Metallocenes are highly active catalysts for the production of precisely designed polyolefins and engineering plastics. Especially zirconocene/methylalumoxane (MAO) catalysts and half-sandwich titanium complexes have opened a frontier in the area of new polymer synthesis and processing. The materials obtained show different microstructures, tacticities and properties compared with conventional polymers. Alternating ethene/propene polymers show lower glass transition temperatures than random copolymers. Constrained geometry catalysts are useful for the synthesis of norbomene/ethene copolymers.

Three olefin polymerization catalysts are supported onto a flat silica wafer employing spin-coating impregnation. These model catalysts feature a defined surface direction of the silica support and thus facilitate the direct correlation between catalyst dispersion and morphology of the polymer product. Depending on the interaction of the catalysts with the silica surface, the catalysts disperse in very different fashions, which induces different constraints on the polymer growth upon gas-phase polymerization. Chemical anchoring of the active species as in the CrOx/SiO2 (Phillips) system results in homogeneous polymer film of up to several 10 mum. In contrast the physisorbed Cp[1,3-(2,6-Me2C6H3)(2)C2H4N2C=N]-TiBz(2)B(C6F5)(3) forms clusters on the flat silica that evolve into highly porous, ball-shaped polymer beads. rac-[Me2Si(2-Me-4-(1-Naph)Ind)(2)]ZrCl2(CH3AlO)(x) forms a film of metallocene catalyst dispersed inside the cocatalyst matrix. Homogeneous regions of this film give rather homogeneous polymer films while local concentrations of active species (hotspots) form crater- and ball-shaped structures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

In order to obtain more detailed information about supported metallocene/methylaluminoxane catalysts, two catalysts are supported onto a flat silicon wafer by spincoating impregnation. These model catalysts are characterized by SEM and EDX showing a film of metallocene catalyst dispersed inside the methylaluminoxane matrix, as well as regions of a localized increased concentration of the catalyst. Applying these model catalysts in a gas-phase polymerization reactor results in rather homogeneous films of polyethylene and polypropylene, respectively. In addition, crater-like and spherical polymer structures can be observed, probably formed by inhomogeneous catalyst distribution.

Two new C1-symmetric zirconocenes of the type [Me2C(3-RCp)(Flu)]ZrCl2 bearing a phenyl (Ph) or a cyclohexyl (cHex) substituent on the cyclopentadienyl ring were synthesized. Copolymerizations of ethene and styrene were carried out using these catalysts and compared to the results obtained with the methyl- and tertbutyl-substituted as well as with the unsubstituted system. By the introduction of the phenyl substituent both the activities and the molar masses could be increased whilst the styrene incorporation was comparable to that achieved with the unsubstituted system. In the case of the alkyl substituted systems (R=Me, tertBu, cHex) the styrene incorporation is decreased drastically and molar masses and activities are also strongly effected.

Metallocene based catalysts are excellent tools in the production of poly-α-olefins. The product properties of these catalysts can be tailor-made by controlling the microstructure as well as the molar mass and the thermal properties. Rac-[Me2Si(2-Me-4-(1-Naphtyl)Ind2]ZrCl2/MAO is a system that exhibits exceptional capabilities in respect to activity and isospecificity while producing polypropenes with high molar masses in the solution process.

Propene was polymerized using rac-dimethylsilylbis(2-methyl-4-(1-naphtyl)indenyl)zirconium dichloride (rac-[Me2Si(2-Me-4-(1-Naphtyl)Ind)2]ZrCl2) under six sets of conditions: in toluene solution, bulk, toluene slurry, bulk with the supported metallocene, a stirred bed with polyethene and a stirred bed with NaCl. The first two procedures were carried out with methylaluminoxane (MAO) as cocatalyst, the latter four were performed with methylaluminoxane supported on silicagel (MAO/SiO2) as activator. The differences between the procedures employed were examined by comparison of the polymer properties of the resulting products and of the activities at different temperatures. The polymerization procedure has a significant influence on the products. The polypropenes obtained with the homogeneous catalyst systems have generally high melting points and molar masses and exhibit very high activities. The heterogeneous analogues, on the other hand, gain enhanced stability by supporting, even at higher temperatures.

Chemie Ingenieur TechnikVolume 73, Issue 7 p. 857-861 Wissenschaftliche Kurzmitteilung Einfluss der Polymerisationsverfahren auf die Produkteigenschaften von Metallocen-Polypropen W. Kaminsky Prof. Dr., W. Kaminsky Prof. Dr.Search for more papers by this authorD. Arrowsmith, D. Arrowsmith Institut für Technische und Makromolekulare Chemie, Universität Hamburg, Bundesstraße 45, D-20146 HamburgSearch for more papers by this authorA. Laban, A. Laban Institut für Technische und Makromolekulare Chemie, Universität Hamburg, Bundesstraße 45, D-20146 HamburgSearch for more papers by this authorP. J. Lemstra, P. J. Lemstra Dutch Polymer Institute, Department of Chemical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, NiederlandeSearch for more papers by this authorJ. Loos, J. Loos Dutch Polymer Institute, Department of Chemical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, NiederlandeSearch for more papers by this authorU. Weingarten, U. Weingarten Institut für Technische und Makromolekulare Chemie, Universität Hamburg, Bundesstraße 45, D-20146 HamburgSearch for more papers by this author W. Kaminsky Prof. Dr., W. Kaminsky Prof. Dr.Search for more papers by this authorD. Arrowsmith, D. Arrowsmith Institut für Technische und Makromolekulare Chemie, Universität Hamburg, Bundesstraße 45, D-20146 HamburgSearch for more papers by this authorA. Laban, A. Laban Institut für Technische und Makromolekulare Chemie, Universität Hamburg, Bundesstraße 45, D-20146 HamburgSearch for more papers by this authorP. J. Lemstra, P. J. Lemstra Dutch Polymer Institute, Department of Chemical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, NiederlandeSearch for more papers by this authorJ. Loos, J. Loos Dutch Polymer Institute, Department of Chemical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, NiederlandeSearch for more papers by this authorU. Weingarten, U. Weingarten Institut für Technische und Makromolekulare Chemie, Universität Hamburg, Bundesstraße 45, D-20146 HamburgSearch for more papers by this author First published: 16 July 2001 https://doi.org/10.1002/1522-2640(200107)73:7<857::AID-CITE857>3.0.CO;2-8AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Volume73, Issue7July, 2001Pages 857-861 RelatedInformation

4,7-Dimethylindenyl lithium or 2,4,7-trimethylindenyl lithium reacts with 1-bromobutane, 1-chloro-2-propene, or 1-bromo-3-methyl-2-butene to give 3-butyl-4,7-dimethyl-1H-indene (1), 3-(2-propene-1-yl)-2,4,7-trimethyl-1H-indene (2), or 3-(3-methyl-2-butene-1-yl)-2,4,7-trimethyl-1H-indene (3), respectively. Deprotonation of 1–3 with n-butyl lithium yields the lithium salts 1a–3a. The reactions of 1a–3a and of [1-(4-pentene-1-yl)indenyl]lithium (4a) with zirconiumtetrachloride produce the complexes bis[1-butyl-4,7-dimethylindenyl]- (1b), bis[1-(2-propene-1-yl)-2,4,7-trimethyl-indenyl]- (2b), bis[1-(3-methyl-2-butene-1-yl)-2,4,7-trimethylindenyl]- (3b) or bis[1-(4-pentene-1-yl)indenyl]zirconium dichloride (4b). The reaction of cyclopentadienylzirconium trichloride with [2-(3-butene-1-yl)-4,7-dimethylindenyl]lithium or [2-(4-pentene-1-yl)-4,7-dimethylindenyl]lithium affords the mixed complexes [2-(3-butene-1-yl)-4,7-dimethylindenyl(cyclopentadienyl)]zirconium dichloride (5c) or [2-(4-pentene-1-yl)-4,7-dimethylindenyl(cyclopentadienyl)]zirconium dichloride (6c). All new compounds were characterized by elemental analysis, 1H- and 13C{1H}-NMR spectroscopy as well as by mass spectrometry. In addition, single-crystal X-ray structural analysis was done for 3b. The complexes 1b–4b, 5c, and 6c were tested as catalysts for the homopolymerization and copolymerization of ethene and propene and the results were compared to those of analogous compounds.

Copolymerizations of ethene and propene were carried out either with the soluble catalyst systems dimethylsilylbis(2-methyl-4-phenylindenyl)zirconiumdichloride/methylaluminoxane (MAO) (1), isopropylidenecyclopentadienylfluorenylzirconiumdichloride/MAO (2) and isopropylidene(3-methylcyclopentadienyl)fluorenylzirconiumdichloride/MAO (3) in toluene or with the supported metallocenes (1)/SiO2, (2)/SiO2 and (3)/SiO2 in the gas phase. Furthermore, terpolymerizations of ethene, propene and 5-ethylidene-2-norbornene (ENB) were performed with the homogeneous system (3) and with the heterogeneous system (3)/SiO2 in the gas phase. The physical and chemical properties of the resulting polymers were compared in order to examine the behavior of the metallocenes when supported. In general, they work in much the same way as their soluble counterparts and the synthesis of EP(D)M co(ter)polymers with the above mentioned metallocenes can easily be transfered to gas phase processes.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A series of new 1-, 2-, and multi-substituted indenes has been synthesized and characterized. The reaction of indenyl lithium or 4,7-dimethylindenyl lithium with alkenyl bromides yielded a mixture of 1- and 3-allylindene (1), 3-(3-buten-1-yl)indene (2), 3-(4-penten-1-yl)indene (3), 3-allyl-4,7-dimethylindene (4), 3-(3-buten-1-yl)-4,7-dimethylindene (5), as well as 3-(4-penten-1-yl)-4,7-dimethylindene (6). The 2-substituted indenes 2-allylindene (7), 2-(3-buten-1-yl)indene (8), 2-(4-penten-1-yl)indene (9), 2-allyl-4,7-dimethylindene (10), 2-(3-buten-1-yl)-4,7-dimethylindene (11), and 2-(4-penten-1-yl)-4,7-dimethylindene (12) were prepared by PdCl2(DPPF) or NiCl2(DPPE) catalyzed cross-coupling reactions of the appropriate Grignard reagents with 2-bromoindene or 2-bromo-4,7-dimethylindene. Alkenylation of 3-methylindenyl lithium and 2,4,7-trimethylindenyl lithium produced 1-(3-buten-1-yl)-3-methylindene (13) or 1-(3-buten-1-yl)-2,4,7-trimethylindene (14), respectively. The indene derivatives 1–14 react with n-butyl lithium in hexane yielding the corresponding lithium salts 1a–14a. Zirconium tetrachloride reacts with 1a, 2a, 4a–6a and 11a–14a under formation of the corresponding bis(indenyl)zirconium dichloride complexes 1b, 2b, 4b–6b and 11b–14b. All compounds were characterized by elemental analysis, 1H and 13C{1H}-NMR spectroscopy and mass spectrometry, 5b and 12b also by single crystal X-ray structural analysis. 1b, 4b–6b and 11b–13b are active catalysts for the polymerization of ethene and propene.

Ethene/propene copolymerisations were carried out at 30 degrees C and 60 degrees C using four different metallocenes [Me2C(3-RCp)(Flu)]ZrCl2 (R = H, Me, Pr-iso, Bu-tert). With increasing size of the substituent distinct changes in the copolymerisation behaviour and polymer microstructure were observed. A copolymerisation model taking into account the heterotopic nature of the metallocenes has been developed which fits the experimental triad distributions obtained. It is concluded that copolymerisation proceeds via chain migratory insertion for R = H and Me whereas a retention mechanism is found for R = Bu-tert. For R = Pr-iso especially at 60 degrees C a defective alternating mechanism seems to be operative.