This work presents the results obtained for the gas chromatography-mass spectrometry (GC-MS) monitoring of the liquid-phase hydrodeoxygenation (HDO) reaction of furfural (FFR) to 2-methylfuran (MF) over a bifunctional Ru/RuOx/C catalyst in the presence of a direct source of H2. Hydrogenation and hydrogenolysis reactions of FFR and of the intermediate furfuryl alcohol (FA), respectively, were independently studied to provide insights on the HDO mechanism. The mass spectra monitoring of the kinetic isotope effect indicated the HDO reaction occurs through a two-step mechanism comprising of an initial ruthenium-mediated hydrogenation reaction of FFR to FA. In the second step, the FA thus formed experiences a hydrogenolysis reaction via ring activation where the hydrogen atoms are firstly attached to the C3 carbon generating a ring activated structure and removing the OH group. The observation of the peaks at m/z 85 and 84 in the mass spectrum of the MF product confirms this reaction pathway.

Non-doped (Hap) and doped hydroxyapatites with Cu2+ and Fe2+ were synthesized and used to study the adsorption of furan (Fur), pyrrole (Pyr), and thiophene (Thi) in single and ternary component systems. Spectroscopic data and N2 isotherms indicated there were no structural alterations in Hap with the incorporation of Cu2+ and Fe2+. For both single and ternary components, the incorporation of the metal ions resulted in an adsorption increment consistent with the hard-soft acid-base concept. When comparing the systems, there is an inversion with Thi (5.41 mg g-1) and Fur (5.51 mg g-1) being the most adsorbed species in the single and ternary components, respectively. Monte Carlo simulations helped explain the observed experimental trends. While the electrostatic effect seems to prevail in the single system, in the ternary one the mass transport phenomenon is also operative implying greater availability of Fur on surface leading to its higher adsorption efficiency.

The aim this research is to develop a HS-SPME/GC-MS method to analyze the carbaryl in blood plasma samples of the rural workers, who live round the perimeter of Chapada do Apodi-CE. This was achieved by chromatographic signal of the 1-naftol, degradation product of carbaryl with the intention of evaluating the degree of exposure of the workers to pesticides, causing chromosome abnormalities as already evidence in appropriate literature. Three different types of covered SPME fibers were tested and a full factorial design with central point in two levels. The variables optimized were temperature and ionic strength and temperature was the response in the design. Study was undertaken to determinate the equilibrium time. The thermal degradation of carbaryl in SPME headspace was analyzed by 1H-NMR. Proposed method achieved low limits of detection and quantification (1.5 and 5 ng mL-1, respectively) with good precision and accuracy, using the method of weighted least squares. However, the proposed method can be considered a good alternative way of monitoring carbaryl in blood plasma by analytical signal of 1-naftol. None of the plasma analyzed presented a concentration of 1-naftol compound higher than limit of detection of the method proposed here.

Volatile organic compounds (VOCs) from ten endophytic fungal species belonging to the Botryosphaeriaceae family were extracted by headspace-solid phase micro-extraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). Thirty-four VOCs were identified. Most of the compounds are sesquiterpenes (14 non-oxygenated and 10 oxygenated), and two linear ketones and eight alcohols were also identified. Multivariate data analysis (PCA and HCA) allowed the differentiation of all investigated species, and proved to be efficient for the differentiation of Neofusicocum parvum and N. ribis, which are considered very similar species. α-Bisabolol, α-selinene, α-cedrene epoxide and guaiol acetate were suggested as biomarkers.

Brazil is one of the three largest producers of fruits in the world, and among those fruit trees, the cashew tree stands out due to the high nutritional and commercial value of its products. During its fruit processing, there are losses in some compounds and few studies address this issue. Over the last decade the conventional system of food production has been substituted for the organic cultivation system, which is a promising alternative source of income given the global demand for healthy food. Therefore, this research aimed to characterize and quantify the prevalent fatty acids found in cashew nuts obtained from conventional and organic cultivation during various stages of processing. The prevalent fatty acids found were palmitic, linoleic, oleic, and stearic acid. The average of these fatty acids were 6.93 ± 0.55; 16.99 ± 0.61; 67.62 ± 1.00 and 8.42 ± 0.55 g/100 g, respectively. There was no reduction in the palmitic, oleic and stearic fatty acid contents during processing. Very little difference was observed between the nuts obtained from conventional and organic cultivation, indicating that the method of cultivation used has little or no influence on the content of cashew nut fatty acids.

Complexos do tipo trans-[Ru(L)(NH3)4(L’)](PF6)n, onde L = 4-cianopiridina (CNpy), NCS-, CN-, e L’ = CNpy, 1,4-ditiano (1,4-dt), 4-mercaptopiridina (pyS) e tionicotinamida (tna), foram sintetizados e caracterizados. SAMs sobre ouro formadas com os complexos que contêm ligantes sulfurados foram estudadas por desorção redutiva e espectroscopia SERS. Dependendo da natureza do ligante L’, a capacidade retiradora do ligante CNpy mostrou ser forte o suficiente para oxidar parcialmente o átomo de rutênio e, em consequência, deslocalizar densidade eletrônica s do ligante localizado em posição trans. Os resultados de desorção redutiva mostraram que a estabilidade das SAMs formadas está diretamente relacionada a este efeito.

Trans-[Ru(L)(NH3)4(L’)](PF6)n type complexes, where L = 4-cyanopyridine (CNpy), NCS-, CN-, and L’ = CNpy, 1,4-dithiane (1,4-dt), 4-mercaptopyridine (pyS) and thionicotinamide (tna), were synthesized and characterized. SAMs on gold of the complexes containing sulfur were studied by reductive desorption and SERS spectroscopy. Depending on the nature of L’, the withdrawing capability of the CNpy ligand is strong enough to partially oxidize the ruthenium atom and, as a consequence, delocalize the s electronic density from the trans located ligand. The reductive desorption results showed that the stability of the SAMs is directly related to this effect.

Um novo derivado da piperazina, 5-oxopiperazinio-3-sulfonato monohidratado, foi produzido a partir de uma rota sintética simples como resultado da adição do íon bisulfito, HSO3-, ao anel e do ataque nucleofílico de moléculas de água a moléculas de pirazina. O material isolado foi caracterizado por RMN, espectrometria de massa, infravermelho e difração de raios-X.

A new derivative of piperazine, 5-oxopiperazinium-3-sulfonate monohydrate, was produced from a simple synthetic route as a result of the nucleophilic addition to HSO3- bisulphite ion and of the nucleophilic attack of water molecules on pyrazine molecules. The isolated material was characterized by means of NMR, mass spectrometry, infrared, and X-ray diffraction.

This work summarizes important aspects of the chemistry of phosphate esters, with special emphasis on: i) advances in the design of enzymatic models for phosphatases; and ii) nerve agents and currently used strategies for detoxification. The physical organic chemical aspects that are responsible by the reactivity of phosphate esters are also discussed.

A adsorção dos corantes aniônicos alaranjado IV, alaranjado G e alaranjado de xilenol pela quitina foi estudada empregando a isoterma de Langmuir. Os parâmetros de adsorção foram determinados utilizando várias regressões lineares da isoterma. Os resultados revelaram que a capacidade de adsorção é dependente do pH. Em pH ácido, os grupos aminos do polímero estão protonados e a cadeia polimérica está carregada positivamente, predominando a adsorção por troca iônica. Deve ocorrer também em pequena extensão adsorção de van der Walls e por ligações de hidrogênio. Para o alaranjado de xilenol uma relação linear com coeficiente angular de 0,726 L mg-1 foi encontrada. O aumento da temperatura diminui a capacidade de adsorção pela quitina, devido ao aumento da etapa de desorção no mecanismo. Os valores de deltaH de -10,9 kJ mol-1 para o alaranjado G e -28,9 kJ mol-1 para o alaranjado IV comprovam uma adsorção de natureza física para estes corantes sobre a superfície da quitina.

The adsorption of the anionic dyes orange IV, orange G and xylenol orange on chitin was studied, employing the Langmuir isotherm. The adsorption parameters were determined utilizing various linear regressions of the isotherm. The results showed that the adsorption capacity is dependent on pH. In acid pH, the polymer amino groups are protonated and the polymer chain is positively charged, with a predominance of adsorption through ion exchange. Van der Waals adsorption, as well as adsorption through hydrogen bonding, is also likely to occur to some extent. For xylenol orange, a linear regression was found, with an angular coefficient of 0.726 L mg-1. The temperature increase reduces adsorption capacity by chitin, due to the enhancement of the desorption step in the mechanism. deltaH values of -10.9 kJ mol-1 for orange G and -28.9 kJ mol-1 for orange IV prove the physical nature of the adsorption by these dyes on the chitin surface.