. of silica 
or alumina. 
Among oxides those having hydrophilic and in particular hydroxylic surfaces 
are especially useful. Examples of such supports include silica, silicate 
and aluminosilicate materials including clays, and magnesium, aluminum, 
zirconium and titanium oxides. Substantially pure silica and unhydrated 
aluminum oxide (alumina) are especially useful and the use of these 
materials as catalyst supports forms a specific and particularly 
beneficial aspect of the invention. 
The pi-arene complexes used in making supported catalysts of the invention 
are reactive towards inorganic halide and oxide surfaces and, thus, the 
practical supported catalysts will not have `sandwich` compounds of the 
type described above as such on their surface. The exposed surfaces of 
oxides, including silicates and aluminosilicates, typically have hydroxyl 
groups on them. This is a result of the high reactivity of the exposed 
hydrogen atoms which pick up hydrogen from any available water, or other 
similar material, to form surface hydroxyl groups. We do not definitely 
know what reaction (or reactions) occur(s) between the pi-complex and the 
surface of the support but where the surface has, for example, surface 
hydroxylation we think it likely that the lanthanide metal will react with 
the O--M group to form a group: 
##STR4## 
This is a net insertion reaction with (starting with a 2:1 
arene:lanthanide complex) loss of one molecule of arene. The pi-complexes 
are so reactive that we believe that they will readily undergo further 
reactions with closely adjacent hydroxyl groups on the surface of the 
support to form species which are inactive or much less active as olefin 
polymerisation catalysts. Thus, to maximize the number of active catalyst 
sites it is desirable to restrict the total number of hydroxyl groups on 
the surface of the support. This can be done by heating the support to 
reduce surface hydroxylation by driving off water or using suitable 
chemicals to react with and, thus, effectively remove a proportion of the 
surface hydroxylation. Oxide supports, as commercially available 
materials, such as silica and alumina can contain bound water as `water 
crystallisation` (whether or not the oxides are themselves arystalline or 
amorphous) as well as having surface hydroxylation. Heating silica or 
alumina e.g. under vacuum, to temperatures above about 300.degree. C. e.g. 
350.degree. to 500.degree. C., for some hours e.g. 2 to 10 hours, seems to 
remove `water of crystallisation` and some surface hydroxylation and 
significantly improves the properties of the catalyst of the invention 
made using the support. Event higher temperatures e.g. up to 800.degree. 
C. or up to 1000.degree. C., may be beneficial in reducing hydroxylation 
further. Of course, complete removal of hydroxylation would not be 
beneficial because it would remove binding sites for the lanthanide 
complex where the support is alumina, it will usually be desirable to 
avoid heating it to a temperature high enough to cause a phase change e.g. 
as can take place from gama-alumina to alpha-alumina at temperatures above 
about 800.degree. C. 
On halide supports such as MgCl.sub.2, we believe that the pi-complexes 
react with the surface but we are not sure whether the reaction is with 
hydroxyl species on the surface of the halide or with the halide itself. 
Suitable halide supports can be made by methods analogous to those used to 
prepare similar such supports from Ziegler-Natta catalysts based on Ti(TV) 
species but, of course, avoiding the use of Ti e.g. as TiCl.sub.4. Thus, 
to generate MgCl.sub.2 supported on silica the support making generally 
described in EP 0371664 A can be used but halogenating the Mg species 
using dry pure HCl rather than TiCl.sub.4. Thus, the silica can be treated 
with a magnesium alkyl e.g. Mg butyl and then with a suitable carboxylic 
acid followed by treatment with HCl. 
That a significant reaction is occurring between the surfaces of these 
supports and the pi-complexes it plain as there is a significant colour 
change. The typically red, blue, green or purple colour of the complex (in 
solution) becomes typically a dark brown colour on oxide supports (silica 
or alumina) and a purple colour on magnesium chloride supports. Further 
the colour of the solution is rapidly removed by reaction of the 
pi-complex with the surface. 
The dimensions of the supported catalyst are primarily determined by the 
support. Generally particles of catalyst support will be in the range 20 
to 100 .mu.m although where polymers are being used as supports the 
particles may be somewhat larger e.g. up to about 1 mm. Especially where 
the support is silica or alumina, or these materials are used as a base 
support e.g. for MgCl.sub.2, the support will typically be porous with a 
specific surface area of from 10 to 2000 more usually 200 to 1000 m.sup.2 
g.sup.-1. 
The supported catalysts can be made straightforwardly by dispersing the dry 
support in a solution of the pi-complex in a suitable volatile solvent 
removing excess liquid and evaporating off the solvent from the treated 
support. The supported catalysts are not as reactive as the pi-complexes 
themselves but are sensitive to moisture etc. and suitable handling 
techniques will be used as are known in the art. 
The processes and catalysts of the invention can be used to polymerise or 
copolymerise olefins. Usually the, or at least one of the, olefin 
monomer(s) is a 1-olefin typically a low molecular weight 1-olefin such as 
ethylene and/or propylene. The polymerisation can be a homopolymerisation 
to give, for example, polyethylene or polypropylene or a copolymerisation 
to give, for example, an ethylene/propylene copolymer, or a copolymer of 
ethylene and/or propylene with a higher olefin e.g., 1-heptene, or a diene 
such as butadiene to give an EPDM type ternary copolymer. Polymerisation 
reactions catalysed with pi-arene complexes of lanthanide metals according 
to the invention do not require the presence of the co-catalysts or 
activators such as aluminium alkyls or halo-alkyls, as are typically 
needed with conventional transition metal catalysts such as those based on 
vanadium, chromium and titanium, rather the polymerisation reaction seems 
to occur freely in the presence of the pi-complex and the olefin monomer. 
However, the presence of such co-catalysts or activators can be tolerated 
by the catalysts of this invention although usually incurring some loss of 
activity. 
The polymerisation can be carried out in the presence of an organic solvent 
or diluent (so-called `diluent` processes), with the olefin monomer in the 
liquid phase providing the reaction medium (so-called `bulk` processes) or 
with the olefin monomer, at least partly, in the gas phase (so-called `gas 
phase` processes) in which the reactor bed of growing particles of polymer 
is either fluidised by the gaseous monomer or is stirred to ensure good 
contact between the monomer and catalyst. 
The reaction conditions for successful catalytic olefin polymerisation in 
this invention do not need to be extreme. We have successfully carried out 
polymerisation at ambient temperature and pressure. Particularly at 
ambient pressure the effective concentration of olefin monomer(s) such as 
ethylene (where this is being polymerised) is low and the use of super 
ambient pressure can be used to speed up polymer production. In practical 
industrial olefin polymerisation processes the pressures used are such as 
to bring the reaction temperatures close to, or even below in the case of 
`bulk` processes, the dew point of the olefin monomer. Again to increase 
polymer production elevated temperatures up to about 100.degree. C., more 
usually up to about 80.degree. C. are commonly used. At 80.degree. C. 
reaction pressures of the order of about 32 bar will typically be used. 
Such conventional temperatures and pressures can be used in the present 
invention. 
The polymers produced by the method of this invention typically have high 
molecular weights comparable with those of currently available polyolefin 
polymers. A difference from such typical polymers is that the products of 
this invention tend to have a much wider range of molecular weights (as 
measured by gel permeation chromatographic polydispersity) than is typical 
with current catalysts. This can be advantageous in deliberately 
broadening the molecular weight range of polyolefins, especially 
polypropylene, e.g. by using combination catalysts. 
The catalysts of the invention are reactive towards hydrogen such that 
hydrogen can be used as a chain transfer agent to modify the average 
molecular weight of the polymer product in olefin, particularly propylene, 
polymerisation reactions. 
The polymerisation of propylene according to the invention gives a 
substantially isotactic polymer without the electron donors that are 
needed to produce isotactic material using currently available 
Ziegler-Natta catalysts such as those based on Ti(IV) species. The 
polymerisation of propylene using the catalysts of the invention forms a 
specific aspect of the invention.

The invention is illustrated by the following Examples. All parts and 
percentages are by weight unless otherwise stated. 
MATERIALS 
pentane 
was purified to remove olefins using sulphuric acid, thoroughly washed with 
water to remove acid residues and dried firstly over calcium chloride and 
then by distillation over Na/K alloy and stored in a Schlenk vessel over a 
potassium mirror under nitrogen. 
n-heptane 
was purified and stored as described for pentane. 
alumina 
used as support was dried in a quartz tube under vacuum (10.sup.-3 mbar) at 
550.degree. C. for 4 hours. The vacuum was maintained during cooling and 
the material stored until use in the evacuated tube. Two grades of 
commercially available material were used Degussa grade C and Ketchen 
grade L. 
magnesium chloride 
used as support was prepared by ball milling under dry nitrogen at ambient 
temperature for two hours and the product stored until used under 
nitrogen. 
ethylene and propylene 
were polymerisation grade materials dried before use by passing through a 
drying column of 4A molecular sieves. Propylene was further purified 
immediately before use by passing through a trap containing potassium on 
glass wool. 
metal pi-complexes 
the pi-complexes used in the Examples were made by metal vapour synthesis 
using the technique generally described in J. Chem. Soc. (Dalton), 1981, 
1938 as illustrated by the synthesis of neodynium di(TTBB) as follows: 
In a rotary metal vapour synthesis apparatus (from Torrovap Industries 
Inc., Ontario, Canada) metallic neodymium was evaporated using electron 
beam heating. This vapour was co-condensed with TTBB vapour at 
-195.degree. C. After warming to room temperature under dry argon, the 
product was dissolved in dry n-heptane removed from the reactor using an 
internal transfer tube and collected in a Schlenk tube as a deep burgundy 
red coloured solution. The solution was filtered through cellite to remove 
solid impurities. The solution had a measured maximum absorption at 535 
nm. This is consistent for the formation of the 2:1 TTBB:neodymium 
pi-complex. 
Further pi-complexes as set out below were also made by this method but 
substituting the appropriate starting materials. The pi-complexes, their 
colours and absorption maxima are as follows 
______________________________________ 
pi-complex colour UV-vis. abs. mas (nm) 
______________________________________ 
Nd di(TTBB) deep burgundy 
535 
Nd ditoluene 
dark brown 
Sm di(TTBB) deep green 
Gd ditoluene 
blue-black 
Gd di(TTBB) deep purple 548 
Er di(TTBB) red 500 
______________________________________ 
EXAMPLE S1 
Preparation of Supported Catalyst 
Neodymium di(TTBB) supported on silica (catalyst S1) was made by adding a 
solution of about 0.8 mmole of the Nd di(TTBB) pi-complex, made as 
described above, under dry argon to a slurry of 5 g of silica (previously 
dried overnight at 350.degree. C.) in dry n-heptane. The colour of the 
solution was discharged virtually instantaneously and the silica assumed a 
uniform dark brown colour. Samples of 1 g of this product were used 
slurried in n-heptane in performing polymerisations. 
EXAMPLES S2 TO S10 
Using the same general method as described in Example S1, the following 
supported catalysts were made but substituting the corresponding 
pi-complex and/or support for the materials used in Example S1. 
______________________________________ 
Supported on silica 
S2 samrium di(TTBB) 
S3 gadolinium ditoluene 
S4 gadolinium di(TTBB) 
S5 erbium di(TTBB) 
Supported on alumina 
S6 neodymium di(TTBB) 
S7 gadolinium di(TTBB) 
S8 erbium di(TTBB) 
Supported on magnesium chloride 
S9 gadolinium di(TTBB) 
S10 erbium di(TTBB) 
______________________________________ 
The alumina supports were of gamma-alumina obtained from Degussa which had 
been dried at 500.degree. C. for at least 3 hours. Magnesium chloride 
supports were made by ball milling anhydrous catalyst grade material for 2 
hours and the resulting powder was used as the support. 
In addition to the supported catalysts four pi-complexes were prepared for 
use as unsupported catalysts for comparison under the codes U1 to U4: 
______________________________________ 
U1 samarium di(TTBB) 
U2 gadolinium ditoluene 
U3 gadolinium di(TTBB) 
U4 erbium di(TTBB) 
______________________________________ 
EXAMPLES P1 TO P17 
Ethylene polymerisation reactions were carried out using the catalysts U1 
to U4 and S1 and S10. The following general route was used. 
A volume of catalyst slurry containing 1 g of supported catalyst was 
transferred via syringe to a clean dry 250 ml glass vessel containing 100 
ml dry deoxygenated n-heptane or toluene (distilled over sodium wire) and 
through which was passed a continuous flow of dry ethylene at atmospheric 
pressure. The suspension was agitated and allowed to react for 1 hour at 
ambient temperature. The suspension gradually thickened and decolourised 
as polymer growth occured. The contents of the vessel were filtered, 
washed with toluene and then heptane and thoroughly dried prior to 
weighing for yield. The polymer collected was identified as polyethylene 
by infra-red spectroscopy. The catalyst activity calculated from the 
polymer yield and the lanthanide analysis as g (polymers) mmol.sup.-1 
(lanthanide metal) hour.sup.-1 is the average activity during the 
reaction. The results are set out in Table 1 below. 
EXAMPLES P18 
Propylene polymerisation reactions were carried out using the catalyst S8. 
The following general route was used. 
An existing 4 liter capacity stainless steel autoclave equipped with an 
outer steam/water heating/cooling jacket and an anchor stirrer was washed 
with a solution of triethyl aluminium in an inert hydrocarbon diluent 
(alkane fraction nominal boiling at 180.degree. C.) overnight at 
65.degree. C. to remove inhibitors. The traces of aluminium compound were 
removed by washing with diluent and the gas space than purged at 
55.degree. C. by admitting 300 mls of polymerisation grade liquid 
propylene and venting down slowly to atmospheric pressure. The catalyst 
component, about 5 g, as a slurry in heptane was then injected using a 
syringe through a serum cap on the top cover entry valve to the autoclave, 
1.5 liters of liquid propylene were immediately added to the autoclave and 
the temperature was maintained at 65.degree. C. with stirring. Unreacted 
propylene was removed by evaporation and the autoclave discharged after 
nitrogen purging. The slurry collected was filtered, washed with heptane 
and dried. 
Infra-red diffuse refluctance spectroscopy detected an organic component 
which was identified as predominantly isotactic polypropylene. 
EXAMPLES P19 TO P21 
Further runs were carried out using various supported catalysts. 
S7--reaction time of 1 hour. 
Infra-red diffuse reflectance spectroscopy detected an organic component 
which was identified as predominantly isotactic polypropylene. Raman 
spectroscopy using a 514 nm argon laser line showed bands at 1459, 1436, 
1329, 1358 and 398 wave numbers indicating the presence of isotactic 
polypropylene. 
S9--reaction time 1 hour (using 4 g supported catalyst containing 40 mg of 
gadolinium suspended in 200 ml n-heptane. 
The product collected from this experiment was suspended in 300 ml of 4M 
aqueous sulphuric acid and stirred at ambient temperature for 4 hours. On 
settling the acid layer was removed and replaced with water. After 
stirring the resulting slurry thoroughly to remove residual acid the 
suspension was filtered and the solid polymer recovered. 
A sample of the product was pressed into a disc for analysis by infra-red 
spectroscopy. The product was identified as predominantly isotactic 
polypropylene. A small quantity of the product was dissolved in 
methylnaphthalene and subjected to gel permeation chromatography. This 
material gave an average molecular weight of 700000 D and had a 
polydispersity of 18.2. 
S8--reaction time 2.5 hours. 
Infra-red diffuse reflectance spectroscopy detected an organic component 
which was identified as predominantly isotactic polypropylene. 
A small quantity of the product was dissolved in methylnaphthalene and 
subjected to gel permeation chromatography. This material gave an average 
molecular weight of 200,000 D and had a polydispersity of 11.1. 
EXAMPLES S11 to S17 
Preparation of Supported Catalyst 
These preparations were carried out in a nitrogen filled glove box fitted 
with a recirculating drying and deoxygenating train. 
A sample (ca. 25 mg) of a metal bisTTBB complex was placed in a 500 ml 
thick walled glass tubular reactor, pentane (100 ml) was added and the 
mixture stirred magnetically to form a solution. A portion (ca. 250 mg) of 
support was weighed in the glove box and added to the stirred solution in 
the reactor. Further pentane (ca. 30 ml) was used to wash any residual 
solid on the walls of the reactor into the solution. 
EXAMPLE P22 TO P28 
The reactor containing the supported metal complex was used to polymerise 
propylene as follows. The reactor lid (having a pressure gauge, 
temperature probe and a closed inlet valve) was fitted onto the top of the 
reactor rube and the sealed assembly was removed from the glove box and 
connected to the reactor manifold. Air in the system in the region of this 
connection was removed using a vacuum line and the reactor was pressurised 
to polymerisation pressure using propylene. 
The suspension in the reactor vessel was stirred for a period of one hour 
at reaction temperature with the reactor pressure automatically maintained 
by a control valve between the reactor and the reservoir. No temperature 
control was applied during reaction. At the end of the reaction period the 
reactor was disconnected from the manifold and vented in a fume cupboard. 
The polymer product was recovered by filtration or evaporation to dryness 
and then drying under vacuum 10 mbar at 60.degree. C. for ca. 2 hours. 
The nature of the metal complex and the support used in Examples S11 to S17 
and the reaction conditions used in Examples P22 to P28 are summarized in 
Table 2a below and the catalyst activities assessed from the yield of 
polymer and properties of the polymer produced are set out in Table 2b 
below. 
The spectra of the polymers obtained in Examples P22 to P28 by recorded 
using a Raman laser microscope (488 nm) indicated that all the polymers 
were substantially isotactic. 
The polymer obtained in Example P25 was further investigated. Integration 
if the isotactic methyl peak (maxm) in the .sup.13 C NMR spectrum (FX 270 
MHz spectrometer on a solution in p-dichlorobenzene) as compared with all 
other methyls suggested that the polymer was 40.32 isotactic and the 
spectrum showed no sign of head to head polymerisation of propylene units. 
TABLE 1 
______________________________________ 
Activity 
Ex (g.mmol.sup.-1 
No Catalyst Medium .hr.sup.-1) 
______________________________________ 
P1 S1 heptane 6.07 
P2 S6 heptane 9.52 
P3 U1 heptane 2.24 
P4 S2 heptane 2.94 
P5 U2 toluene 2.60 
P6 S3 toluene 11.59 
P7 U3 toluene 3.56 
P8 S4 toluene 1.97 
P9 S7 toluene 0.79 
P10 U3 heptane 8.13 
P11 S4 heptane 17.02 
P12 S7 heptane 57.83 
P13 S9 heptane 29.26 
P14 U4 heptane 6.49 
P15 S5 heptane 26.21 
P16 S8 heptane 94.38 
P17 S10 heptane 38.71 
______________________________________ 
TABLE 2a 
______________________________________ 
Reaction Conditions 
Ex Loading 
Pressure 
Temp. 
No Metal Support (%) (bar) (.degree.C.) 
______________________________________ 
S11 Er Alumina 2.6 5.0 24 
S12 Er Alumina 9.4 5.0 65 
S13 Er Alumina 8 5.0 24 
S14 Er Alumina 10 8.5 24 
S15 Er Mg chloride 10 8.5 24 
S16 Gd Alumina 4.7 5.0 24 
S17 Gd Alumina 2.3 5.0 24 
______________________________________ 
TABLE 2b 
______________________________________ 
Head 
Supported to 
Ex Metal Activity Isotactic 
Head 
No Complex (g.mmol.sup.-1) 
(%) % 
______________________________________ 
P22 S11 2.0 
P23 S12 1.0 
P24 S13 0.5 
P25 S14 1.0 40.3 0 
P26 S15 4.6 
P27 S16 0.2 
P28 S17 0.2 
______________________________________