Avaliação das condições operacionais e equilíbrio de fases no processo de produção e purificação do feromônio rincoforol

Abstract

The species Rhynchophorus palmarum attacks several cultures, mainly coconut trees, which have great socioeconomic importance for the development of the country. This pest is the main vector of the red ring disease, contaminating the plants with the nematode Bursaphellencus cocophilos, impairing all their development, and can lead to death. Currently, the most effective method to combat the pest is the use of the aggregation pheromone Rhynchophorol ((2E) -6- methyl-2-hepten-4-ol)), combined with artisanal traps distributed around the planting area. The present project aims to improve the process of production and purification of the pheromone rincoforol, evaluating the conditions that favor the reactive process and the purification of the product, in order to minimize the use of water and reagents, thus generating better operational conditions and lower effluent volumes. For this, a purification methodology was proposed that uses lower volumes of reagents, analyzing the phases generated in each purification step, as well as the product, determining its physical-chemical properties, making it possible to identify the acid character of the organic phase, the variation density and conductivity presented by each phase throughout the process, without significant variations in temperature. The rhynchophorol obtained had pH in the range of 0.62 ± 0.029, density and conductivity equal to 0.8647 ± 0.0042 g / cm3 and 0.70 ± 0.05 μS / cm, respectively, being around 31.40 ° C. In order to verify the efficiency of the proposed methodology, the aqueous phases were analyzed by gas chromatography coupled to a flame ionization detector (GC-FID), being possible to identify and quantify the fractions of Tetrahydrofuran (THF) and rhynchophorol present, as well as to evaluate the efficiency of the washes carried out, resulting in a product containing fractions of organic compounds from the reaction. Then, the study of liquid-liquid balance involving the major components of the system at the end of the synthesis, THF + Rhynchophorol + Water, carried out at 20 ° C and 30 ° C. Characteristic ternary diagrams of type 2 were predicted by the UNIFAC thermodynamic model, in which there is complete solubility between the solute (pheromone) and solvent (THF), with partial miscibility between the binary solutions Rincoforol / Water and Water / THF. However, simulation results of a three-phase flash tank with the NRTL model demonstrated that for temperatures below 341.45 K there is no formation of two liquid phases for the water / THF binary mixture, so that type 1 ternary diagrams must be used. obtained. It was also found that the temperature has a strong influence on the extraction process, a fact justified by the reduction of the phase formation region. From the diagrams and graph of the partition coefficient of rhynchophorol, it was proved that extraction using THF as a solvent is favored at lower temperatures. In addition, thermodynamic modeling was performed with the NRTL and UNIQUAC models by regressing the experimental ELL data. The models reasonably correlated the slope of the tie lines, however the adjustment was not satisfactory because it predicted similar heterogeneous regions for both temperatures, differently from what was observed experimentally. The mean quadratic deviations (RMSD) between the experimental values and correlated by NRTL and UNIQUAC were, respectively, 6.76% and 6.87%. However, the study carried out was fundamental to determine the process variables that need to be monitored, so that the production and purification is more effective, aiming at the production scale-up.