NL9401515A - Novel organometallic compounds and method for polymerizing alkenes with the use of said organometallic compounds as catalysts - Google Patents

Abstract

The invention relates to organometallic compounds according to formula 1 of the formula sheet, where M is Zr, Ti or Hf; A is a readily detachable group, for example a halogen atom, R1 and R5 are preferably Si(CH3)3 or C(CH3)3; R2 is a tertiary alkyl group, for example C(CH3)3; R3 is a hydrogen atom or a low alkyl group; and R4 is a phenyl group. These compounds are suitable for the polymerization of alkenes such as ethylene (ethene) or propene (propylene). They have good catalytic activity and can be prepared in a simple manner. <IMAGE>

Description

Short designation: Novel organotnetal compounds and process for polymerizing olefins using these organ-secretal compounds as catalysts.

The invention provides organorretal compounds of the formula (1) of the formula sheet, wherein R 1 and R 5 are the same or different and each of these symbols is a group C 1 -Q alkyl (3) or Si (Q C, alkyl) 3 in which each of the alkyl groups may be substituted are by one or more phenyl groups, or a group C-QHJC-C 1 -alkyl) 2, a group C 1 -HH 2 (Qq, alkyl) or a group C (¢ ^ ¾) 3, wherein QHj is a phenyl; R2 represents a tertiary alkyl group with the tertiary carbon atom bonded to the diketinimato system; R3 represents a hydrogen atom or a G-C3 alkyl group; R4 represents a phenyl group or a phenyl group substituted by one or more Q-C alkyl groups; M is Zr, Ti or Hf; and A represents a group that can be easily split off.

Preferably R1 and R5 are Si (CH3) 3 or C (CH3) 3; R2 is C (CH3) 3 or C (CHJ: CHc; R3 is a hydrogen atom; R4 is CjHc (phenyl) or 0 ^ 01, -4 (a 4-tolyl group); and A is halogen.

Even more preferably, R1 and R5 are both Si (CH3) 3; R2 is C (CH3) 3; R3 is hydrogen; R4 is Qib; is M Zr; and is A Cl.

The above compounds are suitable as catalysts for the polymerization (both homo- and cc-polymerization) of olefins, e.g., ethylene or propylene.

Numerous catalysts exist for the polymerization of olefins. An important group is formed by the metallocenes, such as those mentioned in Chemistry in Britain, February 1994, namely Cp2ZrCl2 (where Cp = cyclopentadiene) and those according to formulas (2), (3) and (4). The metal locenes have numerous advantages: they can be used to control stereoregularity and molecular weight distribution to yield polymers "tailored" for certain applications, and they are soluble in hydrocarbons to form homogeneous catalytic systems.

The present polymerization catalysts have superior catalytic activity and can be prepared in a very simple manner.

Rerpndino from rZr {N (R) C (Bu2) CHC (Ph) N (R)) & · ,! where R = Si (CHJ, (trimethvlsilvl) and the corresponding hafnium compound ni

The above Zr compound can be prepared by reacting a compound of the formula (7) wherein M 'represents Li or K (D.S.Liu, D. Phil. Thesis, University of Sussex), with an equimolar amount of CJLCs. This reaction can be carried out in diethyl ether-Et-Oi: where Ph = Qit.

The product obtained is converted into Et 2 O with ZrCl 4 to give the desired compound:

Alternatively, the desired compound can be obtained from [Zr {N (R) C (Bu-) CHR} ClJ prepared from ZrCl4 + 1/2 [K {N (R) C (Buc) CHR}] 2 (DS Liu, D. Phil. Thesis, University of Sussex) and an equimolar amount of CHcCN.

The analogous hafnium compound was prepared by a similar method.

Example I

RpT-p-iri-ing of fZr (N (R) C (Ph) C (H) C (Bu ~)> JR} rn1f where R is a trimethylsilyl group

Benzonitrile (0.35 cm3, 3.56 mmol) was slowly added to a solution of [K {N (R) C (Bu ^ CHR} ^ (1.00 g, 3.56 nmol) in Et2 O (ca. 30 cm5) at about 25 ° C. The resulting yellow solution is stirred for about 4 hours, then cooled to -78 ° C and zirconium (IV) chloride (0.80 g, 3.43 nnol) added. is slowly warmed to about 25 ° C and stirred for an additional 12 hours Volatiles are removed at 25 ° C / 1/2 torr The residue is washed with hexane (about 10 cm 3) and then taken up in <3 by extraction ^ Cl2 (ca. 40 cm3) The concentrated filtrate from this extract provided yellow crystals of the title compound (1.82 g, 94%), melting point:> 170 ° C (decomposition) (C 42.0; H 6.14 ; N 5.09. C ^ Cl ^ Zr requires C 42.0; H 6.14; N 5.16%); 2 H NMR (at 360.1 MHz in CDCl3): δ -0.29 and 0.14 (SiMe3, s, 9H), 1.03 (BuS d, 9H), 5.80 (CH, s, 1H), 7.05 (phenyl, m, 4H) and 7.14 (phenyl, m, 1H) (abbreviations: s = singlet, d = doublet, m = multiplet).

The single crystal X-ray data of the title compound are shown in Table 1. The structure can be represented by formula (9).

Example II

Preparation of [Hf {N (R) C (Ph) C (BudNR) ClJ where R = trimethylsilyl

Hafnium (IV) chloride (1.12 g, 3.52 nrnol) was added with stirring to a solution of [Li {N (R) C (Ph) C (H) C (But) NR}] 2 (1, 24 g, 1.76 nmol) in Et 2 O (about 25 cm?) At about -78 ° C. The mixture was slowly heated to about 25 ° C and stirred for an additional 12 hours. Volatile material was removed at 25 ° C / 10'2 torr. The residue was washed with hexane (ca. 10 cm3) and then taken up in ¢ 3¾¾ (ca. 40 cm3) by extraction. The concentrated filtrate from this extract provided light yellow crystals of the title compound (1.36 g, 61%) (C 36.1; H 5.25; N 4.34%. GJ ^ CljHfN- requires C 38.5; H 5.08; N, 4.28%); XH NMR (at 360.1 MHz in CDCl,): δ 0.14 and 0.57 (SiMe3, s, 9H), 1.47 (Buc, d, 9H), 6.15 (CH, s, 1H) 7.49 (phenyl, m, 4H) and 7.53 (phenyl, m, 1H).

Table 1. Intramolecular distances (A) and angles (°) with estimated standard derivatives in brackets a) Bonds

b) Corners

Ethylene and propylene were polymerized using two different catalysts, namely the zirconium compound compound prepared above and a zirconium compound of formula (8) described in Unpublished Netherlands Patent Application 9400919 filed June 7, 1994, which catalysts are referred to herein as A and B, respectively. The polymer is tested for ethylene at 40 bar and room temperature and for propylene at 1 bar and room temperature. The results are given below.

Testing with ethylene at high pressure (40 bar): 100 ml of toluene, 5 ml of a 30% (w / w) solution of co-catalyst MftQ (methylaluminoxane) were placed in an autoclave (0.5 l); Witco) in toluene and 5 ml of a 0.011 M solution of catalyst A or B in toluene. The autoclave was closed, heated to 50 ° C and pressurized with ethylene at 40 bar coder while stirring rapidly. The pressure was kept constant at 40 bar during the test. Immediately after the addition of ethylene, the internal temperature of the reaction mixture rose (to 115 ° C for B and to 85 ° C for A). After 1 hour, the temperature had dropped to 70 ° C (both for A and for B) and the monomer was discarded. To complete the reaction, a solution of 10% concentrated HCl (aqueous) in methanol was added to the reaction mixture. The polymer was collected and washed with HCl / methanol, water and methanol. After drying at 50 ° C for 16 hours, the yield (in g) was determined.

Testing with propylene at low pressure (1 bar): In a 100 ml three-necked flask, ten successively introduced 20 ml of toluene (distilled with Na), 5 ml of a 30% (w / w) solution of MBO in toluene and finally 5 ml of 0.011 M solution of compound A or B in toluene. The reaction mixture was stirred at room temperature for 5 minutes and then degassed under reduced pressure. With rapid stirring, propylene was fed from a buffer vessel containing 2 l of 1 bar propene (1500 mol / mol A or B). The pressure drop was monitored with a mercury manometer. The polymerization was terminated by adding a solution of 10% concentrated HCl (aqueous) in methanol. The polymer was collected and washed with HCl / methanol, water and methanol. After drying at 50 ° C for 16 hours, the yield (1 g) was determined.

Claims (8)

Compounds of formula (1) of the formula sheet, wherein R 1 and R 5 are the same or different and each of these symbols is a group C 1 (VQ alkyl) 3 or SiIQ Q alkyl) 3, wherein each of the alkyl groups may be substituted by one or more phenyl groups, or a group C-CAiG-C, alkyl) 2, a group C (QHc) 2 (C 1 -Q alkyl) or a group C 1 -QRh, wherein CR is a phenyl group; R2 represents a tertiary alkyl group with the tertiary carbon atom bonded to the diketiminato system; R3 represents a hydrogen atom or a C-C3 alkyl group; R4 represents a phenyl group or a phenyl group substituted by one or more C-C4 alkyl groups; M is Zr, Ti or Hf; and A represents a group that can be easily split off. The compound of claim 1, wherein R; and k are Si (CR), or CiCR! -; R2 C (CR)? or is CiCRRCR-; RJ is a hydrogen atom; R4 is C.R or GRCR-4; and A is halogen. The compound of claim 2, wherein R 1 and 11 are both Si (CR); R2 is CICH,); R? is hydrogen; R4 is QHc; M is Zr; and A is Cl. 4. A process for the homopolymerization or polymerization of olefins, characterized in that a compound according to any one of claims 1-3 is used as the catalyst. 5. Process according to claim 4, characterized in that a co-catalyst is also used. 6. Process according to claim 4 or 5, characterized in that ethylene or propylene is subjected to polymerization. A process for preparing a compound of the formula (1), wherein a) a compound (5) of the formula sheet, wherein M 'represents Li or K and R1, R2, R3 and R5 have the meanings given in claim 1 react with a phenyl cyanide, and the reaction product obtained converts MA, wherein A and M have the meanings given in claim 1; cf b) a compound of the formula (5) of the formula sheet reacts with MA, and reacts the complex obtained with a phenyl cyanide. The process according to claim 7, wherein a compound of the formula (7), wherein M 'Li or K and R is a trimethylsilyl group, is reacted with phenyl cyanide, and the resulting reaction product is reacted with ZrX, or HfX, wherein X is a halogen, preferably chlorine; or b) a compound of formula (7), wherein M 'and R have the meanings given in a) above, react with ZrX, or HfX, wherein X is a halogen, preferably chlorine, and react the resulting complex with phenyl cyanide.