Controlled Synthesis of Novel Aryloxide Polynuclear Aluminum Species. Study of Their Catalytic Properties in Polymerization Processes

Abstract

The reaction of AlMe 3 with 3,5-(CF 3 ) 2 C 6 H 3 OH at room temperature renders the dinuclear [AlMe 3) derivative depending on the reaction conditions (solvent and stoichiometry of the reagents). All compounds have been characterized by elemental analysis and NMR spectroscopy, and their crystal structures determined by X-ray diffraction methods. Catalytic studies reveal that these compounds show high activity in ring-opening polymerization of cyclohexene oxide (CHO). The activity in the catalytic process varies significantly with solvent and temperature conditions.

Ring-opening polymerization of cyclohexene oxide using aluminum amine–phenolate complexes

“…Darensbourg and Chung have recently reinvestigated the basicities of a range of ethers and esters, 13 and this statement is in agreement with the reported pK b values. A difference in reactivity for ROP reactions in CH 2 Cl 2 and toluene was also observed by Martínez et al 6 in their study of multinuclear Al complexes for CHO polymerizations, e.g. 96% yield in CH 2 Cl 2 and 75% yield in toluene.…”

Aluminum Aryloxide Compounds as Very Active Catalysts for Glycidyl Methacrylate Selective Ring‐Opening Polymerization

“…Aluminum is the most abundant metal in the earth's crust, and aluminum compounds are also active catalysts in polymerization processes . We are interested in derivatives with functionalized aryloxide groups, as additional functionalities in the ring can influence the structure and reactivity of the species prepared . If the substituents are bulky, the formation of high‐nuclearity species can be prevented and low‐nuclearity compounds are generated, which are usually more reactive than the oligomeric analogues .…”

“…The two phenyl rings from the ligand are not coplanar to this central core (dihedral angle for the aryloxide rings planes is 48.95°). Furthermore, the Me−Al−Me planes are not perpendicular to the Al 2 O 2 core (dihedral angle for the Me−Al−Me planes is 34.4°), which is unusual . This arrangement can be attributed to the bulkiness of the ligand, which imposes distortion to accommodate its bulky substituents.…”

Alternative aluminum-based cocatalysts for the iron-catalyzed oligomerization of ethylene

“…Considering the reaction of the diols with AlMe 3 , different multinuclear aluminum species could be obtained depending on the stoichiometry of the reactants. 10 We therefore tested different 10/AlMe 3 molar ratios (Table 2) at constant Al/Fe molar ratio (500) and observed a maximum of activity for the 2/3 10/AlMe 3 molar ratio (up to 125.5×10 5 g•(mol(Fe)•h) -1 , Table 2, entries 1-6) along with a non negligible exotherm (+40 °C, see ESI). Increasing the molar ratio 10/AlMe 3 and thus the relative number of hydroxyl groups led to a sharp decrease of the activation ability of the cocatalytic mixture ( Table 2, entry 4), until no activity was detected for 10/AlMe 3 = 1/1 or more ( Table 2, entries 5-6).…”