Adriana Maria Bernardes da Silva

Hydrogenation of oleic acid over ruthenium catalysts

Abstract The performance of ruthenium-tin catalysts for the liquid phase selective hydrogenation of oleic acid to unsaturated alcohols has been investigated. Titania-supported ruthenium and ruthenium-tin catalysts prepared by conventional impregnation as well as alumina-supported sol–gel ruthenium and ruthenium-tin catalysts have been used. The hydrogenation over the monometallic ruthenium catalysts leads primarily to the saturated stearic acid, which is then consecutively hydrogenated to the saturated stearyl alcohol. The titania-supported monometallic ruthenium catalyst shows a greater activity than the alumina-supported sol–gel one for the hydrogenation of oleic acid to the saturated stearyl alcohol. The hydrogenation over the bimetallic ruthenium-tin catalysts is characterized by the near total suppression of the hydrogenation of the olefine bond in favor of the activation of the hydrogenation of the carboxylic bond, thus leading to the selective formation of unsaturated alcohols. Besides, these catalysts are active for the cis–trans isomerization reaction of the oleic acid to elaidic acid, in competition with the hydrogenation of the carboxylic group. The impregnated titania-supported ruthenium-tin catalyst shows a better performance than the alumina-supported sol–gel ruthenium-tin catalyst for the selective hydrogenation of oleic acid to unsaturated alcohols.

Hydrogenation of citral over ruthenium-tin catalysts

Citral was chosen to probe the kinetic behavior of the hydrogenation of ,-unsaturated aldehydes over HTR and LTR titania-supported Ru-Sn catalysts. The catalysts were prepared by coimpregnation with ethanolic solutions of RuCl 3 and SnCl2 and characterized using temperature-programmed reduction (TPR). The reaction was studied in a liquid phase semi-batch reactor at 399 K and a hydrogen pressure of 5 MPa. The global activity for the citral hydrogenation of HTR Ru-Sn/TiO2 catalysts as well as the selectivity to the unsaturated alcohols of both LTR and HTR Ru-Sn/TiO2 increased with the Sn/Ru atomic ratio, reaching a maximum at a value of Sn/Ru ∼ 0.2. This suggested a promotion of the CO bond hydrogenation by particular bimetallic Sn-Ru ensembles. Besides, while for Sn/Ru ≤ 0.1 the support effect of titania dominated, for higher values of the atomic ratio the performance of the catalysts was controlled by the promoter effect of tin. A combined effect of the support titania with the promoter tin was clearly detected.

Círculos de Informações, Urbanização e Usos do Território Brasileiro

Este artigo apresenta alguns resultados da pesquisa intitulada circulos globais de informacoes e usos do territorio brasileiro. Temos investigado grandes empresas produtoras de informacoes, tais como firmas de consultoria em gestao, agencias de publicidade e de pesquisa de opiniao, operadores logisticos, agencias de noticias, agencias de rating, entre outras. Sao grandes empresas, em geral transnacionais, que controlam, nos setores respectivos, a producao e a difusao (seletiva e hierarquica) das informacoes. Nos anos 1990, ocorreu acentuada concentracao de capital nestes setores economicos, formando-se verdadeiros monopolios da informacao. Trata-se de profissoes, atividades, empresas, circuitos e circulos de informacoes pouco reconhecidos e insuficientemente avaliados do ponto de vista dos respectivos rebatimentos para a reorganizacao, os usos e a regulacao do territorio brasileiro. Pretendemos com esta pesquisa problematizar o atual alargamento dos contextos da globalizacao na formacao socioespacial brasileira. Palavras-chave: Territorio brasileiro, Empresas de informacao, Urbanizacao. Abstract This article presents some of the results of the global information circles and uses of the Brazilian territory research. We have been investigating big information generating companies, such as management consulting firms, advertising and opinion research agencies, logistic operators, news agencies, rating agencies, among others. These are big companies, usually multinational corporations, that control, in their respective sectors, the production and the (selective and hierarchical) diffusion of information. In the 1990s there was a sharp capital concentration in these economic sectors, forming actual information monopolies. It is professions, activities, companies, circuits and circles that are not well acknowledged and not sufficiently evaluated in terms of their respective aftermath for the reorganization, the use and the regulation of the Brazilian territory. With this research, we intend to discuss the current enlargement of the globalization contexts in the Brazilian sociospacial formation. Key words: Brazilian territory, Information companies, Urbanization. Resumen Este articulo presenta algunos resultados de la investigacion titulada circulos globales de informaciones y usos del territorio brasileno. Se han investigado grandes empresas productoras de informacion, tales como firmas de consultoria en gestion, agencias de publicidad y de investigacion de opinion, tambien, operadores logisticos, agencias de noticias y agencias de rating, entre otras. Son grandes empresas, en general transnacionales, que controlan, en los sectores respectivos, la produccion y difusion (selectiva y jerarquica) de la informacion. En los anos 1990, hubo una gran concentracion de capitales en estos sectores economicos, conformando verdaderos monopolios de informacion. Se trata de profesiones, actividades, empresas, circuitos y circulos de informacion poco reconocidos e insuficientemente evaluados desde el punto de vista de los respectivos rechazos para la reorganizacion, los usos y la regulacion del territorio brasileno. Pretendemos con esta investigacion problematizar la actual ampliacion de los contextos de la globalizacion en la formacion socio-espacial brasilena. Palabras claves: Territorio brasileno, Empresas de informacion, Urbanizacion.