Preparação de amidas graxas derivadas do óleo de maracujá utilizando diferentes métodos catalíticos

Abstract

Fatty N-aciletanolamines, as well as their derivatives, are frequently found in nature. They belong to a class of nonionic compounds widely used for their surfactant properties in detergents and shampoos, as well as in cosmetic and pharmaceutical formulations. The use of renewable raw materials obtained from industrial wastes appears as an interesting alternative for the synthesis of these molecules. Passion fruit seeds, subproducts of the food industry, are rich in triacylglycerols that can originate fatty amides through reactions of direct or indirect aminolysis. In this work we describe the the synthesis fatty amide mixtures obtained through the treatment of passion fruit oil with three different amines in the presence of heterogeneous chemical catalysts or under microwave irradiation. The selected heterogeneous catalysts, previously reported in the literature for transesterification reactions, proved to be effective in direct and indirect aminolysis. The optimization of the reaction conditions (heating mode, amount of catalyst, reaction time) showed that the mixed oxide ZnO.La2CO5.LaOOH (2.3%, w/w) led to the highest conversions (>99%) in a shorter time (8 h). The calix [4]arene p-sulfonic acid previously described for the esterification of fatty acids, was effective in transesterification reactions (96-99 % conversion) and direct aminolysis of triglycerides (50- >99% conversion). After the characterization of passion fruit oils and of the fatty amides mixtures using the usual spectroscopic methods (1H and 13C NMR, IR) their biological properties were evaluated in vitro. The vegetable oils showed antioxidant activity attributed to the presence of tocopherols and to the high index of unsaturation of the present triglycerides. The mixtures were also evaluated for their antibacterial and antifungal potential. The mixture of fatty N'N'-dimetiletilenodiamide mixture was the only one to display activity against the four strains of Candida sp. tested (MIC = 32-128 µg/ml). The incorporation of fatty amides mixtures in creams and soaps are under study.