Titanium Chloride-Triethylaluminum

Karl Ziegler of the Max Planck Institut patented the polymerization of ethylene at ordinary pressures and temperatures in the presence of titanium chloride-triethylaluminum (ffiegler catalyst) but he did not include propylene in his patent application. Hogan and Banks at Phillips and Zletz at Standard Oil of Indiana polymerized propylene in the presence of metal oxides. Ed Vandenburg at Hercules, S.B. lippincott of Standard Oil of New Jersey, and B. Wright of Petrochemicals LTD (Shell), like Natta, re( ived licenses to use the Ziegler catalyst. 

These catalysts form when a soluble metal alkyl like triethylaluminum or diethyl aluminum chloride is combined with a metal salt, like titanium chloride, in a medium of an inert hydrocarbon diluent. The transition metal is reduced during the formation of the catalyst. 

The use of the successful "Ziegler Catalyst" i.e. titanium chloride and triethylaluminum for producii linear polyethylene (HDPE) at ordinaiy temperature and pressure was licensed by Ziegler to Petrochemicals LTD in England (now owned by Shell), Montecatini (now Montedison) in Italy, Farbwerke Hoechst and Hercules in the U.S. Hercules and Stauffer formed a company, Texas Alkyls for the production of Ziegler catalysts. 

When a conventional Ziegler-Natta catalyst such as titanium tetra-chloride-triethylaluminum in tetrahydrofuran is mixed with vinyl chloride, the rate of conversion is quite low (0.01497o/hr at 30°C). On the other hand, when a mixture of titanium tetrachloride and vinyl chloride is mixed with a composition consisting of vinyl chloride, triethylaluminum, and tetrahydrofuran, a substantially faster rate (1.52%/hr at 30 C) is observed in the formation of isotactic poly (vinyl chloride) [201]. 

Related Reagents. Antimony(V) Fluoride Boron Trifluoride Etherate Diethylaluminum Chloride Dimethylaluminum Chloride Ethylaluminum Dichloride Methylaluminum Dichloride Tin(IV) Chloride Titanium(IV) Chloride Triethylaluminum Trimethylaluminum. 

Related Reagents. Dibromomethane-Zinc-Titanium(IV) Chloride Diiodomethane-Zinc-Titanium(IV) Chloride 4R, 5i )-2,2-Dimethyl-4,5-bis(hydroxydiphenylmethyl)-l,3-di-oxolane-Titanium(IV) Chloride Lithium Aluminum Hydride-Titanium(IV) Chloride Titanium(IV) Chloride-Diazabicyclo-[5.4.0]undec-7-ene Titanium(IV) Chloride-2,2,6,6-Tetramethyl-piperidine Titanium(IV) Chloride-Triethylaluminum Titanium-(IV) Chloride-Zinc. 

Sodium hydride Sodium hydrosulfite Sulfur chlorides Sulfuric acid Sulfuryl chloride Tetraethyl lead Tetramethyl lead Thionyl chloride Titanium tetrachloride Toluene diisocyanate Trichlorosilane Triethylaluminum Triethylborane Triisobutylaluminum Trimethylaluminum Trimethylchlorosilane Tripropyl aluminum Vanadium tetrachloride Vinyl trichlorosilane Zirconium tetrachloride... 

Other effects of the ionicity of the catalyst on its activity has been studied by Natta, PaSQUON, Zambelli and Gatti (66). The polymerization of propylene was carried out with alpha titanium trichloride and diethylberylium or triethylaluminum. They found that catalysts from the alkylberylium were more stereospecific than those from alkyl aluminum. On the other hand their study of titanium trichloride with diethylaluminum iodide, diethylaluminum bromide, diethylaluminum chloride or triethylaluminum showed that the greater stereospecificity was produced by the iodide containing catalyst. The less electrophilic catalyst produced greater crystallinity than the corresponding bromide or chloride component. 

Addition of traces of chloride in the form of bis(cyclopentadienyl)-titanium dichloride lowered the yield of polyethylene and initiated the known reduction reaction (129). Finally, it was found that polyethylene formation was caused by traces of water ( 10-8 mol%). Consequently, the yield increased to 500,000 g polyethylene per gram of titanium when two equivalents of trimethyl- or triethylaluminum previously treated with one equivalent of water was added to dimethylbis(cyclopentadienyl)ti-tanium (Table VII). 

No reaction occurs when triethylaluminum, aluminum chloride, stannic chloride, titanium tetrachloride, diethylzinc or triethylboron are used in lieu of an organoaluminum halide or sesquihalide. 

Homogeneous catalysts for the ethylene polymerization based on bis(cyclopenta-dienyl)titanium(IV) compounds [4], tetrabenzyltitanium [14], tetraallylzirconium and hafnium are formed with diethylaluminum chloride, dimethylaluminum chloride or triethylaluminum as co-catalysts. Their activities are poor (less than 200 kg PE/mol catalyst per h), so no industrial application resulted. 

Friedel-Crafts reaction catalysts like anhydrous aluminum chloride are readily soluble in the nitroalkanes. Solutions containing up to 50% aluminum chloride are easily prepared in nitroalkane solvents. These catalytically active complexes, AICI3-RNO2, can be isolated and used in solvents other than the nitroalkane. The reactants in the Friedel-Crafts reaction are often soluble in the nitroalkane reaction medium. Other catalysts like boron trifluoride (BF3), titanium tetrachloride (TiC ), and stannic tetrachloride (SnClj) are also soluble in the nitroalkane solvents. Reaction types which use nitroparaffins as solvents include alkylation of aromatics, acetylation of aromatics, halogenations, nitrations, and the reaction of olefins and hydrogen sulfide to yield mercaptans. Nitroparaffins are used with catalysts such as alkyl-metal (e.g., triethylaluminum, vanadium, or titanium) salts in the polymerization reactions of alkylene oxides, epichlorohydrin, propylene, butylene, vinyl chloride, and vinyl ethers. The nitroparaffin acts as an activator for the catalyst or can serve as the reaction solvent. 

The regioselectivity of nucleophilic additions to the Co(CO)3BF4 complex has also been examined.i Ziegler-Natta polymerization of 2-trimethylsilylmethyl-1,3-butadiene catalyzed by triethylaluminum and titanium(IV) chloride gives predominantly cis-1,4-polymer. However, anionic polymerization yields a polymer whose microstmcture is conqtosed of cis-1,4-, trans-1,4-, and 3,4-units.i ... 

Coordination Catalysts n Catalysts comprising a mixture of (a) an organo-metallic compound such as triethylaluminum or a transition-metal compound, such as titanium tetra-chloride. Known as Ziegler or Ziegler-Natta catalysts, they are used for the polymeri-2ation of olefins and dienes. 

High molecular weight polyindanes were obtained from p-diisopropenyl-benzene using an insoluble complex catalyst of butyllithium/titanium tetra -chloride/hydrogen chloride (Li/Ti ratio of 1.0-2.0) in toluene (72). Polymers with reduced viscosities of 0.81 possessing less than 0.05 % double bonds were obtained. Other complex catalysts, like triethylaluminum/tetrabutyltitanate/ hydrogen chloride (Al/Ti ratio of 1.0-2.0) were also useful (72). 

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