Ethylammonium nitrate: behavior as a bönsted acid catalyst or as a potential nucleophile

ADAM, C.G; FORTUNATO, G.G; MANCINI, P.M.E

Santiago de Compostela, Spain. 13-18 july

Conferencia; 19th IUPAC Conference on Physical Organic Chemistry.; 2008

In the last few years designing solvents has become an important task for chemists, the challenge consisting in developing a ?desired solvent? with particular properties for each application. In connection with this, ionic liquids (ILs) have appeared as a new type of solvents suitable for developing physicochemical processes. ILs technology has been successfully applied in several classical organic reactions, nevertheless, there are few works based on kinetic studies. Even though some of these work analyzing different reactive systems varing the IL, the data kinetic treatments result insufficient. In this direction, this work presents how a reaction media, constitute by a molecular solvent, is modified, by adding small amounts of ethylammonium nitrate (EAN). The molecular solvent selected was acetonitrile (AcN), taking to account that this solvent exhibit synergism on acidity property. The aim is to evaluate if the EAN could affect the normal course of a chemical reaction. In this sense, the challenge is to reveal if this IL has a behavior as a Brönsted acid catalyst or even more, as a potential nucleophile. Hence, we selected two organic reactions as models (i) the aromatic nucleophilic substitution reaction (ANS) between 1-fluoro-2,4-dinitrobenzene (2,4- DNFB) and piperidina (PIP), in order to study the possibility of nucleophile competition; (ii) the addition of amines to 4-N,N (dimethyl) aminobenzaldehide, in order to evaluate EAN as dual acid catalyst and nucleophile. For the ANS, we concluded that, at low concentrations of EAN, two processes are taking placed simultaneously, with ethylamine and PIP as competitive nucleophiles. For the addition to carbonyl compound, the organic salt operates as dual acid catalyst and nucleophile generator, bringing about the quantitative production of 4-(ethylimino) methyl)- N, N-dimethylbenzenamine. In conclusion, the addition of EAN to reaction media, allowed us to develop new synthesis routes.