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Volume 468, Nº 2 (2016)
- Ano: 2016
- Artigos: 2
- URL: https://journals.rcsi.science/0012-5016/issue/view/9197
Physical Chemistry
Gas-phase carbonylation of dimethoxymethane to methyl methoxyacetate over the Cs2.5H0.5PW12O40 catalyst
Resumo
It has been shown that cesium hydrogen phosphotungstate Cs2.5H0.5PW12O40 is a promising catalyst of the gas-phase carbonylation of dimethoxymethane (DMM) to methyl methoxyacetate (MMA). This catalyst provided the MMA selectivity and yield of 54% and 40%, respectively, under mild experimental conditions: T = 110°C, P = 10 bar, and GHSV = 6000 h–1 for DMM/CO/Ar = 4/76/20 mol/mol/mol. The carbonylation of DMM to MMA is accompanied by side reactions of DMM disproportionation into dimethyl ether (DME) and methyl formate (MF), as well as by secondary side reactions of MF decomposition into methanol and CO and methanol dehydration into DME.
85-88
Optimization of the conditions of ethylene polymerization into reactor powders of ultra-high-molecular-weight polyethylene suitable for solid-phase formation into oriented ultra-high-strength and ultra-high-modulus film yarns
Resumo
This study is aimed at searching for approaches to improve conditions of ethylene polymerization into specific reactor powders of ultra-high-molecular-weight polyethylene with special morphology and structure that make the reactor powders capable of being processed from the solid phase without using solvents into ultra-high-strength and ultra-high-modulus articles. The study showed the possibility of alleviating too stringent requirements for temperature, ethylene pressure, and polymerization duration. The correlation between the molecular and density characteristics of the obtained reactor powders and features of solid-state processing was refined, and so was the choice of the optimal catalytic systems working best under the new polymerization conditions.
89-92