A new functionalized ionic liquid, 1-aminoethyl-3-methylimidazolium hexafluorophosphate was synthesized from 1-methylimidazole and 2-bromoethylamine hydrobromide. This ionic liquid was found to be an efficient scavenger for removing excess electrophiles, such as benzoyl chloride, p-toluenesulfochloride, phenyl isothiocyanate, and p-chlorophenyl isocyanate, in a solution-phase parallel synthesis. The resulting ionic liquid derivatives can be separated directly from the reaction mixture. Desired products were obtained with high purity. Only 1.5-2.0 equiv of this scavenger was needed with a sequestration time of less than 35 min. In addition, the used ionic liquid can be regenerated and recycled several times without significant loss of activity.
The Knoevenagel condensation of aromatic aldehydes with malononitrile and ethyl cyanoacetate using amino-functionalized ionic liquid, 1-aminoethyl-3-methylimidazolium hexafluorophosphate as catalyst was successfully performed in aqueous media. The catalyst can be recycled and reused at least six times without apparently loss of activity. Ar CHO CN R Ar R CN H 2 O, r.t. + [2-aemim][PF 6 ] R = CN or CO 2 Et
Without the auxiliary involvement of axial ligands and organic solvents, the ionic manganese porphyrin (1c) with a pyridinium tag embedded in a pyridinium based ionic liquid, [BPy][BF 4 ], efficiently catalyzed the oxidation of styrene and its derivatives under mild conditions, affording high activity/oxide selectivity and good stability even after 5 recycling uses.
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