AU732207B2

AU732207B2 - Catalyst preparation

Info

Publication number: AU732207B2
Application number: AU68321/98A
Authority: AU
Inventors: Eit Drent; Bernard Lucas Feringa; Esther Van Den Beuken
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1997-03-25
Filing date: 1998-03-24
Publication date: 2001-04-12
Anticipated expiration: 2018-03-24
Also published as: AU6832198A; EP0969928A1; BR9808043A; CN1251056A; CA2285080A1; WO1998042440A1; TW472066B; JP2001518134A

Description

CATALYST PREPARATION The invention relates to a process for the polymerization and co-polymerization of ethylenically unsaturated compounds, using a catalyst which is preparable by combining a bidentate ligand, a source of cations and an acid.

of cations and an acid.

1* 20 In WO 96/23010 of Du Pont/U.N. Carolina, a process for the polymerization of olefins is described. This process uses catalysts comprising bisimine Pd(II) and Ni(II) complexes in dichloromethane or toluene.

Since such bisimine complexes are only stable at relatively low temperatures, the olefin polymerization process has to be operated at such temperatures and hence the turnover (moles of product per mole of catalyst) of the latter process is rather low.

The present inventors have now found a catalyst that is much more stable at higher temperatures. Therefore a process for the polymerization or co-polymerisation of ethylenically unsaturated compounds, using this catalyst, can be carried out at higher temperatures. For this reason the turnover of the polymerization process when using the catalyst of the present invention can be much higher than that of the process according to WO 96/23010.

Moreover, the catalyst can be synthesized without exclusion of air while the bisimine catalysts according to WO 96/23010 are prepared from a very airsensitive (bisimine) PdMe 2 complex.

R. E. Rulke et al. disclose in Organometallics (1996) 3022-3031 the ligand N-(2-(diphenylphosphino)benzylidene) (2-(pyridyl)ethyl)amine, PNN. It also discloses that palladium complexes of PNN with

C

C.

C

C WO 98/42440 PCT/EP98/01902 2 4 5 7

I

R R R n in which X P, As, Sb, n 0 or 1,

R

1

R

2 alkyl, alkoxy, aryloxy, cycloalkyl or a substituted or non-substituted (cyclo)aliphatic, (cyclo)olefinic or aromatic group with 1-24 C-atoms, or

R

1 and R 2 may form together a substituted or nonsubstituted cycloaliphatic, cyclo-olefinic or aromatic group

R

3

R

4

R

7

R

8 H, alkyl, alkoxy, aryloxy, cycloalkyl or a substituted or non-substituted (cyclo)aliphatic, (cyclo)olefinic or aromatic group with 1-24 C-atoms, and if n 1:R 5 and/or R 6 H, alkyl, alkoxy, aryloxy, cycloalkyl or a substituted or non-substituted (cyclo)aliphatic,(cyclo)olefinic or aromatic group with 1-24 C-atoms, and C' and C" together with R 3 and R 6 may form a substituted or non-substituted (cyclo)aliphatic, (cyclo)olefinic or aromatic group, R 4 and R 5 being absent in this case, or C' and C" may form an olefinic bond, R 4 and R 5 being absent in this case, with a source of cations of a metal of group 8, 9 or of the Periodic Table of Elements and an acid having a pKa of less than 4.

In the above ligand the moiety X can be phosphorus, arsenic or antimony, phosphorus being the preferred element to be incorporated into the ligand constituting part of the present catalyst.

The present catalyst comprises a metal of group 8, 9 or 10 of the Periodic Table of Elements, as shown on 3~",age 2406 of the Academic Press Dictionary of Science and P.\OPERcc\68321-98 spec doc-06/02/01 -2Ain this case, or C' and C" may form an olefinic bond, R 4 and Rs being absent in this case, with a source of cations of a metal group 8, 9 or 10 of the Periodic Table of Elements and an anion source, derived from an acid having a pKa of less than 4.

Preferably, the acid is p-toluenesulphoric acid or

CF

3

SO

3

H.

The present catalyst comprises a metal of group 8, 9 or 10 of the Periodic Table of Elements, as shown on page 2406 of the Academic Press Dictionary of Science and e WO 98/42440 PCT/EP98/01902 3 Technology, edited by C. Morris, Academic Press Inc., San Diego (1992).

These groups include the metals: Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt. Palladium is the preferred metal of the present polymerization catalyst.

As source of palladium cations, conveniently a palladium salt is used.

Suitable palladium salts are mineral salts, such as palladium sulphate, palladium nitrate and palladium phosphate.

Other suitable palladium salts are salts of sulphonic acids, such as methylsulphonic acid, trifluoromethanesulphonic acid and p-toluenesulphonic acid and salts of carboxylic acids, such as acetic acid and propionic acid, halo-acetic acids, for example trifluoro- and trichloroacetic acid, oxalic acid and citric acid.

As source of palladium cations use may also be made of the metal in its elemental form, or in a zero valent state, e.g. in complex form such as in palladiumdibenzylacetone or palladium-tetrakis-tri-phenylphosphine. These sources are generally applied in combination with a protonic acid, thus yielding the palladium cations in situ.

Palladium salts of carboxylic acids are preferred sources of palladium cations, in particular palladium acetate.

Suitable palladium organometallic complexes can also be used, e.g. cyclo-octadiene palladium chloro-methyl.

The present catalyst can be formed by combining the above ligand and the above source of cations with an anion source, derived from an acid having a pKa 4 in a solvent. As a source of anions such acids comprise

H

2 AsO 4 HF, HJO 3

H

3 P0 3

H

3

PO

4

H

3 P0 7

HNO

3

H

2 SeO 3

H

2 TeO 3

H

2

SO

4

CH

2 CLCOOH, CHCl 2 COOH, CCl 3 COOH, CH 2 BrCOOH,

CH

2

.COHCH

2

(COOH)

3 COOH.CH:CH.COOH(trans),

CH

2 0H.COOH, WO 98/42440 PCT/EP98/01902 -4- COOH.CH:CH.COOH (cis), COOH.CHOH.C- 2 .COOH, COOH.CH 2

.COOH,

CH-

3 .CHOH.COOH, H.COOH, COOH.COOH,

COOH.CHOH.CHOH.COQH,

CH6H 5

.CO.NH.CH

2 .COOH,

C

6

H

4

.(COOH)

2

C

6

H

2

(OH).(NO

2 3 C6H 4 .OH.COOH, C 6

H

4

.NH

2

.SO

3 H, C 5

H

4

N

4 0 3

F

0 F F FIF

F

F -F

F

F F F F F F 0 F F

F

H

FC

3 CF CF H H 3 H H CF 1 3 HQ0 B O H

CF

3 H H CF H H 3 0 FO CF 3 3C H F H H F FO0 B

OF

F H H F p-toluenesulphonic acid and CF 3

SO

3 H, the latter two being preferred. Alternatively salts of these acids can be used.

As an example a catalyst can be prepared by the reactiLon ]between cyclo-octadiene palladium chloro-methyi and silver trifluoromethylsuiphonate.

Suitable solvents for the catalyst preparation process according to the invention are hydrocarbons, alcohols, ethers and ketones or mixtures thereof.

Examples of suitable solvents are toluene, pentane,

CH

2 C12, ChCl 3 dioxane, water, 2-ethylhexanol, ethylene glycol, glycerol, the dimethylether of ethylene glycoi(diglyme) and diethylether, the preferred solvents being toluene, methanol or CH 2 Cl 2 In the bidentate ligand moiety of the present catalyst the groups R 1 and R 2 may be identical or different from each other. Preferably they are identical and both O-methoxyphenyl groups. Advantageously R 1 and R 2 form together a cyclo-octyl group.

The group Rg in the bidentate ligand can be H or any organic group with 1-24 C-atoms. Advantageously Rg is chosen such that the moiety (R 8 is a di-isopropylaniline group.

The present invention also relates to a process for the polymerization of ethylenically unsaturated hydrocarbons using the above catalyst. In the present specification, unless otherwise stated, the term "polymerization" includes "oligomerization" and "dimerization".

Ethylenically unsaturated compounds to be used as starting material in the polymerization process according to the invention include unsaturated hydrocarbons and unsaturated compounds, comprising besides hydrogen and 25 carbon atoms at least one other atom in their molecules o: such as an oxygen or nitrogen atom. Typically, the ethylenically unsaturated compound is an a-olefin or a.

mixture of two or more a-olefins or a mixture of at least one a-olefin and at least one functionalized olefin.

30 Olefins, in particular mono-olefins are preferred starting materials, for example ethene, propene, butenes, pentenes, hexenes, heptenes, octenes, dicyclopentadiene, *ooo P.\OPER~]cc\69321-98 sp-~d-W06/2/01 4-methylpentene, 4-pentenoic acid or its esters, norbornene, functionalized alkenes, possibly containing heteroatoms and mixtures thereof. They may be applied together with other unsaturated hydrocarbons, for example cyclic olef ins such as cyclopentene and cyclohexene, diolef ins such as butadiene, 1,4-pentadiene and WO 98/42440 PCT/EP98/01902 6 hexadiene, olefins substituted by aromatic groups such as styrene, allylbenzene, p-methylstyrene and alphamethylstyrene and acetylenically unsaturated compounds such as acetylene, phenylacetylene and isopropenylacetylene.

The invention is of particular interest for the preparation of co-polymers whereby one of the monomers is a lower olefin, in particular ethene and propene and at least one of the other monomers contains a functional group such as a hydroxy, cyano, anhydride or ester group.

Examples of suitable monomers of this category are 3-buten-l-ol, 5-hexen-l-ol, 10-undecen-l-ol, alkyl esters of acrylic or methacrylic acid such as methylacrylate, methylmethacrylate and ethylacrylate, vinyl esters such as vinylacetate and vinylpropionate and anhydrides such as the anhydride of 5-norbornene-2,3-dicarboxylic acid.

As a suitable co-monomer CO can be applied.

If desired, the polymerization process according to the invention may be carried out in the presence of a suitable solvent. Various solvents such as hydrocarbons, alcohols, ethers, esters and ketones may be used, including an excess of one of the monomers, provided this monomer is in the liquid phase under the reaction conditions of the process.

Surprisingly it has been found that the use of different reaction solvents results in the formation of polymer products having different molecular weights.

Generally the use of an apolar solvent results in the formation of polymers of relatively high molecular weights, whereas the presence of a polar solvent will result in the formation of oligomers, i.e. reaction products containing from two to twenty monomer units. For example, in the event of a reaction solvent, substantially consisting of polar compounds such as water WO 98/42440 PCT/EP98/01902 7 or di- or trihydric alcohols, e.g. ethylene glycol and glycerol, predominantly oligomeric products are formed.

On the other hand with a reaction solvent, substantially consisting of relatively apolar compounds, such as the dimethylether of ethylene glycol (diglyme) or diethylether, polymer products of higher molecular weight can be formed.

In the process according to the invention only catalytic amounts of the catalyst system are required.

Usually the amount of catalyst is in the range of 10-1 to 7 mole per mole of ethylenically unsaturated compound to be polymerized. Preferably, the catalyst is applied in an amount between 10-2 and 10-6 and most preferably in the range of 10-3 to 10-5 mole per mole of ethylenically unsaturated compound to be polymerized.

It will be appreciated that the utility of the products obtained will depend, inter alia, on the molecular weight of the products.

Oligomeric products may find use e.g. as starting materials in the production of plasticizers, lubricants and surfactants. The products of higher molecular weight are of interest as thermoplastics and may be applied for films, sheets, packaging materials and the like.

The process of the invention may be carried out at moderate reaction conditions, both in the event that in a predominantly apolar reaction medium products of relatively high molecular weight are prepared and in the event that in a polar reaction medium oligomers are produced.

Reaction temperatures are usually in the range of to 200 OC, temperatures in the range of 25 to 130 °C being preferred.

Usually superatmospheric reaction pressures are applied, for example in the range of 1 to 100 bar, pressures outside the indicated range not being 8 precluded. Preferably a pressure in the range of 2 to bar is applied.

The catalyst system may suitably be prepared separately, by combining the source of metal cations or a precursor thereof and the other components as defined above in the presence of a suitable solvent, before supplying the monomer(s) to be (co)polymerized. It is also possible to prepare the catalyst in situ by introducing the catalyst components into the reactor and at the same time adding the monomer(s) and any other compound to be present in the reaction medium.

For preparing the catalyst system, the molar amounts of metal compound, the ligand and acid as defined above may be substantially equal. Usually an excess of the acid is preferred, for example up to 10, preferably up to equivalents of acid per gram atom of metal.

The invention is illustrated by the following, nonlimiting examples.

Example 1 Iminophosphine ligands were synthesized from the corresponding amine and aldehyde as shown in Scheme 1: 3 R 3 P 2

SI

RR

2

R

2

N

o~oo NH 2 P p(RI NI-2 L

S

e c WO 98/42440 PCT/EP98/01902 9 The groups R 1

R

2 and R 3 of the ligands L for different catalysts are shown in Table 1: Table 1 L R 1 R2 R3 a Ph H H b Ph Me H c Ph iPr H d m-CH 3 0Ph iPr H e o-CH30Ph H Cl f o-CH 3 0Ph H H g o-CH 3 0Ph H OMe h o-CH 3 0Ph iPr H Ph phenyl Me methyl iPr i-propyl Catalysts were formed by the combination of the bidentate ligands L, Pd(OOC.CH 3 2 and a non-coordinating anion of a weak acid, i.e. p-toluenesulphonic acid (p-TosOH) or CF 3

SO

3 H, via an anion exchange reaction.

Example 2 Procedure for the synthesis of ligand Lh To 1.0 g (2,86 mmol) 2 -[bis(2-methoxyphenyl)phosphino]benzaldehyde in 50 ml toluene was added 0.51 g (2.86 mmol) 2,6 di-isopropylaniline and a catalytic amount p-toluene-sulphonic acid. The solution was refluxed for 4h under Dean-Stark conditions. The solvent was evaporated to yield a yellow oil, which was crystallized from CH 3 0H.

Yield: 1.27 g (87%) WO 98/42440 PCT/EP98/01902 10 Anal. Calc. for C 33

H

36 N0 2 P: C 77.78 H 7.12 N 2.75 P 6.08 Found: C 77.61 H 7.22 N 2.91 P 5.93 The synthesis of ligands La up to and including Lg is carried out along an analogous route.

Example 3 With the aid of the catalysts which have been discussed in Example 1 and Table 1 oligomerization reactions were performed under 20 bar ethylene, at a temperature of 100 OC and in 50 ml solvent CH30H. The catalyst comprised 0.1 mmol Pd(OOC.CH 3 2 0.11 mmol ligand and 0.21 mmol TosOH. The product ratio was determined by gas chromatography.

Higher olefins were obtained, as shown in Table 2 in which the sum of the percentages of the moles of C 6 to C16 approximates 100%.

Table 2 Ligands in ethylene oligomerisation Experiment ligand time

C

6

C

8

C

10

C

12

C

14

C

16 1 La 9 250 85 12 3 2 Lb 9 250 74 15 11 3 Lc 9 250 53 29 13 4 1 4 Ld 5 150 62 26 10 2 Le 5 150 44 23 16 10 5 2 6 Lf 5 500 34 26 19 12 6 3 7 Lg 5 800 36 27 18 12 6 1 8 Lh 5 1100 22 25 22 16 9 6 Turnover number (moles ethylene converted per mole catalyst) WO 98/42440 PCT/EP98/01902 12 Table 2 shows the product ratio for various iminophosphine ligands. Increasing the steric bulk at the nitrogen donor site, resulted in higher molecular weights (compare Experiments 1 and 2 with 3 and 6 with 8).

Furthermore, when more steric bulk on the phosphorus site was introduced (in case of o-methoxy analog Lh) the molecular weight was increased again (compare Experiments 3, 4 and 8).

Remarkably, the activity from 250 to 1100) was increased dramatically, by replacing the two phenyl groups on phosphorus by o-methoxyphenyl groups (Table 2, experiment The catalytic activity was furthermore influenced by electronic effects on the imino donor site; in particular electron releasing groups enhanced the rate. For instance by changing R 3 from chlorine to methoxy (Le-Lg) resulted in the increase of T.O. from 150 to 800.

Furthermore, the isomerization increased at higher temperatures (Table 3) as well as the amount of branched products (Table Decrease of the steric hindrance in the ligand, resulted also in more branched products (compare Lc and Lh).

Table 3 Product ratio dependence on temperature ligand T time T.O. C6 08 010 C12 014 016 (00) M% M% M% M% M% M% Lh 70 16 650 17 24 22 17 12 8 Lh 100 5 1100 22 25 22 16 9 6 Lh 120 5 1650 32 28 20 11 6 3 Table 4 Linearity of 06-012 WO 98/42440 PCTIEP98/01902 14 Fine tuning of the reaction could be achieved by changing solvent and anion. Typical results are summarized in Table 5. By going from MeOH to CH 2 Cl 2 the activity slightly decreased. However, when CF 3

SO

3 was used as counter ion in solvent CH 2 Cl 2 (Exp. the turnover number increased considerably.

Table Exp. ligand solvent anion time TO C 6 08 C 1 0 C12 014 C16 source M% M% M% M% M% M% 1 L'c MeCH p-TosOH 9 250 53 29 13 4 1 2 Lc- CH 2 Cl 2 p-TosOH 12 250 82 15 3 3 Lc CH 2 Cl 2

CF

3

SO

3 H- 9 1000 72 22 4 Lh MeOH CF 3 00 2 qH 5 800 30 28 21 13 7 1 Lh MeOR p-TosOH 5 1100 22 25 22 16 9 6 6 Lh MeOH CF' 3 S0 2 H 5 1100 26 27 22 14 8 3 7 Lh CH 2 C1 2 p-TOSOH 5 750 57 42 0.5 8 Lh diglyme CF 3

SO

3 H 5 1250 63 27 8 2 16 Example 4 Using similar reaction conditions as applied in Example 3, a Pd-catalyst comprising the ligand N-{2-[bis- (2-methoxyphenyl)phosphino]benzylidene}-2,5-(diisopropyl)benzene-amine gave in 1.5 h in ethyleneglycol a turnover number of about 1100 mol/mol Pd. The product ratio was: C6:25%, Cg:27%, C10:23%, C12:17%, C14:5%, C16:3%. The linearity was C 6 C8:92%, C10:86%. The experiment with 40 bar ethylene in methanol gave the following results: C6:26%, C8:26%, C 10 C12:14%, C14:9%, The turnover was about 1350 mol/mol Pd. The number of 1-olefins was also about the same: C6:39%, C8:30%, Ci0:21%.

In conclusion, a new metal based catalyst system for ethylene oligomerization has been developed. Remarkable features are the excellent stability in solvents at high temperatures, the formation of C6-C16 oligomers at these temperatures and the possibility to tune the oligomer selectivity by the iminophosphine ligands.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

go o o

Claims

1. A catalyst obtainable by combining a bidentate ligand with the general formula: R l R4 R5 R 7 X--C 1 11 -C=N-Rg R2 R 3 R 6 n in which X P, As, Sb, n 0 or 1, R I R 2 alkyl, alkoxy, aryloxy, cycloalkyl or a substituted or non-substituted (cyclo)aliphatic, (cyclo)olefinic or aromatic group with 1-24 C-atoms, or R 1 and R 2 may form together a substituted or non- substituted cycloaliphatic, cyclo-olefinic or aromatic group, R 3 R 4 R 7 R 8 H, alkyl, alkoxy, aryloxy, cycloalkyl or a substituted or non-substituted (cyclo)aliphatic, (cyclo)olefinic or aromatic group with 1-24 C-atoms, and if n 1:R 5 and/or R 6 H, alkyl, alkoxy, aryloxy, cycloalkyl or a substituted or non-substituted (cyclo)aliphatic,(cyclo)olefinic or aromatic group with 1-24 C-atoms, and C' and C" together with R 3 and Rg may form a substituted or non-substituted (cyclo)aliphatic, (cyclo)olefinic or aromatic group, R 4 and R 5 being absent in this case, or C' and C" may form an olefinic bond, R 4 and R 5 being absent in this case, with a source of cations of a metal of group 8, 9 or of the Periodic Table of Elements and an acid having a pKa of less than 4. I WO 98/42440 18 PCT/EP98/01902 18

2. A catalyst as claimed in claim 1, characterized in that X P.

3. A catalyst as claimed in claim 1 or 2, characterized in that the metal of group 8, 9 or 10 of the Periodic Table of Elements is Pd.

4. A catalyst as claimed in any one of claims 1-3, characterized in that the acid having a pKa of less than 4 is p-toluenesulphonic acid or CF 3 SO 3 H. A catalyst as claimed in any one of claims 1-4, characterized in that in the bidentate ligand R 1 and R 2 are o-methoxyphenyl groups.

6. A catalyst as claimed in any one of claims characterized in that in the bidentate ligand is a di-isopropylaniline group.

7. A catalyst as claimed in any one of claims 1-6, characterized in that the solvent is toluene, methanol or CH 2 C1 2

8. A process for the polymerization or co-polymerisation of ethylenically unsaturated organic compounds, characterized in that a catalyst is used as claimed in claim any one of claims 1-7.

9. A process as claimed in claim 8, characterized in that the ethylenically unsaturated compound is an a- olefin or a mixture of two or more a-olefins or a mixture of at least one a-olefin and at least one functionalized olefin. A process as claimed in claim 8 or 9, characterized in that the ratio between the molar amount of the ethylenically unsaturated compound(s) and the amount of the catalyst is in the range of from 10:1 to 107:1. PAOPERUJcc6932 1-98 9pcc1do--6/02/0I

19- 1.Process as claimed in claim 1 and substantially as hereinbefore described with reference to Example 3 or 4. DATED this 6 th day of February, 2001 Shell Internationale Research Maatschappij B.V. by DAVIES COLLISON CAVE Patent Attorneys for the Applicant(s) 9 *999** 9 9**9 9 9* S S