Roya Zahedi’s research while affiliated with Amirkabir University of Technology and other places

The new hepta-ether compound as the internal donor was synthesized using the Williamson reaction of dipentaerythritol with sodium hydride as the strong base and iodomethane as the alkyl halide. The hepta-ether compound was characterized by NMR, FTIR, and GC techniques. The MgCl2-supported catalysts incorporated with different amounts of hepta-ether compound as the internal donor and without the internal donor were synthesized and characterized. The propylene polymerization was carried out using these catalysts in the presence of triethylaluminum as a co-catalyst and hydrogen as a chain transfer agent, with and without the external donor. The effect of a new internal donor on propylene polymerization using prepared MgCl2-supported Ziegler-Natta catalysts was investigated.

The multi-ether compounds with different numbers of methoxy groups containing 1,3-dimethoxy-2,2-bis(methoxymethyl)propane and 1-methoxy-2,2-bis(methoxymethyl)butane were synthesized using the Williamson reaction from pentaerythritol and 1,1,1-tris(hydroxymethyl)propane, respectively, in the presence of sodium hydride and methyl iodide in tetrahydrofuran and they were characterized by ¹H NMR, ¹³C NMR, and FTIR spectroscopy. These compounds were employed as external donors in the polymerization of propylene using the industrial Ziegler-Natta catalyst. A commercial spherical MgCl2-supported Ziegler-Natta catalyst containing diisobutyl phthalate as the internal donor was used for the polymerization of propylene. The role of ether compounds and industrial alkoxysilanes on the properties of polypropylene were studied using the xylene solubility method, melt flow index, gel permeation chromatography, scanning electron microscopy, and differential scanning calorimetry. The addition of the electron donors has led to improvements in the activity and selectivity of the Ziegler-Natta catalyst system.

The penta-ether compound was synthesized by the reaction of di(trimethylolpropane) with sodium hydride as the strong base and methyl iodide as the alkyl halide. This compound was characterized by NMR, FTIR, and GC techniques. The MgCl2-supported titanium catalysts were incorporated with varying amounts of penta-ether compound as the internal donor and also the catalysts without the internal donor were synthesized. The synthesized catalysts and the conventional Ziegler- Natta catalyst were characterized. The titanium contents were determined by spectrophotometry, magnesium by complexometric titration and chloride by argentometric titration. The effects of the new internal donor on propylene polymerization with the prepared MgCl2-supported Ziegler-Natta catalysts were investigated and then these results were compared to the results obtained using the conventional diisobutyl phthalate-besed-Ziegler-Natta catalyst. The highest crystallinity degree, melting temperature, and isotacticity of polypropylene were obtained using the catalyst with a penta-ether/Mg molar ratio equal to 0.21.

Two new ethers were synthesized using the Williamson reaction from related alcohols and were used as external donors in propylene polymerization in the presence of the industrial diisobutyl phthalate-based MgCl2-supported Ziegler-Natta catalyst. For comparison the propylene polymerization was carried out in the presence of silane and in the absence of external donors. The produced polymers were characterized by differential scanning calorimetry, xylene extraction, melt flow index, scanning electron microscopy and gel permeation chromatography. The isotacticity, molecular weight and molecular weight distribution, melt flow index, crystallinity degree and thermal properties of polypropylenes were influenced by the type of external donors.

1‐Methoxy‐2,2‐bis(methoxymethyl)butane as a new internal donor was synthesized by the reaction of 1,1,1‐tris(hydroxymethyl)propane with sodium hydride as the base and methyl iodide as the alkyl halide. The tri‐ether compound was characterized by NMR and FTIR techniques. The MgCl 2 ‐supported titanium catalysts were incorporated with varying amounts of 1‐methoxy‐2,2‐bis(methoxymethyl)butane as the internal donor (ID) and also without the internal donor were synthesized, and then the prepared catalysts were characterized. The concentration of titanium, magnesium, and chloride were determined by spectrophotometry and by complexometric and argentometric titration, respectively. The polymerization of propylene was carried out with the prepared catalysts in conjunction with triethylaluminum as a cocatalyst and hydrogen as a chain transfer agent, with and without cyclohexylmethyldimethoxysilane as the external donor. The effects of a new internal donor on MgCl 2 ‐supported Ziegler–Natta catalysts for propylene polymerization were investigated, and then these results were compared to the obtained polypropylenes results, which were obtained using the conventional Ziegler–Natta catalyst containing diisobutyl phthalate as the internal donor. The highest isotacticity, melting temperature, and crystallinity degree of polypropylene were obtained using Cat‐D with an ID/Mg molar ratio equal to 0.44, and the highest catalytic activity is related to Cat‐B with an ID/Mg molar ratio equal to 0.22. The Ziegler–Natta catalysts incorporated with various ID/Mg molar ratios of 1‐methoxy‐2,2‐bis(methoxymethyl)butane were synthesized. The polymerization of propylene was carried out with the prepared catalysts. The highest catalytic activity is related to Cat‐B with an ID/Mg molar ratio equal to 0.22. The catalyst with an optimum ID/Mg molar ratio equal to 0.44 is a favorable catalyst for polymerization of propylene.

The asymmetric unit of the title Schiff base compound, C21H21NO, contains two crystallographicaly independent mol­ecules. The dihedral angles between the naphthalene mean plane and the benzene ring are 29.28 (8) and 26.92.(8)° in the two mol­ecules. An intra­molecular O—H⋯N hydrogen bond and weak intra­molecular C—H⋯O hydrogen bonds stabilize the structure of each independent mol­ecule.