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The development of efficient and eco-friendly methods for the synthesis of elaborate amines is highly desired as they are valuable chemicals. The catalytic alkylation of amines using alcohols as alkylating agents, through the so-called borrowing hydrogen process, satisfies several of the principles of green chemistry. In this paper, four neutral half-sandwich complexes of Ru(II), Rh(III), and Ir(III) have been synthesized and tested as catalysts in the N-benzylation of amines with benzyl alcohol. The new derivatives contain a N^N′ anionic ligand derived from 5-(pyridin-2-ylmethylene)hydantoin (Hpyhy) that has never been tested in metal complexes with catalytic applications. In particular, the Ir derivatives, [(Cp*)IrX(pyhy)] (X = Cl or H), exhibit high activity along with good selectivity in the process. Indeed, the scope of the optimized protocol has been proved in the benzylation of several primary and secondary amines. The selectivity towards monoalkylated or dialkylated amines has been tuned by adjusting the amine:alcohol ratio and the reaction time. Experimental results support a mechanism consisting of three consecutive steps, two of which are Ir catalyzed, and a favorable condensation step without the assistance of the catalyst. Moreover, an unproductive competitive pathway can operate when the reaction is performed in open-air vessels, due to the irreversible release of H2. This route is hampered when the reaction is carried out in close vessels, likely because the release of H2 is reversed through metal-based heterolytic cleavage. From our viewpoint, these results show the potential of the new catalysts in a very attractive and promising methodology for the synthesis of amines., El desarrollo de métodos eficientes y ecológicos para la síntesis de aminas elaboradas es muy deseable, ya que son sustancias químicas valiosas. La alquilación catalítica de aminas utilizando alcoholes como agentes alquilantes, mediante el llamado proceso de préstamo de hidrógeno, satisface varios de los principios de la química verde. En este artículo, se sintetizaron y probaron cuatro complejos semisándwich neutros de Ru(II), Rh(III) e Ir(III) como catalizadores en la N -bencilación de aminas con alcohol bencílico. Las nuevas derivadas contienen un N ^ N′ ligando aniónico derivado de 5-(piridin-2-ilmetileno)hidantoína (Hpyhy) que nunca se ha probado en complejos metálicos con aplicaciones catalíticas. En particular, los derivados de Ir, [(Cp*)IrX(pyhy)] (X = Cl o H), muestran una alta actividad junto con una buena selectividad en el proceso. De hecho, el alcance del protocolo optimizado ha sido probado en la bencilación de varias aminas primarias y secundarias. La selectividad hacia las aminas monoalquiladas o dialquiladas se ha ajustado ajustando la relación amina:alcohol y el tiempo de reacción. Los resultados experimentales respaldan un mecanismo que consta de tres pasos consecutivos, dos de los cuales son catalizados por Ir y un paso de condensación favorable sin la ayuda del catalizador. Además, una vía competitiva improductiva puede operar cuando la reacción se realiza en recipientes al aire libre,2 . Esta ruta se ve obstaculizada cuando la reacción se lleva a cabo en recipientes cerrados, probablemente porque la liberación de H 2 se invierte a través de la escisión heterolítica basada en metales. Desde nuestro punto de vista, estos resultados muestran el potencial de los nuevos catalizadores en una metodología muy atractiva y prometedora para la síntesis de aminas.

CBMM - Companhia Brasileira de Metalurgia e Mineração Aminas aromáticas são compostos com atividades comprovadamente maléficas aos seres humanos. Dentre elas, 2-naftilamina (2NAF) é uma das 120 espécies com ação carcinogênica comprovada, sendo responsável por casos de câncer de bexiga. Ela pode ser empregada como precursora na síntese de diversos azo-corantes e teve uso proibido em diversas partes do mundo. Os métodos cromatográficos acoplados com espectrometria de massa são os mais utilizados no monitoramento destas aminas, apresentando limites de detecção (LOD) na ordem de picogramas. As técnicas eletroquímicas são uma alternativa a estes métodos e possuem como vantagem a instrumentação de menor custo e alta frequência analítica, apesar do maior LD. Este trabalho apresenta um método eletroquímico simples para determinação de 2NAF em perfume por voltametria de pulso diferencial (DPV) empregando um eletrodo de diamante dopado com boro (BDD) tratado catodicamente. A simples diluição da amostra no eletrólito de suporte foi realizada antes da análise eletroquímica. Uma solução de tampão borato de pH 10,0 contendo 20% (v/v) de etanol forneceu respostas estáveis de 2NAF sem a passivação do eletrodo. O tempo de modulação, incremento de potencial e a amplitude de modulação foram otimizados em 20 ms, 6 mV e 70 mV, respectivamente, atingindo um LD estimado em 4,6 nmol L− 1 com faixa linear entre 0,5 e 90 μmol L−1, e DPR < 2,9%. A amostra de perfume analisada apresentou concentração de 2NAF abaixo do valor de LD. Os valores de recuperação para a amostra enriquecida com 2NAF estavam entre 102 e 104%. O método proposto é viável para ser aplicado para detecção e quantificação de 2NAF em amostras de perfume com preparo de amostra simples. Aromatic amines are compounds with activities that are proven to be harmful to humans. Among them, 2-naphthylamine (2NAP) is one of the 120 species with proven carcinogenic action, being responsible for cases of bladder cancer. It may be used as a precursor in the synthesis of various azo dyes and has been banned in many parts of the world. The methods of chromatography coupled with mass spectrometry are the most often used in the monitoring of this amines, showing limit of detection at picogram levels. Electrochemical techniques are an alternative to these methods and have the advantage of lower cost instrumentation and high analytical frequency, despite the higher limit of detection. This work presents a simple electrochemical method for 2NAP determination in perfume by differential-pulse voltammetry (DPV) employing a boron-doped diamond (BDD) electrode cathodically treated. Simple dilution of sample in supporting electrolyte was performed before electrochemical analysis. A borate buffer solution of pH 10.0 containing 20% (v/v) ethanol provided stable responses of 2NAP without electrode passivation. Modulation time, potential step and modulation amplitude were optimized at 20 ms, 6 mV and 70 mV, respectively, which achieved a limit of detection (LOD) of estimated as 4.6 nmol L−1 with a linear range between 0.5 and 90 μmol L−1, and RSD < 2.9%. The analyzed perfume sample presented 2NAP concentration below the LOD value. Recovery values for spiked sample with 2NAP were between 102 and 104%. The proposed method is feasible to be applied for 2NAP detection and quantification on perfume samples with simple sample preparation. Dissertação (Mestrado)

The present study investigated whether intrinsic exercise capacity affects the changes in thermoregulation, metabolism and central dopamine (DA) induced by treadmill running. Male Wistar rats were subjected to three incremental exercises and ranked as low-performance (LP), standard-performance (SP), and high-performance (HP) rats. In the first experiment, abdominal (TABD) and tail (TTAIL) temperatures were registered in these rats during submaximal exercise (SE) at 60% of maximal speed. Immediately after SE, rats were decapitated and concentrations of DA and 3,4-dihydroxyphenylacetic acid (DOPAC) were determined in the preoptic area (POA). In the second experiment, oxygen consumption was measured and mechanical efficiency (ME) was calculated in these rats during an incremental exercise. HP rats ran for longer periods and were fatigued with higher TABDvalues, with no difference in TTAIL. Nevertheless, thermoregulatory efficiency was higher in HP rats, compared with other groups. DA and DOPAC concentrations in the POA were increased by SE, with higher levels in HP compared with LP and SP rats. V̇o2also differed between groups, with HP rats displaying a lower consumption throughout the incremental exercise but a higher V̇o2at fatigue. ME, in turn, was consistently higher in HP than in LP and SP rats. Thus, our results show that HP rats have greater TABDvalues at fatigue, which seem to be related to a higher dopaminergic activity in the POA. Moreover, HP rats exhibited a greater thermoregulatory efficiency during exercise, which can be attributed to a lower V̇o2, but not to changes in tail heat loss mechanisms.NEW & NOTEWORTHY Our findings reveal that rats with higher intrinsic exercise capacities have greater thermoregulatory efficiencies and increased dopaminergic activity in the preoptic area, a key brain area in thermoregulatory control, while exercising. Moreover, higher intrinsic exercise capacities are associated with decreased oxygen consumption for a given exercise intensity, which indicates greater mechanical efficiencies. Collectively, these findings help to advance our knowledge of why some rats of a given strain can exercise for longer periods than others.

Com o objetivo de avaliar a qualidade dos ovos de consumo pela pesquisa dos níveis de aminas bioativas, foram coletados, pelos serviços de inspeção oficiais, 224 amostras de ovos provenientes de cinco regiões distintas do estado de Minas Gerais, durante o período de um ano. As aminas biogênicas (putrescina, cadaverina, feniletilamina, histamina e tiramina) e as poliaminas (espermidina e espermina) foram pesquisadas por cromatografia líquida de alta eficiência e detecção ultravioleta (CLAE/UV) após derivação pré-coluna com cloreto de dansila. Os resultados demonstraram que a putrescina estava presente, em baixas concentrações, em todas as amostras de gema e de albúmen. As demais aminas também foram detectadas, porém em menor frequência, e a espermina somente foi encontrada em uma amostra de albúmen. Foi concluído que os ovos de consumo produzidos no estado de Minas Gerais não são uma fonte considerável de poliaminas, importantes para o crescimento e a proliferação celular, e os baixos teores de aminas biogênicas, formadas pela descarboxilação de aminoácidos por enzimas bacterianas, não representam riscos à saúde do consumidor, o que indica que o ovo apresenta boa qualidade, tomando por base o critério de aminas bioativas. In order to evaluate the quality of commercial eggs by searching the bioactive amine levels, 224 samples of eggs from the five regions of Minas Gerais State were collected during one year by the official inspection service. The biogenic amines (putrescine, cadaverine, phenylethylamine, histamine and tyramine) and the polyamines (spermidine and spermine) were determined by high performance liquid chromatography with ultraviolet detection (HPLC/UV) and pre-column derivatization with dansyl chloride. The results demonstrated the presence of putrescine in all samples of yolk and albumen, but in low concentrations. The other amines were also detected, however, with a lower frequency, and spermine was found only in one sample of albumen. It was concluded that the commercial eggs produced in Minas Gerais State are not a considerable source of polyamines, important for growth and cell proliferation; and low levels of biogenic amine, formed by decarboxylation of amino acids by bacterial enzymes, do not represent risks to consumer health, indicating that it has good quality, based on the bioactive amine criterion.

Methylone (also known as bk-MDMA) is a substituted cathinone developed to elicit similar psychotropic effects as 4-methylenedioxymethamphetamine (MDMA, also known as ecstasy). Although methylone is a scheduled substance, its specific structural features means it generally cannot be detected and quantified using the same conditions commonly employed for ecstasy. This work therefore describes the development of an electroanalytical method for the selective quantification of methylone. This method uses an electropolymerized molecularly imprinted polymer (MIP) on the surface of screen-printed gold electrodes (SPAuEs), using 2-mercaptobenzimidazole (2-MBI) as the building monomer and methylone as the analyte template. The construction and optimization of the SPAuE-MIP sensor was studied, step-by-step, using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Additionally, the direct electrooxidation of methylone was investigated, and methylone-MIP interactions probed computationally. Ultimately, square-wave voltammetry (SWV) quantification of methylone using the SPAuE-MIP sensor was demonstrated to be both sensitive and selective. The electroanalytical determination showed suitable analytical parameters as: intra-day repeatability of 1.5%, a limit of detection (LOD) of 1.1 μmol L−1 (0.23 mg L−1) and a linear range up to 50 μmol L−1 (ca. 10 mg dL−1) with an r2 of 0.996, as well as much higher currents towards the analyte than similar compounds and commonly present interferents.

Selective hydrogenation of alkynes to alkenes and reductive amination are industrially important reactions to synthesize a variety of fine and bulk chemicals. We report herein on a green and convenient approach for Z-alkenes and secondary amines using gold catalyst and formic acid (FA) as a green reductant. Furthermore, we highlight that the key to successfully obtain high reaction rates is to use an appropriate amine, which acts cooperatively with the gold surface, to activate formic acid. Studies with deuterium-labeled hydrogen donors gave insights that the decomposition of Au-formate species is involved in the rate-determining step. Moreover, various valuable secondary amines could be synthetized from readily available nitro and carbonyl compounds. This new strategy provides a cleaner, safer, more efficient and selective way to catalyze the synthesis of Z-alkenes and valuable amines.

As concentrações plasmáticas das aminas triptamina (TRP), tyramina (TYR) e pheniletilamina (PEA) foram determinadas por cromatografia gasosa (CG) de 20 eqüinos sob efeito de sobrecarga por carboidratos (SC). Após 36h da SC os animais foram aleatoriamente divididos em quatro grupos (n=5) e receberam a cada 12h por via iv: solução salina 10mL (GC), ketoprofeno 2,2mg/kg (GK), fenilbutazona 4,4mg/kg (GF) e flunixin meglumine 1,1mg/kg (GFM). As concentrações das aminas TYR e PEA variaram de 0,18 a 164,2mg/L, com diferenças nos tempos avaliados, mas não entre os tratamentos (p

Two molecular receptors based on calix[4]arenes and their interaction with chlorophenoxy acid herbicides in solution and in the solid state have been investigated. From 1H NMR studies it is shown that the conformational changes of the receptor are directly related to the acid strength of the herbicide. Conductance data show that the interaction takes place through a proton transfer reaction from the herbicide to the receptor. This is also reflected in the solid state (X-ray crystallography). Based on these fundamental studies, these receptors were immobilised by grafting them into a silica based solid support. The extracting properties of calix[4]arene modified silica for these pollutants were investigated as a function of the pH of the aqueous solution and the capacities of these materials to remove these pollutants are reported. Titration calorimetry is for the first time explored to determine the factors (kinetics, mass/solution ratio and temperature) contributing to the optimal removal of herbicides from water. These materials can be easily recycled via a pH switching mechanism. After several recycling processes the extraction capacity of these materials remains at the level of 80–90% of the original value., Instituto de Física La Plata

Differential redox homeostasis in normal and malignant cells suggests that pro-oxidant-induced upregulation of cellular reactive oxygen species (ROS) should selectively target cancer cells without compromising the viability of untransformed cells. Consequently, a pro-oxidant deviation well-tolerated by nonmalignant cells might rapidly reach a cell-death threshold in malignant cells already at a high setpoint of constitutive oxidative stress. To test this hypothesis, we took advantage of a selected number of amine-pyridine-based Fe (II) complexes that operate as efficient and robust oxidation catalysts of organic substrates upon reaction with peroxides. Five of these Fe(II)-complexes and the corresponding aminopyridine ligands were selected to evaluate their anticancer properties. We found that the iron complexes failed to display any relevant activity, while the corresponding ligands exhibited significant antiproliferative activity. Among the ligands, none of which were hemolytic, compounds 1, 2 and 5 were cytotoxic in the low micromolar range against a panel of molecularly diverse human cancer cell lines. Importantly, the cytotoxic activity profile of some compounds remained unaltered in epithelial-to-mesenchymal (EMT)-induced stable populations of cancer stem-like cells, which acquired resistance to the well-known ROS inducer doxorubicin. Compounds 1, 2 and 5 inhibited the clonogenicity of cancer cells and induced apoptotic cell death accompanied by caspase 3/7 activation. Flow cytometry analyses indicated that ligands were strong inducers of oxidative stress, leading to a 7-fold increase in intracellular ROS levels. ROS induction was associated with their ability to bind intracellular iron and generate active coordination complexes inside of cells. In contrast, extracellular complexation of iron inhibited the activity of the ligands. Iron complexes showed a high proficiency to cleave DNA through oxidative-dependent mechanisms, suggesting a likely mechanism of cytotoxicity. In summary, we report that, upon chelation of intracellular iron, the pro-oxidant activity of amine-pyrimidine-based iron complexes efficiently kills cancer and cancer stem-like cells, thus providing functional evidence for an efficient family of redox-directed anti-cancer metallodrugs., This work was supported by grants from the Spanish Ministerio de Economia y Competitividad (MINECO), CONSOLIDER-INGENIO 2010 CSD2010-00065, and from the Ministerio de Ciencia e Innovacion (MICINN), SAF2012-38914, Plan Nacional de I+D+I.

This paper addresses the effects of the concentration of lipases, temperature and solvent on the enzymatic acetylation of primary amines. (±)-Heptan-2-amine 1, (±)-4-phenylbutan-2-amine 2, (±)-1,2,3,4-tetrahydronaphthalen-1-amine 3 and (±)-2-methylcyclohexan-1-amine 4 were acetylated using 11 lipases to obtain amides under orbital shaking and microwave radiation. Under microwave radiation the same amines were acetylated only using the CALB. (±)-Heptan-2-amine 1 was subjected to kinetic resolution, under orbital shaking for 7 h employing CALB and ethyl acetate as acylating agent, and converted into (R)-N- (heptan-2-yl)acetamide 5 (c = 42%, 88% ee

The novel [RuCl 2 (PPh 3 ) 2 (4-CH 2 R-pip)] complexes, with R = H (complex 1 ), Ph ( 2 ) or OH ( 3 ), were synthesized and applied as initiators for ROMP of norbornene (NBE) and norbornadiene (NBD) under different reaction times, temperatures and monomer concentrations. There is a clear difference in the homopolymer yields in the order 1 > 2 > 3 at [monomer]/[Ru] molar ratio of 5000, at 25 °C for 5–60 min. Difference in the yields tends to disappear at 50 °C, with quantitative yields for 15–30 min with any type of initiator. Results from copolymers obtained at RT for 60 min from fixed amounts of NBE with four different amounts of NBD suggest that the type of initiator also affects the reactions, with more insertion of NBD with 1 . The occurrence of cross-linking enhanced as the NBD loading increased, evidenced by decrease in the M c and increase in the T g values, besides the influence of the type of initiator.

El tratamiento de concentrados de molibdenita mediante ácido nítrico da lugar a disoluciones en las que, junto al molibdeno aparecen el cobre y el hierro como impurezas. El presente trabajo estudia la purificación de dichas disoluciones empleando la amina terciaria Alamine 336, la sal de amonio cuaternario Aliquat 336 o mezclas de ambos compuestos como agentes de extracción selectivos del molibdeno. La etapa de reextracción se lleva a cabo con disoluciones de hidróxido amónico, obteniéndose disoluciones de molibdato amónico que se pueden recircular al circuito principal de obtención del mismo, Los autores agradecen a la USACH (Chile) y al CSIC (España) la ayuda prestada para la realización •de este trabajo

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:29:48Z No. of bitstreams: 0 Made available in DSpace on 2014-05-27T11:29:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-07-01 This work describes the mutagenic response of Sudan III, an adulterant food dye, using Salmonella typhimurium assay and the generation of hazardous aromatic amines after different oxidation methods of this azo dye. For that, we used metabolic activation by S9, catalytic oxidation by ironporphyrin and electrochemistry oxidation in order to simulate endogenous oxidation conditions. The oxidation reactions promoted discoloration from 65% to 95% of Sudan III at 1×10-4molL-1 and generation of 7.6×10-7molL-1 to 0.31×10-4molL-1 of aniline, o-anisidine, 2-methoxi-5-methylaniline, 4-aminobiphenyl, 4,4'-oxydianiline; 4,4'-diaminodiphenylmethane and 2,6-dimethylaniline. The results were confirmed by LC-MS-MS experiments. We also correlate the mutagenic effects of Sudan III using S. typhimurium with the strain TA1535 in the presence of exogenous metabolic activation (S9) with the metabolization products of this compound. Our findings clearly indicate that aromatic amines are formed due to oxidative reactions that can be promoted by hepatic cells, after the ingestion of Sudan III. Considering that, the use of azo compounds as food dyestuffs should be carefully controlled. © 2013 Elsevier Ltd. Faculdade de Ciências Farmacêuticas de Ribeirão Preto Departamento de Análises Clínicas Toxicológicas e Bromatológicas Universidade de São Paulo, Avenida do Café, s/n, 14040-903 Ribeirão Preto, SP Instituto de Química Departamento de Química Analítica Universidade Estadual Paulista - UNESP, Rua Professor Francisco Degni, 55 Quitandinha, 14800-900 Araraquara, SP Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto Departamento de Química Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, SP Instituto de Química Departamento de Química Analítica Universidade Estadual Paulista - UNESP, Rua Professor Francisco Degni, 55 Quitandinha, 14800-900 Araraquara, SP

Na análise de leite por espectrometria de emissão ótica com plasma induzido (ICP-OES) o produto comercial CFA-C, constituído por aminas terciárias, vêm sendo usado com sucesso como diluente em fase única. Devido ao custo do produto e possibilidades de contaminação durante o armazenamento, decidiu-se desenvolver um outro reagente de propriedades equivalentes ao referido produto. Testes qualitativos mostraram que o produto não contém ácido bórico nem EDTA. Em uma titulação potenciométrica de uma solução aquosa 10% v/v CFA-C com HCl obtiveram-se dois picos potenciométricos e deduziu-se que 90% do ácido foi consumido para neutralização da amina livre e 10% foi gasto para protonar um ânion de ácido fraco usado para formar um tampão de razão molar 10:1, do tipo R3N/R3NH+. Em uma simulação desse reagente preparou-se uma solução 6,06 mol L-1 de monoetanolamina (MEA) e 0,20 mol L-1 ácido cítrico, triprótico, para formar um tampão do mesmo tipo, 10:1, baseado na propriedade do íon citrato em complexar Ca(II). Outro tampão citrato mais diluído (1,52 mol L-1) foi preparado usando trishidroximetilaminometano (TRIS), que é uma amina menos solúvel. Essas misturas foram caracterizadas por análise potenciométrica e termoanalítica. O comportamento desses novos tampões amina/citrato foi adequado e comparável ao produto comercial. Milk analysis can be successfully performed by dilution of samples with CFA-C, a commercial mixture of water-soluble tertiary amines, and measurements by inductively coupled plasma atomic emission spectrometry (ICP-OES). However, due to the costs of this reagent and contamination, the work here described investigated an alternative reagent that could be used instead of CFA-C. Qualitative analysis showed that the commercial mixture does not contain boric acid or EDTA. A potentiometric titration of a CFA-C 10% v/v aqueous solution using HCl as titrant showed two peaks and it was inferred that 90% of the acid was consumed for neutralization of free amines and the remaining 10% was consumed for protonation of an anion of a weak acid employed to generate a buffer R3N/R3NH+ with the molar ratio 10:1. For simulating the CFA-C reagent, it was prepared a solution containing 6.06 mol L-1 monoethanolamine (MEA) plus 0.20 mol L-1 citric acid, triprotic, to form a buffer 10:1. The citrate anion is a good chelating ligand for Ca(II). An other citrate buffer was prepared (1.52 mol L-1) using trishydroxymethylaminomethane (TRIS), which is an amine less soluble in water. These mixtures were characterized by potentiometric and thermal analysis. Both amine/citrate buffers presented a performance comparable to the commercial reagent.

6 páginas, 4 tablas., [ES] En estudios previos se llevó a cabo la deteoeion de oempuestos de interacción a través de sus propiedades fluorescentes a distintos máximos de excitación/emisión durante el procesamiento de pescado, observándose un desplazamiento de la fluorescencia a longitudes de onda mayores como resultado del incremento de la alteración. En el presente trabajo se chequearon distintos tipos de aldehidos al objeto de comparar su capacidad para formar compuestos fluorescentes de distintas longitudes de onda en relación con el procesamiento de pescado. Dichos aldehidos (formaldehido, FA; acetaldehido, AcH; propanal, Pr; hexanal, Hex; 2-hexenal, Hx; benzaldehido, BzH) se hicieron reaccionar con músculo de sardina (Sardina pilchardus) desmenuzada y con n-propilamina a 30°C en oscuridad durante 25 días. Con el aumento del tiempo de reacción, todos los aldehidos estudiados mostraron capacidad para producir un desplazamiento a mayores longitudes de onda de la fluorescencia detectada. Sin embargo se observaron distintas aptitudes, de acuerdo con la estructura y la reactividad de cada aldehido. El desplazamiento fue especialmente pronunciado en los casos de Hx y AcH, mientras que fue bastante pequeño con FAy BzH. En una situación intermedia se situaron Pr y Hex, en los que al igual que durante la alteración de pescado, se observó un incremento en la relación entre las fluorescencias detectadas a 393/463 nm y 327/415 nm al avanzar el tiempo de reacción., [EN] In previous studies interaction compounds formation was accomplished by fluorescence detection at different excitation/ emission wavelength maxima during fish processing. Afluorescence shift towards higher wavelength maxima was then obtained as a result of damage increase. In the present work, different aldehydes were tested in order to compare their ability in producing fluorescent compounds with similar properties to the ones obtained during fish processing. Aldehydes (formaldehyde, FA; acetaldehyde, AcH; propanal, Pr; hexanal, Hex; 2-hexenal Hx; benzaldehyde, BzH) were reacted in model systems with sardine (Sardina pilchardus) muscle and with n-propylamine at 30°C in dark during 25 days. Afluorescence shift was detected for all the aldehydes investigated as long as the reaction time increased. Great differences were observed between aldehydes, according to their chemical structure and reactivity. A sharp shift was detected for Hx and AcH, while little changes were observed in the cases of FA and BzH. As in the case of fish processing, Pr and Hex showed an increasing ratio between fluorescences detected at 393/463 nm and 327/415 nm as long as the reaction time increased., Agradecemos a la Xunta de Galicia la ayuda financiera otorgada (Proyecto FAIR (CEE) CT 95-111).

The possibility of crystallization of ZSM-5 with high Si/Al ratio was evaluated through the combined use of crystallization seeds and organic compounds that are not conventional directing agents for ZSM-5 (ethanol, methylamine, ethylamine, propylamine, butylamine, isopropylamine and diethylamine) in order to find a less toxic and costly route of synthesis. In addition, the influence of the stirring during the crystallization step on the properties of the ZSM-5 obtained in these synthesis conditions was verified. The obtained zeolites were analyzed by X-ray diffractometry in order to understand the effects of the templates. The analyses of NH3-TPD, nitrogen adsorption, SEM, and TG/DTA were performed for the samples with better crystallinity. The procedure was successfully employed for the synthesis of MFI samples using propylamine as an alternative structure-directing agent. Its mean crystallite size ranged from 23 to 24 nm and was efficient in the cracking reaction of n-hexane. Resumo A possibilidade de cristalização da ZSM-5 com alta razão Si/Al foi avaliada através do uso combinado de sementes de cristalização e compostos orgânicos que não são direcionadores convencionais da ZSM-5 (etanol, metilamina, etilamina, propilamina, butilamina, isopropilamina e dietilamina) a fim de encontrar uma rota de síntese menos tóxica e cara. Adicionalmente foi verificada a influência da agitação durante a etapa de cristalização sobre as propriedades da ZSM-5 obtida nessas condições de síntese. As zeólitas obtidas foram analisadas por difratometria de raios X para entender os efeitos dos direcionadores. As análises de NH3-TPD, adsorção de nitrogênio, MEV e TG/DTA foram realizadas para as amostras com melhor cristalinidade. O procedimento foi empregado com sucesso para a síntese de amostras de MFI usando propilamina como agente direcionador de estrutura alternativo. Seu tamanho médio de cristalito variou de 23 a 24 nm e foi eficiente na reação de craqueamento do n-hexano.