The Preparation Of Polyethylene Glycols Complex Ionic Liquids And Their Catalytic Properties

Ionic liquids (ILs) have become one of the hot issues among the green chemistry research areas today for their unique properties, such as low melting point, nonflammability, negligible vapor pressure, good solubility, high thermal stability, recyclability etc. Therefore, ILs have been applied in various fields, and in organic synthesis, they are often used as green solvents and catalysts. With the further studies of ILs and constant pursuit for green chemistry, some traditional ionic liquids can no longer meet the needs of people. Thus, the design of new functional ILs will be one of development directions of ionic liquids.In this paper, two kinds of Poly(ethylene glycol)s (PEG) complex ILs were designed and synthesized. Their catalytic performances in Henry reaction, Michael addition reaction and the oxidative aromatization reaction were investigated.First, a series of quaternary ammonium bases with PEG complex catalysts were designed and applied as catalysts for Henry reaction, Michael addition reaction. Mass spectra, NMR spectra, and TG analysis showed that PEG could form stable complex with quaternary ammonium, which had good catalytic activity in the above two kinds of reactions (up to 99.5% yield). And the catalyst could be reused several times.In the following study, 1-butyl-3-methylimidazolium iodide with PEG complex ILs(PEG-[BMIm]I) were synthesized for oxidative aromatization reactions of Hantzsch 1,4-dihydropyridine compounds, which was also characterized by mass spectra, NMR spectra, and TG analysis. The PEG-[BMIm]I proved to be higher active catalyst and could get higher yield (up to 99.4%) compared with the [BMIm]I.