Advanced Topic 700 of 1102 Inorganic Chemistry
Zeigler-Natta Catalysts
Titanium-based catalysts for stereoregular polymerization of alkenes.
In-depth explanation of Zeigler-Natta Catalysts
Ziegler-Natta catalysts are mixtures of a transition metal halide, usually titanium tetrachloride, TiCl4, with an organoaluminium co-catalyst such as triethylaluminium. Together they polymerize alkenes at low pressure and temperature. Karl Ziegler and Giulio Natta developed them in the 1950s and shared the 1963 Nobel Prize in Chemistry. The alkene coordinates to titanium and inserts into the growing chain, which controls the stereochemistry of each addition. The result is stereoregular polymer, such as isotactic polypropylene, which is stiffer than the older high-pressure product.
Going deeper: Zeigler-Natta Catalysts
Key ideas: TiCl4 or TiCl3 with trialkylaluminium Al(C2H5)3 polymerize ethylene and propylene at low pressure and temperature. Mechanism (Cossee-Arlman): alkene coordinates to a vacant site on Ti, then inserts into the Ti-C bond, growing the chain. Gives high-density, linear polyethylene (HDPE) and isotactic polypropylene with methyl groups on the same side. Nobel prize 1963. Stereocontrol affects crystallinity, strength and melting point.
Common mistakes and connections: Students think the catalyst gives branched polymer; it produces linear, stereoregular chains, unlike free-radical high-pressure LDPE. Co-catalyst Al alkyl activates titanium and scavenges moisture. Molecular weight is regulated by H2. Links to polymers, tacticity, organometallic insertion reactions and heterogeneous catalysis.
Visualization of Zeigler-Natta Catalysts
Propene adds to the growing chain at a titanium centre, one monomer at a time, with the catalyst controlling stereochemistry to give isotactic polypropylene. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Propene polymerized with a TiCl4 and triethylaluminium catalyst gives isotactic polypropylene.
Frequently asked questions about Zeigler-Natta Catalysts
What is Zeigler-Natta Catalysts?
Titanium-based catalysts for stereoregular polymerization of alkenes.
Is Zeigler-Natta Catalysts a beginner, intermediate or advanced topic?
Zeigler-Natta Catalysts is a advanced topic in Inorganic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Zeigler-Natta Catalysts?
Study these earlier topics in Inorganic Chemistry first: Metal Carbonyls, Eighteen Electron Rule, Ferrocene.
What comes after Zeigler-Natta Catalysts?
The next topics in Inorganic Chemistry are Wilkinson's Catalyst and Bioinorganic Chemistry.
Can I practise Zeigler-Natta Catalysts with quizzes?
Yes. The interactive lesson includes a self-check question on Zeigler-Natta Catalysts, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Zeigler-Natta Catalysts fits in Inorganic Chemistry
Zeigler-Natta Catalysts is topic 85 of 113 in Inorganic Chemistry.