Abstract
A mild, efficient, and ecofriendly procedure for cyclotrimerization of aldehydes was realized by using a series of novel Brønsted acidic ionic liquids (BAILs) consisting of double–SO3H groups in cations as catalysts. Good conversion of aldehydes and selectivity of trialkyl-1,3,5-trioxanes were achieved by using 1 mol% of BAILs. In addition, the catalyst system could be recycled and reused at least eight times without apparent loss of activity.
GRAPHICAL ABSTRACT
Notes
a IL/isobutylaldehyde = 0.5% (molar ratio).
a Aldehyde (30 mmol), [Bis-BsPy][CF3SO3]2/aldehyde = 1% (molar ratio), reaction temperature 25 °C, reaction time 60 min.
b [Bis-BsPy][CF3SO3]2/aldehyde = 2% (molar ratio).