AU642009B2 - Process for the preparation of a polyolefin - Google Patents

Description

COMMONWEALTH OF AUSTRALIA9 PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: *.,Complete Specification Lodged: Accepted: 0 Published: Poiority *0 M arne of Applicant ."Vi .:*ddress of Applicant: Actual Inventor: Adres o Srvc HOECHST AKTIENGESELLSCHAFT' D-6230 Frankfurt/Main 80, Federal Republic of Germany HANSFRIEDRICH HERRMANN and LUDWIG BOHM WATERMARK PATENT TRADEMARK ATTORNEYS.

LOCKED BAG NO. 5, HAWTHORN, VICTORIA 3122, AUSTRALIA Complete Specification for the invention entitled: PROCESS' FOR THE PREPARATION OF A POLYOLEFIN The following statement is a full description of this, invention, including the best method of performing it known to -2 The invention thus relates to a process for the prepara- ,tion of a polyolef in by polymerization of an olefin of the formula Ra-CH=CH-Rb in which Re and Rb are identical or different and are a hydrogen atom or a Cl-C 2 0 -alkyl radical or Ra and Rb, together with the carbon atom connecting -them, form a ring having 4 to 10 carbon atoms, ata erpgature of .from. -40 0 C to 150 0 C, at a pressure of from 0.5 to 100 bar,~in solution~or is suspensionj in the presence of a catalyst which comprises a compound of the formula I or II

R

3 R R iR V 0 in--which

M

1 is titanium, zirconium or hafnium,

R

1 and R 2 are identical or different and are a hydrogen atom, a halogen atom, a Cl-Cl-alkyl, group, a alkoxy group, a Cr 8

-C

1 -aryl group, a Cr 6

-C

10 -aryloxy group, a C-Cl.

0 -alkenyl group, a C 7

-C

4 -arylalkyl group, a C 7

-C

4 0 -alkylaryl grovxp or a C.-C 4 -arylalkenyl group, GoesR 3 and R' are identical or different and are a monocyclic or polycyclic hydrocarbon radical which can form a sandwich structure together with the central atomn 11, R* R 5 is

*R

6

*R

6

R

6

R

6

R

6

R

6

R

6

R

6 1 2 12 '2 1 1 =BR, =A1R 6

-S-

1 =SO' =S02,

=_NR

6 =CO, =PR 6 or =P(0)Rr3 where R 6

R

7 and R8 are identical or different and are a hydrogen atom, a halogen atom, a Cl-Cl.-alk-yl group, a Cl-C-fluoroalkyl group, a C 6 -C-fluoroaryl group, a C 6 -Cl-aryl group, a R,441 C 1 -Cl,-alkoxy group, a C.-C 1 0 alkenyl group, a /06 1114Varylalkyl group, a C.-C 4 -arylallcenyl group or a -3

C

7

-C

40 -alkylaryl group, or Rr' and R7 or R6 and R8 in each case together with -the atoms connecting them form a ring, and

M

2 is silicon, germanium or tin, and an aliuninoxane of the formula III

R

9 R9,R

A

1 0-l-O Al R9 nIIR9 f or the linear type and/or of the formula IV 5SS.-I-n+2 (IV) for the cyclic type, where, in the formulae III and IV, the radicals R 9 are identical or. dif ferent and are a Cl-C.-alkyl grqup Qr phenyl or benzyl and n is an integer f rom 2 to 504A: sri. xa*vn~A sarn74r:fa polar aprotick so vent having *a static dielectric constant eat 20 0 C of greater than 3.

The catalyst to be used for the process according to the invention comprises an aluininoxane and a metallocene of the formula I. or II a :R 5 il R2, ():NR2 In these formulae, M1 is a metal from the group comprising titanium, zirconium and hafnium, preferably zirconium and hafnium.

R

1 and R 2 are dentical or diff~arent and are a hydrogen atom, a C3.-Cl-alkyl group, preferably a Cl-C 3 -alkyl group, a C 1

-C

10 alkoxy group, preferably a Cl-C 3 -alkoxy group, a -4 Cr-Clo-aryl group, preferably a CC 8 -aryl group, a CCo aryloxy group, preferably a C6-C 8 -aryloxy group, a 2CO alkenyl group, preferably a C 2

-C

4 -alkenyl group, a C 7

-C

4 arylalkyl group, preferably a C 7

-C:

1 0 -arylalkyl group, a

C

7 -0C 40 -alkylaryl group, preferably a C 7

-C

12 -alkylaryl group, a C 8

-C

4 0 -arylalkenyl group, preferably a C.-C 1 2 -arylalkenyl group, or a halogen atom, preferably chlorine.

R 3 and R 4 are identical or different and are a monocyclic or polycyclic hydrocarbon radical which can form a sandwich structure together with the central atom Ml.

R

3 and R 4 are preferably fluoroenyl, cyclopentadienyl or 4 ~.indenyl, it being possible for the basic structure to carry additional substituents.

R 5 is a single- or multimenibered bridge which links the 11.5radicals R 3 amd R 4 adi 0 R6 12_

_M

1 7

R

R

6

R

6 12 12 _M tl

R

6 12_CR 8 17 27

R

R

6

R

1 12

R

6

R

6 S420

=BR

6 1 =AlR 6 -S- 1 =So,1 =80 2 1 =NR E; =CO, =PR 6 or =P(0)R6 where R 7 and R 8 are identical or different and are a hydrogen atom, a halogen atom, preferably chlorine, a, C -Cq 1 -alkyl group, preferably a Cl-C 3 -alkyl group, in particular a methyl group, a Cl-C 1 0 -fluoroalkyl group, preferably a CF 3 group, a Cr-Cc-fluoroaryl group, preferably 'A pentafluiorophenyl group, a Cr,-Cl-aryl group, prfeaby a Cr,_ 8 -aryl group, a Cl-Cl.

0 -alkoxy group, preferably a Cl-C 4 -alkoxy group, in particular a methoxy group, a C 2 -Cl-alkenyl group, preferably a C 2

"C

4 -alkenyl group, a C 7

-C

4 0 -arylalkyl group, preferably a C 7

-C

1 -arylalkyl group, a ,C 8

-C

40 -arylalkenyl group, preferably a C 8 Cj.-arylalkenyL group, or a C 7

-C

4 -alkylaryl group, preferably a. C 7

-C

12 alkyiaryl group, or R 6and R 7 or Rra and R 8 in each case together with the atoms connecting them form a ring.

'MI is silicon, germaniumn or tin, preferably silicon or germanium.

R 5 is ,pref erably =CR 6 =SiR 6 =GeR 6 R 7

-S-

1 =So, =PR6 or =P (0)R 6 The metAllocenes of the formula I described above can be prepared by the general processes below: *Soo as* 0 *59 66* o b* 5 I

H

2

R

3 '+butyILi M H 3 Li

H

2

R

4 +butylLi HR 4 Li

X-R

5 -X HR 3

R

5

R

4

H

LiR 3

_R

5

-R

4 Li -2 butyl~

S

Se S SO

S

S. S S

S.

*5 S 55.5

S

.5.

R

3

R

5

M

1 ICl (X =Cl, Br,

R

3 LLi- R 5

M

'Cl

R

4 /1 RI 2\R ~LL.It 4 5 r~ I, O-tosyl S. S S S ~5 S. S OS S S S

OS

-6or

H

2

R

3 butylLi 4HR 3

L

R

6

'R

C/

11

R

4 a, HR 3 Li±,.

b, H 2 0 7.R 3

H

R

4

H

00 0 0 0060 3 0

OS

0 000000 0 *0 0 W 000 0S 0 Oso 2 butylLi

R

3 [R6R7C' ]Li 2

M

1 C1 4

R

3 R Cl

C

R7-, C, 0 000000 0 0000 04 0 .000 0 0000

I/

R Li

C

R 7 C 0g00 00 00 0 00 0 0 0 00

R

2 LiM

R

3 6"R The metallocenes of the formula II can be obtained by reacting a metal chloride MlC1 4 successively with the lithium compounds R 3 Li and R 4 Li and possibly R'Li or R 2 Li.

Preferred metallocenes are (arylalkylidene) (9-f luoroenyl) (cyclopentadienyl) zirconium dichloride, (diarylmethylene) (9-f luoroenyl) (cyclopentadienyl) zirconium chloride, 1 7 (dialkylmethylene)(9-fluoroenyl)(cyclopentadienyl)zirconium chloride, biscyclopentadienylzirconium dichloride, (dimethylsilyl) (bisindenyl) zirconium dichloride, (ethylene) (bis-indenyl) zirconium dichloride, (bisdimethylsilyl) (bis-indenyl) zirconium dichloride, (propylene) (bisindenyl)zirconium dichloride, (diphenylmethylene)(9fluoroenyl)(cyclopentadienyl)zirconium dichloride, (biscyclopentadienyl)zirconin dibenzyl and the hafnium analogs of each of these compounds.

The cocatalyst is an aluminoxane of the formula III r' R9 9 /R9 Ri R R9 R9 Al Al Al (III)

*R

for the linear type and/or of the formula IV

I

S--A1 0- (IV) n+2 for the cyclic type. In these formulae, the radicals R 9 are identical or different and are a Cl-C.-alkyl group, *o preferably methyl, ethyl, isobutyl, butyl or neopentyl, .:15 phenyl or benzyl. Particular preference is iiven to methyl. n is an integer from 2 to 50, preferably 5 to However, the precise structure of the aluminoxane is as yet unknown.

The aluminoxane can be prepared in various ways.

One possibility is the careful addition of water to a dilute solution of a trialkylaluminum compound by introducing the solution of the trialkylaluminum compound, preferably trimethyl aluminum and the water, in each case 8 in small portions, into a relatively large amount of an inert solvent, awaiting the cessation of gas evolution between the addition of each portion.

In another process, finely powdered copper sulfat pentahydrate is slurried in toluene, and sufficient trialkylaluminum to provide about 1 mol of CuSOS5H 2 for every 4 Al atoms is added at about -20°C under an inert gas in a glass flask. After slow hydrolysis with elimination of alkare, the reaction mixture is left at room temperature for from 24 to 48 hours, during which it may be necessary to cool the mixture so that the temperature does not exceed 30"C. The copper sulfate is subsequently filtered off from the aluminoxane dissolved in the toluene, and the solution is evaporated in vacuo. It is 15 assumed that, in the preparation process, the lowmolecular-weight aluminoxanes condense with the elimination of trialkylaluminum to form higher oligomers.

Aluminoxanes dre furthermore obtained if trialkylaluminum, preferably trimethyl aluminum, dissolved in an 2 inert aliphatic or aromatic solvent, preferably heptane or toluene, is reacted at a temperature of from -20 to 100°C with aluminum salts, preferably aluminum sulfate, containing water of crystalization. In this reaction, the volume ratio between the solvent and the alkyl aluminum used is from 1:1 to 50:1, preferably 5:1, and the reaction time, which can be monitored through the elimination of the alkane, is from 1 to 200 hours, preferably from to 40 hours.

The aluminum salts containing water of crystalization are in particular those which have a high content of water of crystalization. Particular preference is given to aluminum sulfate hydrate, in particular the compounds Al 2 (S0 4 )'.16H 2 0 and Al 2

(SO,

4 )118H 2 0 having the particularly high water of crystalization content of 16 and 18 mol of

H

2 0/mol of AI 2

(SO

4 3 respectively.

9 A further variant of the preparation of aluminoxanes comprises dissolving trialkylaluminum, preferably trimethyl aluminum, in the suspending agent, preferably in heptane or toluene, in the presence of a solid, for example SiO 2 and then reacting the aluminum compound with water.

In addition to the above-outlined processes for the preparation of aluminoxanes, it is possible to use others. Irrespective of the preparation method, all the aluminoxane solutions have a varying content of unreacted trialkylaluminum, in free form or as an adduct. This content has an effect on the catalytic activity which has as yet not been explained precisely and varies depending on the metallocene compound employed.

S 15 It is possible to preactivate the metallocene, before using the polymerization reaction, using an aluminoxane of the formula III and/or IV. In some cases, this considerably increases the polymerization activity and improves the grain morphology. The preactivation can be omitted if a highly polar solvent is used as the polymerization meditu. This preactivation of the transitionmetal compound is carried out in solution with the fed* metallocene preferably being dissolved in a solution of the aluminoxana in a polar hydrocarbon. Suitable hydrocarbons are aliphatic or aromatic hydrocarbons having a static dielectric constant which at least corresponds to that of toluene. Toluene is preferred.

The polymerization is carried out in a known manner in solution or suspension, continuously or batchwise, in one or more steps, at a temperature of from -40 to 150"C, preferably from -30 to 100 C, in particular from 0 to 0

C.

Olefins of the formula RaCH=CHRb are polymerized (homopolymerized or copolymerized). In this formula, R a and Rb are identical or different and are hydrogen atoms or an 10 alkyl radical having 1 to 20 carbon atoms, it being possible for Ra and Rb, together with the carbon atoms connecting them, to form a ring having 4 to 10 carbon atoms. Examples of 1-olefins of this type are ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, norbornene or norbornadiene. Preference is given to ethylene, propylene, 1-butene and 4-methyl-lpentene.

The total pressure in the polymerization system is from 0.5 to 10G bar. The polymerization is preferably carried out in the industrially particularly useful pressure range of from 5 to 60 bar.

Hydrogen can be used as molecular weight regulator.

SThe metallocene is used in a concentration, based on the 490* *w-A p&rcn^>rbi to 10-7 ol m =retransition 4 methiod, of 4from 10 to 10 mol, preferably from 10 to 10 6 mol, of transition metal per dm 3 of solvent. The aluminoxane is used in a concentration of i from 10 5 to 10-1 mol,ipreferably from 10 5 to 10- 2 mol, per dm 3 of solvent. In principle, however, higher concentra- 120 tions are also possible.

The polymerization is carried out in solution or in suspension. The solvent used is a polar aprotic solvent, in particular a halogenated hydrocarbon, having a static dielectric constant e at 20 0 C of greater than 3, alone or in a mixture, if appropriate in anoither inert solvent.

Examples are Chloroform 4.81 Dichlorofluoromethane 5.34 Chlorobenzene 5.71 p-Chlorotolu6ne 6.08 Chlorodifluoromethane 6.11 1,1,1-Trichloroethane 7.53 Dichloromethane 9.08 o-Dichlorobenzene 9.82 B^ 11 1,2-Dichloroethane 10.65 (cf. CRC Handbook of Chemistry and Physics, 70th Ed.

1989/90, E Preference is given to dichloromethane, 1,2-dichloroethane and 1,1,1-trichloroethane.

The advantage of the use according to the invention of a halogenated hydrocarbon as solvent or suspending agent is the significantly greater polymerization activity and the higher molecular weight of the polymers, compared with the prior art.

C.

The examples below are intended to illustrate the invention.

o

*S

"Example 1: 750 mg of methylaluminoxane (commercial product) (13 mmol of Al) and 1 ymol of Cp 2 ZrClz were dissolved in 700 cm 3 of dry dichloromethane under argon, and the solution was 0$&@fe transferred at 30°C into a 1.5 dm 3 reactor which had previously been evacuated, heated and flushed with argon.

2 bar of ehtylene were added, and the reactor contents 20 were held at 50°C for 5 minutes and polymerized for 2 hours with ethylene at 7 bar. Removal of the suspending agent and drying of the product in vacuo gave 51.4 g of PE having an M, of 670000 (by GPC) and a polydispersity /M of 2.9.

Comparative Example A: Example 1 was repeated using n-pentane (e 1.84) as suspending agent. The yield was 2.5 g.

Comparative Example B: Example 1 was repeated using toluene (e 2.38) as suspending agent. The yield was 31.4 g of PE having a M, 12 of 395000 (by GPC) and a polydispersity M4/M, of 2.9.

Example 2: Carrying out Example 1 in dichloromethane at a polymerization temperature of 30°C gave 73.0 g of polyethylene having a M w of 984000 (by GPC) and a polydispersity M /Mn of 2.8.

Comparative Example C: Example 2 was repeated using toluene (e 2.38) as "suspending agent. The yield was 30.4 g of PE having a M, 10 of 938000 (by GPC) ani' a polydispersity M/M of Example 3: Carrying out the experiment in 1,1, 1-trichloroethane analogously to Example 2 at a polymerization temperature of 30°C gave 61.2 g of polyethylene having a M, of 970000 (by GPC).

4 Example 4: Carrying out the experiment in 1,2-dichloroethane using pmol of CpzZrCI1 analogously to Example 2 at a polymerization temperature of 30"C gave 39.7 g of polyethyl- ,:20 ene having a M of 1020000 (by GPC) and a polydispersity /M of 2.8.

Example 5 to Ethylene polymerizations were carried out analogously to Example 2 in dichloromethane at 50 0 C with the metallocenes summarized in the table. The table shows the metallocene concentration employed, the yield and the molecular weights.

13 Table No. Catalyst [(Awl Zr] CY [g of PE] 1 [kg/n-l] M.A Sie 2 (Ind) 2 ZrCl 2 0.2 31.5 1072 3.1 6. CAH(Ind) 2 Z3:C1 2 0.2 73.6 737 7. Si 2 Me 4 (Ind) 2 ZrC1 2 0.2 80.1 2713.5*) 8. qAH(Ind) 2 ZrC1 2 1.0 68.5 1842.5 9. CPh 2 (F1Qo)(CP) ZrC1 2 1.0 48.9 2261.2*) 2 Zr CH 2 h) 2 1.0 77.7 506.1 2.9 Ind I-Indenyl, Fluo 9-Fluoroenyl, Ph Phenyl Y from the viscosity number in accordance with the Mark-Houwink equation 111- HOECHST AKTIENGESELLSCHAFT HOE 90/F 167 Dr. LO/rh Description Process for the preparation of a polyolefin The invention relates to a process for the preparation of a polyolefin in the presence of a metallocene and an aluminoxane which is carried out in a polar aprotic solvent, in particular a halogenated hydrocarbon.

In the suspension polymerization of 1-olefins, inert hydrocarbons, such as, for example, petroleum fractions o'10 and diesel oils of various boiling ranges, are usually employed as suspending agents.

6 It is known to polymerize ethylene by means of a heterogeneous ziegler catalyst at from -60 to -109 0 C in a halogenated hydrocarbon as solvent (cf. Bestian et al., Angew. Chem. 74, pp. 955-965, 1962). However, such polymerization temperatures are economically unfavorable.

In addition, temperatures above -50°C cause highly branched, oily products to be produced.

It is furthermore known to polymerize propylene at in methylene chloride (cf. Longo et al., Makromol. Chem.

iQ090, pp. 2357-2361 (1989)). The catalyst used is 1,1'ethylenedi(4,5,6,7-tetrahydroindenyl)zirconium dichloride together with trimethyl aluminum and dimethyl aluminum fluoride (DMAF). For comparison, polymerizations are alse carried out in toluene. It is apparent that the system in methylene chloride has greater activity than in toluene, but the yield with the system in toluene is nowhere near achieved.

It has now been found that polar aprotic solvents can advantageously be employed as suspending agents in the suspension polymerization of 1-olefins by means of soluble metallocene/aluminoxane catalysts.

Claims (3)

1. A process fo Ir the preparation of a polyolef in by polymerization of an olef in of the formula Ra-CH=CH-Rbin which Ra and Rb are identical or different and are a hydrogen atom or a Cl-C 20 -alkyl readical or R a andR, together with the carbon atom connecting them, form a ring having 4 to 10 carbon atcms, at a temperature of from -40 0 C to 150 0 C,-ats a, pressure of from 0.5 to 100\ b~-U in solution,\or jm si4spiEthpion A in the presence of a catalyst which coxhpri'ses a comtpound of the formula I or II R3 R 3 R

2 R a in which x1 is titanium, zirconium or hafnium, Flags&: R' and are identical or different and are a hydrogen atom,, a halogen atom, a Cl-Cl-alkyl group, a lCa WAalkoxy group, a Cr 6 -Cl-aryl group, a C 6 -Cl-aryloxy *too group, a C 2 -Cl-alkenyl group, a C 7 -C 40 -arylalkyl group, Ce.a C 7 -C 40 -alkylaryl group or a CB-C 0 -arylalkeny1 group, R 3 and R 4 are identical or different and are a monocyclic 1*20 or polycyclic hydrocarbon radical which can form a sandwich structure together with the central atom M 1 aft; R 5 is R 6 R 6 R 6 R 6 R 6 R 6 R 6 R 6 '2 CR8 s BR', =AlR 6 ,ri, =SO, =S0 2 =NR 6 =CO, =PR or =P (0)R 6 where R 6 R 7 and R 8 are identical or different and are a hydrogen atom, a halogen atom, a Cl-Cl-alkyl group, a Cl-Cl-fluoroalkyl R. group, Ia C6-C-f luoroaryl group, a CS-C 1 ri-aryl group, a CC 1 0 -alkoxy group, a C 2 C 1 -alkenyl group, a 15 C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C-C 40 -alkylaryl group, or R 6 and R 7 or R 6 and R 8 in each case together with the atoms connecting them form a ring, and M 2 is silicon, germanium or tin, and an aluminoxane of the formula III 'Al- O A O- Al R n R (III) S. for the linear type and/or of the formula IV SAl 0 n+2 (IV) for the cyclic type, where in the formulae III and IV, the radicals R 9 are identical or different and are a Ci-C 6 -alkyl group or phenyl or benzyl, and n is an integer L_ Sc. O A \s from 2 to 50,.hi. chr... c LI r- in r v a polar aprotic solvent having a static dielectric constant e at 20 0 C of greater than 3. 0*:0 2. The process as claimed in claim 1, wherein the polar aprotic solvent is a halogenated hydrocarbon.

3. The process as claimed in claim 2, wherein the halogenated hydrocarbon contains one or two carbon atoms ,20 per molecule. S4. The process as claimed in claim 2, wherein the halogenated hydrocarbon is dichloromethane. The process as claimed in claim 1, wherein ethylene is polymerized. DATED this 29th day of April 1991. HOECHST AKTIENGESELLSCHAFT WATERMARK PATENT TRADEMARK ATTORNEYS "THE ATRIUM" 290 BURWOOD ROAD HAWTHORN. VIC. 3122.