Study of Manganese Laurate as Adsorbing Matrix for Undecan-2-one: Factors Affecting Adsorption for Application in Controlled-Release of Pheromones Anderson de Carvalho, Mirelly Fonseca, Diogo Vidal, Ana Cursino, Daniele Firak, et al. Journal of the Brazilian Chemical Society, 2023 One of the greatest challenges faced by agriculture is the use of agrochemicals and the balance between food production and environmental problems associated with the excessive use of these substances. To overcome this issue, pheromones have been used to trap pests that harm crops. This work reports the use of a layered monocarboxylate, manganese laurate (MnL2), as adsorbing matrix for undecan-2-one (methyl nonyl ketone (MNK)), one of the components of the pheromone of the insect Lobiopa insularis, which is a pest in the strawberry cultivar. The manganese laurate was synthesized by a coprecipitation method and was later characterized using X-ray diffractometry, vibrational spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The characterization techniques showed that MNK was adsorbed in the manganese laurate structure in a range of 0.08 to 1.13 mg g-1, and this interaction was investigated in a factorial design experiment, in which the variables temperature, time of contact, and matrix:MNK ratio were investigated. A negative effect of increasing temperatures was observed and attributed to substrate volatilization. The adsorption was favored in increasing molar ratios and times of contact, and ideal conditions for the adsorption could be found, indicating that manganese laurate could be applied in controlledrelease tests.
SYNTHESIS, CHARACTERIZATION AND PHOTOPHYSICAL STUDY OF 4,4’-DIAMINO-2,2’-STILBENEDISULFONATE WITH LANTHANIDE IONS COMPLEXES Roseane Silva Oliveira, Ana Cristina Trindade Cursino, Fabiana Roberta Gonçalves e Silva Hussein, and Chemistry and Chemical Technology, 2022 Complex of 4,4’-diamino-2,2’-stilbenedisulfonic acid (DSD) with trivalent lanthanide ions Eu3+ and Tb3+ were prepared at the ratio of 3:1 (DSD:Ln). The complexes with ions present in the form of powder show black (Eu3+) and brown (Tb3+) colors. The complexometric titration and CHN elemental analysis suggest that these complexes have the general formula Eu(C14H12N2SO3SO3H)3∙3H2O and Tb(C14H12N2SO3SO3H)2(CF3SO3)∙3H2O. The shift of the 330 nm band for DSD to a longer wavelength in the infrared spectra of the complexes and the disappearance of the bands at 2921 and 2623 cm-1 are indicative of the formation of complexes with ions Eu3+ and Tb3+. Thermal analysis shows that DSD is thermally stable up to 573 K and the decomposition process of the complexes shows two and three mass losses for ions Eu3+ and Tb3+, respectively. The analysis of luminescence indicates that the complexes do not present the emission from the lanthanide moiety in the visible region. This may be related to the ligand triplet states, which are probably at lower energy than the emission state of the Eu3+ (5D0) and Tb3+ (5D4) ions.
