| Summary: | 碩士 === 義守大學 === 生物技術與化學工程研究所 === 100 === Room-temperature ionic liquids are defined as organic salts which melt below 373.15K, with very low vapor pressure and selective solubility in many organic and inorganic compounds. Therefore, we use it in this present work as solvent and catalyst.
Chemical reaction of carbon dioxide, by coupling with cyclohexylamine to form 1,3-Dicyclohexylurea, was studied on using ionic liquid “[BMIM]Br” as solvent and catalyst. The reaction parameters were reaction time (2~7 hr), temperature (130~170 ℃), CO2 pressure (20~50, 80~200 bar). The conversion was improved with the increasing of reaction time and temperature. When the reaction time was 6 hrs, temperature at 160 ℃ and 30 bar, the conversion of cyclohexylamine was 67%. When the reaction time was 7 hrs, temperature at 170 ℃and 100 bar (supercritical pressure of CO2), the highest conversion of cyclohexylamine was 91%.
According to the experimental data and reaction mechanism, it was found to be a first-order reaction of cyclohexylamine and CO2; the reaction rate are 0.1365 hr-1, 0.1576 hr-1, 0.1778 hr-1, 0.1904 hr-1 at 130 ℃, 140 ℃, 150 ℃ and 160 ℃ with 30 bar of CO2. The reaction rate are 0.232 hr-1, 0.2578 hr-1, 0.2756 hr-1, 0.3003 hr-1 at 140 ℃, 150 ℃, 160 ℃ and 170 ℃ with 100 bar of CO2. The activation energy was 3918.4 cal/mol and 3155.4 cal/mol respectively.
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