VANADIUM PYRIDINE-IMINE COMPLEX, CATALYTIC SYSTEM COMPRISING SAID VANADIUM PYRIDINE-IMMINE COMPLEX AND A (CO) POLYMERIZATION PROCESS OF CONJUGATED DIENES

Abstract

Vanadium pyridine-imine complex having general formula (I), wherein:R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6, equal to or different from each other, represent a hydrogen atom; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally halogenated cycloalkyl groups optionally substituted, aryl groups optionally substituted;X.sub.1, X.sub.2 and X.sub.3, equal to or different from each other, represent a halogen atom such as, for example, chlorine, bromine, iodine, preferably chlorine; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, OCOR.sub.7 groups or OR.sub.7 groups wherein R.sub.7 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15;Y is selected from ethers such as, for example, diethylether, tetrahydrofuran (THF), dimethoxyethane, preferably is etrahydrofuran (THF);n is 0 or 1. Said vanadium pyridine-imine complex having general formula (I) can be advantageously used in a catalytic system for the (co) polymerization of conjugated dienes.

##STR00001##

Claims

1: A vanadium pyridine-imine complex having a formula (I): ##STR00012## wherein: R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 each independently represent a hydrogen atom, an optionally halogenated linear or branched C.sub.1-C.sub.20 alkyl group, an optionally substituted cycloalkyl group, or an optionally substituted aryl group; X.sub.1, X.sub.2 and X.sub.3 each independently represent a halogen atom a linear or branched C.sub.1-C.sub.20 alkyl group, a OCOR.sub.7 group or a OR.sub.7 group, wherein R.sub.7 is a linear or branched C.sub.1-C.sub.20 alkyl group; Y is an ether; and n is 0 or 1.

2: The vanadium pyridine-imine complex of claim 1, wherein: R.sub.1 represents a hydrogen atom or branched C.sub.1-C.sub.20 alkyl group; R.sub.2 represents an optionally substituted cycloalkyl group or an optionally substituted aryl group; R.sub.3, R.sub.4, R.sub.5 and R.sub.6, each represent a hydrogen atom; X.sub.1, X.sub.2 and X.sub.3, each independently represent a halogen atom; Y is tetrahydrofuran (THF); an n is 1.

3: A catalytic system for (co)polymerization of conjugated dienes, comprising: (a) the vanadium pyridine-imine complex of claim 1; and (b) a co-catalyst that is an aluminum organo-derivative compound.

4: The catalytic system of claim 3, wherein the co-catalyst comprises an aluminoxane having a formula (III):
(R.sub.12).sub.2AlO[Al(R.sub.13)O-].sub.m-Al(R.sub.14).sub.2(III) wherein R.sub.12, R.sub.13 and R.sub.14 each independently represent a hydrogen atom, a halogen atom, or a linear or branched C.sub.1-C.sub.20 alkyl group, cycloalkyl group, or aryl group, optionally substituted with one or more silicon or germanium atoms; and m is an integer of 0 to 1000.

5: A process of (co)polymerizing conjugated dienes, comprising (co)polymerizing one or more conjugated dienes with the catalytic system of claim 3.

6: The process of claim 5, wherein the one or more conjugated dienes comprise 1,3-butadiene or isoprene.

7: The vanadium pyridine-imine complex of claim 1, wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 each independently represent an optionally halogenated linear or branched C.sub.1-C.sub.15 alkyl group.

8: The vanadium pyridine-imine complex of claim 1, wherein X.sub.1, X.sub.2 and X.sub.3 each independently represent a linear or branched C.sub.1-C.sub.15 alkyl group.

9: The vanadium pyridine-imine complex of claim 1, wherein n is 0.

10: The vanadium pyridine-imine complex of claim 1, wherein n is 1.

11: The vanadium pyridine-imine complex of claim 10, wherein Y is selected from the group consisting of diethylether, tetrahydrofuran and dimethoxyethane.

12: The vanadium pyridine-imine complex of claim 2, wherein R.sub.2 is selected from the group consisting of 2,6-di-iso-propylphenyl, 2-methyl-phenyl and 2,4,6-trimethylphenyl.

13: The catalytic system of claim 3, wherein the co-catalyst comprises at least one selected from the group consisting of (b.sub.1), (b.sub.2), (b.sub.3) and (b.sub.4): (b.sub.1) a compound having a formula (II):
Al(R.sub.9)(R.sub.10)(R.sub.11)(II) wherein R.sub.9 represents a hydrogen atom, a fluorine atom, or a linear or branched C.sub.1-C.sub.20 alkyl group, cycloalkyl group, aryl group, alkylaryl group, arylalkyl group, or alkoxy group; R.sub.10 and R.sub.11 each independently represent a linear or branched C.sub.1-C.sub.20 alkyl group, cycloalkyl group, aryl group, alkylaryl group, or arylalkyl group; (b.sub.2) an aluminoxane having a formula (III):
(R.sub.12).sub.2AlO[Al(R.sub.13)O-].sub.m-Al(R.sub.14).sub.2(III) wherein R.sub.12, R.sub.13 and R.sub.14 each independently represent a hydrogen atom, a halogen atom, or a linear or branched C.sub.1-C.sub.20 alkyl group, cycloalkyl group, or aryl group, optionally substituted with one or more silicon or germanium atoms; and m is an integer of 0 to 1000 (b.sub.3) an aluminum organo-derivative compound that is partially hydrolyzed; and (b.sub.4) a halogen-aluminum alkyl having a formula (IV) or (V):
Al(R.sub.15).sub.p(X.sub.3).sub.3-p(IV)
Al.sub.2(R.sub.15).sub.q(X.sub.3).sub.3-q(V) wherein p is 1 or 2; q is an integer of 1 to 5; each R.sub.15 independently represents a linear or branched C.sub.1-C.sub.20 alkyl group; and X.sub.3 represents a chlorine or bromine atom.

Description

EXAMPLES

[0085] Reagents and Materials

[0086] The reagents and materials used in the following examples of the invention, the optional pretreatments thereof and the manufacturer thereof, are reported in the list below: [0087] anhydrous vanadium trichloride (Aldrich): purity degree 99.9%, used as such; [0088] vanadium trichloride:tetrahydrofuran (1:3) complex [VCl.sub.3(THF).sub.3] (Aldrich): purity degree 97%, used as such; [0089] methylaluminoxane (MAO) (toluene solution 10% by weight) (Crompton): used as such; or in the dry form (MAO-dry) obtained by removing the free trimethylaluminum together with the solvent from the toluene solution under vacuum and drying the residue obtained always under vacuum; [0090] modified methylaluminoxane (MAO-modified) (7% toluene solution) (Akzo Nobel): used as such; [0091] tetra-iso-butylaluminoxane (TIBAO) (cyclohexane solution 30% by weight) (Akzo Nobel): used as such; [0092] 2,6-di-iso-propylaniline (Aldrich): used as such; [0093] acetylpyridine (Aldrich): used as such; [0094] 2-pyridinecarboxaldeyde (Aldrich): used as such; [0095] o-toluidine (Aldrich): used as such; [0096] cyclohexylamine (Aldrich): used as such; [0097] 2,4,6-trimethylaniline (Aldrich): used as such; [0098] anhydrous sodium sulphate (Aldrich): purity degree Z 99%, used as such; [0099] heptane (Aldrich): used as such; [0100] formic acid (Aldrich): used as such; [0101] ethyl acetate (Aldrich): used as such; [0102] toluene (Fluka): purity degree >99.5%, maintained under reflux on sodium (Na) for about 8 hours, then distilled and stored on molecular sieves under nitrogen; [0103] pentane (Fluka): purity degree 99%, maintained at reflux on sodium/potassium (Na/K) for about 8 hours, then distilled and stored on molecular sieves under nitrogen; [0104] 1,2-dichlorobenzene (Aldrich): purity degree 99%, maintained at reflux on calcium hydride (CaH.sub.2) for about 8 hours, then distilled trap-to-trap and maintained in nitrogen atmosphere at 4 C.; [0105] hexane (Aldrich): used as such; [0106] 1,3-butadiene (Air Liquide): pure, Z 99.5%, evaporating from the container before of each production, dried by passing through a column packed with molecular sieves and condensed into the reactor which was pre-cooled at 20 C.; [0107] isoprene (Aldrich): pure, Z 99%, maintained at reflux on calcium hydride for 2 hours, then distilled trap-to-trap and maintained in nitrogen atmosphere at 4 C.; [0108] methanol (Carlo Erba, RPE): used as such, or optionally anhydrified by distillation on magnesium (Mg); [0109] hydrochloric acid in aqueous solution at 37% (Aldrich): used as such; [0110] deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) (Acros): used as such; [0111] deuterated chloroform (CDCl.sub.3) (Acros): used as such.

[0112] Analysis and characterization methods, reported below, were used.

[0113] Elementary Analysis

[0114] a) Determination of Vanadium (V)

[0115] For determining the weight amount of vanadium (V) in the vanadium pyridine-imine complexes object of the present invention, an aliquot exactly weighted, operating in dry-box under nitrogen flux, of about 30 mg-50 mg of sample, was placed in an approximately 30 ml platinum crucible, togheter with a mixture of 1 ml of hydrofluoric acid (HF) at 40% (Aldrich), 0.25 ml of sulphuric acid (H.sub.2SO.sub.4) at 96% (Aldrich) and 1 ml of nitric acid (HNO.sub.3) at 70% (Aldrich). The crucible were then heated on a plate increasing the temperature up to the appearance of sulphuric white fumes (about 200 C.). The mixtures thus obtained was cooled at room temperature (20 C.-25 C.), additivated with 1 ml of nitric acid (HNO.sub.3) at 70% (Aldrich) and then brought again to fumes appearance. After having repeated for other two times the sequence, a clear solution, almost without colour, was obtained. Then, 1 ml of nitric acid (HNO.sub.3) at 70% (Aldrich) and about 15 ml of water, were then added, in the cold, then heated to 80 C., for about 30 minutes. The sample thus prepared was diluted with water having a MilliQ purity up to a weight of about 50 g, exactly weighted, in order to obtain a solution on which the instrumental analytical determination by a ICP-OES spectrometer (optical detection plasma) Thermo Optek IRIS Advantage Duo was carried out, by comparison with known concentration solutions. For this aim, for each analyte, a calibration line was prepared in the range 0 ppm-10 ppm, by measuring solutions of a known titre obtained by dilution by weight of certified solutions.

[0116] The sample solution prepared as above was further diluted for weighing so as to obtain concentrations close to those of reference, before carrying out the spectrophotometric detection. All the sample were prepared in duplicate. The results were considered adequate if the individual data of the tests in duplicate did not differ of more than 2% related with respect to their average value.

[0117] b) Chlorine Determination

[0118] For said aim, samples of the vanadium pyridine-imine complexes object of the present invention, about 30 mg-50 mg, were exactly weighted into 100 ml glass in dry-box under nitrogen flux. 2 g of sodium carbonate (Na.sub.2CO.sub.3) (Aldrich) were added and, outside of the dry-box, 50 ml MilliQ water. It is brought to a boil on the plate, under magnetic stirring, for about 30 minutes. After cooling, sulphuric acid (H.sub.2SO.sub.4) (Aldrich) diluted 1/5 was added, up to acid reaction and titration with silver nitrate (AgNO.sub.3) 0.1 N (Aldrich) by potentiometric titrator.

[0119] c) Determination of Carbon, Hydrogen and Nitrogen

[0120] The determination of carbon, hydrogen and nitrogen, in the vanadium pyridine-imine complexes object of the present invention, was carried out by a Carlo Erba Mod. 1106 automated analyzer.

[0121] .sup.13C-HMR and .sup.1H-HMR Spectra

[0122] The .sup.13C-HMR e .sup.1H-HMR spectra were registered by nuclear magnetic resonance spectrometer mod. Bruker Avance 400, by using deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) at 103 C. and hexamethyldisiloxane (HDMS) (Aldrich) as internal standard, or by using deuterated chloroform (CDCl.sub.3) at 25 C. and tetramethylsilane (TMS) (Aldrich) as internal standard. For this aim, polymer solution having concentrations equal to 10% by weight with respect to the total weight of the polymer solution are used.

[0123] The microstructure of the polymers was determined through the analysis of the above-mentioned spectra according to what reported in literature by Mochel, V. D., in Journal of Polymer Science Part A-1: Polymer Chemistry (1972), Vol. 10, Issue 4, pag. 1009-1018, for the polybutadiene, and by Sato H. et al., in Journal of Polymer Science: Polymer Chemistry Edition (1979), Vol. 17, Issue 11, pag. 3551-3558, for the polyisoprene.

[0124] Spectra FT-IR (Solid State, UATR)

[0125] The FT-IR spectra (solid state, UATR) were registered by Bruker IFS 48 spectrophotometer equipped with an horizontal ATR linkage Thermo Spectra-Tech. The section, in which the samples to be analyzed are placed, is a Fresnel ATR accessory (Shelton, Conn., USA) which uses crystals of zirconium selenide (ZnSe) with an angle of incidence of 45 in the horizontal direction.

[0126] The FT-IR spectra (solid state, UATR) of the vanadium pyridine-imine complexes object of the present invention, were obtained by inserting samples of the vanadium pyridine-imine complex to be analyzed in said section.

[0127] FT-IR Spectra

[0128] The FT-IR spectra were registered by Thermo Nicolet Nexus 670 and Bruker IFS 48 spectrophotometers.

[0129] The FT-IR spectra of the polymers, were obtained from polymer films on tablets of potassium bromide (KBr), said films being obtained by deposition of a solution in hot 1,2-dichlorobenzene of the polymer to be analyzed. The concentration of the polymer analyzed solutions was equal to 10% by weight with respect to the total weight of the polymer solution.

[0130] Determination of the Molecular Weight

[0131] The determination of the molecular weight (MW) and of the Polydispersion Index (PDI) of the polymers obtained, was carried out by a Waters GPCV 2000 system, using two detector lines (i.e. differential viscosimeter and refractometer), operating under the following conditions: [0132] two PLgel Mixed-C columns; [0133] solvent/eluent: 1,2-dichlorobenzene (Aldrich); [0134] flux: 0.8 ml/min; [0135] temperature: 145 C.; [0136] measurement of the molecular mass: Universal Calibration method.

[0137] The weight average molecular weight (M.sub.w) and the Polydispersion Index (PDI) corresponding to the M.sub.w/M.sub.n (M.sub.n=number average molecular weight) ratio are reported.

Example 1

[0138] Synthesis of the Ligand Having Formula (L1)

##STR00004##

[0139] In a reactor of 500 ml equipped with a magnetic stirrer, 15.96 g (90 mmoles) of 2,6-di-iso-propylaniline were placed together with 100 ml of methanol, some drops of formic acid and 10.9 g (90 mmoles) of acetyl pyridine: the mixture obtained was left, under stirring, at room temperature, until obtaining the precipitation of a solid product. Said solid product was recovered by filtration, washed with cold methanol and dried, under vacuum, at room temperature, obtaining 16 g of a light-yellow microcrystalline product (yield=64%) having formula (L1).

[0140] Elementary analysis [found (calculated for C.sub.19H.sub.24N.sub.2)]: C, 81.52% (81.38%); H, 8.57% (8.63%); N, 9.90% (9.99%).

[0141] Molecular Weight (MW): 280.41.

[0142] FT-IR (nujol): 1652 cm.sup.1.sub.(CN).

Example 2

[0143] Synthesis of the Ligand Having Formula (L2)

##STR00005##

[0144] In a reactor of 500 ml equipped with a magnetic stirrer, 9.96 g (93 mmoles) of 2-pyridinecarboxaldehyde were placed together with 100 ml of methanol, some drops of formic acid and 9.97 g (93 mmoles) of o-toluidine: the mixture obtained was left, under stirring, at room temperature, for 48 hours. Then, anhydrous sodium sulfate was added and the whole was left, under stirring, at room temperature, for 30 minutes. At the end, the whole was filtered, methanol was removed by distillation at reduced pressure and the yellow oily product obtained was purified by elution on silica gel chromatographic column [eluent:heptane/ethyl acetate mixture in a ratio 90/10 (v/v)], obtaining 15 g of a cold light-yellow solid product (yield=83%) having formula (L2).

[0145] Elementary analysis [found (calculated for C.sub.13H.sub.12N.sub.2)]: C, 80.00% (79.56%); H, 6.32% (6.16%); N, 14.57% (14.27%).

[0146] Molecular Weight (MW): 196.25.

[0147] FT-IR (nujol): 1640 cm.sup.1.sub.(CN).

Example 3

[0148] Synthesis of the Ligand Having Formula (L3)

##STR00006##

[0149] In a reactor of 500 ml equipped with a magnetic stirrer, 9.96 g (93 mmoles) of 2-pyridinecarboxyaldehyde were placed together with 100 ml of methanol, some drops of formic acid and 9.23 g (93 mmoles) of cyclohexylamine: the mixture obtained was left, under stirring, at room temperature, for 48 hours. Then, anhydrous sodium sulfate was added and the whole was left, under stirring, at room temperature, for 30 minutes. At the end, the whole was filtered, the methanol was removed by distillation at reduced pressure and the yellow oily product obtained was purified by elution on silica gel chromatographic column [eluent: heptane/ethyl acetate mixture in a ratio 90/10 (v/v)], obtaining 15 g of a microcrystalline light-yellow product (yield=83%) having formula (L3).

[0150] Elementary analysis [found (calculated for C.sub.12H.sub.16N.sub.2)]: C, 76.27% (76.56%); H, 8.31% (8.57%); N, 14.78% (14.88%).

[0151] Molecular Weight (MW): 188.27.

[0152] FT-IR (nujol): 1646 cm.sup.1.sub.(CN).

Example 4

[0153] Synthesis of the Ligand Having Formula (L4)

##STR00007##

[0154] In a reactor of 500 ml equipped with a magnetic stirrer, 9.96 g (93 mmoles) of 2-pyridinecarboxaldehyde were placed together with 100 ml of methanol, some drops of formic acid and 12.6 g (93 mmoles) of 2,4,6-trimethylaniline: the mixture obtained was left, under stirring, at room temperature, for 48 hours. Then, anhydrous sodium sulfate was added and the whole was left, under stirring, at room temperature, for 30 minutes. At the end, the whole was filtered, the methanol was removed by distillation at reduced pressure and the yellow oily product obtained was purified by elution on silica gel chromatographic column [eluent: heptane/ethyl acetate mixture in a ratio 90/10 (v/v)], and crystallized from cold ethyl ether obtaining 17 g of a crystalline light-yellow product (yield=81%) having formula (L4).

[0155] Elementary analysis [found (calculated for C.sub.15H.sub.16N.sub.2)]: C, 80.27% (80.32%); H, 7.31% (7.19%); N, 12.68% (12.49%).

[0156] Molecular Weight (MW): 224.30.

[0157] FT-IR (nujol): 1640 cm.sup.1.sub.(CN).

Example 5

[0158] Synthesis of the VCl.sub.3(L1)(THF) Complex [GL890 Sample]

##STR00008##

[0159] The vanadium(III)chloride(tris-tetrahydrofuran) [VCl.sub.3(THF).sub.3] (1.05 g; 2.8 mmoles) was introduced into a tailed flask of 100 ml together with toluene (40 ml). Then, a solution of the ligand having formula (L1) (0.790 g; 2.8 mmoles; molar ratio L1/V=1), obtained as described in Example 1, in toluene (15 ml), was added. The mixture obtained was maintained, under stirring, at room temperature, for 48 hours, then the volume of the mixture was reduced to about 10 ml by evaporation, under vacuum, at room temperature and, then, pentane was added (50 ml). An orange/brownish solid precipitate was formed, which was recovered by filtration, washed with pentane (25 ml) and dried under vacuum, at room temperature, obtaining 1.197 g (yield=83.9%) of an orange/brownish solid product corresponding to the VCl.sub.3(L1)(THF) complex.

[0160] Elementary analysis [found (calculated for C.sub.23H.sub.32Cl.sub.3N.sub.2OV)]: C, 54.3% (54.19%); H, 6.1% (6.33%); Cl, 21.0% (20.86%); N, 5.4% (5.49%); V, 10.2% (9.99%).

[0161] Molecular Weight (MW): 509.81.

Example 6

[0162] Synthesis of the VCl.sub.3(L2)(THF) Complex [ZG57 Sample]

##STR00009##

[0163] The vanadium(III)chloride(tris-tetrahydrofuran) [VCl.sub.3(THF).sub.3] (0.583 g; 1.55 mmoles) was introduced into a tailed flask of 100 ml together with toluene (20 ml). Then, a solution of the ligand having formula (L2) (0.304 g; 1.55 mmoles; molar ratio L2/V=1), obtained as described in Example 2, in toluene (10 ml), was added. The mixture obtained was maintained, under stirring, at room temperature, for 48 hours, then the volume of the mixture was reduced to about 10 ml by evaporation, under vacuum, at room temperature and, then, pentane was added (50 ml). An orange solid precipitate formed which was recovered by filtration, washed with pentane (25 ml) and dried under vacuum, at room temperature, obtaining 0.430 g (yield=65%) of an orange solid product corresponding to the VCl.sub.3(L2) (THF) complex.

[0164] Elementary analysis [found (calculated for C.sub.17H.sub.20Cl.sub.3N.sub.2OV)]: C, 47.8% (47.97%); H, 4.8% (4.74%); Cl, 25.2% (24.99%); N, 6.8% (6.58%); V, 12.2% (11.97%).

[0165] Molecular Weight (MW): 425.65.

Example 7

[0166] Synthesis of the VCl.sub.3(L3)(THF) Complex [IP91 Sample]

##STR00010##

[0167] The vanadium(III)chloride(tris-tetrahydrofuran) [VCl.sub.3(THF).sub.3] (0.498 g; 1.33 mmoles) was introduced into a tailed flask of 100 ml together with toluene (16 ml). Then, a solution of the ligand having formula (L3) (0.250 g; 1.33 mmoles; molar ratio L3/V=1), obtained as described in Example 3, in toluene (6 ml), was added. The mixture obtained was maintained, under stirring, at room temperature, for 48 hours, then the volume of the mixture was reduced to about 10 ml by evaporation, under vacuum, at room temperature and, then, pentane was added (50 ml). An orange solid precipitate was formed, which was recovered by filtration, washed with pentane (25 ml) and dried under vacuum, at room temperature, obtaining 0.361 g (yield=65%) of an orange solid product corresponding to the VCl.sub.3(L3) (THF) complex.

[0168] Elementary analysis [found (calculated for C.sub.16H.sub.24Cl.sub.3N.sub.2OV)]: C, 46.3% (46.01%); H, 5.8% (5.79%); Cl, 25.6% (25.46%); N, 6.6% (6.71%); V, 12.4% (12.20%).

[0169] Molecular Weight (MW): 417.68.

Example 8

[0170] Synthesis of the VCl.sub.3(L4) (THF) Complex [GL1442 Sample]

##STR00011##

[0171] The vanadium (III) chloride (tris-tetrahydrofuran) [VCl.sub.3(THF).sub.3] (0.951 g; 2.54 mmoles) was introduced into a tailed flask of 100 ml together with toluene (25 ml). Then, a solution of the ligand having formula (L4) (0.560 g; 2.54 mmoles; molar ratio L4/V=1), obtained as described in Example 4, in toluene (10 ml), was added. The mixture obtained was maintained, under stirring, at room temperature, for 48 hours, then the volume of the mixture was reduced to about 10 ml by evaporation, under vacuum, at room temperature and, then, pentane was added (60 ml). An orange solid precipitate was formed, which was recovered by filtration, washed with pentane (25 ml) and dried under vacuum, at room temperature, obtaining 0.820 g (yield=71.2%) of an orange solid product corresponding to the VCl.sub.3(L4)(THF) complex.

[0172] Elementary analysis [found (calculated for C.sub.19H.sub.24Cl.sub.3N.sub.2OV)]: C, 50.4% (50.30%); H, 5.5% (5.33%); Cl, 23.6% (23.44%); N, 6.0% (6.17%); V, 11.4% (12.23%).

[0173] Molecular Weight (MW): 453.71.

[0174] In FIG. 1 the FT-IR spectrum (solid state, UATR) of the polybutadiene obtained (Absorbance; Wavenumbers) is reported.

Example 9 (GL881)

[0175] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.15 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L1) (THF) complex (sample GL890) (2.55 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 5.1 mg) obtained as described in Example 5. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 1.256 g of polybutadiene having mainly cis-1,4 structure (content of cis-1,4 units equal to 72%) (conversion equal to 89.7%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0176] In FIG. 2 the FT-IR spectrum of the polybutadiene obtained (Absorbance; Wavenumbers) is reported.

Example 10 (GL884)

[0177] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.15 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, dry-methylaluminoxane (MAO-dry) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L1)(THF) complex (sample GL890) (2.55 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 5.1 mg) obtained as described in Example 5. The whole was maintained, under magnetic stirring, at 20 C., for 5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.477 g of polybutadiene having mainly cis-1,4 structure (content of cis-1,4 units equal to 83%) (conversion equal to 34.1%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0178] In FIG. 3 the FT-IR spectrum of the obtained polybutadiene (Absorbance; Wavenumbers) is reported.

[0179] In FIG. 4 the curve GPC (Gel Permeation Chromatography) of the polybutadiene obtained is reported.

Example 11 (GL883)

[0180] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, tetra-iso-butylaluminoxane (TIBAO) in a cyclohexane solution at 30% by weight (6.21 ml; 1.010.sup.2 moles, equal to about 2.98 g) was added and, then, the VCl.sub.3(L1) (THF) complex (sample GL890) (2.55 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 5.1 mg) obtained as described in Example 5. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.477 g of polybutadiene having mainly cis-1,4 structure (content of cis-1,4 units equal to 70%) (conversion equal to 64.5%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

Example 12 (GL892)

[0181] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.15 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, modified methylaluminoxane (MAO-modified) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L1) (THF) complex (sample GL890) (2.2 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 5.1 mg) obtained as described in Example 5. The whole was maintained, under magnetic stirring, at 20 C., for 30 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.825 g of polybutadiene having mainly cis-1,4 structure (content of cis-1,4 units equal to 82%) (conversion equal to 58.9%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0182] In FIG. 5 the FT-IR spectrum of the polybutadiene obtained (Absorbance; Wavenumbers) is reported.

Example 13 (ZG58)

[0183] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.55 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L2) (THF) complex (sample ZG57) (2.15 ml of toluene suspension at a concentration equal to 2 mg/ml; 1105 moles, equal to about 4.3 mg) obtained as described in Example 6. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0184] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.372 g of polybutadiene having a mixed structure (conversion equal to 26.6%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0185] In FIG. 6 the .sup.1H-NMR (above) and .sup.13C-NMR (below) spectra of the polybutadiene obtained are reported.

Example 14 (ZG59)

[0186] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.55 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, dry-methylaluminoxane (MAO-dry) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L2) (THF) complex (sample ZG57) (2.15 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 4.3 mg) obtained as described in Example 6. The whole was maintained, under magnetic stirring, at 20 C., for 3 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0187] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 1.06 g of polybutadiene having a mixed structure (conversion equal to 75.7%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0188] In FIG. 7 the FT-IR spectrum of the polybutadiene obtained (Absorbance; Wavenumbers) is reported.

[0189] In FIG. 8 the .sup.1H-NMR (above) and .sup.13C-NMR (below) spectra of the polybutadiene obtained are reported.

Example 15 (IP96)

[0190] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.6 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L3) (THF) complex (sample IP91) (2.1 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 4.2 mg) obtained as described in Example 7. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0191] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.527 g of polybutadiene having a mixed structure (conversion equal to 37.6%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0192] In FIG. 9 the FT-IR spectrum of the polybutadiene obtained (Absorbance; Wavenumbers) is reported.

Example 16 (IP97)

[0193] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.6 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, dry-methylaluminoxane (MAO-dry) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L3) (THF) complex (sample IP91) (2.1 ml of toluene suspension at a concentration equal to 2 mg/ml; 1105 moles, equal to about 4.2 mg) obtained as described in Example 7. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0194] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.743 g of polybutadiene having a mixed structure (conversion equal to 53.1%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0195] In FIG. 10 the FT-IR spectrum of the polybutadiene obtained (Absorbance; Wavenumbers) is reported.

[0196] In FIG. 11 the .sup.1H-NMR (above) and .sup.13C-NMR (below) spectra of the polybutadiene obtained are reported.

Example 17 (IP92)

[0197] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.45 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L4) (THF) complex (sample GL1442) (2.25 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 4.5 mg) obtained as described in Example 8. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0198] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.756 g of polybutadiene having a mixed structure (conversion equal to 54.0%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0199] In FIG. 12 the .sup.1H-NMR (above) and .sup.13C-NMR (below) spectra of the polybutadiene obtained are reported.

Example 18 (IP93)

[0200] 2 ml of 1,3-butadiene equal to about 1.4 g were cold condensed (20 C.) in a test tube of 25 ml. Then, 7.45 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1.010.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L4) (THF) complex (sample GL1442) (2.25 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 4.5 mg) obtained as described in Example 8. The whole was maintained, under magnetic stirring, at 20 C., for 5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0201] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox1076 (Ciba) antioxidant obtaining 1.14 g of polybutadiene having a mixed structure (conversion equal to 81.4%): further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0202] In FIG. 13 the FT-IR spectrum of the polybutadiene obtained (Absorbance; Wavenumbers) is reported.

Example 19 (GR001)

[0203] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.15 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L1)(THF) complex (sample GL890) (2.55 ml of toluene suspension at a concentration equal to 2 mg/ml; 1105 moles, equal to about 5.1 mg) obtained as described in Example 5. The whole was maintained, under magnetic stirring, at 20 C., for 12 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0204] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.985 g of polyisoprene having mainly cis-1,4 structure (content of cis-1,4 units equal to 79.6%) (conversion equal to 72.4%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

Example 20 (GR002)

[0205] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.15 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, dry-methylaluminoxane (MAO-dry) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L1) (THF) complex (sample GL890) (2.55 ml of toluene suspension at a concentration equal to 2 mg/ml; 1105 moles, equal to about 5.1 mg) obtained as described in Example 5. The whole was maintained, under magnetic stirring, at 20 C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0206] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 1.098 g of polyisoprene having mainly cis-1,4 structure (content of cis-1,4 units equal to 83.8%) (conversion equal to 80.7%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

Example 21 (ZG60)

[0207] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.55 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L2) (THF) complex (sample ZG57) (2.15 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 4.3 mg) obtained as described in Example 6. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0208] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.450 g of polyisoprene having mainly cis-1,4 structure (content of cis-1,4 units equal to 69.1%) (conversion equal to 33.1%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

[0209] In FIG. 14 the .sup.1H-NMR (above) and .sup.13C-NMR (below) spectra of the polyisoprene obtained are reported.

Example 22 (ZG61)

[0210] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.55 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L2) (THF) complex (sample ZG57) (2.15 ml of toluene suspension at a concentration equal to 2 mg/ml; 1105 moles, equal to about 4.3 mg) obtained as described in Example 6. The whole was maintained, under magnetic stirring, at 20 C., for 3 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0211] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.821 g of polyisoprene having mainly cis-1,4 structure (content of 1,4-cis units equal to 71.3%) (conversion equal to 60.4%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

[0212] In FIG. 15 the FT-IR spectrum of the polyisoprene obtained (Absorbance; Wavenumbers) is reported.

[0213] In FIG. 16 the .sup.1H-NMR (above) and .sup.13C-NMR (below) spectra of the polyisoprene obtained are reported.

[0214] In FIG. 17 the GPC curve (Gel Permeation Chromatography) of the polyisoprene obtained is reported.

Example 23 (IP98)

[0215] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.6 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L3) complex (sample IP91) (2.1 ml of toluene suspension at a concentration equal to 2 mg/ml; 1105 moles, equal to about 4.2 mg) obtained as described in Example 7. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0216] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.198 g of polyisoprene having mainly cis-1,4 structure (content of cis-1,4 units equal to 68.5%) (conversion equal to 14.6%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

Example 24 (IP99)

[0217] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.6 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, dry-methylaluminoxane (MAO-dry) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L3) (THF) complex (sample IP91) (2.1 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 4.2 mg) obtained as described in Example 7. The whole was maintained, under magnetic stirring, at 20 C., for 6 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0218] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.413 g of polyisoprene having mainly cis-1,4 structure (content of cis-1,4 units equal to 70.9%) (conversion equal to 30.4%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

[0219] In FIG. 18 the FT-IR spectrum of the polyisoprene obtained (Absorbance; Wavenumbers) is reported.

Example 25 (IP94)

[0220] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.45 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L4) (THF) complex (sample GL1442) (2.25 ml of toluene suspension at a concentration equal to 2 mg/ml; 1105 moles, equal to about 4.5 mg) obtained as described in Example 8. The whole was maintained, under magnetic stirring, at 20 C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0221] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 1.008 g of polyisoprene having mainly cis-1,4 structure (content of cis-1,4 units equal to 70.1%) (conversion equal to 74.1%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

Example 26 (IP95)

[0222] 2 ml of isoprene equal to about 1.36 g were introduced in a test tube of 25 ml. Then, 7.45 ml of toluene were added and the temperature of the solution thus obtained was brought to 20 C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 110.sup.2 moles, equal to about 0.58 g) was added and, then, the VCl.sub.3(L4) (THF) complex (sample GL1442) (2.25 ml of toluene suspension at a concentration equal to 2 mg/ml; 110.sup.5 moles, equal to about 4.5 mg) obtained as described in Example 8. The whole was maintained, under magnetic stirring, at 20 C., for 5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid.

[0223] The obtained polymer was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox 1076 (Ciba) antioxidant obtaining 0.401 g of polyisoprene having mainly cis-1,4 structure (content of cis-1,4 units equal to 71.3%) (conversion equal to 29.5%): further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

[0224] In FIG. 19 the FT-IR spectrum of the polyisoprene obtained (Absorbance; Wavenumbers) is reported.

[0225] In FIG. 20 the .sup.1H-NMR (above) and .sup.13C-NMR (below) spectra of the polyisoprene obtained are reported.

TABLE-US-00001 TABLE 1 Polymerization of 1,3-butadiene with catalytic systems comprising vanadium pyridine-imine complexes Time Conversion cis-1,4 trans-1,4 1,2 M.sub.w Example (hours) (%) (%) (%) (%) (g mol.sup.1) M.sub.w/M.sub.n 9 24 89.7 72.0 0 28.0 157500 2.4 10 5 34.1 83.0 0 17.0 227000 2.2 11 24 64.5 70.0 0 30.0 163800 2.5 12 0.5 58.9 82.0 0 18.0 39000 2.0 13 24 26.6 24.8 11.6 63.6 60900 3.1 14 3 75.7 14.7 29.5 55.8 80100 2.6 15 24 37.6 26.7 18.8 54.5 38300 3.5 16 24 53.1 7.6 42.7 49.7 57700 2.9 17 24 54.0 25.7 14.5 59.8 49700 3.2 18 5 81.4 12.6 34.8 52.6 68000 2.6

TABLE-US-00002 TABLE 2 Polymerization of isoprene with catalytic systems comprising oxo-nitrogen vanadium complexes Time Conversion cis-1,4 trans-1,4 3,4 M.sub.w Example (hour) (%) (%) (%) (%) (g mol.sup.1) M.sub.w/M.sub.n 19 12 72.4 79.6 0 20.4 46500 2.6 20 2 80.7 83.8 0 16.2 55000 2.2 21 24 33.1 69.1 0 30.9 32700 2.7 22 3 60.4 71.3 0 28.7 41000 2.3 23 24 14.6 68.5 0 31.5 20600 3.8 24 6 30.4 70.9 0 29.1 22400 3.5 25 24 74.1 70.1 0 29.9 19400 3.2 26 5 29.5 71.3 0 28.7 20100 3.0