Ultrasound-promoted metal-free homogenous olefins epoxidation and direct conversion of alkenes to cyclic carbonates using catalytic TAIm[X] (X = WO42-, HSO5-) recyclable ionic liquid under mild conditions

A mild and efficient olefin epoxidation and direct conversion of alkenes to cyclic carbonates from alkenes has been developed using catalytic TAIm[X] (X=WO42-, HSO5-) recyclable ionic liquid. [Display omitted] •TAIm[WO4] and TAIm[HSO5] recyclable ILs were synthesized via an anion exchange of the corresponding salts.•The ILs were utilized as two sustainable, recyclable, and efficient catalysts for the olefins H2O2 epoxidation.•The resulting ionic liquids were also used as recyclable solvents for the epoxidation under ultrasound irradiation.•Domino synthesis of cyclic carbonates from terminal and cyclic alkenes was efficiently performed in the presence of low CO2(g) pressure.•TAIm[HSO5] IL showed superior activity than TAIm[WO4] IL in terms of selectivity and efficiency. TAIm[WO4] and TAIm[HSO5] ionic liquids were prepared and used as efficient solvent and recyclable catalysts for the mild epoxidation of olefins and the domino preparation of cyclic carbonate from alkenes under ultrasound irradiation·H2O2 was used as an oxidant. The physical properties and structure of the ionic liquids were studied by various analytical methods including FTIR, EDX, viscosity, and density measurements. High to excellent yields were obtained for a wide variety of olefins whether aliphatic or aromatic types for the epoxides as well as the conversion of cyclic and terminal olefins to cyclic carbonates at low CO2(g) pressure (∼1 atm.). Moderate CO2(g) solubility in the ionic liquids was found. Also, excellent epoxide-selectivity was obtained for all olefins. Scalability of the method demonstrated a direct scalability for the promising gram scale epoxidation of olefins with at least efficiency loss. The TAIm[WO4] and TAIm[HSO5] ionic liquids could be recycled from the homogenous mixture by a simple solvent–solvent extraction, and reused for at least several times with insignificant activity loss.