Carboxilatos de cobre II, zinco II, manganês II e lantânio III como adsorventes do semioquímico undecan-2-ona

Abstract

Among the insects that attack common crops in Brazil, the Lobiopa insularis intensely damage strawberry plantations. To combat insects like the one mentioned above, a trap is generally used on which some type of bait is placed to specifically attract the insect. Pheromones are chemical compounds responsible for transmitting messages between same species individuals, among them, aggregation pheromones attract both genders to a certain place, which is the reason why it is ideal for use as bait. The main component on the aggregation pheromone for the L. insularis is undecan-2-one. Bait efficiency can be improved with a slow-release matrix such as one derived from lamellar materials. One of the characteristics of the lamellar compounds is their well-defined crystalline structure, organized in layers, in which the compound is joined by intralamellar covalent bonds, while the interlayer interaction is due to electrostatic interactions. Between one layer and another, guest compounds can be inserted. In this work, carboxylates derived from lauric acid and stearic acid with copper, zinc, manganese and lanthanum were synthesized by co-precipitation methodology and characterized. Gross reaction yield ranged from 87% to 99%. The X-ray diffractograms confirmed that the synthesized compounds are lamellar and the infrared spectra indicated that the conversion of the initial acid to the carboxylate was efficient. Zinc and manganese carboxylates showed a satisfactory interaction with the pheromone undecan-2-one, that was quantified in different experiment conditions. For the manganese laurate, some of those conditions are part of a design of experiment, a tool that enables experiment optimization. The carboxylates were tested on the following conditions: 2, 8 or 15 days for interaction time; 90°C, 100°C and 110°C for interaction temperature; 1:10, 1:30 and 1:50 for adsorbent proportion. The experimental condition that displayed best results were the one made in 15 days on 90°C with 1:50 of molar equivalent, on which 1,13mg of undecane-2-one was adsorbed per gram of solid. Then the design results suggest that the experimental conditions time and proportion positively affect results, while temperature negatively affects them. Other tests can be made in the future to better define which conditions is ideal for interaction.