813 results on '"Natta"'
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2. Formation of Highly Active Ziegler–Natta Catalysts Clarified by a Multifaceted Characterization Approach
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Toshiaki Taniike, Elena Groppo, Tomohiro Ikeda, Gentoku Takasao, Patchanee Chammingkwan, Toru Wada, Dongzhi Zhu, Alessandro Piovano, Alessia Amodio, and Minoru Terano
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Materials science ,biology ,XRD ,total scattering ,General Chemistry ,Natta ,biology.organism_classification ,Combinatorial chemistry ,Catalysis ,Characterization (materials science) ,electronic properties ,IR spectroscopy ,morphology ,pair distribution function ,synchrotron ,Ziegler-Natta catalysts - Published
- 2021
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3. Blending Behavior of High-Degree Long-Chain-Branched Polypropylene Prepared by Ziegler–Natta Catalysis with Common Polypropylene
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Yawei Qin, Kang Li, Songmei Zhao, and Jin-Yong Dong
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Polypropylene ,Materials science ,Polymer science ,biology ,General Chemical Engineering ,General Chemistry ,Natta ,biology.organism_classification ,Industrial and Manufacturing Engineering ,Degree (temperature) ,Catalysis ,chemistry.chemical_compound ,chemistry ,Long chain - Published
- 2021
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4. Natta chionogaster
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Wesołowska, Wanda and Russell-Smith, Anthony
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Natta ,Arthropoda ,Salticidae ,Arachnida ,Animalia ,Araneae ,Biodiversity ,Natta chionogaster ,Taxonomy - Abstract
Natta chionogaster (Simon, 1901) Cyllobelus chionogaster Simon, 1901a: 151. Cyllobelus australis Peckham & Peckham, 1902: 334. Cyllobelus chionogaster – Simon 1901c: 541, 549, fig. 665. — Peckham & Peckham 1903: 195, pl. 21 fig. 1. Cyllobelus australis – Peckham & Peckham 1903: 194, pl. 21 fig. 2. Natta chionogaster – Wesołowska 1993: 18, figs 1–16. For full reference list see World Spider Catalog (2022). Material examined IVORY COAST • 1 ♂; Lamto; 16 Sep. 1975; “savane, base des herbes”; MNHN • 1 ♂; same collection data as for preceding; 3 Jan. 1975; “savane non-brulée, base des herbes”; MNHN • 1 ♂; Mt Niangbo; 16 Oct. 1975; “savane arborée, sol et herbes”; MNHN. Description For both sexes see Wesołowska (1993). Distribution Widespread in the Afrotropical Region., Published as part of Wesołowska, Wanda & Russell-Smith, Anthony, 2022, Jumping spiders from Ivory Coast collected by J. - C. Ledoux (Araneae, Salticidae), pp. 1-143 in European Journal of Taxonomy 841 (1) on page 69, DOI: 10.5852/ejt.2022.841.1943, http://zenodo.org/record/7195354, {"references":["Simon E. 1901 a. Descriptions d'arachnides nouveaux de la famille des Attidae (suite). Annales de la Societe entomologique de Belgique 45: 141 - 161. Available from https: // www. biodiversitylibrary. org / page / 36148105 [accessed 16 Aug. 2022].","Peckham G. W. & Peckham E. G. 1902. Some new genera and species of Attidae from South Africa. Psyche 9 (312): 330 - 335. https: // doi. org / 10.1155 / 1902 / 13502","Simon E. 1901 c. Histoire naturelle des Araignees. Deuxieme edition, tome second. Roret, Paris. https: // doi. org / 10.5962 / bhl. title. 51973","Peckham G. W. & Peckham E. G. 1903. New species of the family Attidae from South Africa, with notes on the distribution of the genera found in the Ethiopian region. Transactions of the Wisconsin Academy of Sciences, Arts and Letters 14: 173 - 278.","Wesolowska W. 1993. Notes on the genus Natta Karsch, 1879 (Araneae, Salticidae). Genus 4: 17 - 32.","World Spider Catalog. 2022. Version 23.0. Natural History Museum Bern. Available from http: // wsc. nmbe. ch [accessed 6 Jan. 2022]. https: // doi. org / 10.24436 / 2"]}
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- 2022
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5. Natta horizontalis Karsch 1879
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Wesołowska, Wanda and Russell-Smith, Anthony
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Natta ,Arthropoda ,Salticidae ,Natta horizontalis ,Arachnida ,Animalia ,Araneae ,Biodiversity ,Taxonomy - Abstract
Natta horizontalis Karsch, 1879 Natta horizontalis Karsch, 1879: 362. Natta horizontalis – Wesołowska 1993: 25, figs 22–41. For full reference list see World Spider Catalog (2022). Material examined IVORY COAST • 1 ♂; Lamto; 22 Aug. 1975; “sous bois, au sol”; MNHN • 1 ♀; same collection data as for preceding; 12 Aug. 1975; “savane gruyére, hautes des herbes”; MNHN • 1 ♂; same collection data as for preceding; 12 Aug. 1975; “lisière, savane du rocher 1 km E de la station”; MNHN • 1 ♀; same collection data as for preceding; 6 Sep. 1975; “savane, base des herbes”; MNHN • 1 ♀; same collection data as for preceding; 13 Oct. 1975; “savane, au sol”; MNHN • 1 ♀; same collection data as for preceding; “savane, base des herbes”; MNHN • 1 ♀; same collection data as for preceding; 15 Sep. 1975; “sur un nid de magnans aux environs de la station”; MNHN • 1 ♀; Man; 7°24′ N, 7°33′ W; 9 Apr. 1978; “derièrre l’hôpital, forêt secondaire”; MNHN. Description See Wesołowska (1993). Distribution Widely distributed in Africa., Published as part of Wesołowska, Wanda & Russell-Smith, Anthony, 2022, Jumping spiders from Ivory Coast collected by J. - C. Ledoux (Araneae, Salticidae), pp. 1-143 in European Journal of Taxonomy 841 (1) on page 69, DOI: 10.5852/ejt.2022.841.1943, http://zenodo.org/record/7195354, {"references":["Karsch F. 1879. West-afrikanische Arachniden, gesammelt von Herrn Stabsarzt Dr. Falkenstein. Zeitschrift fur die Gesammten Naturwissenschaften 52: 329 - 373.","Wesolowska W. 1993. Notes on the genus Natta Karsch, 1879 (Araneae, Salticidae). Genus 4: 17 - 32.","World Spider Catalog. 2022. Version 23.0. Natural History Museum Bern. Available from http: // wsc. nmbe. ch [accessed 6 Jan. 2022]. https: // doi. org / 10.24436 / 2"]}
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- 2022
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6. Electronic Properties of Ti Sites in Ziegler–Natta Catalysts
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Elena Groppo, Gentoku Takasao, Andrea Martini, Alessandro Piovano, Toru Wada, Toshiaki Taniike, Luca Braglia, Piero Torelli, and Matteo Signorile
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Materials science ,biology ,UV-vis ,General Chemistry ,Natta ,biology.organism_classification ,catalysts ,Catalysis ,NEXAFS ,Ziegler-Natta ,Polymer chemistry ,electronic properties ,Ti ,Electronic properties - Published
- 2021
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7. Probing into Effects of Support Pre-Treatment on the Polymerization Behavior and Morphology Development of Mg(OEt)2-Based Ziegler–Natta Catalysts
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Abdolhannan Sepahi, Maryam Masoori, Mohammad Hossein Jandaghian, Ehsan Nikzinat, Reza Rashedi, and Yasaman Maddah
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inorganic chemicals ,biology ,Chemistry ,organic chemicals ,Stacking ,General Chemistry ,Crystal structure ,Natta ,biology.organism_classification ,Catalysis ,Grain size ,Polymerization ,Chemical engineering ,Particle-size distribution ,Particle size - Abstract
In this study, commercially available, milled, and heat-treated Mg(OEt)2 were used as the precursors in the synthesis procedure of industrially-favorable supported Ziegler–Natta catalysts. The effects of milling and heat-treatment of the support were completely investigated during the catalyst synthesis and polymerization using SEM, PSD, BET, DCS, and XRD techniques. It was found that despite the support treatments had no significant effect on the elemental analysis results of the catalysts, the morphology of the catalyst pores was very sensitive to support manipulation, and bottleneck-type pores were predominated in the catalysts which were made using the non-manipulated supports. On the other hand, the catalysts which were made using the milled and not-milled supports showed a clear difference between the activity, particle size, and particle size distribution of the catalysts. Also, a high level of stacking disorder and high grain size was observed in the crystal structure of the catalyst made using the commercially available support. In the following, competition between fragmentation and replication was investigated in the synthesized samples, and an attempt was made to link the stacking disorder (in the catalyst structure) to the ease of the fragmentation process. Finally, using practical observation, a mechanism was proposed to justify the changes in the morphology of the catalysts during synthesis procedures. We claimed that milling and especially heat-treating of the support leads to the ordering of the MgCl2 stacking structure.
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- 2021
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8. Revealing the Dynamic Behaviors of Tetrahydrofuran for Tailoring the Active Species of Ziegler–Natta Catalysts
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Chuanding Dong, Chen Yuming, Dai Jincheng, Jingdai Wang, Wei Li, Yirong Feng, Qi Zhou, Peng Liang, Chen Mei, Yongrong Yang, Congjing Ren, and Binbo Jiang
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chemistry.chemical_compound ,Materials science ,chemistry ,biology ,Ethylene polymerization ,Organic chemistry ,General Chemistry ,Ziegler–Natta catalyst ,Natta ,biology.organism_classification ,Catalysis ,Tetrahydrofuran - Abstract
A full elucidation of chemisorbed donor behavior is of fundamental importance for tailoring the active species but has not yet been achieved for Ziegler–Natta catalysts. Herein, by exploiting the s...
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- 2021
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9. Investigation of the effect of Mg(OEt)2 manipulation on the ethylene and 1-butene co-polymerization performance of Ziegler-Natta catalysts
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Saeed Houshmandmoayed, Razieh Davand, Yasaman Maddah, Abdolhannan Sepahi, Mohammad Hossein Jandaghian, Reza Rashedi, Kamal Afzali, Ehsan Nikzinat, and Maryam Masoori
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Ethylene ,Materials science ,Polymers and Plastics ,biology ,1-Butene ,02 engineering and technology ,General Chemistry ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Polymerization ,Polymer chemistry ,Materials Chemistry ,Ceramics and Composites ,Particle size ,Ziegler–Natta catalyst ,0210 nano-technology - Abstract
Although Ziegler-Natta catalysts were discovered more than four decades ago, many aspects of their characteristics are not fully understood. The effect of the support particle size on the final pro...
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- 2021
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10. Investigation of the effects of heat treatment parameters during synthesis of titanium-magnesium-based Ziegler-Natta catalysts
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Reza Rashedi, Abdolhannan Sepahi, Maryam Masoori, Yasaman Maddah, Ehsan Nikzinat, and Mohammad Hossein Jandaghian
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inorganic chemicals ,Materials science ,Polymers and Plastics ,chemistry.chemical_element ,macromolecular substances ,02 engineering and technology ,Natta ,010402 general chemistry ,01 natural sciences ,Catalysis ,Aluminium ,Materials Chemistry ,Alkyl ,chemistry.chemical_classification ,biology ,Magnesium ,technology, industry, and agriculture ,General Chemistry ,Polymer ,021001 nanoscience & nanotechnology ,biology.organism_classification ,0104 chemical sciences ,chemistry ,Chemical engineering ,Polymerization ,Ceramics and Composites ,0210 nano-technology ,Titanium - Abstract
Many researchers have studied the effects of donors, promoters and alkyl aluminum compounds on the polymerization catalysts, the polymerization process and the final properties of polymers. Neverth...
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- 2020
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11. Inelastic Neutron Scattering Investigation of MgCl2 Nanoparticle-Based Ziegler–Natta Catalysts for Olefin Polymerization
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Alessandro Piovano, Svemir Rudić, Bartolomeo Civalleri, Alessandro Erba, Eleonora Vottero, Maddalena D’Amore, Elena Groppo, and Andrea Piovano
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Materials science ,phonon dispersion ,biology ,heterogeneous catalysts ,Nanoparticle ,nanostructuration in catalysis ,quantum mechanical simulations ,Natta ,inelastic neutron scattering ,biology.organism_classification ,Inelastic neutron scattering ,Catalysis ,QM simulations ,nanostructuration ,MgCl ,2 ,Physical chemistry ,Olefin polymerization ,General Materials Science - Abstract
The effect of nanosize and structural disorder on the MgCl2 support of Ziegler–Natta catalysts has been investigated in terms of induced changes to their vibrational spectroscopic fingerprint. In p...
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- 2020
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12. Comparative Effects on Recrystallization of Melt-Memory and Liquid–Liquid Phase Separation in Ziegler–Natta and Metallocene Ethylene Copolymers with Bimodal Comonomer Composition Distribution
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Yuan Sang, Xuejian Chen, Rufina G. Alamo, and Minqiao Ren
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Materials science ,Ethylene ,biology ,General Chemical Engineering ,Comonomer ,Recrystallization (metallurgy) ,02 engineering and technology ,General Chemistry ,Natta ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Industrial and Manufacturing Engineering ,Linear low-density polyethylene ,chemistry.chemical_compound ,020401 chemical engineering ,chemistry ,Chemical engineering ,Copolymer ,Liquid liquid ,0204 chemical engineering ,0210 nano-technology ,Metallocene - Abstract
Herein, we study comparatively melt-memory effects on recrystallization of two sets of linear low-density polyethylenes (LLDPE) synthesized with Ziegler–Natta (ZN-LLDPE) and with metallocene cataly...
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- 2020
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13. Effects of titanium dispersion state on distribution and reactivity of active centers in propylene polymerization with MgCl 2 ‐supported Ziegler‐Natta catalysts: A kinetic study based on active center counting
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Amjad Ali, Zhisheng Fu, Zhiqiang Fan, Baiyu Jiang, Yintian Guo, Biao Zhang, and Wenqi Guo
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Materials science ,biology ,Organic Chemistry ,Kinetics ,chemistry.chemical_element ,Natta ,biology.organism_classification ,Catalysis ,Inorganic Chemistry ,Active center ,chemistry ,Polymerization ,Physical chemistry ,Reactivity (chemistry) ,Physical and Theoretical Chemistry ,Dispersion (chemistry) ,Titanium - Published
- 2020
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14. Structure-performance relationship of Mg(OEt)2-based Ziegler-Natta catalysts
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Toru Wada, Ashutosh Thakur, Minoru Terano, Toshiaki Taniike, Toshiki Funako, Patchanee Chammingkwan, and Akanksha Matta
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Pairwise correlation ,biology ,010405 organic chemistry ,Chemistry ,Natta ,010402 general chemistry ,biology.organism_classification ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Chemical engineering ,Ethylene polymerization ,Olefin polymerization ,Particle ,Particle size ,Physical and Theoretical Chemistry - Abstract
A multivariate aspect has hampered the clarification of structure-performance relationships in heterogeneous Ziegler-Natta olefin polymerization catalysis. Here, 16 catalyst samples were prepared using Mg(OEt)2 support precursors with different particle architectures. They were fingerprinted based on a series of characterization and analytical methods. In a pairwise correlation analysis, none of structural features (such as particle size and pore volume) exhibited a clear correlation with ethylene polymerization performance. However, compound features created among different structural features reasonably reproduced the ethylene polymerization activity as well as 1-hexene incorporation efficiency, where a negative influence of pores with the size below 10 nm was dictated.
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- 2020
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15. Polymerization Kinetics of Propylene with the MgCl2-Supported Ziegler-Natta Catalysts—Active Centers with Different Tacticity and Fragmentation of the Catalyst
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Weiping Zheng, Ya-Ping Ma, Aihua He, Huafeng Shao, Liu Chenguang, and Da-Lin Du
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Polypropylene ,010407 polymers ,Materials science ,Polymers and Plastics ,biology ,General Chemical Engineering ,Organic Chemistry ,technology, industry, and agriculture ,Natta ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Active center ,chemistry.chemical_compound ,Stereospecificity ,chemistry ,Polymerization ,Chemical engineering ,Tacticity ,Lamellar structure - Abstract
The catalytic activity and stereospecificity of olefin polymerization by using heterogeneous TiCl4/MgCl2 Ziegler-Natta (Z-N) catalysts are determined by the structure and nature of active centers, which are mysterious and fairly controversial. In this work, the propylene polymerization kinetics under different polymerization temperatures by using Z-N catalysts were investigated through monitoring the concentration of active centers [C*] with different tacticity. SEM was applied to characterize the catalyst morphologies and growing polypropylene (PP) particles. The lamellar thickness and crystallizability of PP obtained under different polymerization conditions were analyzed by DSC and SAXS. The PP fractions and active centers with different tacticity were obtained with solvent extraction fractionation method. The catalytic activity, active centers with different tacticity and propagation rate constant kp, fragmentation of the catalyst, crystalline structure of PP are correlated with temperature and time for propylene polymerizations. The polymerization temperature and time show complex influences on the propylene polymerization. The higher polymerization temperature (60 °C) resulted higher activity, kp and lower [C*], and the isotactic active centers Ci* as the majority ones producing the highest isotactic polypropylene (iPP) components showed much higher kp when compared with the active centers with lower stereoselectivity. Appropriate polymerization time provided full fragmentation of the catalyst and minimum diffusion limitation. This work aims to elucidate the formation and evolution of active centers with different tacticity under different polymerization temperature and time and its relations with the fragmentation of the PP/catalyst particles, and provide the solutions to the improvement of catalyst activity and isotacticity of PP.
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- 2020
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16. <scp>Thermomechanical</scp> properties of poly(1‐butene) synthesized by <scp>Ziegler–Natta</scp> catalyzed polymerization of <scp>1‐butene</scp> in the presence of nucleating agents
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Chuang Li, Gaosheng Gu, Binyuan Liu, Yanfeng Gong, Il Kim, and Xiaopeng Cui
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Materials science ,Polymers and Plastics ,biology ,Organic Chemistry ,Nucleation ,1-Butene ,Natta ,biology.organism_classification ,law.invention ,Catalysis ,chemistry.chemical_compound ,chemistry ,Polymerization ,law ,Polymer chemistry ,Materials Chemistry ,Crystallization - Published
- 2020
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17. Disclosing the Interaction between Carbon Monoxide and Alkylated Ti3+ Species: a Direct Insight into Ziegler–Natta Catalysis
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Jelena Zarupski, Alessandro Piovano, and Elena Groppo
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Olefin fiber ,Letter ,Ziegler-Natta catalyst ,biology ,010405 organic chemistry ,FT-IR spectroscopy ,active sites ,Alkylation ,Natta ,010402 general chemistry ,Photochemistry ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Monomer ,Adsorption ,chemistry ,General Materials Science ,Physical and Theoretical Chemistry ,Ziegler–Natta catalyst ,Carbon monoxide - Abstract
In the field of Ziegler–Natta catalysis for olefin polymerization, carbon monoxide (CO) is used in the industrial practice to quench the reaction when it proceeds too fast, approaching critical levels for the plant safety. The quenching effect is explained as due to the reversible coordination of CO to the titanium active sites, but no direct evidence has been ever reported. In this work, we designed a series of experiments to monitor CO adsorption at variable temperatures on a model Ziegler–Natta catalyst by means of FT-IR spectroscopy. For the first time, we have been able to spectroscopically detect CO coordinated to alkylated Ti3+ sites and the Ti–acyl species formed upon the subsequent insertion of CO into the Ti3+–alkyl bond, both in the absence and in the presence of the olefin monomer. In perspective, this has important implications for the characterization of the active sites in industrial Ziegler–Natta catalysts, even under working conditions.
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- 2020
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18. New Insight into Titanium–Magnesium Ziegler–Natta Catalysts Using Photoluminescence Spectroscopy
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Sergei G. Kazarian, Evgeniy A. Paukshtis, Valentina N. Panchenko, Tatiana S. Glazneva, Anton Yu Shabalin, and Anton I. Kostyukov
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Photoluminescence ,Materials science ,Infrared ,Infrared spectroscopy ,chemistry.chemical_element ,Natta ,010402 general chemistry ,01 natural sciences ,TiCl4 ,Fourier transform infrared spectroscopy ,infrared spectroscopy ,Spectroscopy ,Instrumentation ,biology ,010401 analytical chemistry ,Articles ,biology.organism_classification ,Titanium–magnesium catalysts ,0104 chemical sciences ,Polymerization ,chemistry ,photoluminescence spectroscopy ,infrared ,IR ,Physical chemistry ,dibutyl phthalate ,MgCl2 ,Titanium - Abstract
This paper presents the results of study of titanium–magnesium catalysts often used in polymerization processes, by photoluminescence spectroscopy (PL) in combination with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The interaction of dibutyl phthalate (DBP) with MgCl2was studied at DBPadded/Mg = 0–1 (mol/mol). The luminescence spectra with excitation at 278 nm and the excitation spectra for main emission bands were recorded. It was shown that DBP adsorbed on magnesium chloride, both in the form of donor–acceptor complexes (D+A–) and in the form of molecular complexes. At DBPadded/Mg +A–complexes occur predominantly; with an increase in DBPadded/Mg, the fraction of molecular complexes increases. Molecular complexes are destroyed during the treatment of the support by TiCl4. In this case, the structure of magnesium chloride is disordered and new coordination–unsaturated sites are formed. This work is a first attempt to apply PL spectroscopy in combination with DRIFTS spectroscopy to study titanium–magnesium Ziegler–Natta catalysts. The application of PL spectroscopy to such systems made it possible to detect interactions within and between donor molecules, which would be particularly challenging to achieve using other spectroscopic methods. Both spectroscopic methods provided crucial information about the existence of two types of complexes on the sample surface which is important for tuning the synthesis procedure of the titanium–magnesium catalysts for olefin polymerization.
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- 2020
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19. Assessing 1,9-Decadiene/Propylene Copolymerization with Ziegler-Natta Catalysts to Long-Chain-Branched Polypropylene
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Yawei Qin, Jin-Yong Dong, and Yang Liu
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Polypropylene ,Materials science ,biology ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Natta ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Industrial and Manufacturing Engineering ,Catalysis ,chemistry.chemical_compound ,020401 chemical engineering ,chemistry ,Polymer chemistry ,Copolymer ,Fluorine ,0204 chemical engineering ,0210 nano-technology ,Long chain - Abstract
1,9-decadiene/propylene copolymerization is assessed as a way for Ziegler-Natta catalysts to access long chain-branched polypropylene. A MgCl2/9,9-bis-(methoxymethyl)fluorine/TiCl4 catalyst with tr...
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- 2020
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20. Direct Preparation of Transparent Isotactic Polypropylene with Supported Ziegler–Natta Catalysts Containing Novel Eco-friendly Internal Electron Donors
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Zhong Zhao, Jianjun Yi, Hongming Li, Qigu Huang, Feng Nan, Shaomeng Zhang, Hongchao Yu, Jiaojiao Zhang, and Xiaoqi Xia
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Materials science ,biology ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,Natta ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Environmentally friendly ,Industrial and Manufacturing Engineering ,Catalysis ,020401 chemical engineering ,Chemical engineering ,Tacticity ,0204 chemical engineering ,0210 nano-technology - Abstract
This study reported novel eco-friendly Ziegler-Natta catalysts containing bio-derived maleic rosinate tri-n-butyl and maleic rosinate tri-n-octyl as internal electron donors for propylene polymeriz...
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- 2020
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21. Non‐isothermal crystallization of Ziegler Natta i ‐PP‐graphene nanocomposite: DSC and new model prediction
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Abdullah K. Ahmed, Dev R. Pradhan, Mamdouh A. Al-Harthi, Ahmed Abdelaal, and Muhammad Atiqullah
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Nanocomposite ,Materials science ,biology ,Graphene ,General Chemical Engineering ,Model prediction ,Isothermal crystallization ,Natta ,biology.organism_classification ,law.invention ,symbols.namesake ,Chemical engineering ,law ,symbols ,Raman spectroscopy - Published
- 2020
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22. Natta horizontalis Karsch 1879
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Wesołowska, Wanda and Szűts, Tamás
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Natta ,Arthropoda ,Salticidae ,Natta horizontalis ,Arachnida ,Animalia ,Araneae ,Biodiversity ,Taxonomy - Abstract
Natta horizontalis Karsch, 1879 Natta horizontalis Karsch 1879: 362. Pochyta moschensis Caporiacco, 1947: 249, pl. 2, fig. 76 (D ♀), syn. n. For full reference list see World Spider Catalog (2021). Type material. Holotype of P. moschensis, female: TANZANIA: Moshi [Moschi in German], 3°20’S 37°20’E, Ran stream, leg. VI-VII.1906, leg. K. Kittenberger (HNHM). Remarks. The holotype of Pochyta moschensis is in good condition. There is no doubt that this specimen has been misidentified, and that in reality it is Natta horizontalis, common species in Africa. The first author knows N. horizontalis very well and redescribed it (Wesołowska 1993)., Published as part of Wesołowska, Wanda & Szűts, Tamás, 2021, A revision of the genus Pochyta Simon, with descriptions of new species (Araneae: Salticidae: Thiratoscirtina), pp. 1-41 in Zootaxa 5052 (1) on page 38, DOI: 10.11646/zootaxa.5052.1.1, http://zenodo.org/record/5565881, {"references":["Karsch, F. (1879) West-afrikanische Arachniden, gesammelt von Herrn Stabsarzt Dr. Falkenstein. Zeitschrift fur die Gesammten Naturwissenschaften, 52, 329 - 373.","Caporiacco, L. di (1947) Arachnida Africae Orientalis, a dominibus Kittenberger, Kovacs et Bornemisza lecta, in Museo Nationali Hungarico servata. Annales Historico-Naturales Musei Nationalis Hungarici, 40, 97 - 257.","World Spider Catalog (2021) World Spider Catalog. Version 22.5. Natural History Museum Bern. Available from: http: // wsc. nmbe. ch (accessed 17 May 2021) https: // doi. org / 10.24436 / 2","Wesolowska, W. (1993) Notes on the genus Natta Karsch, 1879 (Araneae, Salticidae). Genus, 4 (1), 17 - 32."]}
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- 2021
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23. Internal donors on supported Ziegler Natta catalysts for isotactic polypropylene: a brief tutorial review
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Poornima Bhagavath, J. B. Sainani, K. M. Samith, and Bharat R. Paghadar
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chemistry.chemical_classification ,Polypropylene ,Materials science ,Polymers and Plastics ,biology ,Polymer science ,Organic Chemistry ,Regioselectivity ,Polymer ,Natta ,biology.organism_classification ,Catalysis ,chemistry.chemical_compound ,chemistry ,Tacticity ,Materials Chemistry ,Comparison study ,Bifunctional - Abstract
The scientific and technical advances in the field of polymer science has been abundant in recent years. Amongst the various polymeric materials available in market, synthesis of polyolefins has been in the forefront since decades. A major challenge in this domain remains in attaining stereoregular polyolefins especially polypropylene (PP) and significant efforts were carried out by synthesizing various internal donors (ID) aiding the catalysts involved in producing them. This short review gives an overview of i) various generations of Ziegler–Natta (ZN) catalyst systems ii) general classes of ID that has been demonstrated by the researchers over the past decades iii) their influence on PP isotacticity and polymer properties. The coordination modes of different donor classes on supported ZN system and comparative study especially between phthalate and diether ID classes were also addressed here. This review also presents the studies carried out on phthalate catalyst structure analysis, detailed comparison study on phthalate and diether IDs in terms of PP isotacticity, regioselectivity, hydrogen response, and also their cross combination study and competitive behavior. Further a brief description on other structurally varied IDs like malonates, maleates, silyl diol esters, bifunctional donors, multi ether donors demonstrated for isotactic PP were also presented. Studies conducted on compatibility of incorporation of two different classes of IDs on a single supported ZN system for the fundamental understanding of the catalyst behavior; and also on how mixed donor approach enables in tuning the catalyst for polymer properties were also presented. This review also provides an opportunity to the young minds and the basic researchers from academic point of view by and large to create new polymeric materials with useful properties or modify the existing materials for new applications by incorporating new IDs for further improvisation of the stereo regularity in obtaining the polymers. Graphic Abstract
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- 2021
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24. Investigation of Chain Microstructure of Polypropylene Polymerized by Ziegler–Natta Catalysts with Diester and Diether Compound as Internal Donor via Hydrogen Chain Transfer
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Yin Xuemin, Yawei Qin, and Jin-Yong Dong
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Polypropylene ,Materials science ,biology ,Hydrogen ,General Chemical Engineering ,chemistry.chemical_element ,Chain transfer ,02 engineering and technology ,General Chemistry ,Diisobutyl phthalate ,Natta ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Industrial and Manufacturing Engineering ,Catalysis ,chemistry.chemical_compound ,020401 chemical engineering ,chemistry ,Polymerization ,Polymer chemistry ,Fluorine ,0204 chemical engineering ,0210 nano-technology - Abstract
Two series of polypropylene samples (PP) were prepared with two MgCl2/TiCl4-type catalysts with diisobutyl phthalate and 9,9-bis(methoxymethyl)fluorine as internal donors (named as cat1 and cat2), ...
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- 2020
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25. Fundamental aspects of heterogeneous Ziegler–Natta olefin polymerization catalysis: an experimental and computational overview
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Jugal Kumawat and Virendrakumar Gupta
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Materials science ,Polymers and Plastics ,biology ,Catalyst support ,Organic Chemistry ,Bioengineering ,Polyethylene ,Natta ,biology.organism_classification ,Biochemistry ,Polyolefin ,Catalysis ,chemistry.chemical_compound ,chemistry ,Polymerization ,Chemical engineering ,Olefin polymerization ,Experimental work - Abstract
MgCl2 supported Ziegler–Natta (Z–N) catalysts have emerged as the most exciting chemical process for polyolefin technology, which is responsible for the production of ∼150 million tons of polyolefin (polyethylene and polypropylene) per annum. However, fundamental chemistry of Z–N catalysts is not fully understood yet due to their multi-component nature as well as heterogeneous systems. Therefore, in this review, we have highlighted the chronological development of a heterogeneous Z–N catalyst and its polymerization (ethylene, propylene and 1-butene) process including termination steps. Then, we have discussed different structural and chemical aspects of the catalyst support, catalytically active sites, cocatalyst, internal/external electron donors and their different combinations. In the last two decades, density functional theory (DFT) has been employed in Z–N systems to strengthen the experimental work as well as to understand mechanistic aspects of Z–N systems. Future directions of Z–N catalysts have also been discussed.
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- 2020
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26. The blocky structure of Ziegler–Natta 'random' copolymers: myths and experimental evidence
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Claudio De Rosa, Anna Malafronte, Giovanni Talarico, Rocco Di Girolamo, Finizia Auriemma, Miriam Scoti, Odda Ruiz de Ballesteros, De Rosa, C., Ruiz De Ballesteros, O., Di Girolamo, R., Malafronte, A., Auriemma, F., Talarico, G., and Scoti, M.
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Materials science ,Ethylene ,Polymers and Plastics ,biology ,Organic Chemistry ,Bioengineering ,Natta ,biology.organism_classification ,Biochemistry ,law.invention ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Tacticity ,Copolymer ,Molecule ,Polybutene ,Crystallization - Abstract
The crystallization behavior of butene-ethylene random isotactic copolymers prepared with a Ziegler-Natta catalyst, in particular the surprising crystallization of form II of isotactic polybutene in samples with a high ethylene concentration, provides novel evidence of the long-debated blocky molecular structure of these "random" copolymers.
- Published
- 2020
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27. Ziegler‐Natta Catalysts
- Author
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Adriano G. Fisch
- Subjects
Materials science ,biology ,Polymerization ,Polymer chemistry ,Natta ,biology.organism_classification ,Catalysis - Published
- 2019
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28. Ziegler–Natta Catalysts: Regioselectivity and 'Hydrogen Response'
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Anika Meppelder, Antonio Vittoria, Vincenzo Busico, Roberta Cipullo, Nic Friederichs, Vittoria, A., Meppelder, A., Friederichs, N., Busico, V., and Cipullo, R.
- Subjects
External Donor ,Materials science ,Hydrogen ,chemistry.chemical_element ,Natta ,010402 general chemistry ,01 natural sciences ,Catalysis ,Propene ,chemistry.chemical_compound ,Tacticity ,biology ,010405 organic chemistry ,Regioselectivity ,General Chemistry ,hydrogen response ,biology.organism_classification ,Combinatorial chemistry ,isotactic polypropylene ,0104 chemical sciences ,chemistry ,Polymerization ,regioselectivity ,Ziegler-Natta catalysts ,Internal Donor - Abstract
Advanced High Throughput Experimentation (HTE) methods were applied to quantify the regioselectivity and the so-called "hydrogen response" in propene polymerization of four Ziegler-Natta catalysts representative of the three latest industrial generations (i.e., modified with a dialkyl phthalate, 1,3-dimethoxypropane or dialkyl succinate Internal Donor), used in combination with AlEt3 and a library of eight alkoxysilane External Donors with large structural diversity. At odds with stereoselectivity, regioselectivity turned out to be only modestly impacted by the chemical structure of the electron donors used as surface modifiers. A clear and simple relationship between regioselectivity and "hydrogen response", and, therefore, polymer molecular weight modulation was highlighted.
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- 2019
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29. Entanglement Formation Mechanism in the POSS Modified Heterogeneous Ziegler–Natta Catalysts
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Wei Li, Chuanding Dong, Chen Yuming, Yongrong Yang, Binbo Jiang, Jingdai Wang, Peng Liang, and Zhen Yue
- Subjects
Mechanical property ,Materials science ,Polymers and Plastics ,biology ,Organic Chemistry ,02 engineering and technology ,Quantum entanglement ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Inorganic Chemistry ,Ultrahigh molecular weight polyethylene ,Chemical engineering ,Materials Chemistry ,0210 nano-technology ,Mechanism (sociology) - Abstract
Chain entanglement was very important for adjusting the processability and mechanical property of nascent ultrahigh molecular weight polyethylene (UHMWPE). So far, it is still a mystery to unravel ...
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- 2019
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30. Role of a Multidentate Carbonate Donor in MgCl2-Supported Ziegler–Natta Olefin Polymerization Catalysis: An Experimental and Computational Approach
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Virendrakumar Gupta, Jugal Kumawat, and Parthiv M Trivedi
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Olefin fiber ,Denticity ,biology ,Chemistry ,Electron donor ,02 engineering and technology ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,General Energy ,Polymer chemistry ,Carbonate ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
A new multidentate carbonate (3,3,3′,3′-tetramethyl-2,2′,3,3′-tetrahydro-1,1′-spirobiindane-5,5′,6,6′-tetracarbonate) is studied as a potential internal electron donor for Ziegler–Natta (Z–N) catal...
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- 2019
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31. High Throughput Experimentation Protocol for Quantitative Measurements of Regioselectivity in Ziegler–Natta Polypropylene Catalysis
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Vincenzo Busico, Antonio Vittoria, Alessio Mingione, Roberta Cipullo, Raffaele Andrea Abbate, Vittoria, Antonio, Mingione, Alessio, Abbate, Raffaele Andrea, Cipullo, Roberta, and Busico, Vincenzo
- Subjects
Quantitative structure–activity relationship ,Materials science ,biology ,General Chemical Engineering ,Regioselectivity ,02 engineering and technology ,General Chemistry ,Carbon-13 NMR ,Natta ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Combinatorial chemistry ,Industrial and Manufacturing Engineering ,Catalysis ,Propene ,chemistry.chemical_compound ,020401 chemical engineering ,chemistry ,Hydrogenolysis ,Ziegler-Natta catalysts, regioselectivity, hydrogen response, High Throughput Experimentation, polypropylene ,0204 chemical engineering ,0210 nano-technology ,Throughput (business) - Abstract
This paper introduces a high throughput experimentation method for fast and accurate evaluations of regioselectivity in Ziegler–Natta (ZN) propene polymerizations. With a simple protocol, the (very low) fraction of regio-irregular 2,1 monomeric units in the polymers can be quantitated by means of 13C NMR chain-end analyses on single H2-terminated polypropylene samples. The method, that was successfully validated for three representative ZN catalyst systems, also provides information on catalyst “dormancy” and propensity to undergo chain hydrogenolysis. This opens the door to the rapid and accurate implementation of quantitative structure–activity relationship (QSAR) databases of regioselectivity and “hydrogen response” in this important industrial catalysis.
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- 2019
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32. Poly(olefin)-Based Anion Exchange Membranes Prepared Using Ziegler–Natta Polymerization
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Tawanda J. Zimudzi, William E. Mustain, Michael A. Yandrasits, Douglas I. Kushner, Shaofei Song, Xiong Peng, Zhisheng Fu, Michael T. Kwasny, Gregory N. Tew, Nayan Saikia, Liang Zhu, Michael A. Hickner, and Xuedi Yu
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Olefin fiber ,Polymers and Plastics ,biology ,Ion exchange ,Chemistry ,Organic Chemistry ,02 engineering and technology ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Membrane ,Polymerization ,Polymer chemistry ,Materials Chemistry ,Copolymer ,0210 nano-technology - Abstract
Bromoalkyl-functionalized poly(olefin)s were synthesized by copolymerization of 4-(4-methylphenyl)-1-butene with 11-bromo-1-undecene using Ziegler–Natta polymerization. The resulting bromoalkyl-fun...
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- 2019
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33. Tailor‐made controlled rheology polypropylenes from metallocene and Ziegler–Natta resins
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Shouliang Nie and Costas Tzoganakis
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Materials science ,Polymers and Plastics ,biology ,Polymer science ,02 engineering and technology ,General Chemistry ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Rheology ,chemistry ,Materials Chemistry ,0210 nano-technology ,Metallocene - Published
- 2019
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34. Modification of Si/Mg Composite Supported Ziegler- Natta Ti-based Catalysts for Propylene Polymerization Using the Third Metal Elements
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Wei Zhu, Pingkai Jiang, Zhou Tian, and Boping Liu
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Metal ,Materials science ,Polymers and Plastics ,Polymerization ,biology ,Chemical engineering ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Natta ,Mg composite ,biology.organism_classification ,Catalysis - Published
- 2019
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35. Enhancing stereoselectivity of propylene polymerization with MgCl2-supported Ziegler-Natta catalysts by electron donor: Strong effects of titanium dispersion state
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Zhiqiang Fan, Zhenmei Cheng, Zhen Zhang, He Feng, Zhisheng Fu, Yuhong Weng, Baiyu Jiang, and Pengjia Yang
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biology ,010405 organic chemistry ,Chemistry ,Process Chemistry and Technology ,Electron donor ,General Chemistry ,Natta ,010402 general chemistry ,biology.organism_classification ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,Polymerization ,Tacticity ,Polymer chemistry ,Stereoselectivity ,Reactivity (chemistry) - Abstract
Propylene polymerization with two TiCl4/MgCl2 catalysts (Cat-1: Ti 0.1%; Cat-2: Ti 1.0%) showed different responses to (cyclo-C5H9)2Si(OCH3)2 (De) addition. Cat-1 was deactivated more than Cat-2 by De. Amount of three groups of active centers producing atactic, medium isotactic and isotactic polypropylene chains were all reduced by De addition, but those of Cat-1 were reduced more. Reactivity of the isospecific active centers (kpi) was enhanced by De, but kpi of Cat-2 was changed more sensitively than Cat-1. The lower stereoselectivity of Cat-1 than Cat-2 are attributable to weaker De adsorption on its surface Mg, and the more sparsely dispersed Ti species on Cat-1 is responsible for weak De adsorption.
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- 2019
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36. Nobel Prizes Relating to Organometallic Chemistry
- Author
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Kohtaro Osakada
- Subjects
Materials science ,biology ,Polymer science ,Negishi coupling ,Nobel prizes ,Enantioselective synthesis ,Electrically conductive ,Natta ,biology.organism_classification ,Catalysis ,chemistry.chemical_compound ,chemistry ,Olefin polymerization ,Organometallic chemistry - Abstract
This chapter presents fascinating insights into the research that earned its investigators Nobel Prizes in the field of organometallic chemistry: Karl Ziegler and Giulio Natta for olefin polymerization catalysts (1963), Ernst Otto Fischer and Geoffrey Wilkinson for sandwich compounds (1973), Alan J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa for electrically conductive polymers (2000), William S. Knowles, Ryoji Noyori and K. Barry Sharpless for asymmetric catalysis (2001), Yves Chauvin, Robert H. Grubbs and Richard R. Schrock for olefin metathesis (2005), and Richard F. Heck, Eiichi Negishi and Akira Suzuki for Pd-catalyzed cross-coupling reactions (2010).
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- 2021
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37. Catalysis by Organometallic Complexes
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Hiroshi Nakazawa
- Subjects
chemistry.chemical_compound ,Wacker process ,Olefin fiber ,chemistry ,biology ,Organic chemistry ,Natta ,biology.organism_classification ,Monsanto process ,Isomerization ,Organometallic chemistry ,Hydroformylation ,Catalysis - Abstract
By combining the elementary reactions described in Chapter 6, transformations catalyzed by organometallic complexes can be constructed. This chapter introduces representative reaction systems catalyzed by organometallic complexes, and outlines the reactions occurring. Ziegler catalysts, prepared from tetrachlorotitanium (TiCl4) and alkylaluminium reagents (AlEt3 or AlEt2Cl), and Natta catalysts, prepared from crystalline TiCl3 and alkylaluminium, are very effective for olefin and propylene polymerization, respectively. This development was a paradigm shift, and Ziegler and Natta received the Nobel Prize in Chemistry in 1963 for their discoveries in the field of the chemistry and technology of high polymers. Transition metal complexes serve as catalysts and are used industrially, such as in olefin isomerization, olefin hydroformylation, the production of acetaldehyde by ethylene oxidation (the Wacker process) and the production of acetic acid from methanol and carbon monoxide (the Monsanto process). These catalytic systems successfully apply the elementary organometallic chemistry reactions described in this book and the basis of the catalytic action in these reactions is explained.
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- 2021
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38. Progress in MgCl2 supported Ziegler-Natta catalyzed polyolefin products and applications
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Parthiv M Trivedi and Virendrakumar Gupta
- Subjects
chemistry.chemical_classification ,Reaction conditions ,Materials science ,Polymers and Plastics ,Polymer science ,biology ,Organic Chemistry ,02 engineering and technology ,Polymer ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Polyolefin ,chemistry.chemical_compound ,chemistry ,Polymerization ,Materials Chemistry ,Olefin polymerization ,0210 nano-technology - Abstract
The innovation of Ziegler-Natta (Z-N) catalysts opened a novel aspect of chemistry in terms of polyolefin formation. Significant progress of more than fifty years in catalytic olefin polymerization simplified polyolefin production by optimizing the reaction conditions and internal donors. In this review, we particularly emphasized on recent development on different internal donor based Z-N catalyst systems, the role of external electron donors and co-catalyst chemistry. Furthermore, the Ziegler-Natta catalyst system, polymerization reaction, and polymer process technologies gradually upgrading to produce different polyolefin products. In particular, polyolefin fibers, composites, foam, blends and polyolefin-based 3D-printing products targeted in this review for substantial benefits of both society and highly diversified industries.
- Published
- 2021
- Full Text
- View/download PDF
39. Sustainable rosin acid ester as internal electron donors in Ziegler-Natta catalysts for synthesis of isotactic polypropylene with high melt flow rate
- Author
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Qigu Huang, Qing Miao, Xiaoqi Xia, Shaomeng Zhang, Feng Zhu, Zhong Zhao, Jianjun Yi, Hongchao Yu, Chunman Li, and Jiaojiao Zhang
- Subjects
inorganic chemicals ,Polypropylene ,Materials science ,Polymers and Plastics ,biology ,chemistry.chemical_element ,General Chemistry ,Natta ,biology.organism_classification ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Polymerization ,Tacticity ,Materials Chemistry ,Ceramics and Composites ,Ziegler–Natta catalyst ,Melt flow index ,Titanium - Abstract
In this contribution, novel bio-derived rosin acid ester compounds have been developed and used as internal electron donors to prepare MgCl2 supported titanium catalysts for propylene polymerization. The results of the polymerization showed that tri-n-amyl maleate, triiso-amyl maleate and tri-n-heptyl maleate as internal electron donors in Ziegler-Natta catalysts all have high polymerization activity and stereoregularity. In particular, the Ziegler-Natta catalyst with tri-n-amyl maleate as the internal electron donor has the highest activity (up to 33.4 kgPP·gCat−1·h−1) for propylene polymerization and the isotacticity of polypropylene is as high as 96.8% determined by 13C NMR. Simultaneously, the obtained polypropylene with a relatively broad molecular weight distribution of 9.0 and melt flow rate of 160.3 g/10 min, which is beneficial to processing and has practical industrial application value when used as the basic material of melt blown cloth for medical mask.
- Published
- 2021
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40. Spectroscopic Signature and Structure of Active Centers in Ziegler-Natta Polymerization Catalysts revealed by Electron Paramagnetic Resonance
- Author
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Jan Blahut, Gunnar Jeschke, Anton Ashuiev, Vincent Monteil, Guido Pintacuda, Sébastien Norsic, Christophe Copéret, Jean Raynaud, Matthieu Humbert, Keith Searles, Anne Lesage, Daniel Klose, David Gajan, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)
- Subjects
inorganic chemicals ,Ethylene ,Keith ,020209 energy ,Anton ,02 engineering and technology ,Natta ,sebastien ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Catalysis ,law.invention ,chemistry.chemical_compound ,gajan ,law ,david ,et al. (2020): Spectroscopic Signature and Structure of Active Centers in Ziegler-Natta Polymerization Catalysts revealed by Electron Paramagnetic Resonance. ChemRxiv. Preprint ,0202 electrical engineering, electronic engineering, information engineering ,[CHIM]Chemical Sciences ,mathieu ,Ziegler–Natta catalyst ,Electron paramagnetic resonance ,Bimetallic strip ,biology ,blahut ,humber ,Polyethylene ,biology.organism_classification ,3. Good health ,0104 chemical sciences ,jean ,Searles ,chemistry ,Polymerization ,CC BY-NC-ND 4.0 Citation information: Ashuiev ,norsic - Abstract
Despite decades of extensive studies, the atomic-scale structure of the active sites in heterogeneous Ziegler-Natta (ZN) catalysts, one of the most important processes of the chemical industry, remains elusive and a matter of debate. In the present work, the structure of “active sites” of ZN catalysts in the absence of ethylene, referred to as “dormant active sites”, is elucidated from magnetic resonance experiments, carried out on samples reacted with increasing amounts of BCl3 so as to enhance the concentration of active sites and observe clear spectroscopic signatures. Using EPR and NMR spectroscopies, in particular 2D HYSCORE experiments complemented by DFT calculations, we show that the activated ZN catalysts contain bimetallic alkyl-Ti(III),Al species whose amount is directly linked to the polymerization activity of MgCl2-supported Ziegler-Natta catalysts. This connects those spectroscopic signatures to the active species formed in the presence of ethylene, and enables us propose an ethylene polymerization mechanism on the observed bimetallic alkyl-Ti(III),Al species based on DFT computations
- Published
- 2020
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41. In-chain functionalized syndiotactic 1,2-polybutadiene by a Ziegler–Natta iron(<scp>iii</scp>) catalytic system
- Author
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Rixin Cong, Feng Wang, Heng Liu, Xuequan Zhang, Huaqiang Zhang, Shanshan Liang, and Yanming Hu
- Subjects
chemistry.chemical_classification ,biology ,General Chemical Engineering ,Comonomer ,02 engineering and technology ,General Chemistry ,Polymer ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Polybutadiene ,chemistry ,Polymerization ,Tacticity ,Polymer chemistry ,Copolymer ,0210 nano-technology - Abstract
Copolymerization of 1,3-butadiene with four 1-substituted 1,3-diene comonomers bearing amino and alkyoxy groups by a Ziegler–Natta iron(III) catalytic system to access in-chain functionalized syndiotactic 1,2-polybutadiene is reported herein. The polar comonomer content can be easily regulated by varying the comonomer loadings or polymerization conditions, affording functionalized syndiotactic 1,2-polybutadiene with different amounts of functionalities. The incorporation of a polar comonomer showed little influence on the 1,2-content and stereoregularity of the resulting polymers, giving a 1,2-structure as high as ∼85% and an rrrr pentad of 81.0%. Significantly improved surface properties of the polymers was obtained after incorporation of polar comonomer, as revealed from the remarkably decreased water contact angles.
- Published
- 2019
- Full Text
- View/download PDF
42. Mechanistic study on comonomer effect in ethylene/1-hexene copolymerization with TiCl4/MgCl2 model Ziegler-Natta catalysts
- Author
-
Aihua He, Xiaoyu Liu, Baiyu Jiang, Zhiqiang Fan, Zhisheng Fu, and Yuhong Weng
- Subjects
inorganic chemicals ,Ethylene ,biology ,010405 organic chemistry ,Comonomer ,Natta ,010402 general chemistry ,biology.organism_classification ,01 natural sciences ,Chloride ,Catalysis ,0104 chemical sciences ,1-Hexene ,Active center ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,medicine ,Copolymer ,Physical and Theoretical Chemistry ,medicine.drug - Abstract
Two MgCl2-supported Ziegler-Natta model catalysts were prepared by contacting activated MgCl2 with deficient or excess amount of TiCl4. Ethylene/1-hexene copolymerization with the catalysts was conducted under different 1-hexene feed, and active center concentration of the reaction system was determined by quench-labeling method using thiophene-2-carbonyl chloride as the quencher. The catalytic activity was only moderately enhanced (increment
- Published
- 2019
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43. Ziegler‐Natta catalysts
- Author
-
W. Kaminsky
- Subjects
Materials science ,biology ,Organic chemistry ,Natta ,biology.organism_classification ,Catalysis - Published
- 2020
- Full Text
- View/download PDF
44. Ziegler‐Natta catalysis
- Author
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W. Kaminsky and M. Vathauser
- Subjects
Materials science ,biology ,Polymer chemistry ,Natta ,biology.organism_classification ,Catalysis - Published
- 2020
- Full Text
- View/download PDF
45. Synthesis of Perylene-Tagged Internal and External Electron Donors for Magnesium Dichloride Supported Ziegler–Natta Catalysts
- Author
-
Dmitry V. Uborsky, Georgy P. Goryunov, Bogdan A. Guzeev, Dmitry Y. Mladentsev, Alexander Z. Voskoboynikov, and Mikhail I. Sharikov
- Subjects
biology ,010405 organic chemistry ,Chemistry ,Magnesium ,Organic Chemistry ,chemistry.chemical_element ,Crystal structure ,Natta ,010402 general chemistry ,biology.organism_classification ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Column chromatography ,Fluorescence microscope ,Physical chemistry ,Absorption (chemistry) ,Perylene - Abstract
We report on the synthesis of three perylene-tagged electron donors representing three major types – phthalates, diethers, and alkoxysilanes – which are of importance for the subsequent studies of MgCl2-supported Ziegler–Natta catalysts by means of laser scanning confocal fluorescence microscopy. The obtained products were unambiguously characterized, including by X-ray crystal structure analysis; their photophysical properties (absorption and emission spectra) were investigated as well. Additionally, a reliable and convenient protocol for the multigram synthesis of the required starting material – 3-bromoperylene (PerBr) – was developed. The key step of this method was synthesis of trialkylsilyl-substituted perylenes, which were further separated by means of flash chromatography followed by conversion of the isolated 3-trialkylsilyl-substituted product to PerBr.
- Published
- 2018
- Full Text
- View/download PDF
46. Different behaviors of metallocene and Ziegler-Natta catalysts in ethylene/1,5-hexadiene copolymerization
- Author
-
Naeimeh Bahri-Laleh, Mehdi Nekoomanesh-Haghighi, Sanaz Rahmatiyan, and Ahad Hanifpour
- Subjects
Ethylene ,Materials science ,Polymers and Plastics ,biology ,Organic Chemistry ,02 engineering and technology ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Polyolefin ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,0210 nano-technology ,Metallocene - Published
- 2018
- Full Text
- View/download PDF
47. Measurement of excitation functions of natTa(p,x) reactions up to 44.2 MeV
- Author
-
Muhammad Zaman, Gui Nyun Kim, Kwangsoo Kim, Muhammad Shahid, Haladhara Naik, Sung-Chul Yang, and Mansoureh Tatari
- Subjects
Physics ,Nuclear reaction ,Code (set theory) ,biology ,010308 nuclear & particles physics ,Health, Toxicology and Mutagenesis ,Activation technique ,Public Health, Environmental and Occupational Health ,Natta ,Proton energy ,biology.organism_classification ,01 natural sciences ,Pollution ,010305 fluids & plasmas ,Analytical Chemistry ,Nuclear physics ,Data set ,Nuclear Energy and Engineering ,0103 physical sciences ,Radiology, Nuclear Medicine and imaging ,Spectroscopy ,Excitation - Abstract
We measured the excitation functions of natTa(p,x)177,178W, natTa(p,x)176,177,178m1,180gTa, and natTa(p,x)175,179m2,180mHf reactions up to the proton energy of 44.2 MeV using the stacked-foil activation technique. The measured results were compared with the literature data as well as with the theoretical values obtained from the TENDL-2017 library based on the TALYS-1.9 code. The integral yields for thick target of the investigated radionuclides were determined from the measured excitation functions. The purpose was to provide a new data set for the formation of the investigated radionuclides applicable in medicine and industry and to provide information that could support in testing and understanding the nuclear reaction theories.
- Published
- 2018
- Full Text
- View/download PDF
48. Optimization of UHMWPE/graphene nanocomposite preparation by single-supported Ziegler-Natta catalytic system via RSM
- Author
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Mojtaba Shafiee and Ali Akbari
- Subjects
Nanocomposite ,Materials science ,Polymers and Plastics ,biology ,Graphene ,02 engineering and technology ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,Polymerization ,Chemical engineering ,law ,0210 nano-technology - Published
- 2018
- Full Text
- View/download PDF
49. Ziegler–Natta Catalysts
- Author
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Yue Yu and Zhiqiang Fan
- Subjects
Materials science ,Polymerization ,biology ,010405 organic chemistry ,Polymer chemistry ,Ziegler–Natta catalyst ,Natta ,010402 general chemistry ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis - Published
- 2018
- Full Text
- View/download PDF
50. High-precision Molecular Modelling for Ziegler-Natta Catalysts
- Author
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Minoru Terano and Toshiaki Taniike
- Subjects
Materials science ,biology ,Energy Engineering and Power Technology ,02 engineering and technology ,Natta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Fuel Technology ,Chemical engineering ,Density functional calculation ,Ziegler–Natta catalyst ,0210 nano-technology - Published
- 2018
- Full Text
- View/download PDF
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