Catalisadores de paladio suportados na hidrogenação seletiva de hexadienos em fase liquida : efeito da adição de estanho e prata

Orientador: Mario de Jesus Mendes, François Bozan-VerdurazTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica e Universite de Paris 7-Denis DiderotResumo: Foram preparados por impregnação difusional dez catalisadores à base de paládio, paládio-estanho e paládio-prata, suportados em alumina e óxido de titânio, para uso na hidrogenação seletiva de hexa-I,3-dieno e de hexa-I,5-dieno, em fase líquida. Foram utilizadas várias técnicas físico-químicas para caracterizar tanto as soluções iniciais cqmo os sólidos obtidos durante os vários estágios da preparação. As espécies identifícadas evidenciaram a existência de interações entre os precursores e os suportes durante a impregnação e a secagem...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digitalAbstract: Ten palladium, palladium-tin and palladium-silver based catalysts, supported on alumina and titania, were prepared by diffusional impregnation for using in the selective hydrogenation of hexa-l,3-diene and hexa-l,5-diene, in liquid phase. Both the starting solutions and the solids obtained during all stages of the preparation step were characterized by several physical-chemical techniques. The identified species showed that precursor-support interactions take place during impregnation and drying...Note: The complete abstract is available with the full electronic digital thesis or dissertationsDoutoradoDoutor em Engenharia Químic

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Biogasoline Obtained Using Catalytic Pyrolysis of <i>Desmodesmus</i> sp. Microalgae: Comparison between Dry Biomass and n-Hexane Extract

The present work deals with the production of hydrocarbons in the C5–C12 range obtained from the fast micropyrolysis of a laboratory-grown Desmodesmus sp. microalgae. It compares the properties of this specific fraction of hydrocarbons using or not using transition alumina catalysts during pyrolysis in experiments with both pure dried microalgae and its n-hexane extract. The microalgae were characterised using thermogravimetry (TG) and CHN analysis; the n-hexane extract was analysed through Fourier transform infrared spectroscopy (FTIR). The pyrolysis experiments were performed in a multi-shot pyrolyser connected online with a gas chromatograph coupled to a mass spectrometer (GC/MS). The composition of the C5–C12 fraction was compared to that of an industrial pyrolysis gasoline. The results of pyrolysis at 600 °C show that the alumina catalyst increases the quantity of C5–C12 hydrocarbon families when compared to purely thermal pyrolysis, representing about 40% of all the dry microalgae pyrolysis products. In the case of n-hexane extract, the C5–C12 area fraction corresponds to 33.5% of the whole products’ area when pyrolysis is conducted with an alumina catalyst. A detailed analysis shows that linear molecules, mainly unsaturated, are predominant in the products. Dry biomass formed more aromatic but less cyclic and alkylated molecules in relation to the n-hexane extract. Nitrogen products, essentially alkylated pyrroles, were produced in large quantities when dry biomass was used but were below the detection limit when pyrolysing the extracts. Thus, the extraction with hexane proved to be an effective way to remove nitrogen compounds, which are undesirable in fuels. The estimated low heating values of the present C5–C12 pyrolysis hydrocarbon fractions (between 43 and 44 MJ/kg) are quite comparable to the reported values for reformulated and conventional industrial gasolines (42 and 43 MJ/kg, respectively)

Prospecção‌ ‌Tecnológica‌ ‌de‌ ‌Patentes‌ ‌Sobre‌ ‌Cultivos‌ ‌de‌ ‌Microalgas‌ ‌Visando‌ ‌à‌ ‌Produção‌ ‌de‌ ‌ Biodiesel‌ ‌

The unsustainable model of intensive use of fossil fuels has driven the development of research on obtaining cleaner and more financially viable alternatives such as biodiesel produced from the biomass obtained through the cultivation of microalgae. This research carried out a prospective study of patents on the cultivation of microalgae for the production of biodiesel using the Code of Cooperative Patent Classification System (CCP), C12N1/12 combined with C12P7/649, as the best search strategy, resulting in a total of 309 patents, grouped in 103 families. The results confirm that this technology is developing rapidly. The greatest number of patent deposits and depositors were from the United States of America, China and South Korea, with the great majority of deposits still being made by individual depositors.O modelo insustentável do uso intensivo de combustíveis fósseis tem impulsionado o desenvolvimento de pesquisas cujo objetivo prioritário é a obtenção de alternativas mais limpas e financeiramente viáveis. Dentre essas alternativas, insere-se o biodiesel produzido a partir da biomassa obtida mediante o cultivo de microalgas. Essa pesquisa realizou um estudo prospectivo de patentes sobre o cultivo de microalgas para a produção de biodiesel utilizando o código do Sistema Cooperativo de Classificação de Patentes (CCP), C12N1/12 combinado com C12P7/649, como melhor estratégia de busca, chegando a um total de 309 patentes, agrupadas em 103 famílias. Os resultados refletiram que essa tecnologia se encontra em plena difusão, havendo maior número de depósitos e depositantes nos Estados Unidos da América, China e Coreia do Sul, e que os principais depositantes ainda são as pessoas físicas.

Prospecção Tecnológica de Patentes a Respeito da Produção de Diesel Verde a partir de Microalgas com Catalisadores de Nióbio por Pirólise Rápida

In recent periods microalgae have been investigated as a source of raw material to produce biofuels, due to their high productivity, high lipid content and ability to grow in a wide variety of climates and spaces without competing with food production. This work aims to identify the patents related to the production of green diesel from microalgae using pyrolysis processes and niobium-based catalysts. For this, a search was conducted in the database - Espacenet followed by the National Institute of Industrial Property (INPI), for codes indexed in the International Patent Classification (CIP). The results show that technologies using rapid pyrolysis and niobium catalysts to transform lipids from microalgae into green fuels are non-existent, which may justify a study in the area.Nos dias de hoje, as microalgas vêm sendo investigadas como fonte de matéria-prima para produzir biocombustíveis devido à sua alta produtividade, ao elevado teor lipídico e à capacidade de crescer em uma grande variedade de climas e de espaços, sem competir com a produção de alimentos. Este trabalho tem como finalidade identificar as patentes referentes à produção de diesel verde a partir de microalgas, empregando catalisadores de nióbio no processo de pirólise. Para isso, foi realizada uma pesquisa nos bancos de dados Espacenet e Instituto Nacional da Propriedade Industrial (INPI), por meio de códigos indexados na Classificação Internacional de Patentes (CIP). Os resultados mostram que não foram encontradas tecnologias usando pirólise rápida e catalisadores de nióbio para transformar os lipídios de microalgas em combustíveis verdes, o que pode justificar a necessidade de um estudo na área

Physical Chemistry Chemical Physics

p. 491-498Palladium, palladiumÈtin and palladiumÈsilver catalysts, supported on two alumina samples with di erent acidity, have been prepared by di usional impregnation for use in the selective hydrogenation of hexa-1,5- diene and hexa-1,3-diene in the liquid phase. UVÈVISÈNIR (transmission and di use reÑectance) studies of the palladium starting solutions and of the solids obtained during all preparation stages (impregnation, drying, calcination) show that the nature of the supported precursor species depends on the acidity of the alumina. Palladium tetrachloropalladate (strongly bound anionic species) are predominant on the more acidic alumina while the more basic one favours the formation of weakly bound neutral complexes through exchange of chloride ligands with hydroxy groups and water. The nature of these species inÑuences not only the particle size of monometallic Pd samples (the stronger the interaction, the smaller the metal particle size), but also the nature of the Ðnal bimetallic PdÈAg catalysts ; a PdÈAg solid solution is observed on the bimetallic catalyst prepared by interaction of a cationic Ag precursor with supported PdCl whereas interaction with neutral 42~, Pd species leads to separate metal phases. The interaction of Sn precursor solutions with supported PdII species induces the formation of heteronuclear species which decompose upon drying; Pd or phases 2Sn Pd3Sn are detected on the Ðnal catalysts, depending on the initial Pd/Sn ratio and on the nature of the Sn precursor solvent (using ethanol favours the formation of Pd3Sn)

Identification of Cyanobacteria and Its Potential Toxins in the Joanes I Reservoir, Bahia, Brazil

The Joanes I Reservoir is responsible for 40% of the drinking water supply of the Metropolitan Region of Salvador, Bahia, Brazil. For water sources such as this, there is concern regarding the proliferation of potentially toxin-producing cyanobacteria, which can cause environmental and public health impacts. To evaluate the presence of cyanobacteria and their cyanotoxins in the water of this reservoir, the cyanobacteria were identified by microscopy; the presence of the genes of the cyanotoxin-producing cyanobacteria was detected by molecular methods (polymerase chain reaction (PCR)/sequencing); and the presence of toxins was determined by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The water samples were collected at four sampling points in the Joanes I Reservoir in a monitoring campaign conducted during the occurrence of phytoplankton blooms, and the water quality parameters were also analysed. Ten cyanobacteria species/genera were identified at the monitoring sites, including five potentially cyanotoxin-producing species, such as Cylindrospermopsis raciborskii, Cylindrospermopsis cf. acuminato-crispa, Aphanocapsa sp., Phormidium sp., and Pseudanabaena sp. A positive result for the presence of the cylindrospermopsin toxin was confirmed at two sampling points by LC-MS/MS, which indicated that the populations are actively producing toxins. The analysis of the PCR products using the HEPF/HEPR primer pair for the detection of the microcystin biosynthesis gene mcyE was positive for the analysed samples. The results of this study point to the worrisome condition of this reservoir, from which water is collected for public supply, and indicate the importance of the joint use of different methods for the analysis of cyanobacteria and their toxins in reservoir monitoring