Title of Invention

A CATALYTIC COMPOSITION OBTAINED BY MIXING AND AN ETHYLENE OLIGOMERIZATION PROCESS

Abstract A process for oligomerising ethylene to produce I-butene and/or l-hexene uses a catalytic composition obtained by mixing at least one chromium compound with at least one aryloxy aluminium compound with general formula RnAl(R'O)3-n where R is a linear or branched hydrocarbyl radical containing I to 30 carbon atoms, R'O is an aryloxy radical containing 6 to 80 carbon atoms and n is a whole number which can take the values 0, I or 2, and with at least one other hydrocarbyl aluminium compound selected from tris(hydrocarbyl)aluminium compounds or chlorinated or brominated hydrocarbyl aluminium compounds. The catalytic composition is also claimed.
Full Text

The present invention relates to a catalytic composition obtained by mixing and an ethylene oligomerizaticn process.
Processes for producing alpha olefins from ethylene generally lead to an ensemble of oligomers containing 4 to 30 carbon atoms, or even more than 30, and the olefins are then separated by distillation. Over the past few years, demand for lower oligomers, essentially 1-butene, 1-hexene and 1-octene, which are used as co-monomers with ethylene for the manufacture of linear low density polyethylene, has been increasing.
Few catalysts exist which selectively produce a particular oligomer, as is the case when dimerising ethylene to 1-butene with a titanium based catalyst. However, chromium based catalysts are known to lead to the formation of mainly 1-hexene, with polyethylene to a greater or lesser extent, the proportion of butenes and octenes in the products being very small (R. M. Manyik, W. E. Walker, T. P. Wilson, J. Catal, 1977, 47, 197 and J. R. Briggs, J. Chem. Soc, Chem. Commun. 1989, 674 and references cited therein). Catalysts which enable selective trimerisation of ethylene have recently been claimed (United States patent US-A-5 198 563, US-A-5 288 823, US-Ao 382 738, European patent EP-A-0 608 447, EP-A-0 611 743, EP-A-0 614 865). Such catalysts are prepared from a chromium salt and a metal amide, in particular a pyrrolide. Other catalysts use an aluminoxane and a chromium complex with a chelating phosphine (US-A-5 550 305).
We have now discovered in the present invention that a catalytic composition obtained by mixing at least one chromium compound with at least one aryloxy aluminium compound and with at least one hydrocarbyl aluminium compound has particular selectivity for the formation of 1-butene and/or 1-hexene by oligomerisation of ethylene.
More precisely, the improved catalytic composition is obtained by mixing:

• at least one chromium compound which may contain one or more identical or different anions, for example selected from the group formed by halides, carboxylates, acetylacetonates, alkoxy anions and aryloxy anions;
• with at least one aryloxy aluminium compound with general formula RnAl(R'O)3.„ in which n is a whole number which can take the values 0, 1 or 2, R is a linear or branched hydrocarbyl radical containing 1 to 30 carbon atoms, and R'O is an aryloxy radical containing 6 to 80 carbon atoms;
• and with at least one hydrocarbyl aluminium compound with general formula AlR"mX3-m where R" is a hydrocarbyl radical containing 1 to 6 carbon atoms, X is a chlorine or bromine atom and m is a number from 1 to 3.
The chromium compound can be a chromium (II) or chromium (III) salt but also a salt with a different oxidation number which may contain one or more identical or different anions such as halides, carboxylates, acetylacetonates, alkoxy anions, or aryloxy anions. The chromium compounds preferably used in the invention are chromium (III) compounds as they are more accessible, but a chromium (I) or chromium (II) compound would also be suitable.
The chromium compounds selected can advantageously be dissolved in a hydrocarbon medium by complexing with an organic oxygen-containing compound such as an ether or an ester or a compound selected from the group formed by acetals and ketals, resulting from condensation of an aldehyde or a ketone with a mono-alcohol or a poly-alcohol, such as di-2,2-(2-ethylhexyloxy)propane.
The aryloxy aluminium compound is selected from aryloxy aluminium compounds with general formula RnAl(R'O)3.n in which n is a whole number which can take the values 0, 1 or 2, R is a linear or branched hydrocarbyl radical containing 1 to 30 carbon atoms, for example alkyl,.cycloalkyl, alkenyl, aryl, or substituted aralkyl, aryl or cycloalkyl, preferably a hydrocarbyl residue containing 2 to 10 carbon atoms. Non limiting examples of R are an ethyl, n-propyl, isopropyl,

n-butyl, isobutyl, cyclohexyl, benzyl, diphenylmethyl, phenyl, 2-methylphenyl, or a 2,6-diphenylphenyl residue. R'O is an aryloxy radical containing 6 to 80 carbon atoms.
Preferred aryloxy aluminium compounds comprise an aryloxy radical R'O with general formula:

where R1, R2, R3, R4, R5, which may be identical or different, represent a hydrogen, halogen or hydrocarbyl radical, for example alkyl, cycloalkyl, alkenyl, aryl, or substituted aralkyl, aryl or cycloalkyl, preferably containing 1 to 16 carbon atoms, in particular 1 to 10 carbon atoms. Non limiting examples of R1, R2, R3, R4 or R5 are a methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl, benzyl, phenyl, 2-methyl-2-phenylprop-l-yl residue.
Preferred non-limiting examples of aryloxy radicals are: 4-phenylphenoxy, 2-phenylphenoxy, 2,6-diphenylphenoxy, 2,4,6-triphenylphenoxy, 2,3,5,6-tetraphenylphenoxy, 2,4-ditert-butyl-6-phenylphenoxy, 2,6-diisopropylphenoxy, 2,6-dimethylphenoxy, 2,6-ditert-butylphenoxy, 4-methyl-2,6-ditert-butylphenoxy, 2,6-dichloro-4-tert-butylphenoxy, and 2,6-dibromo-4-tert-butylphenoxy. When the aryloxy hydrocarbyl aluminium compound is selected from aluminium aryloxides with general formula RA1(R'0)2, the two aryloxy radicals can be carried by the same molecule such as a biphenoxy, binaphthoxy or 1,8-naphthalene-dioxy radical, which may or may not be substituted by alkyl, aryl, or halide radicals.

Particularly preferred compounds are bis(2,6-diphenylphenoxy) isobutyl aluminium or bis(2,6-diphenylphenoxy) ethyl aluminium.
The preparation of the compound RnA(R'O)3.0 is known in the literature. Any process for preparing this compound may be suitable such as, for example, the reaction of a phenol R'OH with a trialkylaluminium AIR3 in an organic solvent, for example a hydrocarbon or an ether.
The hydrocarbyl aluminium compounds used in the invention are
represented by the general formula AIR"mX3.m where R" is a hydrocarbyl radical,
preferably an alkyl radical containing 1 to 6 carbon atoms, X is a chlorine or
bromine atom, preferably a chlorine atom, and m is a number in the range 1 to 3.
Non limiting examples are: dichloroethylaluminium, ethylaluminium sesquichloride,
chlorodiethylaluminium, chlorodiisobutylaluminium, triethylaluminium,
tripropylaluminium, and triisobutylaluminium. The preferred hydrocarbyl aluminium compound is triethylaluminium.
The catalyst components .can be brought into contact in a solvent constituted by a saturated hydrocarbon such as hexane, cyclohexane, heptane, butane, or isobutane, by an unsaturated hydrocarbon such as a monoolefm or a diolefin containing, for example, 4 to 20 carbon atoms, or by an aromatic hydrocarbon such as benzene, toluene, xylene, mesitylene, or ethylbenzene, used pure or as a mixture.
The concentration of chromium in the catalytic solution can vary from 1 X 10-5 to 0.1 mole/1, preferably 5 x 10-5 to 1 x 10 mole/1. The molar ratio between the aryloxy aluminium compound and the chromium compound can be between 1:1 and 30:1, preferably between 1:1 and 20:1. The molar ratio between the hydrocarbyl aluminium and the chromium compound is selected so as to be between 1:1 and 35:1, preferably between 1:1 and 15:1.

The order of mixing the three constituents of the catalytic composition is not critical. However, the chromium compound is preferably first mixed with the aryloxy aluminium compound, and then added to the hydrocarbyl aluminium compound.
The ethylene oligomerisation reaction can be carried out at a total pressure in the range 0.5 MPa and 15 MPa, preferably in the range 1 to 8 MPa, and at a temperature in the range 20°C and 180°C, preferably in the range 50°C to 160°C.
In one particular implementation of the catalytic oligomerisation reaction carried out batchwise, a set volume of the catalytic solution, prepared as described above, is introduced into a reactor provided with the usual stirring, heating and cooling means, then pressurised with ethylene to the desired pressure, and the temperature is adjusted to the desired value. The oligomerisation reactor is kept under constant pressure by introducing ethylene until the total volume of liquid product represents, for example, between 2 and 50 times the volume of the catalytic solution initially introduced. The catalyst is then destroyed using any normal means known to the skilled person, then the reaction products and the solvent are extracted and separated.
For a continuous operation, implementation is preferably as follows: the catalytic solution is injected at the same time as the ethylene into a reactor which is stirred using conventional stirring means or by external recirculation, and kept at the desired temperature. The components of the catalyst can also be separately injected into the reaction medium, for example the product of the interaction of the chromium compound with the aryloxy aluminium compound with formula RnAl(R'O)3.n and the hydrocarbyl aluminium compound represented by general formula AlR"mX3.m . Ethylene is introduced using a pressure activated inlet valve which keeps the pressure constant. The reaction mixture is extracted by means of a liquid level activated valve so as to maintain the liquid level constant. The

catalyst is continuously destroyed using any normal means which is known to the skilled person, then the reaction products and solvent are separated, for example by distillation. Non transformed ethylene can be recycled to the reactor.
Accordingly, the present invention provides a catalytic composition obtained by mixing at least one known chromium compound such as herein described with at least one aryloxy aluminium compound with general formula RnAl(R'O)3_n in which n is a whole number which can take the values 0, 1 or 2, R is a linear or branched hydrocarbyl radical containing 1 to 30 carbon atoms, and R'O is an aryloxy radical containing 6 to 80 carbon atoms; and with at least one hydrocarbyl aluminium compound with general formula AlR"mX3_m where R" is a hydrocarbyl radical containing 1 to 6 carbon atoms, X is a chlorine or bromine atom and m is a number from 1 to 3.
Accordingly the present invention also provides an ethylene oligomerization process carried out in the presence of a catalytic composition such as herein described.

The following examples illustrate the invention without limiting its scope.
EXAMPLE 1
0.5 X 10"' moles of chromium (III) 2-ethylhexanoate in solution in a mineral oil was introduced kept from humidity, into a 100 ml glass flask under an inert atmosphere and the solution was heated for one hour under a vacuum of 10"" torr then diluted with 25 ml of toluene which had been distilled under an inert atmosphere.
The following were introduced in order under ethylene at ambient temperature into a stainless steel autoclave with a working volume of 100 ml provided with a double envelope to regulate the temperature by oil circulation: 5 ml of the chromium (III) 2-ethylhexanoate solution prepared above, i.e., 0.1 x 10' moles of chromium, 8 ml of a 0.1 M bis(2,6-diphenylphenoxy)-isobutylaluminium solution in toluene, i.e., 0.8 x 10-3 moles, and 0.8 x 10' moles of triethylaluminium in solution in 8 ml of toluene. The temperature was raised to 120°C and the ethylene pressure was kept at 5 MPa.
After one hour of reaction, introduction of ethylene was halted and the catalyst was deactivated by injecting 0.5 ml of ethanol in solution in 1.5 ml of toluene using an air lock which could be pressurised to a pressure higher than that of the autoclave. The reactor was cooled and degassed then the gas and liquid were analysed by gas chromatography. 19 g of ethylene had been consumed in one hour. The composition of the products is given in Table 1. 18% by weight of solid polymer with respect to the ethylene consumed was also recovered.
EXAMPLE 2

With the same apparatus as that used in Example 1 and under the same conditions, with the exception that half the amount of bis(2,6-diphenylphenoxy)isobutylaluminium was introduced, 12 g of ethylene was consumed in one hour of reaction. The product composition is shown in Table 1. 30% by weight of solid polymer with respect to the ethylene consumed was also recovered.
EXAMPLE 3
With the same apparatus as that used in Example 1 and under the same conditions, with the exception that no bis(2,6-diphenylphenoxy)isobutylaluminium was introduced, 1 g of ethylene was consumed in one hour of reaction. The product composition is shown in Table 1. 72% by weight of polymer with respect to the ethylene consumed was also recovered.
EXAMPLE 4
With the same apparatus as that used in Example 1 and under the same conditions, with the exception that the pressure was 3 MPa and the molar ratio of bis(2,6-diphenylphenoxy)isobutylaluminium/Cr was 5/1, 14 g of ethylene was consumed in one hour of reaction. The product composition is shown in Table 1. 20% by weight of solid polymer with respect to the ethylene consumed was also recovered.
EXAMPLE 5
With the same apparatus as that used in Example 1 and under the same conditions, with the exception that the bis(2,6-diphenylphenoxy)isobutylaluminium was replaced by bis(2,6-tert-butylphenoxy)isobutylaluminium, 5 g of ethylene was consumed in one hour of reaction. The product composition is shown in Table 1. 35% by weight of solid polymer with respect to the ethylene consumed was also recovered.

With the same apparatus as that used in Example 1 and under the same conditions, with the exception that the pressure was 3 MPa and the molar ratio of bis(2,6-diphenylphenoxy)isobutylaluminium/Cr was 10/1, and the triethylaluminium/Cr molar ratio was 5/1, 5 g of ethylene was consumed in one hour of reaction. The product composition is shown in Table 1. 40% by weight of solid polymer with respect to the ethylene consumed was also recovered.
EXAMPLE 7
With the same apparatus as that used in Example 1 and under the same conditions, with the exception that the bis(2,6-diphenylphenoxy)isobutylaluminium was replaced by bis-2,6-diphenylphenoxydiethylylaluminium, the bis-2,6-diphenylphenoxydiethylaluminium/Cr molar ratio was 4/1 and the triethylaluminium/Cr molar ratio was 10/1, 5.4 g of ethylene was consumed in one hour of reaction. The product composition is shown in Table 1. 41% by weight of solid polymer with respect to the ethylene consumed was also recovered.

Depending on the catalytic composition selected, the process of the invention thus essentially produces 1-butene and/or 1-hexene or mixtures thereof, to the exclusion of higher olefins, and with high selectivity for alpha olefins.


WE CLAIM:
1. A catalytic composition obtained by mixing:
at least one known chromium compound such as herein described
with at least one aryloxy aluminium compound with general formula
RnAl(R'O)3.n in which n is a whole number which can take the values 0,
1 or 2, R is a linear or branched hydrocarbyl radical containing 1 to 30
carbon atoms, and R'O is an aryloxy radical containing 6 to 80 carbon
atoms;
and with at least one hydrocarbyl aluminium compound with general
formula AlR"mX3.m where R" is a hydrocarbyl radical containing 1 to 6
carbon atoms, X is a chlorine or bromine atom and m is a number from
1 to 3.
2. The composition according to claim 1, wherein the chromium compound comprises one or more identical or different anions selected from the group formed by halides, carboxylates, acetylacetonates, and alkoxy and aryloxy anions.
3. The composition according to claim 1 or claim 2, wherein the aryloxy aluminium compound with general formula RnAl(R'O)3.n, the aryloxy radical R'O has general formula:

where R], R2, R3, R4? R5. which may be identical or different, represent a hydrogen, a halogen or a hydrocarbyl radical containing 1 to 16 carbon atoms.

4. The catalyst composition according to claim 1, wherein said chromium compound is first mixed with said aryloxyaluminum compound and is then added to the hydrocarbyl aluminum compound.
5. The composition according to any one of claims 1 to 3, wherein the aryloxy aluminium compound is bis(2,6-diphenylphenoxy) isobutylaluminium or bis(2,6-diphenylphenoxy)ethylaluminium.
6. The composition according to any one of claims 1 to 5, wherein the hydrocarbyl aluminium compound is dichloroethylaluminium, ethylaluminium sesquichloride, chlorodiethylaluminium, chlorodiisobutylaluminium, triethylaluminium, tripropylaluminium, or triisobutylaluminium.
7. The composition according to any one of claims 1 to 5, wherein the hydrocarbyl aluminium compound is triethylaluminium.
8. The composition according to any one of claims 1 to 7, wherein the catalyst components are brought into contact in a solvent comprising of a saturated, unsaturated, olefinic ordiolefmic or aromatic hydrocarbon.
9. The composition according to any one of claims 1 to 8, wherein the concentration of chromium in the catalytic solution is in the range 1 x 10-5 to
0.1 mole/1.
10. The composition according to any one of claims 1 to 9, wherein the molar ratio
between the aryloxy aluminium compound and the chromium compound is in
the range 1:1 to 30:1 and the mole ratio between the hydrocarbyl aluminium
and the chromium compound is in the range 1:1 to 35:1.

11. An ethylene oligomerization process carried out in the presence of a catalytic composition according to any one of claims 1 to 10.
12. The process according to claim 11, wherein the ethylene oligomerisation reaction is carried out at a pressure in the range 0.5 MPa to 15 MPa and at a temperature in the range 20oC to 180oC.
13. The process according to claims 11 and 12, which is continuous wherein said catalyst solution is injected at the same time as the ethylene into a reactor under stirring.
14. A catalytic composition substantially as herein described and exemplified.
15. An ethylene oligomerization process substantially as herein described and exemplified.


Documents:

1319-mas-1998-abstract.pdf

1319-mas-1998-claims duplicate.pdf

1319-mas-1998-claims original.pdf

1319-mas-1998-correspondance others.pdf

1319-mas-1998-correspondance po.pdf

1319-mas-1998-description complete duplicate.pdf

1319-mas-1998-description complete original.pdf

1319-mas-1998-form 1.pdf

1319-mas-1998-form 26.pdf

1319-mas-1998-form 3.pdf

1319-mas-1998-other documents.pdf


Patent Number 205216
Indian Patent Application Number 1319/MAS/1998
PG Journal Number 26/2007
Publication Date 29-Jun-2007
Grant Date 22-Mar-2007
Date of Filing 17-Jun-1998
Name of Patentee INSTITUT FRANCAIS DU PETROLE
Applicant Address 4, avenue de Bois Preau, 92852 Rueil-Malmaison,,
Inventors:
# Inventor's Name Inventor's Address
1 LUCIEN SAUSSINE, 2 PLACE DES FRERES TISSANDIER 72890 CROISSY SUR SEINE
2 DOMINIQUE COMMEREUC 32 RUE ABEL VACHER 92190 MEUDON
3 SEBASTIEN DROCHON 1 AVENUE MAISTRASSE 92500 RUEIL MALMAISON
PCT International Classification Number B01D031/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 97/07613 1997-06-17 France