This paper deals with the monitoring cyclo-addition of CO2 to methyl methacrylate （MMA）-glycidyl methacrylate （GMA） copolymers using spectral （IH-NMR and FTIR） and chemical （elemental analysis and titration） m...This paper deals with the monitoring cyclo-addition of CO2 to methyl methacrylate （MMA）-glycidyl methacrylate （GMA） copolymers using spectral （IH-NMR and FTIR） and chemical （elemental analysis and titration） methods. Thus, poly（MMA-co-GMA）, was first prepared via solution polymerization. The copolymer was then treated with CO2 gas flow in the presence of cetyltrimethyl ammoniumbromide as a catalyst. In terms of the carbonation reaction time, the terpolymer poly（MMA-eo-GMA-co-2-oxo-l,3-dioxolane-4-yl-methyl methacrylate） was prepared in various yield of CO2 fixation （〉 90%）. The peak intensity changes in the 1H-NMR and FTIR spectra provided excellent demonstrative techniques to monitor the carbonation reaction progression. In a comparative analytical viewpoint, the NMR and elemental analysis were recognized to be the most accurate ways to follow the cyclo-addition reaction progression. However, titration was recognized to be the most preferred method, because it is a very inexpensive, facile and available method with a reasonable cost- accuracy balance.展开更多
Ethylene polymerization was carried out by immobilization of rac-ethylenebis（1-indenyl）zirconium dichloride （Et（Ind）2ZrCl2） and rac-dimethylsilylbis（1-indenyl）zirconium dichloride （Me2Si（Ind）2ZrCl2） preact...Ethylene polymerization was carried out by immobilization of rac-ethylenebis（1-indenyl）zirconium dichloride （Et（Ind）2ZrCl2） and rac-dimethylsilylbis（1-indenyl）zirconium dichloride （Me2Si（Ind）2ZrCl2） preactivated with methylaluminoxane （MAO） on calcinated silica at different temperatures. Polymerizations of ethylene were conducted at different temperatures to find the optimized polymerization temperature for maximum activity of the catalyst. The Me2Si bridge catalyst showed higher activity at the lower polymerization temperature compared to the Et bridge catalyst. The highest catalytic activities were obtained at temperatures about 50 ~C and 70 ~C for Me2Si（Ind）2ZrC1JMAO and Et（Ind）zZrCI2/MAO catalysts systems, respectively. Inductively coupled plasma-atomic emission spectroscopy results and polymerization activity results confirmed that the best temperature for calcinating silica was about 450 ℃ for both catalysts systems. The melting points of the produced polyethylene were about 130 ℃, which could be attributed to the linear structure of HDPE.展开更多
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 t...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 MgCl_2-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 ZieglerNatta 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 MgCl_2-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 pentaether/Mg molar ratio equal to 0.21.展开更多
文摘This paper deals with the monitoring cyclo-addition of CO2 to methyl methacrylate （MMA）-glycidyl methacrylate （GMA） copolymers using spectral （IH-NMR and FTIR） and chemical （elemental analysis and titration） methods. Thus, poly（MMA-co-GMA）, was first prepared via solution polymerization. The copolymer was then treated with CO2 gas flow in the presence of cetyltrimethyl ammoniumbromide as a catalyst. In terms of the carbonation reaction time, the terpolymer poly（MMA-eo-GMA-co-2-oxo-l,3-dioxolane-4-yl-methyl methacrylate） was prepared in various yield of CO2 fixation （〉 90%）. The peak intensity changes in the 1H-NMR and FTIR spectra provided excellent demonstrative techniques to monitor the carbonation reaction progression. In a comparative analytical viewpoint, the NMR and elemental analysis were recognized to be the most accurate ways to follow the cyclo-addition reaction progression. However, titration was recognized to be the most preferred method, because it is a very inexpensive, facile and available method with a reasonable cost- accuracy balance.
基金financially supported by the National Iranian Petrochemical Company Research and Technology(NIPC-RT)
文摘Ethylene polymerization was carried out by immobilization of rac-ethylenebis（1-indenyl）zirconium dichloride （Et（Ind）2ZrCl2） and rac-dimethylsilylbis（1-indenyl）zirconium dichloride （Me2Si（Ind）2ZrCl2） preactivated with methylaluminoxane （MAO） on calcinated silica at different temperatures. Polymerizations of ethylene were conducted at different temperatures to find the optimized polymerization temperature for maximum activity of the catalyst. The Me2Si bridge catalyst showed higher activity at the lower polymerization temperature compared to the Et bridge catalyst. The highest catalytic activities were obtained at temperatures about 50 ~C and 70 ~C for Me2Si（Ind）2ZrC1JMAO and Et（Ind）zZrCI2/MAO catalysts systems, respectively. Inductively coupled plasma-atomic emission spectroscopy results and polymerization activity results confirmed that the best temperature for calcinating silica was about 450 ℃ for both catalysts systems. The melting points of the produced polyethylene were about 130 ℃, which could be attributed to the linear structure of HDPE.
基金financially supported by the Marun Petrochemical Co.,Mahshahr,Iran
文摘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 MgCl_2-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 ZieglerNatta 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 MgCl_2-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 pentaether/Mg molar ratio equal to 0.21.
