MgCl2 center dot 4((CH3)(2)CHCH2OH): A new molecular adduct for the preparation of TiClx/MgCl2 catalyst for olefin polymerization

A new molecular adduct of MgCl2 with isobutanol, namely MgCl2 center dot 4((CH3)(2)CHCH2OH) (MgiBOH), has been prepared as a precursor to the supporting material for an olefin polymerization catalyst. The MgiBOH adduct and final titanated Ziegler-Natta catalysts have been thoroughly characterized by powder XRD, thermal analysis, Raman spectroscopy and solid-state NMR for structural and spectroscopy aspects. A peak observed at 712 cm(-1) in the Raman spectra of MgiBOH indicates the characteristic Mg-O-6 breathing mode and the formation of the adduct. The diffraction feature at 2 theta = 7.8 degrees (d = 11.223 angstrom) in the XRD confirms the adduct formation and the layered structure. The aim of the present article is to study how the insertion of a bulky isobutanol moiety affects the structural and electronic properties of the MgCl2 isobutanol molecular adduct. Indeed, the focus of the present study is to explore how the presence of isobutanol, in the initial molecular adduct, influences the final Z-N catalyst properties and its activity

Preferential oxidation of carbon monoxide in hydrogen-rich streams over CuO/CeO2 catalysts: How nano (and subnano) structure affects catalytic activity and selectivity

Preferential oxidation of carbon monoxide in hydrogen-rich streams needs a suitable catalyst that selectively oxidizes CO avoiding H2 oxidation. Among the proposed catalysts, copper oxide supported on ceria (CuO/CeO2) received wide interest due to its intrinsic activity and selectivity and low cost with respect to noble metals. In particular, it has been shown that the performances are significantly affected by optimizing the copper-ceria interaction, and then the copper dispersion. In this light, reducing to nanoscale levels has been proven to be the solution. In this chapter, results of the effect of nano and subnano structures of CuO/CeO2 catalysts on the CO-PROX performance are reviewed and critically discussed. At nanosize, Cu dispersion and oxygen mobility are both enhanced. Furthermore, the copper reduction to the metallic Cu (H2 oxidation sites) is limited and CO2 desorption is activated at lower temperatures. The role of dopants and/or supports as graphene and carbon nanotubes in improving the intrinsic activity and the resistance to the inhibiting effect of carbon dioxide and water vapor are also discussed, highlighting the effect of dopants on the modification of the redox properties by increasing bulk and/or surface oxygen vacancies