M.C. White, Chem 153 EMPolymerization-297- Week of november 18. 2002 Ziegler natta polymerization What has guided my research has been solely the wish to do something that gave me jo that is a joy from finding, somehow or somewhere, something really novel.At least at the utset, the only thing of value aimed for is an accretion in knowledge, rather than new In an attempted distillation of ethyllithium, Ziegler such as Et2AlH displayed even higher activities observed ethylene and higher a-olefins. He reasoned towards ethylene n higher aluminum alkyls that could be readily that the following process was occuring hydrolyzed to pre alcohols - + Lih CAH tPC Ziegler found that traces of Ni salts (accidently Lih incorporated during cleaning the reactor)resulted only in butene and r,Alh AH+ Eisch Chem. Edu. 1983(60)1009 If traces of Ni salts could make such a dramatic impact on the The stereochemistry of polypropylene significantly influences its physical properties. Isotactic course of ethylene oligermerizations, Ziegler wondered what other polymers are the most useful commercially with such physical properties as high tensile etals may do. An exploration of this curiosity led to the strength and high melting points (165C) Cl/Et AlCI catalyzed Zeigler Natta polymerization(Nobel Prize, 63)which is currently used commercially to produce 15 million tons of polyethylene and polypropylene annually Ziegler's original process for ethylene polymerization: 人人人人人人 TICI/AIR3 polyethylene stereochemistry at adjacent carbons bons Physical properties line with a melting Ziegler Angew. Chem. 1955 (67)54 Natta extends this to propylene polymerization. He finds that by regularity of the surface of the heterogeneous catalyst is increased. This results in a greater specificity in polymerization with the amount of desired isotactic polypropylene inreasing from 40% to 90%. atactic: stereorandom polymer that behaves as an amorphous 人 For other polymer tacticities see: Coates Chem. Rev. 2000(100)1223 Natta Angew. Chem. 1956(68)393M.C. White, Chem 153 EM Polymerization -297- Week of November 18, 2002 Ziegler Natta Polymerization Natta Angew. Chem. 1956 (68) 393. "What has guided my research has been solely the wish to do something that gave me joy, that is a joy from finding, somehow or somewhere, something really novel...At least at the outset, the only thing of value aimed for is an accretion in knowledge, rather than new applications." Karl Ziegler. Li ∆ LiH Li ∆ LiH Al H 100oC Al Al Al Al H If traces of Ni salts could make such a dramatic impact on the course of ethylene oligermerizations, Ziegler wondered what other metals may do... An exploration of this curiosity led to the TiCl3/Et2AlCl catalyzed Zeigler Natta polymerization (Nobel Prize, 1963) which is currently used commercially to produce ~ 15 million tons of polyethylene and polypropylene annually. Ziegler's original process for ethylene polymerization: TiCl4/AlR3 n polyethylene Ziegler Angew. Chem. 1955 (67) 541. Natta extends this to propylene polymerization. He finds that by using crystalline TiCl3, the regularity of the surface of the heterogeneous catalyst is increased. This results in a greater stereospecificity in polymerization with the amount of desired isotactic polypropylene inreasing from 40% to 90%. TiCl3/AlR3 n polypropylene The stereochemistry of polypropylene significantly influences its physical properties. Isotactic polymers are the most useful commercially with such physical properties as high tensile strength and high melting points (~165oC). In an attempted distillation of ethyllithium, Ziegler observed ethylene and higher α-olefins. He reasoned that the following process was occuring: + β-hydride elimination propagation β-hydride elimination + Organoaluminum compounds such as Et2AlH displayed even higher activities towards ethylene resulting in higher aluminum alkyls that could be readily hydrolyzed to produce higher alcohols. Ziegler found that traces of Ni salts (accidently incorporated during cleaning the reactor) resulted only in butene and R2AlH. Ni salts + Eisch J. Chem. Edu. 1983 (60) 1009. isotactic: stereoregular material, long sequences having the same stereochemistry at adjacent carbons. Physical properties: crystalline thermoplastic. syndiotactic: long sequences having the opposite stereochemistry at adjacent carbons. Physical properties: semicrystalline with a melting temperature ~ 100oC. atactic: stereorandom polymer that behaves as an amorphous gum elastomer. For other polymer tacticities see: Coates Chem. Rev. 2000 (100) 1223