EP0807097A1

EP0807097A1 - Olefin oligomer production process

Info

Publication number: EP0807097A1
Application number: EP96901315A
Authority: EP
Inventors: Stefan Seelert; Hans-Joachim Müller; Bernd Lothar Marczinke; Franz Langhauser; Christoph Janiak
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1995-02-01
Filing date: 1996-01-20
Publication date: 1997-11-19
Also published as: WO1996023750A1

Abstract

A process is disclosed for producing olefin oligomers. Olefins are oligomerised in the presence of metallocene catalyst systems. As catalyst systems, metallocene complexes having the general formula (I) [C5H(5-p)Rp][C5H5]MX1X2, in which R stands for bulky residues, are used. The olefin oligomers are useful as starting materials for the production of lubricants, fuel and oil additives, and as macromonomers.

Description

Process for the preparation of olefin oligomers

description

The present invention relates to an improved process for the preparation of olefin oligomers by oligomerization of olefins in the presence of metallocene catalyst systems.

The invention further relates to olefin oligomers obtainable by a process according to claims 1 to 3, and the use of the oligomers for the production of lubricants and fuel additives.

Olefin oligomers are valuable starting products for the production of fuel and oil additives, lubricants and plasticizers. They can also be used as macromonomers.

It is generally advantageous if the modified products, such as lubricants, available from the olefin oligomers have a relatively high molecular weight.

It is therefore generally advantageous if the starting materials themselves, ie the olefin-oligomer mixture, already have a relatively high molecular weight.

EP-A 0 596 553 describes olefin oligomerizations with metallocene catalysts, the two cyclopentadienyl ligands of which are differently alkyl-substituted.

It is disadvantageous that oligomers with a low molecular weight are obtained, that very special, preparatively complex metallocene complexes are used as catalyst components and that the productivity of the catalyst systems leaves something to be desired.

EP-A 0 540 108 describes the preparation of olefin oligomers with metallocene catalysts which are aryl-substituted.

Another disadvantage here is that very special, preparative complex metallocene complexes are used as catalyst components and that the productivity of the catalyst systems leaves something to be desired.

EP-A 0 257 696 describes the oligomerization of α-olefins with metallocene catalysts. With this method, however, only dimers are formed. The object of the present invention was therefore to improve. Providing processes for the production of olefin oligomers having a relatively high molecular weight Mw from olefins using easily accessible catalyst systems.

Accordingly, a process for the production of olefin oligomers by oligomerization of olefins in the presence of metallocene catalyst systems has been found, using catalyst systems which are active ingredients

A) Metallocene complexes of the general formula I

[C ₅ H ₍₅ _ _p) R _p ] [C ₅ H ₅ ] MX1X ² I

in which the substituents and indices have the following meaning:

[C5H5] a cyclopentadienyl unit

[C ₅ H ( ₅ _p) R _p . a cyclopentadienyl unit p substituted with bulky C - to C ₃ o-carbon or silicon-organic radicals R an integer value from 2 to 5

M is a titanium, zirconium or hafnium atom

X ¹ , X ² a formally negatively charged leaving atom or a formally negatively charged leaving group

and

B) an acceptor compound for the substituents X ¹ , X ² of component A) as an activator

contain.

In addition, the olefin oligomers obtainable by the process according to claims 1 to 3 were found, and the use of the oligomers for the production of lubricants and fuel additives.

Of the olefins, linear and ring-shaped ones with 2 to 12 C atoms are generally suitable, for example α-olefins such as ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 4-methylpentene-1 or vinylcyclohexane, and also olefins with an internal double bond such as E- and Z-2-butene, E- and Z-2-pentene, E- and Z -3-witches. Cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclonones, cyclodecene and norbornene are suitable as cycloolefins. C ₂ - to C -α-01efins, such as ethylene, propene, 1-butene and in particular propene, are preferably used.

In addition to the pure olefins, it is of course also possible to oligomerize mixtures of different olefins having 2 to 12 carbon atoms. The molar ratio of the individual olefin components to one another is generally not critical if one considers that the amount of ethylene units in the cooligomers is generally 0.01 to 5 mol%, preferably 0.01 to 3 mol%, in total is particularly 0.01 to 2 mol%.

The metallocene component I of the catalyst system is a so-called titanocene-zirconocene and hafnocene derivative, hence complexes of titanium, zirconium and hafnium, in which the metal atom M is bonded between two substituted cyclopentadienyl groups, the remaining valences of the central atom M are saturated by easily exchangeable leaving atoms or leaving groups X.

Suitable metallocene complexes are those with the general formula [C ₅ H ( ₅ _ _P ) R _P ] [CsHs.MXiX ² I, in which M is titanium, zirconium or hafnium, preferably zirconium.

[C ₅ H ₅ ] stands for the unsubstituted cyclopentadienyl ligand. [C ₅ H ( ₅ _ _P ) R _p ] stands for a cyclopentadienyl ligand substituted with bulky C ₃ to C ₃₀ hydrocarbon or organosilicon radicals R.

A bulky radical is generally understood to mean a substituent which is preferably but not necessarily branched to the ring atom in the α or higher position.

R thus stands for all bulky aliphatic and aromatic carbon-organic and silicon-organic groups with at least 3 carbon atoms, such as i-propyl, i-butyl, sec-butyl, tert-butyl, neo-pentyl , Cyclohexyl, 2, 6-dimethylphenyl, 2,6-di-tert-butylphenyl, 2,6-di-tert-butyl-4-methylphenyl, 2,4,6-trimethylphenyl, 2,4,6 -Tri-tert-butyl-phenyl, benzyl, neophyl, trimethylsilyl, triethylsilyl, triphenylsilyl, tritolylsilyl and tert-butyldimethylsilyl. R is preferably tert-butyl and trimethylsilyl and in particular tert-butyl.

There may be 2 to 5 such substituents attached to the cyclopentadienyl moiety, the position of the substituents on the ring not being critical. Three substituents on the ring are preferably bonded in positions 1,2,4, two substituents on the ring in 1,3 positions.

Easily exchangeable leaving atoms or leaving groups X ¹ , X ^{2 of} the metallocene complexes of the general formula I may be mentioned: hydrogen, halogen such as fluorine, bromine, iodine and preferably chlorine. In addition, alcoholates such as methanolate, ethanolate, n- and i-propanolate, phenolate, trifluoromethylphenolate, naphtholate, silanolate may be mentioned.

Also recommended for X ¹ , X ^{2 are} particularly aliphatic C ¹ -C 10 -alkyl radicals, in particular methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neo -Pentyl, hexyl, preferably methyl, tert-butyl and neo-pentyl. Furthermore, alicyclic C ₃ to C ₂ hydrocarbon radicals, such as cyclopropyl, cyclobutyl, cyclopentyl and in particular cyclohexyl or C ₅ to C ₂ o-bicycloalkyl, such as bicyclopentyl, and in particular bicycloheptyl and bicyclooctyl.

Examples of substituents X ¹ , x ² with aromatic structural units are C genannt to cis aryl, preferably phenyl, or naphthyl, alkyl aryl or arylalkyl, each having 1 to 10 C atoms in the alkyl radical and 6 to 20 C atoms in the aryl radical such as tolyl, benzyl.

Examples of suitable metallocene complexes I are: [cyclopentadienyl (1,3-di-tert-butylcyclopentadienyl)] zirconium dichloride, [cyclopentadienyl (1,3-bis (trimethylsilyl) cyclopentadienyl)] zirconium dichloride, [cyclopentadienyl (1, 3-di-isopropylcyclopentadienyl)] zirconium dichloride.

The metallocene complexes of the general formula I can be prepared in a simple manner by known processes, e.g. Brauer (ed.): Handbuch der preparative inorganic chemistry, volume 2, 3rd editions, pages 1395 to 1397, Enke, Stuttgart 1978. A preferred process is based on the lithium salts of the appropriately substituted cyclopentadienyls, which are reacted with the monocyclopentadienyl transition metal halides.

Only one metallocene complex is expediently used in the oligomerization reaction, but it is also possible to use mixtures of different metallocene complexes.

In addition to the metallocene complexes A), the catalyst systems according to the invention also contain activators B) which are known per se and are also called cocatalysts in the literature. In general, they alkylate the transition metal component A) of Catalyst system and / or abstract a ligand X ¹ or X ² from the transition metal component, so that ultimately a catalyst system for the oligomerization of olefinically unsaturated hydrocarbons can arise. In general, organometallic compounds of the 1st to 3rd main group or the 2nd subgroup of the periodic table are suitable for these tasks, but other acceptor compounds such as, for example, carbocation salts can also be used.

Particularly suitable activator compounds are aluminum organyl, boron organyle and carbocation salts. Open-chain or cyclic alumoxane compounds of the general formula II or III are preferred, which can be obtained according to US Pat. No. 4,794,096 by reacting aluminum trialkyls with water.

Rl *

AI- 4-0 A1- + R ^l

Rl m II

Rl

4-o —AI H— III

I ^m

R ^l

Herein R ^{i is} a C_ to C _ß alkyl group, preferably methyl or ethyl group and m is an integer from 5 to 30, preferably 10 to 25.

As a rule, the oligomeric alumoxane compounds are present as mixtures of both linear and cyclic chain molecules of different lengths, so that m is to be regarded as the mean.

Also suitable as cocatalysts are generally aluminum organyls of the general formula Al (R ² ) ₃ , where R ^{2 is} hydrogen, C, ~ to Cio-alkyl, preferably Cχ ~ to C - alkyl, especially methyl, ethyl, butyl and iso-butyl. In addition, R ^{2 can} also represent arylalkyl or alkylaryl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical.

Aluminum alkyls A1 (R ² > _{3) are} furthermore suitable in which R ² can mean fluorine, chlorine, bromine or iodine in addition to the radicals defined above, with the proviso that at least one radical R ^{2 is} a C-organic radical or is a hydrogen atom. Particularly preferred compounds are trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, diisobutyl aluminum hydride, diethyl aluminum chloride. In addition, organic compounds are also very suitable as activators, for example tris-arylboron compounds, preferably tris (pentafluorophenyDbor, furthermore salts of carbonium ions, preferably triphenylmethyltetraarylborate, in particular triphenylmethyltetra (pentafluorophenyl) borate.

The Al, B or C compounds mentioned are known or can be obtained in a manner known per se.

The activators can be used alone or as mixtures in the catalyst system.

The activator component B) is preferably used in a molar excess with respect to the metal complex A).

The molar ratio of activator B) to metal complex A) is generally 100: 1 to 10000: 1, preferably 200: 1 to 1000: 1.

The constituents of the catalyst systems according to the invention can be introduced into the oligomerization reactor individually or as a mixture in any order. The metallocene complex is preferably mixed with at least one activator component before it enters the reactor, that is to say preactivated.

The oligomers according to the invention can be prepared in the conventional reactors used for the oligomerization of olefins, either batchwise or preferably continuously. Suitable reactors include continuously operated stirred kettles, it also being possible to use a series of several stirred kettles connected in series.

The oligomerization can be carried out in the gas phase, in a suspension, in liquid monomers and in inert solvents. In the case of oligomerization in solvents, in particular liquid hydrocarbons such as benzene, ethylbenzene or toluene are used.

In a preferred process according to the invention for producing the olefin oligomers, the oligomeric aluminoxane compound, preferably as a solution in toluene, is initially introduced. For this purpose, for example, the olefin with 2 to 12 carbon atoms is added and the temperature is raised. After the metallocene complex has been added, the mixture is oligomerized for 20 to 800 minutes, preferably 40 to 500 minutes. The temperatures here are from 0 to 250 ° C., preferably from 20 to 200 ° C., and the work is carried out at pressures from 100 to 300,000 kPa, preferably in the range from 100 to 10,000 kPa and in particular in the range from 100 to 4000 kPa.

The oligomerization can therefore be carried out using the low-pressure, medium-pressure and high-pressure processes. The amount of catalyst used is not critical.

This gives oligomers with molecular weights Mw (weight average) of generally 100 to 20,000, preferably 100 to 10,000, in particular 100 to 8000, which have a high content of terminal vinylidene double bonds.

The degree of polymerization of the olefin oligomers is generally in the range from 2 to 500, preferably in the range from 2 to 300.

The molecular weight distribution Mw / Mn (weight average / number average), measured with the method of gel permeation chromatography (GPC) at 35 ° C. with polystyrene gel as column material and THF as solvent against the polystyrene standard of the olefin oligomers thus obtained, is in generally 2 to 3.5, preferably 2 to 3.

The olefin oligomers obtained in this way can be further processed with the usual chemical reactions, such as hydoformylation or hydroamination or a combination of both methods, to functionalized oligo-olefins which are suitable, for example, as lubricants or fuel or oil additives are. Because of their double bond content, the olefin oligomers obtained can also be used as macromonomers.

Examples

Manufacture of olefin oligomers

example 1

Propene oligomerization

240 ml of a 0.063 molar methylalumoxane solution in toluene were placed in a 1 l stirred autoclave, 300 g (7.1 mol) of liquid propene were condensed and heated to 50.degree. A pressure of 13 bar was established. Then 11.9 mg (0.03 mmol) of [cyclopentadienyl (1,3-di-tert-butylcyclopentadienyl)] zirconium dichloride, dissolved in 10.0 ml of 1.5 molar toluene methylaluminoxane solution (AI: Zr = 1000: 1) added. The mixture was then oligomerized for 60 minutes, the reactor was depressurized and 33.1 g of propene oligomer were isolated. The productivity of the catalyst system was 12.3 kg oligomers / g Zr x h; Mw = 2720, Mn = 1600.

Example 2

The procedure was as in Example 1, but the oligomerization was now carried out at 25 ° C. instead of at 50 ° C. 44.5 g of propene oligomers were obtained. The productivity of the catalyst system was 16.6 kg oligomers / g Zr x h; Mw = 6498, Mn = 3610.

Comparative example V2

The procedure was as in Example 2, but a catalyst system consisting of 4 mg (0.014 mmol) of bis (cyclopentadienyl) zirconium dichloride was dissolved in 8.2 ml of 1.7 molar toluene methylaluminoxane solution (Al: Zr = 1000: 1) used and the oligomerization time was 67.5 h. 107.2 g of propene oligomers were obtained. The productivity of the ^'catalyst system now amounted to 1.3 kg oligomers / g Zr xh; Mw = 2082, Mn = 1090.

Claims

claims

1. Process for the preparation of olefin oligomers by oligomerization of olefins in the presence of metallocene catalyst systems, characterized in that catalyst systems are used which are active ingredients

A) Metallocene complexes of the general formula I

[C ₅ H ( ₅ _ _p ) R _p ] [C ₅ H ₅ ] MX1X ² I

in which the substituents and indices have the following meaning:

[C5H5] a cyclopentadienyl unit [C ₅ H ( ₅ _p) R _p ] a cyclopentadienyl unit substituted with bulky C ₃ - to C ₃ o-carbon or silicon-organic radicals R.

p is an integer from 2 to 5

M a titanium, zirconium or

Hafnium atom X ¹ , X ^{2 is} a formally negatively charged leaving atom or a formally negatively charged leaving group

and

contain.

2. The method according to claim 1, characterized in that the catalyst systems contain, as activators, open-chain or cyclic aluminoxane compounds of the general formula II or III R ^l .

AI E- 0 AI R ^l Rl m II

R ^l

4-o AI III

I ^m

R ^l

wherein R ^{i is} a Ci- to C _δ alkyl group and m is an integer from 5 to 30.

3. The method according to claims 1 to 2, characterized gekennzeich¬ net that the substituents X ¹ , X ^{2 is} halogen, H, C_- to Cio-alkyl or Ci- to Cio-alkoxy.

4. olefin oligomers obtainable by a process according to claims 1 to 3.

5. Use of the olefin oligomers for the production of lubricants or fuel additives.