Obtenção e caracterização de ésteres etílicos e metílicos, celulose e celulose regenerada a partir dos frutos da Moringa oleifera

Abstract

The Moringa oleifera, known in Brazil as white acacia, is a tree native from India and proliferated in several countries around the world, with practically all its parts (flowers, fruits, leaves and roots) having some industrial use. The objective of the present work was to use the mature fruit M. oleifera, from a biorrefinery perspective, to obtain methyl and ethyl esters (biodiesel) from the seed oil and to evaluate the potential of the lignocellulosic residues (pods and seed shells) in the extraction of cellulose and production of cellulose derivatives. From the peeled seeds, yields of up to 40% of the oil were obtained, from which methyl esters (EM) and ethyl esters (EE) were produced by homogeneous alkaline catalysis, which had some characteristics analyzed. The products of the synthesis, EM and EE, presented an esters content of approximately 73% and 77%, respectively, induction period (IP) of almost 28 h and 18 h and relative density within the established by the ANP (Agência Nacional do Petróleo, Gás Natural e Biocombustíveis). The esters produced had the capacity to raise the IP of a low stability biodiesel when used in blends. The best result was obtained with EM, which when added to a soybean biodiesel with IP of 3 h in the proportion of 50%, produced a blend with IP above the minimum of 8 h required by ANP standards. In the structural characterization of the lignocellulosic residues, it was found that the pods had a higher cellulose content than the shells (34 % vs 26 %). The cellulose was extracted by delignification in two steps, the first acid and the second, alkaline, followed by bleaching of the pulp. The resulting holocellulose was treated with KOH solution to hemicelluloses removal and cellulose insulation. In addition to the higher cellulose content, the cellulose of the pods has a higher average viscosimetric molecular mass in comparison to the bark cellulose and therefore better capacity for the formation of regenerated cellulose membranes. The membranes were produced using a solution of cuproethylenediamine in an adaptation of the cupramonium method, characterized in relation to water transport and its morphology was evaluated in Scanning Electron Microscopy. X-Ray Diffraction analysis showed the conversion of type I (native) cellulose into type II (regenerated) and Thermogravimetric Analyzes showed a gain in the stability of the materials throughout the process, between the purification and production of the regenerated cellulose. The integrated use of the M. oleifera fruit appears to be promising since its oil can be used in the production of biodiesel of good stability and the pods are presented as a good source for obtaining cellulose that can be used in the production of cellulose derivatives.