Ciências Exatas e da Terra: Últimas Submissões
Resultados 21-30 de 5974
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Planejamento territorial do COSIPLAN/IIRSA : avanços, retrocessos e perspectivas
(2022) [Artigo de periódico]O planejamento econômico ganhou dimensão internacional com a Revolução Russa sendo criticado por neoliberais na década de 1940. A ideia do planejamento econômico havia chegado à América Latina na década de 1920 sendo ... -
Identificação de hidrocarbonetos aromáticos polinucleados em amostras de petróleo brasileiro
(1991) [Artigo de periódico] -
Oligomerização de propeno catalisada por complexos dicatiônicos de níquel : efeito de co-catalisadores do tipo alquilalumínio
(1996) [Artigo de periódico]Propene is oligomerized in the presence of Ni(MeCN)₆(BF₄)₂ and alkylaluminum compounds like Al₂Et₆₋nCln (n = 0, 2, 3 or 4). The catalyst system perfomance is determinated by the cocatalyst type. Under mild reaction conditions ... -
Uso de RMN de ¹3C e de 3¹P no acompanhamento da síntese de fosfinitos e de catalisadores catiônicos de ródio
(1996) [Artigo de periódico]Phosphinites and thiophosfites derived from bicyclic and polycylic strained molecules like norbonanes, endo-endo and endo-exo tetracyclic dodecanes compounds, and their respective cationic Rhodium catalysis, were prepared. ... -
Disproportionation of rosin from Pinus elliotti : obtention of emulsifier for polymerization
(1995) [Artigo de periódico]The pulverized, molten or solubilized, rosin from Pinus elliotti was disproportionated by using S, NaI, S and I₂ or Pd/C as catalysts. The disproportionated rosin was saponified in aqueous or alcoholic KOH solutions. The ... -
Placas cerâmicas contendo lodo de ETA e cinza de casca de arroz: correlação de suas propriedades físico-químicas com sua microestrutura
(2018) [Artigo de periódico]Pressed ceramic plates were made from mixtures with different proportions containing kaolinite clay, silica extracted from the rice husk ash after controlled burning at controlled temperature and sludge from a water treatment ... -
Isolation and identification of toxic chlorinated organic compounds present in black liquor of bleached cellulose pulp from Southern Brazil
(1989) [Artigo de periódico]Chemical components of untreated black liquor of cellulose pulp from Southern Brazil were extracted using macromolecular XAD-4 resin. The following compounds were identified qualitatively and/or quantitatively by capillary ... -
The preparation of keim's ethylene oligomerization catalyst : an introductory experiment in organometallic chemistry
(1988) [Artigo de periódico]A convenient sequence of reactions leading to Keim's ethylene polymerization catalyst [Ni(Ph)(PPh₃){Ph₂PCHC(O)Ph}] is proposed here as a practical exercise for undergraduate students. The reactions are straightforward and ... -
Metátese catalítica de olefinas
(1993) [Artigo de periódico]The metathesis olefin reaction was reviewed. All the different types of reactions in this field were covered. Reactions of non-functionalized and functionalized olefins were exemplified. The importance of these kind of ... -
Determinação condutimétrica do coeficiente de difusão de ácidos carboxílicos em solução aquosa
(1991) [Artigo de periódico]The conductimetric technique proposed by Harned and French has been used to measure diffusion coefficients of aqueous solutions of formic acid and acetic acid at 25ºC. A poplypropilene conductimetric diffusion cell was ...