Inserting carbon dioxide (CO2) into ammonia molecules to produce urea is a traditional CO2 utilization method. An ionic liquid (IL), 1-butyl-3-methylimidazolium bromide ([Bmim]Br), was used as reaction medium and [Bmim]Br/KOH as catalyst. This study investigates CO2 carbonylation of cyclohexylamine and its reaction performance in a number of low- and high-pressure CO2/IL systems. The reaction yield was greatly increased as pressure ranges changed from 15–50 bar to 80–100 bar; the physiochemical properties of substrates and catalyst were greatly affected by CO2 in supercritical state. The yield was improved from 69% at 30 bar to 91.6% at 100 bar, much better than a previous study result of 53.5%, but as pressures further increased, a significant decrease was observed. The reaction activation energy was calculated to be 3.942 and 4.354 kcal/mol in mild and supercritical conditions. This process shows a low threshold reaction energy and great potential for industrial applications to store CO2 in amine molecular structures.
|Number of pages||6|
|Journal||Journal of the Chinese Institute of Engineers, Transactions of the Chinese Institute of Engineers,Series A|
|Publication status||Published - 2016 Oct 2|
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