: The heterogeneity of color distribution between sapwood and heartwood limits the market for wood from fast-growth plantations of tropical species. Wood color is associated with wood extractives contents. This study presents the relationship between wood color parameters measured by the CIELab color system and total amount of extractives and phenolic-type extractives in ethanol-toluene and hot water extracts of wood from two fast-growth plantation species. The results demonstrated that the difference in sapwood and hardwood color in Vochysia guatemalensis and Acacia mangium is caused by lower concentrations of extractives in sapwood of both species. Additionally, variations in total extractive and phenolic content have different effects on the color parameters (L*, a* and b*) of both species studied. In Vochysia guatemalensis wood, parameter L* decreases as total extractive and phenolic content increases; however, parameter a* increases as the content of extractives and phenols increases. In Acacia mangium, the amount of phenols showed no relationship with the color parameters. The ethanol-toluene total extractive content, however, shows a relationship with several color parameters. An increase in the content of total extractives in water and ethanol-toluene increases parameter a*, but decreases parameter L*.

Lignocellulosic residues resulting from agricultural activities and urban centers cause pollution. A possible solution to this problem is to combine these residues with woody plants to produce particleboards. The purpose of this study was to evaluate decay resistance, coating and burning properties and the change of color caused by accelerated weathering of particleboards manufactured with a combination of 3 woody species used for commercial reforestation in tropical areas (Cupressus lusitanica, Gmelina arborea and Tectona grandis), pineapple (Ananas comosus) leaves from the crown and the plant (PL), empty fruit bunch of Elaeis guineensis (EBF) and tetra pak packages (TP). According to the results, the mixtures of T. grandis and EFB were classified as moderately resistant and other mixtures (woody species and PL or TP) were classified as slightly resistant. The finish performance test determined that the mixtures with TP presented the best performance, followed by the mixtures with oil palm components and the mixtures composed of pineapple leaves. Regarding lacquer consumption, no differences were found between the mixtures. The combustion test determined that particleboards with TP and EFB showed the highest resistance to combustion, while pineapple presented the lowest resistances to combustion. In the accelerated weathering exposure test, the mixtures of the three species with TP showed the best performance in accelerated weathering. Contrariwise, the mixtures with pineapple leaves showed the lowest resistance to accelerated weathering. Oil palm particleboards presented lower resistance to weathering than TP, though higher than pineapple leaves' resistance.

Particleboards were manufactured from oil palm fruit, the oil palm mesocarp fiber of Elaeis guineensis, the leaves of pineapple (Ananas comosus) and the sawdust from three fast-growing species of trees (Gmelina arborea, Tectona grandis and Cupressus lusitanica). The chemical and anatomical compositions of E. guineensis and A. comosus and their effects on urea-formaldehyde adhesive were investigated. Afterwards, the particle combination of the fiber of E. guineensis and A. comosus with the sawdust of three species was investigated. The results showed that the fiber of Elaeis guineensis has a higher oil content than that of the pineapple leaf, and the pineapple leaf has large fiber of over 5 mm. The fiber of E. guineensis must be washed with water to increase the adhesion of particles. The best combination of agricultural fiber and sawdust of fast growth tropical species is 50%-50%, respectively (waste agriculture and sawdust, w/w %). It was shown that the pineapple leaf and the empty fruit of oil palm can be substituted for conventional wood-based particleboards.

El objetivo del presente trabajo fue sintetizar moléculas (cromóforos) que tuviesen la capacidad de combinarse con sustancias macrocíclicas para preparar macromoléculas (quimiosensores) que pudiesen utilizarse para la detección selectiva de cationes Hg2+, Cd2+ y Pb2+ en agua. Para ello se sintetizaron derivados 1,8-naftilimida a partir de reacciones de aminación entre el anhídrido 4-bromo-1,8-naftálico y diferentes alquilaminas de cadena variable (n = 2, 4). La funcionalización de los derivados 1,8-naftilimidas en posición 4 se realizó mediante reacciones de sustitución de halógeno utilizando bromoalquilaminas (n = 2, 4). Se lograron sintetizar cuatro cromóforos: el N-(2-cloroetil)-1,8-naftilamida, el N-(3-cloropropil)-1,8-naftilamida, el 4-bromo-N-(2-cloroetil)-1,8-naftilamida y el 4-bromo-N-(3-cloropropil)-1,8-naftilamida. Se obtuvieron espectros UV y 1H-RMN de los cromóforos preparados, que sugieren que los compuestos preparados efectivamente corresponden a los planificados. En consecuencia, como un siguiente paso, se procederá a utilizar los cromóforos sintetizados en reacciones de acoplamiento con compuestos macrocíclicos para preparar los potenciales quimiosensores.