Estudo cinético da degradação térmica e catalítica de petróleo pesado usando Al-MCM-41

The mesoporous nanostructured materials have been studied for application in the oil industry, in particular Al-MCM-41, due to the surface area around 800 to 1.000 m2 g-1 and, pore diameters ranging from 2 to 10 nm, suitable for catalysis to large molecules such as heavy oil. The MCM-41 has been synthesized by hydrothermal method, on which aluminum was added, in the ratio Si/Al equal to 50, to increase the generation of active acid sites in the nanotubes. The catalyst was characterized by X-ray diffraction (XRD), surface area by the BET method and, the average pore volume BJH method using the N2 adsorption, absorption spectroscopy in the infrared Fourier Transform (FT-IR) and determination of surface acidity with application of a probe molecule - n-butylamine. The catalyst showed well-defined structural properties and consistent with the literature. The overall objective was to test the Al-MCM-41 as catalyst and thermogravimetric perform tests, using two samples of heavy oil with API º equal to 14.0 and 18.5. Assays were performed using a temperature range of 30-900 ° C and heating ratios (β) ranging from 5, 10 and 20 °C min-1.The aim was to verify the thermogravimetric profiles of these oils when subjected to the action of the catalyst Al- MCM-41. Therefore, the percentage ranged catalyst applied 1, 3, 5, 10 and 20 wt%, and from the TG data were applied two different kinetic models: Ozawa-Flynn-Wall (OFW) and Kissinger-Akahrira-Sunose (KAS).The apparent activation energies found for both models had similar values and were lower for the second event of mass loss known as cracking zone, indicating a more effective performance of Al-MCM-41 in that area. Furthermore, there was a more pronounced reduction in the value of activation energy for between 10 and 20% by weight of the oil-catalyst mixture. It was concluded that the Al-MCM-41 catalyst has applicability in heavy oils to reduce the apparent activation energy of a catalyst-oil system, and the best result with 20% by weight of Al-MCM-41

Differences in mushroom bodies morphogenesis in workers, queens and drones of Apis mellifera: Neuroblasts proliferation and death

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Classification of basis states for (p-f)-nuclei (41 <= A <= 80) with minimal configuration energy

We give a complete classification of basis with unitari (U(A-1), U(3)) and permutational (S)A)) symmetries. Thse are suitable as functions for (p-f)- nuclei (41<= A <= 80) with minimal configuration energy. We also give a brief survey of way in which are obtained.

Production of biodiesel by esterification of palmitic acid over mesoporous aluminosilicate Al-MCM-41

Biodiesel has been obtained by esterification of palmitic acid with methanol, ethanol and isopropanol in the presence of Al-MCM-41 mesoporous molecular sieves with Si/Al ratios of 8.16 and 32. The catalytic acids were synthesized at room temperature and characterized by atomic absorption spectrometry (AAS), thermal analysis (TG/DTA), X-ray diffraction (XRD), nitrogen absorption (BET/BJH), infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The reaction was carried out at 130 degrees C whilst stirring at 500 rpm, with an alcohol/acid molar ratio of 60 and 0.6 wt% catalyst for 2 h. The alcohol reactivity follows the order methanol > ethanol > isopropanol. The catalyst Al-MCM-41 with ratio Si/Al = 8 produced the largest conversion values for the alcohols studied. The data followed a rather satisfactory approximation to first-order kinetics. (C) 2008 Elsevier Ltd. All rights reserved.

Preparation of different basic Si-MCM-41 catalysts and application in the Knoevenagel and Claisen-Schmidt condensation reactions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of the catalyst MCM-41 on the kinetic of the thermal decomposition of poly(ethylene terephthalate)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Photoelectrocatalytical degradation of basic blue 41 dye using nanoporous semiconductor of Ti/TiO2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermogravimetric investigations during the synthesis of silica-based MCM-41

MCM-41 material was synthesized starting from hydrogel containing colloidal fumed silica, sodium silicate, cetyltetramethylammonium bromide (CTMABr) as surfactant, and distilled water as solvent. These reactants were mixed to obtain a gel with the following composition: 4SiO(2):1Na(2)O:1CTMABr:200H(2)O. The hydrogel with pH=14 was hydrothermally treated at 100 degreesC, for 4 days. Each day, the pH was measured, and then adjusted to 9.5-10 by using 30% acetic acid solution. Thermogravimetry was the main technique, which was used to monitor the participation of the surfactant on the MCM-41 nanophase, being possible to determine the temperature ranges relative to water desorption as well as the surfactant decomposition and silanol condensation.

Kinetic evaluation of the pyrolysis of high density polyethylene over H-AlMCM-41 material

The AlMCM-41 material with Si/Al=50 was synthesized by hydrothermal method, using cethyltrimethylammonium as template. The protonic H-AlMCM-41 acid form was obtained by ion exchange with ammonium chloride solution and subsequent calcination. The characterization of the material by several techniques showed that a good-quality MCM-41 material was obtained. High-density polyethylene (HDPE) has been submitted to thermal degradation alone, and in presence of the exchanged H-AlMCM-41 catalyst at a concentration of 1: 1 in mass (H-AlMCM-41/HDPE). The reactor was connected on line to a gas chromatograph connected to a mass spectrometer. This process was evaluated by thermogravimetry (TG), from 350 to 600degreesC, under helium dynamic atmosphere, with heating rates of 5.0; 10.0 and 20.0 degreesC/min. From TG curves, the activation energy, calculated using a multiple heating rate integral kinetic method, decreased from 225.5 KJ.mol(-1), for the pure polymer (HDPE), to 184.7 KJ.mol(-1), in the presence of the catalyst (H-AlMCM-41/HDPE).

Oxidative Stress Impairs Vasorelaxation Induced by the Soluble Guanylyl Cyclase Activator BAY 41-2272 in Spontaneously Hypertensive Rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PREVENCAO DE TROMBOFLEBITES PELO USO DE HEPARINA EM PACIENTES TRATADOS COM ANFOTERICINA B

The authors studied the incidence of thrombophlebitis in 41 patients treated intravenously with amphotericin B. The patients were divided in two different group: Group 1: patients treated with amphotericin B and hydrocortisone with heparin (1000 UI); Group 2: patients treated with amphotericin B and hydrocortisone. The results showed 23.81% of incidence of thrombophlebitis in Group 1 and 90% in Group 2. Thrombophlebitis in Group 1 ranged from mild to moderate without any change during the drug therapy. In Group 2, the incidence was 66.67% and the thrombophlebitis were severe being necessary the withdrawn of the drugs in 35.0% of the cases. We concluded that heparin, in low doses, in association with amphotericin B, was an efficient drug preventing or reducing the development of thrombophlebitis.

PLANINDEX: 41-001

Contiene resumenes bibliograficos de documentos sobre planificacion y desarrollo en America Latina, recogidos y procesados en el marco del Sistema de Informacion para la Planificacion en America Latina y el Caribe (INFOPLAN).

Induction pegylated interferon Alfa-2a and high dose ribavirin do not increase SVR in heavy patients with HCV genotype 1 and high viral loads

Background & Aims Patients infected with hepatitis C virus (HCV) genotype 1, body weight <85 kg, and high baseline viral load respond poorly to standard doses of pegylated interferon (peginterferon) and ribavirin. We evaluated intensified therapy with peginterferon alfa-2a plus ribavirin. Methods This double-blind randomized trial included HCV genotype 1-infected outpatients from hepatology clinics with body weight <85 kg and HCV RNA titer <400,000 IU/mL. Patients were randomized to 180 μg/wk peginterferon alfa-2a for 48 weeks plus 1200 mg/day ribavirin (standard of care) (group A, n = 191) or 1400/1600 mg/day ribavirin (group B, n = 189). Additional groups included 360 μg/wk peginterferon alfa-2a for 12 weeks then 180 μg/wk peginterferon alfa-2a for 36 weeks plus 1200 mg/day ribavirin (group C, n = 382) or 1400/1600 mg/day ribavirin (group D, n = 383). Follow-up lasted 24 weeks after treatment. Results Sustained virologic response rates (HCV RNA level <15 IU/mL at end of follow-up) in groups A, B, C, and D were 38%, 43%, 44%, and 41%, respectively. There were no significant differences among the 4 groups or between pooled peginterferon alfa-2a regimens (A + B vs C + D: odds ratio [OR], 1.08; 95% confidence interval [CI], 0.831.39; P = .584) or pooled ribavirin regimens (A + C vs B + D: OR, 1.00; 95% CI, 0.791.28; P = .974). Conclusions In patients infected with HCV genotype 1 who are difficult to treat (high viral load, body weight <85 kg), a 12-week induction regimen of peginterferon alfa-2a and/or higher-dose ribavirin is not more effective than the standard regimen. © 2010 AGA Institute.