O impacto do PADCT na química brasileira: uma visão acadêmica

An appraisal has been conducted of the impact PADCT (Support Program for Scientific and Technological Development) has caused on brazilian Chemistry and Chemical Engineering over a ten years period (1985-1995). During this time PADCT invested US$ 87.5 million dollars to support both scientific and technolgical development of chemistry. The main results, from an academic point of view, has been the strengthening of support services for academic research, including libraries and analytical facilities, and a consequent increase of the number and quality of human resources trained at the graduate level as well as a significant increase in the number of scientific publications.

A evolução da pós-graduação em química no Brasil

The post-graduate teaching of chemistry in Brazil over the last years is discussed, including comparisons with some other sciences and also experiences in the United States and the United Kingdom. We have also compared the more recent situation with the previous decade, which leads us to a favourable conclusion as to the results obtained in the teaching of post-graduate students in chemistry. Some conclusions and recommendations are made with respect to the near future.

A evolução da química brasileira

The recent evolution of chemical research in Brazil is analyzed. Progress has been substantial according to principal indicators. The contributions of the Brazilian Chemical Society are pointed out.

A química na região nordeste: o papel da SBQ

In the opportunity of the 20th year of foundation of the Brazilian Chemical Society, the role of this organization in behalf of the development of Science, in particular of Chemistry, is analysed by the way it is observed by someone that has been working in the Northeast of this Country.

A química na região norte

A historical overview of CHEMISTRY SCIENCE from the beginning of the ESCOLA DE QUÍMICA INDUSTRIAL DO PARÁ in the northern region of Brazil is given. Reports were conducted on graduate and under graduate coursework within research and teaching institutions in each State of the Amazon region. Data collection included teaching, research and industrial activities.

As primeiras vinte reuniões anuais da SBQ: uma visão da evolução da química no Brasil

An analysis of the different activities carried out during the first twenty annual meetings (1978-1997) of the Brazilian Chemical Society (SBQ) is presented. The number of papers in the abstract book increased from around 300 in the biennium 78/79 to around 1230 in 96/97. The papers contained in the different sections of the abstract book in the 1st (1978), 10th (1987) and 19th (1996) annual meetings were grouped according to the regions of Brazil the authors' institutions were from, or abroad, and also considering whether the paper came from one institution or was a collaboration between two or more institutions. The relative contribution of the southeastern and northern regions decreased from 77% and 3.0% of the total in 1978 to 63% and 1.2% in 1996, respectively, while those of the northeastern, southern and midwestern regions increased from 12%, 4.8% and 0.6% to 15%, 13%, and 2.6%, respectively; the relative contribution of institutions from abroad also increased from 2.4% to 4.0%. Chemistry of Natural Products and Organic Chemistry decreased their relative contribution from around 55% in 1978 to around 28% in 1996, an evolution towards a more balanced development of the different areas of chemistry in Brazil.

Preparo de óxido de nióbio suportado em alumina por deposição química em fase vapor: caracterização por espectroscopia vibracional e termogravimetria

Alumina supported niobium oxide was prepared by chemical vapor deposition (CVD) of NbCl5. The alumina was calcined and pretreated at differents temperatures in order to vary the density of OH groups on the surface which was determined by thermogravimetric analysis. A good correlation was found between the amount of anchored niobium and the total number of anionic sites (oxide and hydroxyl groups) on the surface of the alumina. The infrared spectra on the OH stretching region indicate that OH groups coordinated to at least one tetrahedral aluminum were more reactive towards NbCl5.

Aplicação de pigmentos de flores no ensino de química

In the present work, the pH dependent colour change of the crude flower extracts is suggested as subject in teaching chemical or acid-base equilibria, visual indicators and some aspects of spectrophotometric concepts and applications. The vegetal species used are commonly found in Brazil, and the extraction methodology proposed is inexpensive and easy to perform in secondary schools and in general chemistry or instrumental undergraduate courses. A bibliographic review about the use of vegetal extracts in chemical education and a discussion of the flower colour are also presented.

Caracterização química e física de vermicomposto e avaliação de sua capacidade em adsorver cobre e zinco

The physical and chemical characterization of vermicompost from bovine manure has been studied. It was examined the pH and cation exchangeable capacity (CEC), organic matter content, electric conductivity and elementary and XRD analyses, among other characteristics. The vermicompost was then applied to the retention and competition of metal micronutrients and pollutants (Cu and Zn) from metal nitrate solutions. The retention was affected by both the pH and adsorption time, while the competitive character of these metals for the substrate was relevant to each pH examined.

Nova rota de preparação do 2-cloro-1,3,2-dioxofosfolana e 2-cloro-4,5-benzo-1,3,2-dioxofosfolana e caracterização por espectroscopia de RMN multinuclear

A new method for the preparation of 2-chloro-1,3,2-dioxaphospholane (1) and 2-chloro-4,5-benzo-1,3,2-dioxaphospholane (2), are reported. The modifications introduced in the synthetic route improved the yield and facilitated the control of reaction, but the synthesis require longer reaction time. The compounds were characterized by ¹H, 13C{¹H} and31P{¹H} NMR spectroscopy. Due to the complexity of the spin system AA'BB'X (A, A', B, B' = ¹H; X = 31P) of 2, a simulation of the ¹H NMR spectra was done and it's in agreement with the bibliography.

Determinação permanganimétrica de íons Fe3+ com o uso de zinco metálico como redutor - uma contribuição ao ensino de química analítica

The classical volumetric titration of Fe2+ with MnO4-, used in some routine analysis as well as in undergraduate courses was improved. SnCl2 (to reduce Fe3+ to Fe2+) and HgCl2 (to oxidize excess SnCl2) were substituted by metallic zinc in boiling solutions, thus avoiding the toxic HgCl2 and Hg2Cl2; nitrate ions do not interfere in the improved methodology (it is an interference in the classical one) and the reproducibility of the determinations is increased by using metallic zinc. Determinations by students of undergraduate courses are discussed.

Influência do material do alambique na composição química das aguardentes de cana-de-açúcar

This paper describes variations in the profile of the main volatile organic compounds present in Brazilian sugar cane spirits distilled in copper and stainless steel distillers. The main organic compounds: aldehydes, ketones, carboxylic acids, alcohols and esters, were determined through High Performance Liquid Chromatography (HPLC) and High Resolution Gas Cromatography (HRGC). The spirits produced in copper distillers exhibit higher contents of aldehydes with respect to the ones produced in stainless steel. The inverse is true with respect to the higher alcohol and ester contents. No significant variation has been observed for the carboxylic acids.

Inibidores seletivos de prostaglandina endoperóxido sintase-2 (PGHS-2): nova estratégia para o tratamento da inflamação

Prostaglandins (PG's), produced from arachidonic acid metabolism, are potent mediators of inflammation. Nonsteroidal anti-inflammatory (NSAIDs) exert their effects by inhibition of prostaglandin endoperoxide synthase (PGHS) enzyme, which catalyses the first committed step in arachidonic acid metabolism. Two isoforms of PGHS are known: PGHS-1, constitutively expressed in most tissues, and is responsible for physiological production of PG's. The second isoform, PGHS-2, is induced by cytokines, mitogens and endotoxins in inflammatory cells, and appears to be responsible for the elevated production of PG's during inflammation. With the recent discovery of the inducible PGHS (PGHS-2), the medicinal chemist now possesses a novel target for designing therapeutic agents that could provide suitable anti-inflammatory activity without the ulcerogenic and renal side effects associated with currently available NSAIDs, all of which inhibit both PGHS-1 and PGHS-2.