Daniela Gonçalves de Abreu

Supported iron(III)porphyrins pentafluorophenyl-derivatives as catalysts in epoxidation reactions by H2O2: the role of the silica-support and sulfonatophenyl residues in the activation of the peroxidic bond

Abstract Ionic Fe(III)porphyrins pentafluorophenyl-derivatives: 5,10,15-tris(pentafluorophenyl)-20-(4- N -methylpyridyl)porphyrin iron(III) ([Fe{M(4- N -MePy)TPFP}] 2+ ), 5,10,15-tris(4- N -methylpyridyl)-20-(pentafluorophenyl)porphyrin iron(III) ([Fe{T(4- N -MePy)MPFP}] 4+ ) and 5,10,15-tris(pentafluorophenyl)-20-(3-sulfonatophenyl)porphyrin iron(III) ([Fe{M(3-SO 3 P)TPFP}]) immobilised on silica gel (SiO 2 ) and modified silica with sulfonatophenyl (SiSO 3 − ), propylimidazole (IPG), sulfonatophenyl plus propylimidazole (SiSO 3 − (IPG)), propyltrimethylammonium (SiN + ) and propyltrimethylammonium plus propylimidazole (SiN + (IPG)) were studied in the epoxidation of ( Z )-cyclooctene by H 2 O 2 . The better yields of product, cis -epoxycyclooctane, were achieved with the catalytic systems, [Fe{M(4- N -MePy)TPFP}]-SiSO 3 (IPG), [Fe{M(3-SO 3 P)TPFP}]-IPG and [Fe{M(3-SO 3 P)TPFP}]-SiO 2 , where is more probable to have available sulfonatophenyl groups. That is, where there is no ionic binding Fe(III)porphyrin-support via sulfonatophenyl. A charge effect supplied by the available sulfonatophenyl residues and a more polar microenvironment provided by the silica-support promote the heterolytic cleavage of the OO bond, which is essential to obtain high yields of products in oxidation reactions. Effects of general acid–base catalysis, as occurs in enzymes, and higher reduction potential provided by electron-withdrawing groups, present on porphyrin ring or axial ligand, as recently reported by Nam and coworkers for homogeneous Fe(III)porphyrins, to promote the heterolysis of the OO bond are ruled out.

Uma proposta para o ensino da Química Analítica Qualitativa

In recent years, because of the need for a more flexible curriculum established by the Curriculum Guidelines of the National Brazilian Education (law 9394/96), the pedagogical project of the Chemistry course of FFCLRP/USP has undergone alterations, amongst them the gradual reduction of the hours devoted to the discipline Qualitative Analytical Chemistry. In this context, this discipline has been carefully analyzed and reorganized in order to allow the elimination of redundancies and the introduction of activities considered important for the professional formation of both chemists and chemistry teachers. In this work, we will discuss the main strategies adopted in this reorganization with the objective of making the teaching/learning process more dynamic and efficient.

Um panorama sobre a abordagem ambiental no currículo de cursos de formação inicial de professores de química da região sudeste

This work analysed the contents of 701 disciplines from 22 chemistry courses that prepare chemistry teachers in 16 public Universities in Southeastern Brazil. Only a small number (23) of disciplines showed an explicit relationship between human activities and the environment. A total of 11 theoretical and 193 experimental disciplines explored to some extent scientific and technological aspects related to the environment, but did not include their relationship with society. As the experimental disciplines supposedly include some kind of waste treatment, this may explain why secondary school chemistry teachers work mainly on recycling programs and waste issues at their schools. The aim of this work is to provide information on which to base a much needed discussion about how to better prepare our chemistry teachers to act as Environmental Educators at school, as the Brazilian Education Legislation requires.

Construção de instrumentos teórico-metodológicos para captar a formação de professores

Research on the profile of environmental educators has required a research methodology appropriate for capturing their training process. Since when researching teacher education we are before something that is not materially established and is dynamic, how can one take the training of environmental educators as a research object? To construct an answer to this question, this study required theoretical and methodological tools that enabled grasping the training of teachers in their educational activities. The training of environmental educators requires an environment in which everyone has a voice and can share experiences, review their knowledge and produce new meanings from a critical perspective. The creation of a learning community in a public school established a favorable context for teacher education. We confirmed that, if planned and organized, Horario de Trabalho Pedagogico Coletivo (Collective Pedagogical Worktime) can intentionally contribute to teacher education. Activity theory offered resources both from the point of view of teaching, by providing a basis for the organization of meetings with secondary school teachers, always taking into account the intentionality of training, and from the methodological point of view, by allowing us to grasp our object, that is, the training process in its movement. In the interaction between subjects, they were able to expand their views and there were changes of meanings related to environmental issues. When evoking a thought, a reflection, a subject enables the others to revisit their positions and knowledge. Thus, knowledge is formed with new quality and so are individuals.