An Efficient Bifunctional Ionic Liquid [BIL] as Solvent and Catalyst System for O-Alkylation of Phenols Under Solvent-Free Conditions: An Environmental Benign Approach

Abstract

Background: Bifunctional ionic liquid [BIL] was found to be a highly effective catalyst for ether synthesis without any inorganic base or solvent. Using this protocol, different aryl substitutions were reacted with different phenols in good to excellent yields. The BIL is reusable without any loss in catalytic activity for nine consecutive cycles. The Williamson reaction is a convenient renovation in fine chemical synthesis since the ethers are important in both bulk and fine industrial chemicals preparation and academic applications. Method: The mixture of the phenol (1mmol), alcohol (1.2 mmol), and BIL ionic liquid (0.3 mol%) was added to a round-bottomed flask (100 mL) with continuous stirring for 1 hour. Objective: The aim of this study is to highlight the use of BIL to synthesize mixed ethers using substituted phenols and to study the reusability in the next cycle. Results: The products obtained were phenol and substituted phenols containing withdrawing substituents in respectable yields. However, the reactions involving substituted phenols containing electron-donating groups often afford the corresponding products in low yields. Conclusion: BIL is found to be an effective catalyst in the etherification of various unsymmetrical ethers under mild conditions. Bifunctional ionic liquid as a solvent and catalyst will show real rewards by providing a ‘green’ method with the safer procedure, less reaction time periods, mild conditions, easy separation, and ionic liquid recycle.