Metal complexes in catalytic transformations of olefins. 6. Mechanism of formation and characteristics of the precursors of active centers of ethylene dimerization to butene-1 in the Ti(O-n-Bu)4-AlEt3 system in ethers

Reaction of Ti(O-n-Bu)₄ (TBT) with AlR₃ (R = Me, Et,i-Bu) in solvents such as R₂O, Py, and Et₃N, reduces Ti(IV) to Ti(III), Ti(II), or Ti(I). The organotitanium compounds formed by the reaction of TBT with organoaluminum compounds (OAC) undergo homolytic decomposition at the bond in Ti-C. Isotopic exchange analysis using C₂D₄ suggested the formation of particles containing Ti-CH₂CH₂-Ti, Al-CH₂CH₂-Al, Al-CH₂CH₂-Ti, M=CHCH₃, and MMCHCH₃ (M, M = Al or Ti) fragments. An ESR spectral analysis established that reaction of TBT with TEA in R₂O, Py, and Et₃N environments produced two types of paramagnetic complexes, precursors of active centers of ethylene dimerization. The influence of various factors on the kinetics of accumulation and consumption of these complexes was investigated and their structures are suggested.Deceased.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1516–1525, July, 1992.