CA1077509A - Organo-metallic compounds of aluminum as components of catalysts used for the polymerization of olefins - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE:
There are disclosed new starting components for use in preparing catalysts for the polymerization and co-polymerization of olefins. The new staring components are compounds having the general formulae R2AlOR" and/or RA1 (OH")2' in which R represents alkyl radicals containing 1 to 12 carbon atoms and R" has one of the following struc-tures:

(I) or (II)

Description

` ` ~L0775~9 It is known to polymerize ethylene and alpha-olefin~
to high polymer yields in contact with catalysts prepared from tran~ition metal ~alt~ and organometallic compounds of metals belonging to Groups I to III inclu~ive of the Mendel-yeev Periodic Table, and preferably from ~uch ca-talysts pre-pared from the tran~ition metal salts and or~sanometallic compounds OI aluminum,.
It i~ al~o known to polymerize ethylene and alpha-olefins to high polymer yields in contact with catalysts pre-pared from organometalllc compounds o~ metals belonging to aroup6 I-III inclu~ive o~ the Mendelyeev Periodic Table, pre-ferably such ¢ompound~ of al~minum, and the products ob-tained by contaoting a titanium compound with a mag~esium compound in an active ~tate.
Although the or~anometallic compounds o~ aluminum u~ed as o~e oomponent in preparing the known cataly~ts ha~e been, in praoti~e and for the most part, $he Al trialkyls and dial~yl Al halides, organometallic compound~ of Al of the type R2AlORI or RAl (OR~)2 have been mentioned generically.
However~ the cataly6-ts obtained from such compounds a~
R2AlORI a~ the organometallic component are either who~ly inactive in the polymeri~ation o~ olefins or exhibit low activity only at high.temperature~ above 100C.
Example~ of such Al compound~ of that type, R2AlOR~, are those in which R' i~ a~ alkyl radical ~uch a~ methyl, ethyl9 propyl, etc. tl or aul aryl radical 8UC~1 as p~enylO
Organometallic compound~ of ~1 of the formula RAl (ORI 32 gield catalyst~3 vvhich are quite inactive in the polymerization of olefin~9 even at high temperature~30 3 An ob~ect of the pre~eIlt invention wa~ to provide ne~ catalyst-forming compcnents havillg the formula R2AlOR"
and/or P~l (OR")2 w~ich, with tran~ition me~al compownds, ~ r ';~' ~;., lC~77509 yield.-~cataly~t~ which are h$gh1y active in the polymerization and copolymeri~ation of olefin~.
This a~d other obae~ts are achieved by the present invention in accordance with which w~ have fownd it po~ible to obtain catalyæ-ts one ~tarting componenti of u~ioh corre~-ponds to the formula R2AlOR" and/or RAl (OR")2, provided -that the radical R" i8 ~uitab~y sel~ctad ~d correspond~ to one of the following structures: :

lI ~ \ 4 or (II) 6 `~ 3 Surpri~ingly9 we have f~und that when R" in the com-pounds R2AlOR~ and/or RA1 (ORn)2 corresponds to formulae I or II, and R is an alkyl gxoup containing from 1 to 12 oar-~ bon atom~, inclusiYe, the cataly~t resulking from the oom-- bination of the compounds R2AlOR~' and/or RAl (OR"32 with - txan~ition metal compounds9 exhibit an activity in the po lymerization and copolymerization of olefins, and in particular o~ ethylene and/or alpha-olefin~, which i5 similar to that of tha catalysts p.repared ~rom Al trialkyl~ at the temperature~
: ~ormally used in commercial operations.
In the R2AlOR~ and RAl (OR")2 in ~hlch R" has structure (I) or ~II); there are pre~ent9 in position 2 and 6 in ~tructu~e (I) and in position 2, and optionally also in position 8, in structurc (II), radical~ at lea~t one of which i~ capable of proYiding a ~teric hindrance higher than that o~ th0 group -C~ 5 and, when th~ radicals in said two position~ are di~ferent, the other radical being an alkyl radical ~uch as methyl, ethyl9 propyl and the like, or an . aryl radical such a~ phenyl.
Th~ radicals which ~xhibit a ~t~ric hindranc~ higher

-2 .

`" ` 1~77S~

than that of ~C2H5 pre~ent in either one or both of the t~o po~ition~ mentioned, are ~enarally alkyl radicals and pre-ferably branched alkyl~ containing 3 or more carbon atom~.
. Examples of ~uch radicals are: -iC3H7; -n.C4~9; ~toC~Hg~
i90~mglg noepentyl, and the like.
Other o~ample~ of radicals which exert steric hindrance, a~d which may be present in particular in po~ition~
2 a~d~or 6 o~ structure (I) are t~ose corre~ponding to thc following formula:
, ~ AlR2 R"L~ CH~ -in which R ha~ the same meaning a~ indicated above and R"
i8 a radical which exerts a ~teric hindrance higher than -a2H5.
Atom~ or groups ~hich are not reactive with the alkyl Al compound~ may be ~re~ent as ~ubætituent~ i~ po~ition~

3, 4 and 5 o~ ~tructure (I) and in poSitionB 3, 4~ 5, 6 and 7 of ~tructure ~II). Examples of such ~ubstituents include haloge~ atoms and alkyl, aryl, alkaryl and aral~yl group~.
In par~icular, the sub~tituent in po~ition 4 o~
~tructure (I) may con~ist of the group R2A10 ~ ~ CII2 ~}CR2~ O AlR2 ; in which R ha~ the ~me meaning a~ indicated above.
The compound~ R2A10~" can b~ prepared by known method~, ~tarting from cQmpounds Al~ and Rl'OH, which ge-: 30 nerally react a~cording to the following reaction:
Al~ + RnOH~ lOR" + RH.
~h~ reactlon can be carried out in a hydrocarbon '~

`" 1g:~775~9 .
~olvent at room ~emperature or lligher~
~ nother metho~ of preparing the compounds 1~2A10~"consists in reacting AlR3 with Al ~OR")3 acoording to the ~; following stoich:iomet.ry:
2 AlR ~ Al ~OR~ 3 R2.AlOR~', and a-t room temperature or higher.
The compounds RAl (OR")2 can also be prepared by ~ I{nown methods, according to any o:~ the following reac-tions:
~ (1) A1~3 + 2R"OH --~ RAl (OR")2 ~ 21UI
(2) R2AlOR" -~ R"OH -~ R~l ~~")2 + ~I
: (3) AlR3 ~ 2~1 (0~")3 ~ 3R~1 (~'`)2' and a t room temperature or abo~e.
As already .indicated, the final ca-talysts of the in~en-tion ar~ prepared from starti:n~ components which com-prise (A) the new catalyet-forming components which are -the compounds R2AlOR" or I~l (OR")2 as def:ined herein and (B) compounds o~ transition me-tals. . .:
Such final ca-talysts are active in the polymerization of olefins, in particular o~ ethylene and/or alpha-olefins of the formula CH2 - C~IX, in which ~ is a radical containing from 1 -to 6 carbo:n atoms, such as propylene9 butene-l, l-met~lylpent~ne, and. -the l:ike.
When the monomer to be polymeri~ed is propylene, and in order to increase the stereospecificity of the catalyst, .. ~ the organometallic Al compounds, R2Al (OR") and RAl ~ORl')2 .~ can be partially complexed ~Yith electron-donor compounds as ~ described, for example, in Applicant's Canadlan pa-tent Nos.
.~ 1,002,693, 1,002,694 and 1,002,695.
- Catalyst-forming components (B) comprise -transition . ~o metal compound~ such as halogenated Ti compound~, e.g~, TiC14, T:iBr~9 3TiC13.AlC13, ~i ha.lo-a].coholates, etc., Ti. alcoholates;
vanad~um or zirconni.u.m halides 9uch as VC:l4, VOC13t ZrC14, etc., ~"', -.
~ ~ , ,~, ' ! . ' . . , ' . , . ' ,. ~ : , ' ~L~77SID9 and ~imilar transition metal compou~ds; or compl~xes o~ t~e fo:~mula ( II I ~ ~UmM ~X2mY D nl~
in which M = Mg~ ~ and/or Ca;
m _ a number ~rom 0,5 to 2.0, inclusi~re;
M~ = Ti~ r arld/or Zr;
X _ Cl, Br or I;
Y = one or more atom3 or groups~ either the same or diff0rent, æelected from halogen atoms, halogen atoms and, contempora~eously, o:~ygen atoms, -NR2, O O
-OR, -SR, ~O-C-R, and -O-S-R groups, in which R i~ a hydrocarbon radical, in par-ticular an alkyl, aryl, cycloalkyl or aralkyl radical; acetylac0tonate anion; acetylacetonate anion and, contemporaneou~ly, oxyg~n atoms;
such atoma or group~ being present in an amount sufficient to sati~fy the valency 0~ ~t;
n = i~ a numb¢r ~rom 0.5m to 20m9 inclusive; and E - an electron-do~ar compound selected ~rom -the following clas~es of compoundæ:
; . ( a) ester~ of or~;anio carbo:~ylic acid~;
'. ( b) alcohol~;
:. (c) esters:
..
(d) amines;
(e) esters of carbonie acid;
3 ( f) nitrile~; and (g) est~rs of pho3phoric and phosphorous acid a~d phosphorou~ o~ychloride.

.. .~

~07~51~

In formula (III), a p.. lrt oi the Ti, V and/or 7~:r may be subs-ti-tutecl by Al in such amount -that the atomic ra-tio between Al and the o-ther metals is froM 0.1.1 to 2:1, inclusive.
Such complexes and -the method of preparing them are described in Applican-t's copending Canadian application : Serial No. 2~9,104, flled March 26, 1976.
- As catalyst-forming components (s) comprising compounds of the transition me-tals, it is possible to employ, also, solid products containing, besides -the transition me-tal, also magnesium and a halogen, selec-ted from chlorine and . bromine, and characterized at least either by a surface area : larger than 3 m /g or by an X-rays spectrwn showing a halo, . -the intensity peak of which is at a lat-tice distance _ comprised be-tween 2.43 and 3.20 A, when chlorine is contained in the catalyst component in a C1/Mg ratio ~ l; conversely, when the ; catalyst componen-t contains bromine in a Br/Mg ra-tio ~ 1, the halo is a-t a distance d comprised between 2.80 and 3.25 A. ;
The catalyst components containing a transition me-tal, magnesium and a halogen (chlorine and/or bromine) can be prepared according to various methods. A preferred method consists in subjectiny a mixture comprising a -transition me-tal ; and anhydrous magnesium chloride or bromide to a grinding ; treatment, at.least until the surface area becomes larger -than 3 m2/g or until there appears, in the X-ray spectrum ~ of the ground product, a halo, the intensity peak of which -.......... is in one of the ranges specified above.
~ Alternatively, the catalyst components containing -:~ tlle transition mctal, maqllcsi~ ancl thc l~a].o~cn may i)c prepared by reacting a liquid halogena-ted compound o~ the transition me-tal with a magnesium oxygenated compound such ..... . .. .

~7~75~

a~, for instance, MgO, Mg (OH) Cl, magnesium carbonate9 or MgX (OR), in which X is halogen and R i~ an alkyl or aryl radical containing from ~ to 15 carbon atoms, inclu~i~e.
The reaction may be conducted either in the presence or absence Qf an inert hydrocarbon diluent, at a temperature generally ranging from 20 to 150C~
The catalytic component (B) containing the tran~ition metal may be prepared, also~ by reacting a liquid halogenated compound of the transition metal with a magne~ium complex of the typ~ ~gX2.nD, in which X i~ chlorine or bromine, D i~
a molecule of water, of an alcohol or of an electron-donor compound 6elected, for instance, from ethers, amine3~ e~ters, nitr~les a~d other analogou~ compounds. In thi~ embodiment, th~ rcact.ion i8 conducted in the presence of an exce~s of the transition me~al compound.
I~ all these preparation~, it is preferable to employ, a~ compounds o~ the tra~sition metal~, haloge~ated compounds of titanium, vanadium or zirconium~ selected in particular from among~t ~iCl3~ TiCl4, VCl4, VOCl~, halo-: 20 alcoholates of titaniu~, ZrC14 and other similar compound~.
U~e of compound~ o~ the type R~ lORN or RAl ~OR'1)2 a~ component (A) of the catalyst~ ha~ the followin~ advan-tage3 over the u~ of the ~l trialkyls as cataly~t-forming component~:
'!,', ( 1~ the compo~ds according to thi~ invention are 1~19 reactive than the aluminum trialkyl6 to~a~Y ox~gen, alld therefore they are-le~s .~ hazardou~ ~ince, unlike the Al trialkyl~, they are not flammable;
~0 ( 2) ~ompound Rl'OH~ preferably employed for pre-.,:
paring R2,glOR~ or RAl ( OR~ ) 29 may be a phe-nolic antiaxidizing agent z of th0 type ge-- - . . . . . .
.. .~.

~C~77S1~9 :

nerally added as additive to the polymer, after it i~ dried a~d before the drawing process (e$tru~ioll, gra~alation)~ in the commeroial proces~ for producing polyolafin~. :
The la~t-mentioned operation pe~ts an intimate co~tact of the polymer with the additive ~o a~ to enable it to efficaciou~ly - exert it~ stabilizing action.
(3) in the most-up-to-date plant~ for polymerizing olefins9 the tendency i9 to obtain the polymer in the fo~m of ~pheric or spheroidal par-ticle~ during the polym~rization, in ~hich . ~o~n~ the polymer can be directly utilized bg the users, without expensive drawing and pelletizing operation~. In thi~ case9 however, it becomes rather dif~icult to ~ix the stabilizing agent as intimately with the ;;
polyDIer a~ i8 nece~aIy to attain a satis-factorg stabilization.
`~ 20 ~en a compou~d of tha t3rpe ~22A10~ or i RAl ~OR")2 i~ used as t~e organometallic compone~t o~ the cataly~t~ in acoorda~ce ~ith thio invention, then on deactivat:lon of the cataly~t at the conclusion of the polymerization, for examp1e by me~s o~ steam, the compound RnO~IV that ha~ ~ormed by hydrolysi~ o~ the aluminum organometallic compou~d remains intimately mixed with the polymer, and i~
thu~ able to, alld ¢apable of e:E~iciently 3 exerti~g it~ stabili~in~ action;

(4) ill the polym~rization o~ olefill~ inL the gas pha~e, that iB ge}~erally conduct~d according . . : ' ',, . ` ! . . ' ` . ' 775~9 to the fluid bed ~echni~ue, it i~ ab~olutely ne¢e~ary to repeatedly convey an inten~e olefinis9 flow through the fluid bed, in order to r~move the heat of reaction, to feed the monomer and to get a good flui~iæation. It is nece3~ar~r9 therefore, to ¢ontinuou~ly replace the aluminum orgi~nometallic compound~
that ti~ke part in the cataly~i~ and exhibit a generally not ~egligible vapor teni3ion at the polymerization temperature, wher~fore uch compounds are entrained bg the fluidizing gai~ stream. The accumulatio~ of conventional aluminum organometallic compounds in the gas recycling circuit i9 furthermore a i~ource of hazard due to their in~lammability. The u-tilization of organometalli¢ compoundis o~ the type R2AlOR" or ~Al (OR")2 entirely remo~es.
such drawba¢k, a~ theGe compoundi3 are general- -ly in the solid ~ta te and exhibit a practical-ly negligible vapor tan~ion;
finally, the use of solid organometallic compou~d~ of aluminum of the type R~AlOR" or RAl (QR")2 as oataly~t-forming oomponent in accorda~ce with thc preeen-t in~ention pre~ents7 ; ::
~-~ during t~e polymer~zat~on of ol~fin~ in the `, gas phase, the caking of polgmer particles due to tac~ines~ cau~ed by the presenc~ of the ~,:
alumi~um alkyl compounds u~ed con~entionally and w~ich are liquid under tha polymerization condition~.
The polymeriza-tion o~ olefins9 ~nd especia:Lly o~
eth,ylene and/or alpha-ol0fins, with th~ cataly~t~ prepared, _9-_ ~al7~56~
.
according to this invention, from compouncls of the type R2AlOR`' or RAl (ORU)2, i~ generally conduc-ted acco~ding ko knolivn method~ by operating in a ga~ phase or in a liquid pha~e, either in the presence or ab~ence o~ an inert hydro-carbon diluent.
~he polymerization temperature i~ generally com-prised between 0 and 120C9 preferably between 50 and 90~C.
The Al/tra~sition metal ratio may vary over a ~ide range. In general it is preferable to operate with the ratio of from 5 to ~OO,OOO, .inclu~ive.
The following e~amples are given to illustrate the invention in more detail and are not intended to be limiting.

_ ~4 ml o~ Al (C2H5)3 (100 m, moles) were dissolved in 25 ml o~ anhydrous and deaerated n-heptane; a ~olution of 22 g (100 m. m~le~) o~ 2,6-ditert. bu~yl-paracre~ol were dropped in 2 hours into the ~olution obtained. The ~olution ~as then heated to 90C until conclusio~ of the reaction, ' thus obtaining an 1 M. solution of (C2H5)2 Al~(2,6-di-ter.
; 28 butyl-paracre~oxy).
A catalyst-forming component (~ wa~ prepared by co-grinding C13TiCOH3 and anhydrou~ ~gC12 in a 3teel ball mill and in such a ratio a~ to have a titanium content of

5.3% by weight; on X-rays examination, the coground product wa~ fou~d to give a spectrum with a halo having its inten~it~
peak at a lattice distance compri~ed between 2.43 and 3.20 A.
:' 22~6 mg of the coground product w~re introduced, along with 8 ml of the solution containing the alumi~um compound aIld 100 ml of anhydrou~ and desulphllrized n-heptane, into a ~ainle~s steel polymerization autoclav~ ha~ing a eap~city o~ 3 lit~rs e~uipped with ~ anchor stirrer and heated to 85C.

--10-- .

~C~775~9~
`
Hydrogen (7 atm. ) and ethylene (6 atm. 3 whore introduc~d into the autoclave until a total pras~ure of 13 atm. wa~ reached and which wa5 kept constant during t~e polymerization by feeding ethylene continuou~ly.
Polymerization was stopped after 4 hours, the polymer produced was ~eparated by filtr~tlon and dried, to obtain 230 g o:f polyethylene ( l9i, 000 g of polymer/g of tita-ium) 9 having an ir~erent vi~co~ity of 1., ~ dl/g.
The test wa~ xepeated USiIlg 18 mg of catalytic component containing titanium ~nd magnesium and 8 m. mole~
f a solution in n-heptane of (C~5)2A~OC6H
ln this case only traces of poly0thyl~ne were obtained. T~i~
prove~ that oatalytic component~ of the type R2AlOR", in whic~
R" i~ a phenyl radical that ln position~ 2 and/or 6 doe~
not carry sub~tituents with steric hindrance higher than that of -C2H5, are practically inactive. r ~A~ 2 ~xample 1 was repeated u~ing~ as cataly~t-forming, component ( B), 24 mg of the product prepared by dry cogrindingg in a steel ball mill, TiCl4 and anhydrou~ ~gCl? in such a ratio as to have 8 tit~nium oontent of 3.g % by we~ght. In thi~ way, 390 g of polyethylene (420,000 g o:E polymer/g of titanium), having an in~erent ~isco~ity of 1.55 dl/g9 were ~, obtalned.
:'` .
;
:Example 2 wa~ repeatedg U~illg 9.4 mg o~ the cataly~t-îo~ming component (B) a~d ~tarting from a gas~ou~ mixture ~on-~isting of 9 atm~ of ethylene and 4 atm. of hydrogen~ 280 g of polyethylene ~ 760, 000 g ~f polym~r/g of tit~ium), h~vin~
30 a~ inherent vieco~ity o~ 2.55 dl/g, wars obtained.
~ y way of comparislon9 a compo~d OI the typ~
(C2H5)~AlOR"~ in which R~ is ~77SC~

C~3 ~ C~l3 l o .
`" ' (2-6 dimethylphenyl) was prepar0d and u~ed as catalyst-forming component (A)~
~o this purpose, 1.22 ~ oP 29 6-dimethylphenol ~10 m. mole~), dis~olved in 20 ml of n-heptans9 were dropped ~ :
into 1.4 ml of Al(C2~5)~ (10 m. moles). It ~a~ then heated to B0C until conclusion of thc reactio~.
~ ample 3 was repeated using 20 mg of' the catalytic component containing titanium and magnesium, and the ~olution of compound R2AIlORa in which R" is 296-dimethylphenyl prepared as above. In this run however, only 2 g of` poly~tyle~e were obtained.
Also, by way of compari~on~ a compound of the type (C2H5)2A~OR~, in which R" iB
"~

,~ ~ C-CH
: ~J JH3 (2-tert.butyl~phenyl) was prepared and used as catalyst-forming component (A).
To thi~ purposa9 1.5~ ml (10 m. moles) of 2-tert.
butyL- .phenol7 diluted with n-hapta~e to 20 ml, were ~ropped illt~ 1-4 Dll of Al~C2H5)3 (~0 m. moles~. The mass waæ
heated to 80C u~til conclusion of the r~action. ~x~mple ~ ;
was repea-ted, using 16 m~ of the cataly~t-forming component containing titanium a~d magnesium, and the solution of compound R2ALOR" in which R" is 2 tertubutglpheny:L obtained as indicated herein. Only 3.5 g Qf polyethylene we:re obtained~
The~e two comparative te~t~ un~guivocally confirm 75c3~

that, when in positlon 2 and/or 6 of radicals ~n Of com~
pound~ of the type R2A~OR~

6 ~ 2 5 ~ 0 ~ 13 at lea~t one substituent group ~ith steric hindrance higher than that of the group -C2E5 i8 not pre~e~t, and both po-~itions 2 and 6 are not ~ub~titued, the catalysts obtained therefrom are practically inefficient.
EXA~PIE 4 TiC14-ethylben~oate and anhydrous MgC12 were dry ` coground in such a ratio a~ to have a titanium content o~ 5%
.' by weight. On X-rays exami~ation, t~e coground produc-t has a sp~ctrum 3imilar to that o~ the catalitic component of '~ Example 1.
., ,~ 99.4 Mg of the eoground product were introduced, .~ along with 6 ml of the solution o~ (C ~5)2Al-(2s6-di-ter. ~ ;l butyl-paracre~oxy), prepared acc~rding to Example 1, and with 350 ml of de~ulphurized a~hydrou~ n-heptan~, into a , 20 polymerization au~oclav~9 made o~ ~tainleæ~ ~teel, having a capacity of ~000 ml, equipped with an anohor stirrer and , ~eated to 60C9 into which 0.15 atm. of hydrogen had bee~
; previou~ly i~troduced. Sub~e~uently, propylene wa~ fed to the ~utoelave until a total pre~ure of 5 atm. wa~ reached and which was kept constant for the duration of tha poly~e-rization, by feeding propylane continuou~ly. Af~er 2 hours . ~
and ~0 minute~, the polymerlzation reaction was ~topped.
~h~ polypropyle~e thu~ obtained wa~ isolated by treatment of the polym~rization rea¢tion ma~ with me~hanol and acetone.
It amounted to 435 g ~88,000 g of polymer/g of titanil,lm).
The polymer exhibited a~ inherent ~ cosity of 1. 67 dl/g ~d, on e~traction with boiling ~eptane, (~6 hours in a -~3~

1~775a~9 Eumagawa apparatus) left a heptane insoluble ~isotact-lc) residue of 54.5 ~.

6 ml of a ~olution o~ (C2H5)2Al-(2,6-di~ter.butyl-paracresoxy), prepared as i~ Example 1, was diluted to 50 ml with n-heptane and reacted with 162 mg of ethyl para-ani~ate for 10 minutes at 25C~ U~ing 97 mg o~ a cataly~t forming -;~
component containing titanium and magnesium as in Æxample 4, and the ~olution of (C2H5)2Al-(2,6-di-ter.butyl-paracresoxy) a~ co-catalyst, a~ter a 5-hour polymeri&ation under the condition~ of Exampl~ 4, 105 g o~ polypro~ n~ (22~000 g of polymer/g of titanium) 9 having an inherent vi8c09ity of 2.1~
dl/g and a residue~ on ~xtraction with heptane, of 89.6%, ~ere obtained .
. EXAMPI,E 6 A ~olution of 11 g ( 50 moles) of 2,6 di-terO butyl-.
paracresol in 60 ml of anhydrou~ deacrated n-h~ptane ~a~
dropped into 12,6 ml (50 m. mole3) o~ hl(iso C4Hg)3 in 2 hour~.
A~ter heating at 90C u~til co~clu~ion of the reaction, a 0.8 M solution of (i~o-a4~9)2Al-~2,6-di-ter.butyl-paracresoxy) wa~ thus obtained.
Example 4 was repeated, employing 4704 mg o~ the ca-taly~t-forming component containing titanium and magnesium, and 7 ml o~ the Golution of compound (i~o-C4Hg)2Al-(2,6-di-ter.butyl-para¢resoxy) as co-catalyst. A~ter a 5-hour poly-merization at 80C, 61 g of polyprop~lene ~26~000 g of polymer/g of titanium, ha~ing an inherent vi~co~ity of 1,11 dl/g and a re~idue, on extraction with heptane, of 70.5% were obtained.

A ~tainle~s ~teel autoclave having a capacity of - 3V00 ml, eguipped with an anchor ~tlrrer, was f~d with about 50 g of t~oroughly dry polypropylene -in powder fo~m, along : ~14-.
, 13775~9 with 5 m~ of a catalyst-forming oomponent prepared by dry cogrinding TiC14 and anhydrous ~gC12 in such a ratio a~
to have a titanium content of 3.9~ by wei~ht, alo~g ~ith 8 m.
moles of a ~olution of (C2H5)2 Al;(2,6-di-ter.butyl-para-oresoxy)~ prepared as in Example 1 and diluted to 50 ml with n-heptane. After havlng evaporated -~he solvent by heating to 80C, 0.5 atm. of hydrogen ancl ethylene were introduced into the autoclave, until a tbtal pressure of 15 atm. was reached. ~he pre~sure wa3 ~ep-t constant for the -~ 10 duratio~ of the polymerization by ~eding ethylene continuou~ly.
; Polymeri2ation was ~topped a~ter'2 hour and 100 g of po lyet~ylene (500,000 g of polymer/g of titanium) were obtained.

1.39 ml of Al(C2H5)3 (10 m. moles) were dissolved ~, in 22 ml of anhydrous deaerated n-heptane, and a solution of 1.78 g ~10 m. moles)of 2-tert. butyl-496-dimethyl phe~ol in 27 ml of n-heptane wa~ dropped in over a period of one hour.
The mass was then heated at 80C until the reaction was oon-cluded.
Example 3 was repeatad, usin 20 mg uf the catalyst-forming component (B) and, as component (A) or co-catalyst, the fore~oing solution. 98 g o~ polyethylene (125,000 g o~
polymer/g of titanium) were thu6 obtained.

2 g (10 m.moles) of 2,6~di-tertD buty~ phenol, dissolved in 50 ml of ~-heptane, were dropped into 1~4 ml of Al(C~H5)3 (~0 m. mole~) diluted to 20 ml with a~hydrous and deaer~ted n-heptane, and the resulting solution wa~ heated at 80C until conclu3ion of the reaction.
~SO Example 3 wa~ repeated, employing 21 mg of the cataly~t forming component ( B) aMd the ~olution de~cribed hereinbefore . a~ co-cataly~t . 240 g of polye-thylene ~ 288, 000 . ' : ~ ` . , .. !

~ ~ ~775~
g of polymer/g of tita~:lwm) were obtailled.
XAMP~E 1 O
20 m. mole~ of 29 6-di-ter. butyl-paracresol, di~-- solved in 20 ml OI a~hydrous deaerated n-hepta~e, were drop-ped into 20 ml of a solution prepared according to :Example 1 (containing (C2H5)2Al-~2,6-di-ter. butyl-paracre BOXy)c The : whole was diluted to 100 ml with n-heptane and heated -to 90C until conclu~ion Qf the reaction, thus obtaining a compound of the type (RAl(OR")2 ~nd, more particularly, RA1(2,6-di-ter. butyl-paracre~oxy)2.
Example 3 wa~ repeatedp employing ~ mg of cataly~t-forming component (B) and 80 ml o~ the ~oregoing ~olution as co-ca~alyst. In th:is way, 60 g o~ polyethylelle (81,000 g of polymc r/g o~ tltanium) wc re o btaincd, '~
, .
.

~ '

Claims (19)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Components of catalysts for the polymerization of olefins, having a structure defined by one of the following formulas: R2AlOR" and RAl(OR")2 in which R represents alkyl radicals containing from 1 to 12 carbon atoms inclusive, and R"
corresponds to one of the following structures (I) or (II):

(I) or (II) wherein in positions 2 and 6 in structure (I) and positions 2 and 8 in structure (II) there are present radicals at least one of which exerts a steric hindrance higher than that of the group -C2H5 and is selected from the group consisting of alkyl radicals containing at least 3 carbon atoms.

2. Catalyst components according to claim 1, in which if only one of the radicals in positions 2 and 6 in structure (I), or in positions 2 and 8 in structure (II) is a radical which exerts a steric hindrance higher than that of the group -C2H5, the other radicals in said positions are selected from the group consisting of alkyl and aryl radicals.

3. Catalyst components according to claim 2, in which the radical different from the radical which exerts a steric hindrance higher than that of the group -C2H5 is selected from the group consisting of methyl, ethyl, propyl and phenyl radicals.

4. Catalyst-forming components according to claim 1, in which the radicals which exert a steric hindrance higher than that of the group -C2H5 are branched alkyl radicals.

5. Components according to claim l, further characterized in -that the radicals which exert a steric hindrance higher than that of the group -C2H5 are selected from the group consisting of i-C3H7, t-C4H3, i-C4Hg, isoamyl and neopentyl.

6. Catalyst-forming components according to claim 1, characterized in that in positions 2 or 6 of structure (I) there are present radicals having the formula in which formula R is an alkyl radical containing from 1 to 12 carbon atoms, inclusive, and R"' is a radical having a steric hindrance higher than that of the group -C2H5.

7. Catalyst-forming components according to claim 6, in which R"' is an alkyl radical containing at least 3 carbon atoms.

8. Catalyst-forming components according to claim 7, in which R"' is a branched alkyl radical.

9. Catalyst-forming components according to claim 1, further characterized in that the substituents in positions 3, 4 and 5 in structure (I), and in positions 3, 4, 5, 6 and 7 in structure (II) are atoms or groups which are not reactive with alkyl aluminum compounds.

10. Catalyst-forming components according to claim 9, further characterized in that said substituents which are not reactive with alkyl aluminum compounds are halogen atoms or alkyl, aryl, alkaryl or aralkyl groups.

11. Catalyst-forming components according to claim 1, characterized in that the substituent at position 4 in structure (I) has the formula:

12. Catalysts for polymerizing olefins, comprised of the catalyst-forming components (A) an organometallic compound of Al having the formulae R2AlOR" and/or RAl(OR")2 in which R is an alkyl group containing from 1 to 12 carbon atoms, inclusive and R" corresponds to one of the structures (I) or (II) as defined in claim 1 and (B) a transition metal compound or complex.

13. Catalysts for polymerizing olefins according to claim 12, component (B) of which is a complex of a transition metal having the formula:

MmM'X2mY.nE

wherein:
M = Mg, Mn and/or Ca;
m = a number from 0.5 to 2, inclusive;
M' = Ti, V and/or Zr;
X = C1, Br or I;
Y = one or more atoms or groups, the same or different, and selected from the group consisting of halogen atoms, oxygen atoms; -NR2, -OR, -SR, , groups in which R is a O O
hydrocarbon radical; acetylacetonate anion, oxygen atoms;
such groups or atoms being present in an amount to satisfy the valence of M';
n = a number from 0.5 m to 20 m, inclusive;
E = an electron-donor compound selected from the following classes of compounds:
(a) esters of organic carboxylic acids;
(b) alcohols;
(c) ethers;
(d) amines;
(e) esters of carbonic acid;
(f) nitriles; and (g) esters of phosphoric and phosphorous acid and phosphorous oxychloride.

14. Catalysts for polymerizing olefins according to claim 13, further characterized in that in the groups -NR2, -OR, -SR, , , R is an alkyl, aryl, cycloalkyl or aralkyl radical.

15. Catalysts for polymerizing olefins according to claim 13, and component (B) of which contains a transition metal, magnesium and a halogen selected from the group consisting of chlorine and bromine, said component being characterized in having a surface area higher than 3 m2/g and/or in having an x-rays spectrum comprising a halo the intensity peak of which is at a lattice distance d comprised between 2.43 .ANG. and 3.20 .ANG. when the halogen is chlorine and present in said catalyst-forming component in a Cl/Mg ratio ?1, and between 2.80 .ANG. and 3.25 .ANG.
when the halogen is bromine and present in said catalyst-forming component in a Br/Mg ratio ?1.

16. Catalysts for polymerizing olefins according to claim 15, further characterized in that, in component (B) the transition metal is Ti, V or Zr.

17. Process for polymerizing ethylene, alpha-olefins, or mixtures thereof, which comprises polymerizing the olefin or olefin mixture in contact with a catalyst according to claim 12.

18. Process according to claim 17, in which the olefin polymerized is propylene.

19. Process according to claim 17, in which the polymerization of the olefins is carried out in the gas phase.