Synthesis\nand Evaluation of Trialkyl Ammonium Tetrakis(perfluorophenyl)\nAluminate, a Highly Efficient Activator for High-Temperature Ethylene-α-Olefin\nCopolymerization Reactions

The new salt, [HNMe(C<sub>18</sub>H<sub>37</sub>)<sub>2</sub>][Al(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], was prepared\nand was shown to\nbe highly effective as an activator for Group IV precatalysts in high-temperature\nethylene-1-octene copolymerization reactions. The performance of this\nactivator closely mirrors that of the state-of-the-art activator borate-based\nanalogue. Unlike the borate analogue, the aluminate activator reacts\nreadily with water at ambient temperature, generating pentafluorobenzene,\nthe only fluorine-containing product. Such a feature might be helpful\nwhen preparing polymers without any charged contaminants. Unlike some\nof the other aluminum compounds containing perfluorophenyl groups,\n[HNMe(C<sub>18</sub>H<sub>37</sub>)<sub>2</sub>][Al(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>] was found <i>not</i> to be impact-sensitive\nand is stable at ambient temperature for months. Detailed evaluation\nof this aluminate salt and several other aluminum alkyls/aryls (e.g.,\nAl(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>(THF), Al(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>, AlEt<sub>3</sub>, and MMAO-3A) was carried\nout to evaluate their reactive chemistry and safety profiles.