1117-91-5Relevant articles and documents
Mechanism of the reaction of vinyl chloride with (α-diimine)PdMe + species
Kilyanek, Stefan M.,Stoebenau, Edward J.,Vinayavekhin, Nawaporn,Jordan, Richard F.
experimental part, p. 1750 - 1760 (2010/06/13)
The reaction of vinyl chloride (VC) with (α-diimine)PdMe+ species yields (α-diimine)PdCl(propene)+. Isotope labeling experiments using the deuterium-labeled vinyl chlorides 1-VC-d1 and Z-VC-d1 combined with DFT
Zr-alkyl isomerization in ansa-zirconocene-catalyzed olefin polymerizations. Contributions to stereoerror formation and chain termination
Leclerc, Margarete K.,Brintzinger, Hans H.
, p. 9024 - 9032 (2007/10/03)
In polymers made from (E)- or (Z)-[1-D]propene with methyl alumoxane (MAO)-activated ansa-zirconocene catalysts, signals of deuterium-labeled mrrm pentads document that stereoerrors arise mainly from an isomerization of the Zr-bound chain end. Reduced D-atom redistribution in poly( [2-D]propene) indicates a kinetic isotope effect of k(H)/k(D) ~ 3 for the β-H/D transfer associated with the isomerization reaction. In all poly([1- and [2-D]propenes) studied, D-labeled mmmm pentads occur with a probability similar to that of D-labeled mrrm pentads; this observation requires further mechanistic clarification. Olefinic chain ends of polymers obtained with C2H4(thind)2ZrCl2-MAO from (E)- or (Z)-[1-D]propene deviate in their D-label distributions from the expected stereochemistry. Isomerization of the Zr-bound chain end, probably via a Zr-bound tertiary alkyl intermediate, thus contributes also to chain-growth termination. With the sterically hindered catalyst Me2Si(2-Me-4-tBu-C5H2)2ZrCl2-MAO, almost all chain terminations appear to occur via chain-end isomerization, which does not lead to stereoerrors here. With the high-performance catalyst Me2Si(2-Me-benz[e]indenyl)2ZrCl2-MAO, finally, no D-label is found in the mrrm and mmmm pentad signals; here, Zr-alkyl isomerization can apparently not compete with the high rate of olefin insertion.
Mechanism of Propene-Deuterium Addition and Exchange Reaction over Silica-Supported ZrO2
Naito, Shuichi,Tanimoto, Mitsutoshi
, p. 3205 - 3211 (2007/10/02)
The mechanism of propene-deuterium reaction over unsupported and silica-supported ZrO2 catalysts was studied with kinetic investigation as well as microwave spectroscopic analysis of monodeuteriopropene. Unsupported ZrO2 exhibited the identical catalytic behavior for C3H6-D2 reaction with other oxide catalysts previously reported: Only propane-d2 was selectively formed in the addition process, with no hydrogen exchange in propene. By supporting on silica, the rate of C3H6-D2 reaction increased considerably, with the decrease of activation energy. Hydrogen exchange in propene proceeded simultaneously with addition via associative mechanism through propyl and isopropyl intermediates. Small particles of ZrO2 were proposed as active sites of this characteristic catalytic behavior.