Introduction of chromium species into the (SiO2/MgO/MgCl2)·TiClx Ziegler–Natta catalyst for better catalytic performance

The Effect of Titanium Tetra-Butoxide Catalyst on the Olefin Polymerization

The purpose of this study was to assess the ability of titanium Ti(IV) alkyloxy compounds supported by organic polymer polyvinyl chloride (PVC) to polymerize ethylene by feeding triethylaluminium (TEA) as a cocatalyst. Additionally, the impacts of the molar ratio of [Al]/[Ti] on the catalytic activities in ethylene’s polymerization and of the comonomer through utilization of diverse quantities of comonomers on a similar or identical activity were studied. The optimal molar ratio of [Al]/[Ti] was 773:1, and the prepared catalyst had an initial activity of up to 2.3 kg PE/mol Ti. h. when the copolymer was incorporated with 64 mmol of 1-octene. The average molecular weight (M_w) of the copolymer produced with the catalysts was between 97 kg/mol and 326 kg/mol. A significant decrease in the M_w was observed, and PDI broadened with increasing concentration of 1-hexene because of the comonomer’s stronger chain transfer capacity. The quick deactivation of titanium butoxide Ti(OBu)₄ on the polymers was found to be associated with increasing oxidation when supported by the catalyst. The presence of Ti(III) after reduction with the aluminum alkyls cleaves the carbon-chlorine bonds of the polymer, producing an inactive polymeric Ti(IV) complex. The results show that synergistic effects play an important role in enhancing the observed rate of reaction, as illustrated by evidence from scanning electron microscopy (SEM). The diffusion of cocatalysts within catalytic precursor particles may also explain the progression of cobweb structures in the polymer particles.

Phenolic sensor development based on chromium oxide-decorated carbon nanotubes for environmental safety

A nanocomposite (NC) composed of chromium(III)oxide nanomaterials decorated carbon nanotubes (Cr₂O₃-CNT NC) was prepared via a simple solution method with reducing agents in an alkaline medium. The Cr₂O₃-CNT NC was characterized using ultraviolet-visible (UV/Vs.) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (XEDS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM). The Cr₂O₃-CNT composite was deposited on a flat glassy carbon electrode (GCE) with conducting nafion (5%) binders to produce a sensor that exhibited fast response and high selectivity toward 4-methoxyphenol (4MP) in phosphate buffer phase at pH 7. Furthermore, the sensor performance parameters, including the sensitivity, lower detection range, reliability, and reproducibility, ease of integration, long-term stability, and selectivity were investigated in detail. The calibration plot was found to be linear in the concentration range of 0.01 nM-0.1 μM. The sensitivity and detection limit were calculated as 1.4768 μA cm^-2 μM^-1 and 0.06428 ± 0.0002 nM (at a signal-to-noise ratio of 3), respectively. Thus, it was concluded that the proposed selective and efficient sensor represents a promising approach to effectively detect toxic phenolic compounds in the environment with acceptable and reliable results.