PYRIDINE COMPLEX OF ZIRCONIUM, CATALYTIC SYSTEM COMPRISING SAID PYRIDINE COMPLEX OF ZIRCONIUM AND PROCESS OF (CO)POLYMERIZATION OF CONJUGATED DIENES
20170247397 · 2017-08-31
Assignee
Inventors
- Guido Pampaloni (Pontedera, IT)
- Giovanni RCCI (Parma, IT)
- Anna Sommazzi (Santa Margherita Ligure, IT)
- Francesco MASI (Santa'Angelo Lodigiano, IT)
- Giuseppe LEONE (Milano, IT)
Cpc classification
International classification
Abstract
Pyridine complex of zirconium having general formula (I): Said pyridine complex of zirconium having general formula (I) may advantageously be used in a catalytic system for the (co)polymerization of conjugated dienes.
##STR00001##
Claims
1. Pyridine complex of zirconium having general formula (I): ##STR00030## in which: R.sub.1 and R.sub.2, identical or different, represent a hydrogen atom; or are selected from linear or branched, optionally halogenated C.sub.1-C.sub.20, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.3, R.sub.4, R.sub.5 and R.sub.6, identical or different, represent a hydrogen atom; or are selected from linear or branched, optionally halogenated C.sub.1-C.sub.20, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups, nitro groups, hydroxyl groups, amino groups; X.sub.1, X.sub.2 and X.sub.3, identical or different, represent a halogen atom; or are selected from linear or branched C.sub.1-C.sub.20, alkyl groups, —OCOR.sub.7 groups or —OR.sub.7 groups in which R.sub.7 is selected from linear or branched C.sub.1-C.sub.20, alkyl groups; or one of X.sub.1, X.sub.2 and X.sub.3 represents a group having general formula (II): ##STR00031## in which R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6, have the same meanings described above.
2. Pyridine complex of zirconium having general formula (I) according to claim 1, in which: R.sub.1 and R.sub.2, identical or different, represent a hydrogen atom; or are selected from C.sub.1-C.sub.20 alkyl groups, optionally substituted aryl groups, or phenyl substituted with one or more methyl, iso-propyl, tert-butyl groups; R.sub.3, R.sub.4, R.sub.5 and R.sub.6, identical to each other, represent a hydrogen atom; X.sub.1, X.sub.2 and X.sub.3, identical or different, represent a halogen atom or one of X.sub.1, X.sub.2 and X.sub.3 represents a group having general formula (II): ##STR00032## in which R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6, have the same meanings described above.
3. Catalytic system for the (co)polymerization of conjugated dienes comprising: (a) at least one pyridine complex of zirconium having general formula (I) according to claim 1; (b) at least one co-catalyst selected from organic compounds of an element M′ different from carbon, said element M′ being selected from elements belonging to groups 2, 12, 13, or 14, of the Periodic Table of the Elements.
4. Catalytic system for the (co)polymerization of conjugated dienes according to claim 3, wherein said co-catalyst (b) is selected from (b.sub.1) aluminium alkyls having general formula (IV):
Al(X′).sub.n(R.sub.8).sub.3-n (IV) in which X′ represents a halogen atom; R.sub.8 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups, aryl groups, said groups being optionally substituted with one or more atoms of silicon or germanium; and n is an integer ranging from 0 to 2.
5. Catalytic system for the (co)polymerization of conjugated dienes according to claim 3, wherein said co-catalyst (b) is selected from (b.sub.2) organo-oxygenated compounds of an element M′ different from carbon belonging to groups 13 or 14 of the Periodic Table of the Elements.
6. Catalytic system for the (co)polymerization of conjugated dienes according to claim 3, wherein said co-catalyst (b) is selected from (b.sub.3) compounds or mixtures of organometallic compounds of an element M′ different from carbon able of react with the pyridine complex of zirconium having general formula (I), extracting from this a σ-linked substituent X.sub.1, X.sub.2 or X.sub.3, to form on the one hand at least one neutral compound, and on the other a ionic compound consisting of a cation containing the metal (Zr) coordinated by the ligand, and of a non-coordinating organic anion containing the metal M′, whose negative charge is delocalized on a multicentric structure.
7. Catalytic system for the (co)polymerization of conjugated dienes according to claim 4, wherein said aluminium alkyls (b.sub.1) having general formula (IV) are tri-ethyl-aluminium, tri-iso-butyl aluminium (TIBA), di-iso-butyl aluminium hydride (DIBAH).
8. Catalytic system for the (co)polymerization of conjugated dienes according to claim 5, wherein said organo-oxygenated compounds (b.sub.2) are selected from aluminoxanes having general formula (V):
(R.sub.9).sub.2—Al—O—[—Al(R.sub.10)—O—].sub.p—Al—(R.sub.11).sub.2 (V) in which R.sub.9, R.sub.10 and R.sub.11, identical or different, represent a hydrogen atom, a halogen atom; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups, aryl groups, said groups being optionally substituted with one or more atoms of silicon or germanium; and p is an integer ranging from 0 to 1000.
9. Catalytic system for the (co)polymerization of conjugated dienes according to claim 8, in which said organo-oxygenated compound (b.sub.2) is methylaluminoxane (MAO) as such or in dry form (MAO-dry).
10. Catalytic system for the (co)polymerization of conjugated dienes according to claim 6, wherein said compounds and/or mixtures of compounds (b.sub.3) are selected from organic compounds of aluminium and boron, represented by the following general formulae:
[(R.sub.C).sub.WH.sub.4-W].[B(R.sub.D).sub.4].sup.−; B(R.sub.D).sub.3; AI(R.sub.D).sub.3; B(R.sub.D).sub.3P; [Ph.sub.3C].sup.+.[B(R.sub.D).sub.4].sup.−; [(R.sub.C).sub.3PH].sup.+.[B(R.sub.D).sub.4].sup.−; [Li].sup.+.[B(R.sub.D).sub.4].sup.−; [Li].sup.+.[Al(R.sub.D).sub.4].sup.− in which w is an integer ranging from 0 to 3, each R.sub.C group independently represents an alkyl group or an aryl group having from 1 to 10 carbon atoms and each R.sub.D group independently represents a partially or totally, fluorinated aryl group, having from 6 to 20 carbon atoms, P represents an optionally substituted pyrrole radical.
11. The process of (co)polymerization of conjugated dienes, characterized by the use of the catalytic system according to claim 4.
12. The process of polymerization of 1,3-butadiene, characterized by the use of the catalytic system according to claim 4.
Description
EXAMPLES
[0121] Reagents and Materials
[0122] The following list states the reagents and materials used in the following examples of the invention, any optional pre-treatments thereof, and the manufacturer thereof: [0123] 2,6-di-iso-propylaniline (Aldrich): used as such; [0124] 2-tert-butylaniline (Aldrich): used as such; [0125] 2-benzoylpyridine (Aldrich): used as such; [0126] aniline (Aldrich): distilled at reduced pressure and kept in inert atmosphere; [0127] 2,4,6-tri-methylaniline (Aldrich): used as such; [0128] 2-pyridincarboxyaldehyde (Aldrich): used as such; [0129] 2-acetylpyridine (Aldrich): used as such; [0130] dichloromethane (Carlo Erba, RPE): used as such; [0131] methanol (Carlo Erba, RPE): used as such, or optionally anhydrified by distillation over magnesium (Mg); [0132] sodium boro hydride (Aldrich): used as such; [0133] ethyl acetate (Aldrich): used as such; [0134] hexane (Aldrich): pure, ≧99%, distilled over sodium (Na) in an inert atmosphere; [0135] ethyl ether (Aldrich): used as such; [0136] formic acid (Aldrich): used as such; [0137] heptane (Aldrich): pure, ≧99%, distilled over sodium (Na) in an inert atmosphere; [0138] sodium sulphate (Aldrich): used as such; [0139] chloroform (Aldrich): used as such; [0140] toluene (Aldrich): pure, ≧99.5%, distilled over sodium (Na) in an inert atmosphere; [0141] zirconium tetrachloride (ZrCl.sub.4) (Stream Chemicals): used as such; [0142] zirconium tetrachloride:tetrahydrofuran complex (1:2) [ZrCl.sub.4(THF).sub.2] (Aldrich): used as such; [0143] tetrahydrofuran (THF) (Carlo Erba, RPE): kept under reflux over potassium/benzophenone and then distilled under nitrogen; [0144] lithium n-butyl (Aldrich): used as such; [0145] 1,3-butadiene (Air Liquide): pure, ≧99,5%, evaporated from the container prior to any production, dried by passing through a column packed with molecular sieves, and condensed within the reactor which has been pre-cooled to −20° C.; [0146] methylaluminoxane (MAO) (toluene solution at 10% by weight) (Aldrich): used as such, or in dry form (MAO-dry) obtained by removing the free tri-methyl-aluminium together with the solvent from the toluene solution under vacuum and drying the residue obtained still under vacuum; [0147] hydrochloric acid in aqueous solution at 37% (Aldrich): used as such; [0148] tri-iso-butyl-aluminium (TIBA) (Aldrich): used as such; [0149] deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) (Acros): used as such; [0150] deuterated chloroform (CDCl.sub.3) (Acros): used as such.
[0151] The following analysis and characterization methodologies were used.
[0152] Elemental Analysis
[0153] a) Zr Determination
[0154] To determine the amount of zirconium (Zr) by weight in the pyridine complexes of zirconium used for the purpose of the present invention, an exactly weighed aliquot, working in a dry box under nitrogen flow, of approximately 30 mg-50 mg of sample, was placed in a platinum crucible of approximately 30 ml, together with a mixture of 1 ml of 40% hydrofluoric acid (HF), 0.25 ml of 96% sulphuric acid (H.sub.2SO.sub.4), and 1 ml of 70% nitric acid (HNO.sub.3). The crucible was subsequently heated on a plate, increasing the temperature until white sulphur fumes appeared (approximately 200° C.). The mixture thus obtained was cooled to room temperature (20° C.-25° C.), 1 ml of 70% nitric acid (HNO.sub.3) was added, and was then brought back to the point where fumes appeared. After the sequence was repeated two more times, a clear and almost colourless solution was obtained. Subsequently, in the cold, 1 ml of nitric acid (HNO.sub.3) and approximately 15 ml of water were added, whilst heating to 80° C., for approximately 30 minutes. The sample thus prepared was diluted with Milli-Q-purity water up to a weight of approximately 50 g, exactly weight, to obtain a solution on which the instrumental analytic determination was carried out using a Thermo Optek IRIS Advantage Duo ICP-OES (optical emission plasma) spectrometer, by comparison with solutions of known concentration. For this purpose, for each analyte, a calibration curve was prepared in the range 0 ppm-10 ppm by measuring solutions of a known titre obtained by dilution by weight of certified solutions.
[0155] The solution of the sample prepared as above was further diluted by weight so as to obtain concentrations close to the reference concentrations, before carrying out the spectrophotometry detection. All of the samples were prepared in duplicate. The results were considered acceptable if the individual data of the duplicate tests differed by no more than 2% from the average value thereof.
[0156] b) Chlorine Determination
[0157] For this purpose, samples of the pyridine complexes of zirconium used for the purpose of the present invention, approximately 30 mg-50 mg, were weighed exactly in 100 ml glass beakers in a dry box under nitrogen flow. 2 g of sodium carbonate (Na.sub.2CO.sub.3) were added and, outside the dry box, 50 ml of Mili-Q water. This was brought to boiling on a plate, under magnetic stirring, for approximately 30 minutes. It was left to cool, ⅕ dilute sulphuric acid (H.sub.2SO.sub.4) was added, until an acidic reaction, and titration was carried out using silver nitrate (AgNO.sub.3) 0.1 N with potentiometric titrator.
[0158] c) Carbon, Hydrogen and Nitrogen Determination
[0159] The carbon, hydrogen and nitrogen were determined, in the pyridine complexes of zirconium used for the purpose of the present invention, as well as in the ligands used for the purpose of the present invention, using an automatic Carlo Erba 1106 analyser.
[0160] .sup.13C-HMR and .sup.1H-HMR Spectra
[0161] The .sup.13C-HMR and .sup.1H-HMR spectra were recorded using a Bruker Avance 400 nuclear magnetic resonance spectrometer, using deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) at 103 C, and hexamethyldisiloxane (HDMS) as an internal standard, or using deuterated chloroform (CDCl.sub.3), at 25° C., and tetramethylsilane (TMS) as an internal standard. For this purpose, polymer solutions having concentrations of 10% by weight with respect to the total weight of the polymer solution were used.
[0162] The microstructure of the polymers [i.e. content of 1,4-trans units (%)] was determined by analysing the aforementioned spectra on the basis of what is reported in literature by Mochel, V. D., in “Journal of Polymer Science Part A-1: Polymer Chemistry” (1972), Vol. 10, Issue 4, pp. 1009-1018.
[0163] FTIR-ATR Spectra
[0164] The FTIR-ATR spectra were recorded using a Bruker IFS 48 spectrophotometer, equipped with a Thermo Spectra-Tech horizontal ATR connection. The section in which the samples to be analysed are placed is a Fresnel ATR accessory (Shelton, Conn., USA) which uses zirconium selenide crystals (ZnSe) with an angle of incidence of 45° in a horizontal direction. The FTIR-ATR spectra of the pyridine complexes of zirconium used in the present invention were obtained by inserting samples of the pyridine complex of zirconium to be analysed into said section.
[0165] FT-IR Spectra
[0166] The FT-IR spectra were recorded using Thermo Nicolet Nexus 670 and Bruker IFS 48 spectrophometers.
[0167] The FT-IR spectra of the polymers were obtained from polymer films on potassium bromide (KBr) tablets, said film being obtained by depositing a solution of the polymer to be analysed in hot o-dichlorobenzene. The concentration of the polymer solutions analysed was 10% by weight with respect to the total weight of the polymer solution.
[0168] Thermal Analysis (DSC)
[0169] DSC (Differential Scanning calorimetry) thermal analysis, for the purpose of determining the melting point (T.sub.m) and the crystallization temperature (T.sub.c) of the polymers obtained, was carried out using a Perkin Elmer Pyris differential scanning calorimeter. For this purpose, 5 mg of polymer were analysed at a scanning speed ranging from 1° C./min to 20 C/min, in an inert nitrogen atmosphere.
[0170] Molecular Weight Determination
[0171] The molecular weight (MW) of the polymers obtained was carried out by GPC (Gel Permeation Chromatography), working at the following conditions: [0172] Agilent 1100 pump; [0173] Agilent 1100 I.R. detector; [0174] Mixed-A PL column [0175] solvent/eluent: tetrahydrofuran (THF); [0176] flow rate: 1 ml/min; [0177] temperature: 25° C. [0178] calculation of molecular mass: Universal Calibration method.
[0179] The weight-average molecular weight (M.sub.w) and the polydispersion index (PDI) corresponding to the ratio M.sub.w/M.sub.n (M.sub.n=number-average molecular weight) are given.
[0180] Gas Chromatography-Mass Spectrometry (GC-MS)
[0181] Gas chromatography-mass spectrometry (GC-MS) was carried out using a Thermo ISQ single-quadrupole mass spectrometer. For this purpose, samples of the ligands to be analysed were solubilized in methylene chloride (CH.sub.2Cl.sub.2) at a concentration of 0.1 mg/ml and were analysed using said spectrometer, working in the following conditions: [0182] means of ionization: Electronic Ionization (EI); [0183] GC ramp: 50° C. per 2 min.; heating at a rate of 10° C./min up to 300° C.; [0184] injector temperature: 300° C.; [0185] injection volume: 1.30 μl; [0186] “transfer line” temperature: 280° C.; [0187] ion source temperature: 250° C.; [0188] quadropole scanning parameters: 35 amu-500 amu with a scanning time of 0.2 s.
Example 1
[0189] Synthesis of the Ligand Having Formula (L1)
##STR00008##
[0190] 1.1 Synthesis of the Compound Having Formula (L1a)
##STR00009##
[0191] In a 500 ml flask, provided with a Dean-Stark trap for azeotropic water removal, to a solution of 2,6-di-iso-propylaniline (27.93 g, 157.5 mmol) in dichloromethane (300 ml), was added 2-pyridinecarboxyaldehyde (16.86 g, 157.5 mmol). The mixture obtained was heated under reflux for 20 hours and subsequently dried under vacuum, to obtain 41.7 g of a yellow solid (yield=99%) corresponding to the compound having formula (L1a).
[0192] Elemental analysis [found (calculated)]: C: 81.14% (81.16%); H: 8.33% (8.32%); N: 10.6% (10.52%).
[0193] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.72 (d, 1H, PyH), 8.32 (s, 1H CH═N), 8.27 (d, 1H PyH), 7.86 (t, 1H PyH), 7.39 (m, 1H PyH), 7.11-7.20 (m, 3H ArH), 3.00 (sept, 2H CHMe.sub.2), 1.18 (d, 12H C(CH.sub.3).sub.2).
[0194] 1.2 Synthesis of the Ligand Having Formula (L1)
[0195] Into a 2 litre reactor, provided with a stirrer, were loaded 28 g (105.1 mmol) of the compound having formula (L1a) obtained as described above and 1800 ml of anhydrous methanol: the whole was cooled to 0° C. and subsequently sodium boron hydride (70 g, 1850 mmol) was added in small portions. The mixture obtained was left, under stirring, at room temperature, overnight, and subsequently quenched with brine and extracted using ethyl acetate. The solvent was subsequently removed by distillation at reduced pressure, and the residue obtained was purified by elution in a silica gel chromatography column [eluent: hexane/ethyl acetate mixture in 9/1 ratio (v/v)], and subsequently treated with cold ethyl ether, to obtain 16.9 g of a white crystalline solid (yield=60%) corresponding to the ligand having formula (L1).
[0196] GC-MS: M.sup.+=m/z 268; [M-C.sub.3H.sub.7].sup.+=m/z 225; [M-C.sub.6H.sub.6N].sup.+=m/z 176; m/z 93 C.sub.6H.sub.7N.
[0197] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.61 (d, 1H,o-PyH), 7.66 (td, 1H, PyH), 7.30 (d, 1H, PyH), 7.21 (m, 1H, PyH), 7.04-7.12 (m, 3H, ArH), 4.20 (s, 2H, CH.sub.2), 4.10 (s, 1H, NH), 3.47 (m, 2H, —CH(CH.sub.3).sub.2), 1.42 (d, 12H, —CH(CH.sub.3).sub.2).
Example 2
[0198] Synthesis of the Ligand Having Formula (L2)
##STR00010##
[0199] 2.1 Synthesis of the CHmpound Having Formula (L2a)
##STR00011##
[0200] In a 500 ml flask, to a solution of 2,6-di-iso-propylaniline (13.3 g, 75 mmol) in methanol (300 ml), was added 2-acetylpyridine (9.1 g, 75 mmol): the mixture obtained was left, under stirring, at room temperature, for 48 hours. The precipitate obtained was filtered and subsequently dried under vacuum, to obtain 14 g of a yellow crystalline powder (yield=67%) corresponding to the compound having formula (L2a).
[0201] Elemental analysis [found (calculated)]: C: 81.37% (81.38%); H: 8.64% (8.63%); N: 10.01% (9.99%).
[0202] .sup.1H-NMR (CDCl.sub.3, δ ppm) 8.69 (d, 1H, PyH), 8.38 (d, 1H, PyH), 7.82 (t, 1H, PyH), 7.39 (m, 1H, PyH), 7.11-7.20 (m, 3H, ArH), 2.75 (m, 2H, CHMe.sub.2), 2.21 (s, 3H, N═CH-Me), 1.15 (d, 12H, CH(CH.sub.3).sub.2).
[0203] 2.2 Synthesis of the Ligand Having Formula (L2)
[0204] Into a 2 litre reactor, provided with a stirrer, were loaded 24 g (85 mmol) of the compound having formula (L2a) obtained as described above and 900 ml of anhydrous methanol: the whole was cooled to 0° C. and subsequently sodium boron hydride (48.6 g, 1285 mmol) was added in small portions. The mixture obtained was left, under stirring, at room temperature, overnight, and subsequently quenched with brine and extracted using ethyl acetate. The solvent was subsequently removed by distillation at reduced pressure, and the residue obtained was purified by elution in a silica gel chromatography column [eluent: hexane/ethyl acetate mixture in 9/1 ratio (v/v)], and subsequently treated with cold ethyl ether, to obtain 11 g of a white crystalline solid (yield=46%) corresponding to the ligand having formula (L2).
[0205] Elemental analysis [found (calculated)]: C: 81.03% (80.80%); H: 9.42% (9.28%); N: 10.01% (9.92%).
[0206] GC-MS: M.sup.+=m/z 282; [M-C.sub.3H.sub.7].sup.+=m/z 239; [M-C.sub.7H.sub.8N].sup.+=m/z 176; [M-C.sub.12H.sub.18N].sup.+=m/z 106.
[0207] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.64 (d, 1H, HPy), 7.53 (dt, 1H, HPy), 7.2 (d, 1H, HPy), 7.00-7.12 (m, 1H, HPy; m, 3H, ArH), 4.0-4.2 (m, 1H, NCH(CH.sub.3); m, 1H, NH), 3.30 (sept, 2H, —CH(CH.sub.3).sub.2), 1.55 (d, 3H, —NCH(CH.sub.3)), 1.10 (s, 12H, —CH(CH.sub.3).sub.2).
Example 3
[0208] Synthesis of the Ligand Having Formula (L3)
##STR00012##
[0209] 3.1 Synthesis of the Compound Having Formula (L3a)
##STR00013##
[0210] In a 500 ml flask, to a solution of 2-tert-butylaniline (15.89 g, 106.5 mmol) in methanol (300 ml), was added 2-acetylpyridine (12.9 g, 106.5 mmol): the mixture obtained was left, under stirring, at room temperature, for 48 hours. The solvent was subsequently removed by evaporation and the residue obtained was crystallized using methanol, to obtain 20 g of a yellow crystalline powder (yield=75%) corresponding to the compound having formula (L3a).
[0211] Elemental analysis [found (calculated)]: C: 81.17% (80.91%); H: 8.14% (7.99%); N: 10.91% (11.10%).
[0212] 3.2 Synthesis of the Ligand Having Formula (L3)
[0213] Into a 2 litre reactor, provided with a stirrer, were loaded 28 g (111 mmol) of the compound having formula (L3a) obtained as described above and 800 ml of anhydrous methanol: the whole was cooled to 0° C. and subsequently sodium boron hydride (38 g, 1004 mmol) was added in small portions. The mixture obtained was left, under stirring, at room temperature, overnight, and subsequently quenched with brine and extracted using ethyl acetate. The solvent was subsequently removed by distillation at reduced pressure, and the residue obtained was purified by elution in a silica gel chromatography column [eluent: hexane/ethyl acetate mixture in 9/1 ratio (v/v)], and subsequently treated with cold ethyl ether, to obtain 11 g of a white crystalline solid (yield=39%) corresponding to the ligand having formula (L3).
[0214] Elemental analysis [found (calculated)]: C: 80.00% (80.27%); H: 9.12% (8.72%); N: 11.31% (11.01%).
[0215] GC-MS: M.sup.+=m/z 254; [M-CH.sub.3].sup.+=m/z 239; [M-C.sub.4H.sub.9].sup.+=m/z 197; m/z=183; m/z 132 C.sub.7H.sub.10N.sub.2; [M-C.sub.10H.sub.14N].sup.+=m/z 106; [M-C.sub.12H.sub.18N].sup.+=m/z 78.
[0216] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.64 (d, 1H, HPy), 7.7 (td, 1H, PyH), 7.36 (d, 1H, HPy), 7.25 (d, 1H, ArH), 7.18 (td, 1H, PyH), 6.98 (td, 1H, PyH), 6.98 (td, 1H, PyH), 6.48 (d, 1H, PyH), 5.0 (broad s, 1H, NH), 4.7 (q, 1H, NCH(CH.sub.3)), 1.57 (d, 3H, —NCH(CH.sub.3)), 1.5 (s, 9H, —C(CH.sub.3).sub.3).
Example 4
[0217] Synthesis of the Ligand Having Formula (L4)
##STR00014##
[0218] 4.1 Synthesis of the Compound Having Formula (L4a)
##STR00015##
[0219] In a 500 ml flask, to a solution of 2-benzoylpyridine (20 g, 109 mmol) in methanol (200 ml), were added aniline (11.2 g, 120 mmol) and a few drops of formic acid: the mixture obtained was left, under stirring, at room temperature, for 48 hours. Subsequently, the mixture obtained was dried under vacuum and the residue obtained was purified by elution in a silica gel chromatography column [eluent: heptane/ethyl acetate mixture in 99/1 ratio (v/v)], to obtain 14.4 g of a yellowish oil (yield=51%) corresponding to the compound having formula
[0220] (L4a).
[0221] Elemental analysis [found (calculated)]: C: 84.00% (83.69%); H: 5.83% (5.46%); N: 11.52% (10.84%).
[0222] GC-MS: M.sup.+=m/z 258; m/z 180, 155, 77, 51.
[0223] 4.2 Synthesis of the Ligand Having Formula (L4)
[0224] Into a 2 litre reactor, provided with a stirrer, were loaded 14 g (85 mmol) of the compound having formula (L4a) obtained as described above and 900 ml of anhydrous methanol: the whole was cooled to 0° C. and subsequently sodium boron hydride (31 g, 819 mmol) was added in small portions. The mixture obtained was left, under stirring, at room temperature, overnight, and subsequently quenched with brine and extracted using ethyl acetate. The solvent was subsequently removed by distillation at reduced pressure, and the residue obtained was purified by elution in a silica gel chromatography column [eluent: hexane/ethyl acetate mixture in 9/1 ratio (v/v)], and subsequently treated with cold ethyl ether, to obtain 12.5 g of a white crystalline solid (yield=56.5%) corresponding to the ligand having formula (L4).
[0225] Elemental analysis [found (calculated)]: C: 83.30% (83.04%); H: 6.87% (6.19%); N: 11.01% (10.76%).
[0226] GC-MS: M.sup.+=m/z 260; m/z 182, 168, 104, 77 51.
[0227] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.6 (m 1H, PyH), 7.62-7.69 (m 1H, PyH), 7.45-7.50 (m 2H, ArH), 7.30-7.38 (m, 1H, HPy; m 2H, ArH), 7.23-7.27 (m, 1H, ArH), 7.18-7.21 (m, 1H, PyH), 7.05-7.13 (m, 2H, NH—ArH), 6.60-6.65 (m, 3H, NH—ArH), 5.55 (s, 1H, NH), 5.50 (s, 1H, —NCH).
Example 5
[0228] Synthesis of the Ligand Having Formula (L5)
##STR00016##
[0229] 5.1 Synthesis of the Compound Having Formula (L5a)
##STR00017##
[0230] In a 500 ml flask, to a solution of aniline (26.1 g, 280 mmol) in methanol (250 ml), were added 2-pyridinecarboxyaldehyde (30 g, 280 mmol) and a few drops of formic acid: the mixture obtained was left, under stirring, at room temperature, for 48 hours. Subsequently, the mixture obtained was dried under vacuum and the residue obtained was purified by elution in a silica gel chromatography column [eluent: heptane/ethyl acetate mixture in 99/1 ratio (v/v)], to obtain 38 g of a yellowish solid (yield=74.5%) corresponding to the compound having formula (L5a).
[0231] Elemental analysis [found (calculated)]: C: 80.00% (79.10%); H: 5.83% (5.53%); N: 15.71% (15.37%).
[0232] .sup.1H-NMR (CDCl.sub.3, δ ppm) 8.70 (d, 1H, HPy), 8.59 (s, 1H CH═N), 8.19 (d, 1H, HPy), 7.77 (dt, 1H, HPy), 7.23-7.42 (m, 1H, HPy; m, 5H, Ar).
[0233] 5.2 Synthesis of the Ligand Having Formula (L5)
[0234] Into a 2 litre reactor, provided with a stirrer, were loaded 13 g (71.3 mmol) of the compound having formula (L5a) obtained as described above and 700 ml of anhydrous methanol: the whole was cooled to 0° C. and subsequently sodium boron hydride (40 g, 1057 mmol) was added in small portions. The mixture obtained was left, under stirring, at room temperature, overnight, and subsequently quenched with brine and extracted using ethyl acetate. The solvent was subsequently removed by distillation at reduced pressure, and the residue obtained was purified by elution in a silica gel chromatography column [eluent: hexane/ethyl acetate mixture in 9/1 ratio (v/v)], and subsequently treated with cold ethyl ether, to obtain 9.12 g of a white crystalline solid (yield=69.5%) corresponding to the ligand having formula (L5).
[0235] GC-MS: M.sup.+=m/z 184; [M-C.sub.6H.sub.6N].sup.+=m/z 106; [M-C.sub.7H.sub.7N.sub.2].sup.+=m/z 77.
[0236] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.60 (dd, 1H, PyH), 7.64 (m, 1H, PyH), 7.35 (d, 1H, PyH), 7.22-7.17 (m, 1H, Py, 2H, ArH), 6.75 (dt, 1H, ArH), 6.69 (d, 2H, ArH), 4.8 (s, 1H, NH), 4.48 (s, 2H, Py-CH.sub.2N).
Example 6
[0237] Synthesis of the Ligand Having Formula (L6)
##STR00018##
[0238] 6.1 Synthesis of the Compound Having Formula (L6a)
##STR00019##
[0239] In a 500 ml flask, to a solution of 2,6-dimethylaniline (31 g, 250 mmol) in methanol (250 ml), were added 2-pyridinecarboxyaldehyde (26.8 g, 250 mmol) and a few drops of formic acid: the mixture obtained was left, under stirring, at room temperature, for 24 hours. Subsequently, the mixture obtained was dried over sodium sulphate and filtered, and the solvent was removed by evaporation under vacuum: the residue obtained was washed with cold methanol, to obtain 47 g of an orange solid (yield=89%) corresponding to the compound having formula (L6a).
[0240] Elemental analysis [found (calculated)]: C: 80.00% (79.97%); H: 6.81% (6.71%); N: 13.71% (13.37%).
[0241] .sup.1H-NMR (CDCl.sub.3, δ ppm) 8.70 (d, 1H, HPy), 8.33 (s, 1H, CH═N), 8.23 (d, 1H, HPy), 7.82 (dt, 1H, HPy), 7.38 (ddd, 1H, HPy), 6.91-7.15 (m, 5H, Ar), 2.16 (s, 6H, Ar—CH.sub.3).
[0242] 6.2 Synthesis of the Ligand Having Formula (L6)
[0243] Into a 2 litre reactor, provided with a stirrer, were loaded 18 g (85.6 mmol) of the compound having formula (L6a) obtained as described above and 800 ml of anhydrous methanol: the whole was cooled to 0° C. and subsequently sodium boron hydride (24 g, 634 mmol) was added in small portions. The mixture obtained was left, under stirring, at room temperature, overnight, and subsequently quenched with brine and extracted using ethyl acetate. The solvent was subsequently removed by distillation at reduced pressure, and the residue obtained was purified by elution in a silica gel chromatography column [eluent: hexane/ethyl acetate mixture in 9/1 ratio (v/v)], and subsequently treated with cold ethyl ether, to obtain 9.15 g of a white crystalline solid (yield=50.4%) corresponding to the ligand having formula (L6).
[0244] GC-MS: M.sup.+=m/z 212; [M-C.sub.6H.sub.6N].sup.+=m/z 120.
[0245] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.63 (d, 1H, PyH), 7.65 (dt, 1H, PyH), 7.27 (d, 1H, PyH), 7.20 (dd, 1H, PyH), 7.02 (d, 2H, ArH), 6.85 (m, 1H, ArH), 4.4 (broad s, 1H, NH), 4.31 (s, 2H, Py-CH.sub.2N), 2.35 (s, 6H, ArCH.sub.3).
Example 7
[0246] Synthesis of the Ligand Having Formula (L7)
##STR00020##
[0247] 7.1 Synthesis of the Compound Having Formula (L7a)
##STR00021##
[0248] In a 500 ml flask, to a solution of 2,4,6-trimethylaniline (12.6 g, 93 mmol) in methanol (250 ml), were added 2-pyridinecarboxyaldehyde (10 g, 93 mmol) and a few drops of formic acid: the mixture obtained was left, under stirring, at room temperature, for 48 hours. Subsequently, the solvent was removed by evaporation under vacuum and the oily residue obtained was purified by elution in a silica gel chromatoghraphy column [eluent: heptane/ethyl acetate mixture in 99/1 ratio (v/v)], to obtain 17 g of a yellowish solid (yield=81%) corresponding to the compound having formula (L7a).
[0249] Elemental analysis [found (calculated)]: C: 80.56% (80.32%); H: 7.22% (7.19%); N: 13.11% (12.49%).
[0250] GC-MS: M.sup.+=m/z 224; [M-CH.sub.3].sup.+=m/z 209; [M-C.sub.5H.sub.4N].sup.+=m/z 146.
[0251] .sup.1H-NMR (CDCl.sub.3, δ ppm) 8.70 (m, 1 H, HPy), 8.35 (s, 1H CH═N), 8.29 (d, 1 H, HPy), 7.84 (tdd, 1H, HPy), 7.41 (m, 1H, HPy), 6.91 (s, 2H ArH), 2.31 (s, 3H Ar(CH.sub.3)), 2.10 (s, 6H Ar(CH.sub.3).sub.2).
[0252] 7.2 Synthesis of the Ligand Having Formula (L7)
[0253] Into a 2 litre reactor, provided with a stirrer, were loaded 13 g (58 mmol) of the compound having formula (L7a) obtained as described above, 80 ml of anhydrous methanol, 80 ml of chloroform, and sodium boron hydride (2.2 g, 58 mmol) in small portions. The mixture obtained was left, under stirring, at room temperature, overnight. The solvents were subsequently removed by distillation at reduced pressure, and the residue obtained was extracted using a mixture of ethyl acetate (50 ml) and water (50 ml). The organic extracts obtained were washed using water until neutral, anhydrified over sodium sulphate, filtered, and subjected to distillation at reduced pressure to remove the remaining solvent, to obtained an oily yellow-coloured residue. To said oily residue were added 25 ml of cold heptane, to obtain 5.15 g of a white crystalline solid (yield=39%) corresponding to the ligand having formula (L7).
[0254] GC-MS: M.sup.+=m/z 226; [M-C.sub.6H.sub.6N].sup.+=m/z 134.
[0255] .sup.1H-NMR (CDCl.sub.3, δ ppm): 8.59 (d, 1H, PyH), 7.65 (dt, 1H, PyH), 7.27 (d, 1H, PyH), 7.20 (m, 1 H, PyH), 6.8 (d, 2H, ArH), 4.2 (s, 2H, Py-CH.sub.2N), 4.1 (broad s, 1 H, NH), 2.28 (s, 6H, ArCH.sub.3), 2.2 (s, 3H, Ar—CH.sub.3).
Example 8
[0256] Synthesis of ZrCl.sub.3(L1) [Sample BM2-199]
##STR00022##
[0257] Zirconium tetrachloride (ZrCl.sub.4) (0.500 g; 2.14 mmol) was introduced into a 100 ml long-necked flask together with a solution of the ligand having formula (L1) (0.599 g; 2.22 mmol; L1/Zr molar ratio=1.03), obtained as described in Example 1, in toluene (15 ml). The mixture obtained was left, under stirring, at room temperature, for 30 minutes, and subsequently heated under reflux for 2 hours. The solid formed was recovered by filtration, washed with heptane (2×2 ml) and dried at reduced pressure, at room temperature, to obtain 0.66 g (yield=66%) of a clear yellow microcrystalline solid product corresponding to the ZrCl.sub.3(L1) complex.
[0258] Elemental analysis [found (calculated)]: C: 45.87% (46.49%); H: 4.65% (4.98%); N: 5.45% (6.02%); Zr: 18.72% (19.62%); Cl: 21.65% (22.87%).
[0259]
[0260]
Example 9
[0261] Synthesis of ZrCl.sub.3(L2) [Sample BM2-207]
##STR00023##
[0262] Zirconium tetrachloride (ZrCl.sub.4) (0.398 g; 1.71 mmol) was introduced into a 100 ml long-necked flask together with a solution of the ligand having formula (L2) (0.507 g; 1.80 mmol; L2/Zr molar ratio=1.05), obtained as described in Example 2, in toluene (10 ml). The mixture obtained was left, under stirring, at room temperature, for 30 minutes, and subsequently heated under reflux for 2 hours. The solid formed was recovered by filtration, washed with heptane (2×2 ml) and dried at reduced pressure, at room temperature, to obtain 0.71 g (yield=86%) of a clear yellow microcrystalline solid product corresponding to the ZrCl.sub.3(L2) complex.
[0263] Elemental analysis [found (calculated)]: C: 46.87% (47.64%); H: 4.85% (5.26%); N: 5.21% (5.84%); Zr: 19.87% (19.04%); Cl: 21.89% (22.20%).
[0264]
[0265]
Example 10
[0266] Synthesis of ZrCl.sub.3(L3) [Sample MT-2]
##STR00024##
[0267] Zirconium tetrachloride (ZrCl.sub.4) (0.525 g; 2.25 mmol) was introduced into a 100 ml long-necked flask together with a solution of the ligand having formula (L3) (0.570 g; 2.24 mmol; L3/Zr molar ratio=1), obtained as described in Example 3, in toluene (10 ml). The mixture obtained was left, under stirring, at room temperature, for 30 minutes, and subsequently heated under reflux for 2 hours. The solid formed was recovered by filtration, washed with heptane (2×2 ml) and dried at reduced pressure, at room temperature, to obtain 0.81 g (yield=80%) of a clear yellow microcrystalline solid product corresponding to the ZrCl.sub.3(L3) complex.
[0268] Elemental analysis [found (calculated)]: C: 44.82% (45.28%); H: 4.05% (4.69%); N: 5.95% (6.21%); Zr: 19.99% (20.23%); Cl: 23.00% (23.58%).
Example 11
[0269] Synthesis of ZrCl.sub.3(L5) [Sample MT-4]
##STR00025##
[0270] Zirconium tetrachloride (ZrCl.sub.4) (0.368 g; 1.58 mmol) was introduced into a 100 ml long-necked flask together with a solution of the ligand having formula (L5) (0.289 g; 1.58 mmol; L5/Zr molar ratio=1), obtained as described in Example 5, in toluene (10 ml). The mixture obtained was left, under stirring, at room temperature, for 30 minutes, and subsequently heated under reflux for 2 hours. The solid formed was recovered by filtration, washed with heptane (2×2 ml) and dried at reduced pressure, at room temperature, to obtain 0.26 g (yield=43%) of a clear yellow microcrystalline solid product corresponding to the ZrCl.sub.3(L5) complex.
[0271] Elemental analysis [found (calculated)]: C: 36.87% (37.85%); H: 2.65% (2.91%); N: 6.95% (7.36%); Zr: 22.98% (23.95%); Cl: 27.42% (27.93%).
[0272]
Example 12
[0273] Synthesis of ZrCl.sub.3(L6) [Sample MT-30]
##STR00026##
[0274] Zirconium tetrachloride (ZrCl.sub.4) (0.317 g; 1.36 mmol) was introduced into a 100 ml long-necked flask together with a solution of the ligand having formula (L6) (0.289 g; 1.36 mmol; L6/Zr molar ratio=1), obtained as described in Example 6, in toluene (10 ml). The mixture obtained was left, under stirring, at room temperature, for 30 minutes, and subsequently heated under reflux for 2 hours. The solid formed was recovered by filtration, washed with heptane (2×2 ml) and dried at reduced pressure, at room temperature, to obtain 0.50 g (yield=90%) of a clear yellow microcrystalline solid product corresponding to the ZrCl.sub.3(L6) complex.
[0275] Elemental analysis [found (calculated)]: C: 41.52% (41.12%); H: 3.15% (3.70%); N: 6.15% (6.85%); Zr: 21.95% (22.31%); Cl: 25.75% (26.01%).
Example 13
[0276] Synthesis of ZrCl.sub.3(L7) [Sample MT-52]
##STR00027##
[0277] Zirconium tetrachloride (ZrCl.sub.4) (0.351 g; 1.51 mmol) was introduced into a 100 ml long-necked flask together with a solution of the ligand having formula (L7) (0.341 g; 1.51 mmol; L7/Zr molar ratio=1), obtained as described in Example 7, in toluene (10 ml). The mixture obtained was left, under stirring, at room temperature, for 30 minutes, and subsequently heated under reflux for 2 hours. The solid formed was recovered by filtration, washed with heptane (2×2 ml) and dried at reduced pressure, at room temperature, to obtain 0.50 g (yield=78%) of a clear yellow microcrystalline solid product corresponding to the ZrCl.sub.3(L7) complex.
[0278] Elemental analysis [found (calculated)]: C: 42.00% (42.60%); H: 3.75% (4.05%); N: 6.01% (6.62%); Zr: 20.87% (21.57%); Cl: 24.98% (25.15%).
Example 14
[0279] Synthesis of ZrCl.sub.3(L4) [Sample MT-56]
##STR00028##
[0280] Zirconium tetrachloride (ZrCl.sub.4) (0.212 g; 0.910 mmol) was introduced into a 100 ml long-necked flask together with a solution of the ligand having formula (L4) (0.236 g; 0.910 mmol; L4/Zr molar ratio=1), obtained as described in Example 4, in toluene (10 ml). The mixture obtained was left, under stirring, at room temperature, for 30 minutes, and subsequently heated under reflux for 2 hours. The solid formed was recovered by filtration, washed with heptane (2×2 ml) and dried at reduced pressure, at room temperature, to obtain 0.245 g (yield=62%) of a clear yellow microcrystalline solid product corresponding to the ZrCl.sub.3(L4) complex.
[0281] Elemental analysis [found (calculated)]: C: 46.88% (47.32%); H: 3.01% (3.30%); N: 5.76% (6.13%); Zr: 29.44% (19.96%); Cl: 24.01% (23.27%).
Example 15
[0282] Synthesis of ZrCl.sub.2(L5).sub.2 [Sample MT-81]
##STR00029##
[0283] Into a 100 ml long-necked flask was introduced a solution of the ligand having formula (L5) (0.38 g; 2.08 mmol), obtained as described in Example 5, in tetrahydrofuran (10 ml): the whole was cooled to −70° C. and subsequently a solution of lithium-n-butyl (0.87 ml, 2.17 mmol) in hexane was added drop by drop, to obtain a yellow-orange suspension. The suspension obtained was heated to room temperature and left, under stirring, at this temperature, for 3 hours. Subsequently, a solution of zirconium tetrachloride tetrahydrofuran (1:2) [ZrCl.sub.4(THF).sub.2] (0.391 g; 1.04 mmol; L5/Zr molar ratio=2) in tetrahydrofuran (30 ml) was added drop by drop: after the addition of the first 10 ml an orange solution was obtained, whilst at the end of the addition a yellow solution was obtained, which was left, under stirring, at room temperature, for one night. Subsequently, the solvent was removed by distillation at reduced pressure, at room temperature, to obtain a yellow residue, which was treated with dichloromethane (15 ml). The suspension obtained was filtered and the filtrate was concentrated to half volume, treating with hexane (20 ml), and kept at −30° C. for one night. Subsequently, the residue obtained was recovered by filtration, washed with heptane (2×1 ml) and dried under vacuum, at room temperature, to obtain 0.27 g (yield=35%) of a brown microcrystalline solid product corresponding to the ZrCl.sub.2(L5).sub.2 complex.
[0284] Elemental analysis [found (calculated)]: C. 53.79% (53.54%); H: 3.89% (4.19%); N: 10.99% (10.60%); Zr: 18.01% (17.26%); Cl: 12.98% (13.41%).
Example 16 (GL957)
[0285] Into a 50 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 4.65 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, methylaluminoxane (MAO) in a toluene solution (15.75 ml; 2.5×10.sup.−2 mol, equal to approximately 1.45 g) was added, followed by the ZrCl.sub.3(L1) complex [sample BM2-199] (4.6 ml of toluene solution at a concentration of 5 mg/ml; 5×10.sup.−5 mol, equal to approximately 23 mg) obtained as described in Example 8. The whole was kept, under magnetic stirring, at 20° C., for 6 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 0.97 g of polybutadiene having a content of 1,4-trans units of 96%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0286]
Example 17 (GL959)
[0287] Into a 50 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 4.45 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, methylaluminoxane (MAO) in a toluene solution (15.75 ml; 2.5×10.sup.−2 mol, equal to approximately 1.45 g) was added, followed by the ZrCl.sub.3(L2) complex [sample BM2-207] (4.8 ml of toluene solution at a concentration of 5 mg/ml; 5×10.sup.−5 mol, equal to approximately 24 mg) obtained as described in Example 9. The whole was kept, under magnetic stirring, at 20° C., for 7 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 0.63 g of polybutadiene having a content of 1,4-trans units of 95%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0288]
[0289]
[0290]
Example 18 (MM20)
[0291] Into a first 50 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 10.1 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, dry methylaluminoxane (MAOdry) in a toluene solution (10 ml; 3×10.sup.−2 mol, equal to approximately 1.74 g) was added. Into a second 10 ml test tube were introduced the ZrCl.sub.3(L2) complex [sample BM2-207] (2.9 ml of toluene solution at a concentration of 5 mg/ml; 3×10.sup.−5 mol, equal to approximately 14.4 mg) obtained as described in Example 9 and tri-ethyl-aluminium (2 ml of toluene solution at a concentration of 0.052 g/ml; 9×10.sup.4 mol, equal to approximately 104 mg): the whole was kept, under stirring, at room temperature, for 10 minutes, and the solution obtained was completely added to said first test tube. The whole was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 1.24 g of polybutadiene having a content of 1,4-trans units of 99%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0292]
[0293]
[0294]
[0295]
[0296]
Example 19 (G1125)
[0297] Into a first 25 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 9.3 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, dry methylaluminoxane (MAOdry) in a toluene solution (10 ml; 3×10.sup.−2 mol, equal to approximately 1.74 g) was added. Into a second 10 ml test tube were introduced the ZrCl.sub.3(L3) complex [sample MT-2] (2.7 ml of toluene solution ata concentration of 5 mg/ml; 3×10.sup.−5 mol, equal to approximately 13.4 mg) obtained as described in Example 10 and di-iso-butyl-aluminium hydride (DIBAH) (3 ml of toluene solution at a concentration of 0.040 g/m1; 8.4×10.sup.−4 mol, equal to approximately 120 mg): the whole was kept, under stirring, at room temperature, for 10 minutes, and the solution obtained was completely added to said first test tube. The whole was kept, under magnetic stirring, at 20° C., for 4 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 1.24 g of polybutadiene having a content of 1,4-trans units of 99%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0298]
Example 20 (G1112)
[0299] Into a 25 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 5.15 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, methylaluminoxane (MAO) in a toluene solution (15.75 ml; 2.5×10.sup.−2 mol, equal to approximately 1.45 g) was added, followed by the ZrCl.sub.3(L6) complex [sample MT-30] (4.1 ml of toluene solution at a concentration of 5 mg/ml; 3×10.sup.−5 mol, equal to approximately 20.5 mg) obtained as described in Example 12. The whole was kept, under magnetic stirring, at 20° C., for 7 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 0.68 g of polybutadiene having a content of 1,4-trans units of 95%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0300]
[0301]
Example 21 (MM21)
[0302] Into a first 25 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 9.54 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, dry methylaluminoxane (MAOdry) in a toluene solution (10 ml; 3×10.sup.−2 mol, equal to approximately 1.74 g) was added. Into a second 10 ml test tube were introduced the ZrCl.sub.3(L6) complex [sample MT-30] (2.7 ml of toluene solution ata concentration of 5 mg/ml; 3×10.sup.−5 mol, equal to approximately 13.44 mg) obtained as described in Example 12 and tri-iso-butyl-aluminium (TIBA) (3 ml of toluene solution at a concentration of 0.056 g/m1; 8.4×10.sup.−4 mol, equal to approximately 167 mg): the whole was kept, under stirring, at room temperature, for 10 minutes, and the solution obtained was completely added to said first test tube. The whole was kept, under magnetic stirring, at 20° C., for 4 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 1.15 g of polybutadiene having a content of 1,4-trans units of 99%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0303]
[0304]
Example 22 (G1120)
[0305] Into a 25 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 4.65 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, methylaluminoxane (MAO) in a toluene solution (15.75 ml; 2.5×10.sup.−2 mol, equal to approximately 1.45 g) was added, followed by the ZrCl.sub.3(L4) complex [sample MT-56] (4.6 ml of toluene solution at a concentration of 5 mg/ml; 5×10.sup.−5 mol, equal to approximately 23 mg) obtained as described in Example 14. The whole was kept, under magnetic stirring, at 20° C., for 6 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 0.55 g of polybutadiene having a content of 1,4-trans units of 95%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0306]
Example 23 (G1121)
[0307] Into a 25 ml test tube were condensed, in the cold (−20° C.), 2 ml of 1,3-butadiene, equal to approximately 1.4 g. Subsequently, 2.15 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Subsequently, methylaluminoxane (MAO) in a toluene solution (15.75 ml; 2.5×10.sup.−2 mol, equal to approximately 1.45 g) was added, followed by the ZrCl.sub.2(L5).sub.2 complex [sample MT-81] (5.3 ml of toluene solution at a concentration of 5 mg/ml; 5×10.sup.−5 mol, equal to approximately 26.4 mg) obtained as described in Example 15. The whole was kept, under magnetic stirring, at 20° C., for 5 hours. The polymerization was subsequently quenched by adding 2 ml of methanol containing a few drops of hydrochloric acid. The polymer obtained was subsequently coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba), to obtain 1.36 g of polybutadiene having a content of 1,4-trans units of 94%: further features of the process and of the polybutadiene obtained are shown in Table 1.
[0308]
[0309]
TABLE-US-00001 TABLE 1 Polymerization of 1,3-butadiene using catalytic systems comprising complexes of zirconium Time Yield Conversion 1,4-trans M.sub.w T.sub.m.sup.(a) T.sub.c.sup.(b) Example (min) (g) (%) (%) (g × mol.sup.−1) M.sub.w/M.sub.n (° C.) (° C.) 16 6 0.97 69.3 96 465500 2.8 119.9 103.8 17 7 0.63 45.0 95 347710 3.3 118.6 101.3 18 2 1.24 88.6 99 597200 1.9 134.8 116.5 19 4 0.84 60.0 99 752000 2.0 137.2 118.1 20 7 0.68 48.6 95 580500 2.6 133.9 116.1 21 4 1.15 82.1 99 816500 2.0 139.1 120.3 22 6 0.55 39.3 95 1273591 1.6 124.7 109.2 23 5 1.36 97.1 94 1950000 1.6 120.8 103.1 .sup.(a)melting point; .sup.(b)crystallization temperature.