Catalytic Properties of Two Complexes of chromium(III) and cobalt(II) with Nitrilotriacetate, Dipicolinate, and 4-Acetylpyridine

In this paper, a synthesis of two innovative coordination compounds, based on chromium(III) and cobalt(II) ions with N,O-donor ligands (nitrilotriacetate, dipicolinate) and 4-acetylpyridine, is reported. The obtained metal-organic compounds were structurally characterized using the single-crystal X-ray diffraction (XRD) method. The well-defined chromium(III) and cobalt(II) complexes were used as precatalysts in the oligomerization reaction of 2-chloro-2-propen-1-ol and 2-propen-1-ol with methylaluminoxane (MMAO) as an activator. The products of the oligomerization reaction were subjected to full physicochemical characteristics, i.e., time-of-flight mass spectrometry (MALDI-TOF-MS), TGA, and differential scanning calorimetry (DSC) methods. The catalytic activity of the precatalysts in both reactions was calculated and compared with other catalysts known in the literature.

Ni-Based Complexes in Selective Ethylene Oligomerization Processes

Linear alpha-olefins are widely used in the petrochemical industry and the world demand for these compounds increases annually. At present, the main method for producing linear alpha-olefins is the homogeneous catalytic ethylene oligomerization. This review presents modern nickel catalysts for this process, mainly systems for obtaining of one of the most demanded oligomer—1-butene—which is used for the production of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE). The dependence of the catalytic performance on the composition and the structure of the used activated complexes, the electronic and coordination states of the nickel center was considered.