In:
Molecules, MDPI AG, Vol. 26, No. 9 ( 2021-05-10), p. 2827-
Abstract:
Homogeneous olefin polymerization catalysts are activated in situ with a co-catalyst ([PhN(Me)2-H]+[B(C6F5)4] − or [Ph3C]+[B(C6F5)4] −) in bulk polymerization media. These co-catalysts are insoluble in hydrocarbon solvents, requiring excess co-catalyst ( 〉 3 eq.). Feeding the activated species as a solution in an aliphatic hydrocarbon solvent may be advantageous over the in situ activation method. In this study, highly pure and soluble ammonium tetrakis(pentafluorophenyl)borates ([Me(C18H37)2N-H]+[B(C6F5)4] − and [(C18H37)2NH2]+[B(C6F5)4] −) containing neither water nor Cl− salt impurities were prepared easily via the acid–base reaction of [PhN(Me)2-H]+[B(C6F5)4] − and the corresponding amine. Using the prepared ammonium salts, the activation reactions of commercial-process-relevant metallocene (rac-[ethylenebis(tetrahydroindenyl)]Zr(Me)2 (1-ZrMe2), [Ph2C(Cp)(3,6-tBu2Flu)] Hf(Me)2 (3-HfMe2), [Ph2C(Cp)(2,7-tBu2Flu)]Hf(Me)2 (4-HfMe2)) and half-metallocene complexes ([(η5-Me4C5)Si(Me)2(κ-NtBu)] Ti(Me)2 (5-TiMe2), [(η5-Me4C5)(C9H9(κ-N))]Ti(Me)2 (6-TiMe2), and [(η5-Me3C7H1S)(C10H11(κ-N))] Ti(Me)2 (7-TiMe2)) were monitored in C6D12 with 1H NMR spectroscopy. Stable [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4] − species were cleanly generated from 1-ZrMe2, 3-HfMe2, and 4-HfMe2, while the species types generated from 5-TiMe2, 6-TiMe2, and 7-TiMe2 were unstable for subsequent transformation to other species (presumably, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4] −-type species). [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4] −-type species were also prepared from 5-TiCl(Me) and 6-TiCl(Me), which were newly prepared in this study. The prepared [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4] −-, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4] −-, and [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4] −-type species, which are soluble and stable in aliphatic hydrocarbon solvents, were highly active in ethylene/1-octene copolymerization performed in aliphatic hydrocarbon solvents.
Type of Medium:
Online Resource
ISSN:
1420-3049
DOI:
10.3390/molecules26092827
Language:
English
Publisher:
MDPI AG
Publication Date:
2021
detail.hit.zdb_id:
2008644-1
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