964 resultados para undergraduate organic chemistry teaching


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Modern society is characterized by being in evolution finds, technology strides and every day becomes the setting in which we live. At school, however, we found no features of these changes, the years pass and the methodological tools remain unchanged. In this paper we analyze an object produced by the Learning Network Interactive Virtual Education - RIVED to discuss whether it covers the content and answers to the questions proposed by the National Curricular and Curricular Proposal of the State of Sao Paulo, and may be inserted in the educational environment, both to perform a qualitative analysis, focusing on information retrieval. The results showed that the Learning Objects: Abundance, has most of the proposals relating to the subject of study, prepared by the NCP and the Proposed Structure for the State of Sao Paulo, so it is valid for teachers to use this tool trying that with a new approach, we can give students a better understanding of chemical concepts

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This work presents results of art state that searched articles to bring in its wake the relationship between Teaching of Chemistry (TC), Environmental Education (EE) and the Teaching of Chemistry directed from the Science Technology and Society (STS) standpoint. The research was carried by articles surveying in major magazines Brazilian Environmental Education and a reference in the research magazine of Science Education, being performed a qualitative analysis of those items that were identified. It was noted that little is produced on the subject of interest within this field, in mid-1998 to June 2012. In the articles analyzed did not find a perspective that allied relationship STS and EE, or EE, STS and TC. Nine articles were found in relation EE and TC, and TC and three articles STS, constituting two thematic axes: Relationship between Environmental Education and the Teaching of Chemistry and Relationship between Science and Technology Society and Chemistry Teaching, The discussion was given from the contents that comprised the categories created. The first axis involved: a) Teacher of Chemistry and EA b) Contents of Chemistry and EE, and c) Concepts and practices of EE Chemistry teachers. The second axis of the categories are: a) formative processes and conceptions of chemistry teachers in STS: b) Analysis of TC practice focusing STS. There were works produced by the same authors, who mostly used the same theme in different magazines for publication only changing the perspective of analyzing the results. Finally, a scenario indicates that restricted thematic research and the need to advance with future work

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This paper describes the main phases of development of an Institute of Chemistry in relation with national policy from the academic field. Its history begins with a proposal to meet the demand for chemistry teacher education and goes on to become a major center for research, education and extension. Throughout its 50 years of history, the Institution has faced numerous challenges by adopting strategies that have established and revealed its institutional habitus. To this end, we use some of René Kaës’s concepts about the development of groups and institutions, highlighting mainly the origins, expectations and covenants that underpinned its foundation, and the entire process of its expansion and institutionalization. Our main focus, also interpreted based on the theory of Pierre Bourdieu and followers, is the establishment of its institutional habitus, i.e., how it interprets and organizes its institutional teaching, research and extension activities within the context of the academic field. The peculiarity of the process has been the mismatch between internal and external pressures. Even though presenting the results of a case study, in general, our methodology can improve the understanding of institution’s development in relation with educational policy.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The lack of motivation and the excessive quantity of subject memorization are some of the main causes for the disinterest of students when learning chemistry. To change this scene, it's necessary that the teachers reinvent themselves and innovate during their classes, making use of alternative methodologies for the chemistry teaching process. The objectives of this work are to evaluate, from a constructive methodology approach, the characteristics, possibilities and limitations of some techniques and methods of teaching. This analysis allowed to present the results in the form of a table summarizing these characteristics and can be useful for teachers to choose the right strategy to be used

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Pós-graduação em Educação para a Ciência - FC

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Ozone, first discovered in the mid 1800’s, is a triatomic allotrope of oxygen that is a powerful oxidant. For over a century, research has been conducted into the synthetic application and mechanism of reactions of ozone with organic compounds. One of the major areas of interest has been the ozonolysis of alkenes. The production of carbonyl compounds is the most common synthetic application of ozonolysis. The generally accepted mechanism developed by Rudolf Criegee for this reaction involves the 1,3-electrocyclic addition of ozone to the π bond of the alkene to form a 1,2,3-trioxolane or primary ozonide. The primary ozonide is unstable at temperatures above -100 °C and undergoes cycloreversion to produce the carbonyl oxide and carbonyl intermediates. These intermediates then recombine in another 1,3-electrocyclic addition step to form the 1,2,4-trioxolane or final ozonide. While the final ozonide is often isolable, most synthetic applications of ozonolysis require a subsequent reductive or oxidative step to form the desired carbonyl compound. During investigations into the nucleophilic trapping of the reactive carbonyl oxide, it was discovered that when amines were used as additives, an increased amount of reaction time was required in order to consume all of the starting material. Surprisingly, significant amounts of aldehydes and a suppression of ozonide formation also occurred which led to the discovery that amine N-oxides formed by the ozonation of the amine additives in the reaction were intercepting the carbonyl oxide. From the observed production of aldehydes, our proposed mechanism for the in situ reductive ozonolysis reaction with amine N-oxides involves the nucleophilic trapping of the carbonyl oxide intermediate to produce a zwitterionic adduct that fragments into 1O2, amine and the carbonyl thereby avoiding the formation of peroxidic intermediates. With the successful total syntheses of peroxyacarnoates A and D by Dr. Chunping Xu, the asymmetric total synthesis of peroxyplakorate A3 was investigated. The peroxyplakoric acids are cyclic peroxide natural products isolated from the Plakortis species of marine sponge that have been found to exhibit activity against malaria, cancer and fungi. Even though the peroxyplakorates differ from the peroxyacarnoates in the polyunsaturated tail and the head group, the lessons learned from the syntheses of the peroxyacarnoates have proven to be valuable in the asymmetric synthesis of peroxyplakorate A3. The challenges for the asymmetric synthesis of peroxyplakorate A3 include the stereospecific formation of the 3-methoxy-1,2-dioxane core with a propionate head group and the introduction of oxidation sensitive dienyl tail in the presence of a reduction sensitive 1,2-dioxane core. It was found that the stereochemistry of two of the chiral centers could be controlled by an anti-aldol reaction of a chiral propionate followed by the stereospecific intramolecular cyclization of a hydroperoxyacetal. The regioselective ozonolysis of a 1,2-disubstituted alkene in the presence of a terminal alkyne forms the required hydroperoxyacetal as a mixture of diastereomers. Finally, the dienyl tail is introduced by a hydrometallation/iodination of the alkyne to produce a vinyl iodide followed by a palladium catalyzed coupling reaction. While the coupling reaction was unsuccessful in these attempts, it is still believed that the intramolecular cyclization to introduce the 1,2-dioxane core could prove to be a general solution to many other cyclic peroxides natural products.

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Rhodium-catalyzed asymmetric hydroboration in conjunction with directing groups can be used control relative and absolute stereochemistry. Hydroboration has the potential to create new C–C, C–O, and C–N bonds from an intermediate C–B bond with retention of stereochemistry. Desymmetrization resulting in the loss of one or more symmetry elements can give rise to molecular chirality, i.e., the conversion of a prochiral molecule to one that is chiral. Unsaturated amides and esters hold the potential for two-point binding to the rhodium catalyst and have been shown to direct the regiochemistry and impact stereochemistry in asymmetric hydroborations of acyclic β,γ-unsaturated substrates. In the present study, the pendant amide functionality directs the hydroboration cis in the cyclic substrates studied; the corresponding ester substrates do so to a lesser extent. The enantioselectivity is determined by regioselective addition to the re or si site of the rhodium-complexed alkene. The effect of catalyst, ligand and borane on the observed diastereoselectivity and enantioselectivity for a variety of cyclopentenyl ester and amide substrates is discussed.