Amphiphilic Ionic Liquids: Developing Diels-Alder Reactions in Aqueous Micellar Systems

ADAM, C.; CLAUDIA D. DELLA ROSA; BRAVO, MA VIRGINIA; JESICA SOFFIETTI

Buenos Aires

Simposio; GS03-Global Symposium on Ionic Liquids (JE-II CIBIQ) ?A WCCE11 Joint Event; 2023

In recent years, an important objective to realize is the development of sustainable production processes using chemical methodologies that are clean and efficient. One of the principles of Green Chemistry is the reduction of auxiliary substances, thus ionic liquids (ILs) arise as a potential sustainable alternative. An interesting medium for the development of reactions within the scope of Green Chemistry is ILs with an amphiphilic character. There have been reports of the formation of aqueous micelles of ILs with long chain alkanes as their substituted cation, especially in the form of N-alkylimidazoles and N,N-dialkylimidazoles [2a].The Diels-Alder (DA) cycloaddition reaction represents one of the most important tools in organic synthesis. It is considered a reaction with atomic economy which is an extremely relevant aspect in DA polar reactions. In this research the effects of aqueous micellar systems formed with imidazole (Him) and methyl imidazole (mim) ILs such as [C12mim][Br], [C12Him][CH3SO3 ], [C12Him][CF3CO2 ], [C16mim][Br], [C16Him][CH3SO3], [C16Him][CF3CO2], on DA cycloaddition reactions. The studies were referenced using aqueous micellar system formed by conventional surfactants like SDS and CTAB. The challenge lies in obtaining information on the behavior of ILs in order to maximize their benefits and uses, ultimately replacing molecular solvents with ILs and creating greener methods and techniques. We have demonstrated that 2-nitrofuran acts like a dienophile in thermal DA reactions with a normal electron demand in conventional reactions (200 and 150°C, 72 hrs) [2b]. For this study, the reaction was modeled with 2-nitrofuran and isoprene due to the production of benzofurans which are precursors of agrochemicals. In this study, variables were optimized such as the ratio of dieno:dienophile, temperature and time of reaction. The reactions took place at values above the corresponding CMC (Critical Micellar Concentration), with ratio of dieno:dienophile 6:1, temperatures of 90 and 120°C for 48 and 72 hours. The results indicate that aqueous micellar systems formed by amphiphilic ILs improve the yields of cycloadducts which are more than when we used traditional surfactants. While also permitting an improved solubilization of non-polarsubstrates under less drastic reaction conditions. References 1- Anastas, P.T.; Warner, J:C. (1998). Green Chemistry. Theory and Practice, Oxford University Press: New York, p 30.2- a) Adam, C.G.; Bravo, M.V.; Granados, A.M. (2017). Anion Influence on Aggregation Behavior of Imidazolium-Based Ionic Liquid in Aqueous Solutions: Effect on Diverse Chemical Processes. Industrial & Engineering Chemistry Research, 56 (5), 1214-1222.b) Della Rosa, C.; Kneeteman, M.N. and Mancini, P.M.E. (2005). 2-Nitrofurans as dienophiles in Diels-Alder reactions. Tetrahedron Lett. 46, 8711-8714.