Cyclic carbonate synthesis from CO2and epoxides using zinc(II) complexes of arylhydrazones of β-diketones

Zinc(II) complexes of arylhydrazones of β-diketones (AHBD) were used for the first time as catalysts combined with tetrabutylammonium bromide (TBABr), in the coupling reaction between CO2 and epoxides. The influence of pressure and temperature on cyclic carbonate formation was investigated, as well as the catalytic activity toward different substrates (e.g. styrene oxide, propylene oxide and cyclohexene oxide). The molar ratio between metal complex and TBABr was determined for maximum catalytic activity

CO2 + ionic liquid biphasic system for reaction/product separation in the synthesis of cyclic carbonates

The possibility of using supercritical CO2 (scCO2) technology as a second step for extracting propylene carbonate produced from the coupling reaction between propylene oxide and CO2, was investigated. The coupling reaction was performed under biphasic gas-liquid conditions, using a zinc(II) complex of arylhydrazones of β-diketones (Zn(II)-AHBD) as metal catalyst, combined with tetrabutylammonium bromide (TBABr). 1-Ethyl-3-methylimidazolium ethyl sulfate ([EMIM][EtSO4]) and methyltrioctylammonium chloride ([ALIQUAT][Cl]) were explored as reaction solvents, in order to efficiently solubilize the catalyst and retain the catalyst inside the reactor during the product extraction step. Results obtained were compared with other common used solvents as methyl ethyl ketone (MEK), ethyl lactate (EL), and polyethylene glycol 400 (PEG 400). [ALIQUAT][Cl] was selected as the most promising solvent and scCO2 extraction was effectively applied as a second step to isolate propylene carbonate from the catalyst system. Following this strategy, the catalyst system was reused three times, without loss of activity. © 201

CO2 + ionic liquid biphasic system for reaction/product separation in the synthesis of cyclic carbonates

The possibility of using supercritical CO2 (scCO2) technology as a second step for extracting propylene carbonate produced from the coupling reaction between propylene oxide and CO2, was investigated. The coupling reaction was performed under biphasic gas-liquid conditions, using a zinc(II) complex of arylhydrazones of β-diketones (Zn(II)-AHBD) as metal catalyst, combined with tetrabutylammonium bromide (TBABr). 1-Ethyl-3-methylimidazolium ethyl sulfate ([EMIM][EtSO4]) and methyltrioctylammonium chloride ([ALIQUAT][Cl]) were explored as reaction solvents, in order to efficiently solubilize the catalyst and retain the catalyst inside the reactor during the product extraction step. Results obtained were compared with other common used solvents as methyl ethyl ketone (MEK), ethyl lactate (EL), and polyethylene glycol 400 (PEG 400). [ALIQUAT][Cl] was selected as the most promising solvent and scCO2 extraction was effectively applied as a second step to isolate propylene carbonate from the catalyst system. Following this strategy, the catalyst system was reused three times, without loss of activity. © 201