Sample records for copper complexes
from WorldWideScience.org

Sample records 1 - 11 shown.



1

Borohidreto complexos de cobre (I) contendo difosfinas: caracterização espectroscópica e comportamento térmico/ Tetrahydroborate complexes of copper (I) with diphosphines: spectroscopic characterization and thermal behavior

Haddad, Paula S.; Mauro, Antonio E.; Frem, Regina C.G.
2001-12-01

Resumo em inglês Tetrahydroborate complexes of copper (I) with bidentate phosphines, [Cu(eta²-BH4)(dppm)] (1), [Cu(eta²-BH4)(dppe)] (2), [Cu(eta²-BH4)(cis-dppet)] (3) and [Cu(eta²-BH4)(dppb)] (4) (dppm = bis(diphenylphosphino)methane; dppe = 1,2-bis(diphenylphosphino) ethane; cis-dppet = 1,2-cis(diphenylphosphino)ethene; dppb = 1,4-bis(diphenylphosphino)butane) were prepared and characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR data (mais) for 1-4 showed bands typical of a bidentate coordination of BH4 group to the copper atom and the 31P{¹H} NMR spectra indicated that the phosphorous atoms are chelating the metal centre. The thermal behavior of the compounds was investigated and suggested that their thermal stability is influenced by the phosphines. Their thermal stability decreased as follows: [Cu(eta²-BH4)(dppe)] (2) > [Cu(eta²-BH4)(dppm)] (1) > [Cu(eta²-BH4)(dppb)] (4) > [Cu(eta²-BH4)(cis-dppet)] (3). According to thermal analysis and X-ray diffraction patterns all compounds decomposed giving Cu(BO2)2, CuO, CuO2 and Cu as final products.

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2

Estudos comparativos entre carvão ativado e resina de troca iônica para adsorção de ouro, cobre e ferro/ Comparative study of activated carbon and ion-exchange resin for the adsorption of gold, copper and iron

Araujo, Danielle Marques; Yoshida, Maria Irene; Stapelfeldt, Frank; Carvalho, Cornélio Freitas; Donnici, Cláudio Luiz; Kastner, Geraldo F.
2009-12-01

Resumo em português O objetivo desse trabalho é a adsorção de cianocomplexos de ouro, cobre e ferro de efluentes que são gerados no processo de beneficiamento do minério de ouro. Para a adsorção foram testadas duas alternativas: resina de troca aniônica com base fraca e o carvão ativado quimicamente modificado. A resina utilizada foi a LEWATIT MP 62 da Bayer S.A. O processo de modificação química do carvão ocorreu em duas etapas: nitração do carvão ativado comercial, seguida (mais) de redução do grupo nitro (NO2) para grupo amino (NH2). Os testes de adsorção revelaram que o carvão ativado modificado apresentou pior eficiência na recuperação de complexos de Au, em relação ao carvão ativado sem tratamento, e que ambos não adsorveram complexos de Cu e Fe. A resina foi a que apresentou melhor recuperação dos complexos de ouro (100%), cobre (99%) e ferro (100%). Resumo em inglês Herein, the adsorption of gold, copper, and iron cyano complexes fromeffluents of t gold ore processing is presented. . For recovery, two alternatives were tested: weak-base ion - exchange resin and chemically modified activated carbon. The resin used was LEWATIT MP 62 from Bayer S.A. Chemical modification was carried out in two steps: nitration of commercial activated carbon followed by the reduction of the nitro group (NO2) to amino group (NH2). Adsorption testes reveal (mais) ed that activated carbon presented poorer efficiency in the recovery of Au complexes in relation to untreated activated carbon, and that they did not adsorb either Cu or Fe complexes. Resin recovered Cu (99%) and Fe(100%) and Au (100%) complexes was the best.

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3

Efeito estrutura da matriz na adsorção de cianocomplexos metálicos em resinas de poliestireno

Riani, Josiane Costa; Carlos, Versiane Albis Leão; Silva, Carlos Antônio da
2004-06-01

Resumo em português O objetivo desse trabalho é a utilização de resinas de troca-iônica, base forte, na adsorção de cianocomplexos metálicos, visando a sua reciclagem. São utilizadas soluções sintéticas que simulam diferentes efluentes da lixiviação do minério de ouro, contendo concentrações de ferro, de zinco e de cobre, variando entre 50 e 500mg/l. São realizados ensaios de adsorção, em batelada, utilizando dois tipos de resinas comerciais: Ionac SR-7 (matriz de poliesti (mais) reno, tripropilamônio quaternário como grupo de troca) e Dowex 1X8 (matriz de poliestireno, trimetilamônio quaternário como grupo de troca). Em ambas resinas houve uma adsorção maior do cianocomplexo de zinco com relação aos outros cianocomplexos metálicos existentes em solução. A ordem do carregamento, nesse caso, foi Zn>Cu>Fe. A resina Dowex 1X8 apresentou um maior carregamento dos cianocomplexos de zinco e de cobre, quando comparados com os carregamentos da outra resina. As diferentes afinidades são discutidas em função das características físico-químicas dos complexos e das estruturas das resinas. Resumo em inglês This work aims the recycling of cyanide applying strong base ion exchange resins for the adsorption of metallic cyanocomplexes. The experiments were carried out with synthetic solutions simulating those found in the cyanidation of gold ores. The solutions are made up of copper, iron and zinc with concentrations raging from 50mg/L to 500mg/L. Batch adsorption experiments were carried out with two commercial strong base resins: Ionac SR-7 (polystyrene, tripropylammonium) an (mais) d Dowex 1X8 (gel type, polystyrene, trimethylammonium). The tripropilammonium resin Ionac SR-7 presents a larger loading of zinc cyanide compared with those of copper and iron. The affinity sequence observed was Zn>Cu>Fe. Dowex 1X8 resin shows the highest uptake of both zinc and copper due to its high exchange capacity. The affinity sequence is similar to that of Ionac SR-7 resin. The different affinities achieved are discussed based on both the physic-chemical features of the complexes and the resin structure.

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4

Comparação de soluções salinas na eluição de resinas poliméricas de diferentes matrizes carregadas com cianocomplexos de ouro e cobre

Oliveira, Adélia Moreira; Leão, Versiane Albis; Silva, Carlos Antônio da
2006-03-01

Resumo em português Resinas troca iônica base forte destacam-se como uma alternativa para reduzir o impacto do uso de CN- pela indústria do ouro. Embora a adsorção com resinas possa ser facilmente realizada, a eluição enfrenta alguns problemas, sendo a etapa-chave do processo. O objetivo desse trabalho é estudar o carregamento e a eluição das resinas Purolite A500® e Bayer AP247®, carregadas com cianocomplexo de ouro e cobre. As resinas foram carregadas em ensaios batelada a 25ºC (mais) e depois eluídas, em coluna, com soluções 1,0mol/L dos eluentes NaSCN e NaNO3. As soluções 1mol/L de íons nitrato de sódio não foram capazes de eluir o cianeto de ouro de resinas com matriz de poliestireno (Purolite A500®). Por outro lado, eluíram ambos os complexos da resina poliacrílica (Bayer AP247®). Tanto na resina Purolite A500®, quanto na resina Bayer AP247®, o eluente NaSCN aumenta a recuperação e a velocidade de eluição dos cianocomplexos metálicos, quando comparado com o eluente NaNO3. Resumo em inglês Ion exchange resins can be applied in cyanide recycling to address growing environmental concerns about the use of cyanide during gold extraction. Although sorption with resins can be easily accomplished, elution is the key step and presents some problems. This work aims to study both loading and elution of two resins with different matrixes, Purolite A500® and Bayer AP247®, loaded with copper- and gold cyanocomplexes. Both resins were loaded at 25ºC (batchwise) and co (mais) lumn elutions were performed at 50°C with either 1mol/L NaNO3 or NaSCN solutions. It has been found that 1mol/L nitrate solutions could not elute gold from polysterene resins(Purolite A500®). Conversely, both cyanocomplexes were removed from the Bayer AP247® resin. For both resins, NaSCN (1mol/L) solutions increased metals yield as well as elution rates of both complexes.

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5

Absorção, translocação e utilização de zinco, cobre e manganês por mudas enxertadas de Coffea arabica/ Absorption, translocation and utilization of zinc, copper and manganese in grafted seedlings of Coffea arabica

Tomaz, Marcelo Antonio; Martinez, Herminia Emilia Pietro; Sakiyama, Ney Sussumu; Cruz, Cosme Damião; Pereira, Antonio Alves
2006-04-01

Resumo em português Comparativamente ao pé-franco, a combinação enxerto/porta-enxerto altera os complexos mecanismos de "feedback" entre parte aérea e raízes, afetando de maneira positiva ou negativa a eficiência nutricional da planta. Este trabalho teve como objetivo avaliar, em cultivo hidropônico, a eficiência da absorção, translocação e utilização de Zn, Cu e Mn por mudas de Coffea arabica L., de acordo com o porta-enxerto utilizado. O experimento foi realizado em casa de v (mais) egetação, por um período de 170 dias, em vasos que continham areia como substrato, recebendo solução nutritiva circulante. Utilizaram-se, como enxerto, quatro genótipos de C. arabica: os cultivares Catuaí Vermelho IAC 15 e Oeiras MG 6851 e os híbridos 'H 419-10-3-1-5' e 'H 514-5-5-3' , e, como porta-enxerto, quatro genótipos, sendo três de Coffea canephora Pierre ex Froenher: Apoatã LC 2258, Conilon Muriaé-1 e RC EMCAPA 8141 (recombinação entre clones da variedade Robustão Capixaba - EMCAPA 8141) e uma linhagem de Coffea arabica L.: Mundo Novo IAC 376-4, além de quatro pés-francos. O delineamento experimental utilizado foi em blocos casualizados com 20 tratamentos, quatro repetições e uma planta por parcela. A eficiência nutricional das mudas quanto ao Zn, Cu e Mn variou de acordo com a combinação enxerto/porta-enxerto. A progênie 'H 514-5-5-3' foi mais eficiente quanto à utilização de Zn, Cu e Mn e produção de matéria seca, quando combinada com os porta-enxertos Apoatã LC 2258 e Mundo Novo IAC 376-4. O Catuaí Vermelho IAC 15 foi mais eficiente na utilização de Cu e Mn quando combinado com Apoatã LC 2258. Resumo em inglês There are complexes feedback mechanisms involving the relationship rootstock/scion, whick can positively or negatively affect the plant nutrient efficiency use. The goal of the present work was to evaluate the efficiency of uptake, translocation and utilization of Zn, Cu and Mn in coffee seedlings. The experiment was carried out in a greenhouse over 170 days using circulating nutrient solution in pots with sand medium. Four Coffea arabica L. genotypes were used as grafts: (mais) Catuaí Vermelho IAC 15 and Oeiras MG 6851, and the hybrids 'H 419-10-3-1-5' and 'H 514-5-5-3' . Three genotypes of Coffea canephora Pierre et Froenher were used as rootstocks: Apoatã LC 2258, Conilon Muriaé-1 and RC EMCAPA 8141 (recombination among clones of the variety Robustão Capixaba - EMCAPA 8141), one line of C. arabica: Mundo Novo IAC 376-4, and four additional non-grafted plants. The experiment was in a randomized block design with 20 treatments, four replications and one plant per plot. The nutritional efficiency of the coffee seedlings for Zn, Cu and Mn varied according to the graft/rootstock combination. Progeny 'H 514-5-5-3' proved to be the most effective regarding Zn, Cu and Mn utilization and dry matter yield when combined with the rootstocks Apoatã LC 2258 and Mundo Novo IAC 376-4. Catuaí Vermelho IAC 15 was more effective for Cu and Mn utilization when combined with Apoatã LC 2258.

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6

Tecnologia limpa para redução de impacto ambiental do cianeto na mineração de ouro

Riani, Josiani Costa; Pina, Pablo dos Santos; Leão, Versiane Albis
2007-03-01

Resumo em português Esse trabalho discute a aplicação de resinas de troca iônica com matriz poliacrílica para a adsorção de cianocomplexos metálicos. Ensaios em batelada mostraram que as resinas possuem elevada afinidade para os cianocomplexos de ferro e de zinco em relação aos de cobre. Já a eluição, estudada em coluna, indicou que soluções de tiocianato de sódio a 1mol/L são capazes de eluir os ciancomplexos dos três metais. Já soluções de nitrato de sódio, na mesma co (mais) ncentração, não são efetivas para a eluição do cianeto de zinco. Um processo de eluição seletiva é proposto onde os cianocomplexos de cobre e de ferro são eluídos com solução íons NO3-. Em seguida, o zinco é eluído com NaSCN. Ambos eluentes foram capazes de concentrar os cianocomplexos de solução, o que tem efeito benéfico nas etapas subseqüentes de regeneração do cianeto. Resumo em inglês A study on metal cyanocomplexes sorption on polyacrylic ion exchange resins has been undertaken. Batch sorption experiments have shown that polyacrylic resins have a high affinity for zinc and iron cyanides compared to copper complexes. Elution studies performed in column experiments have also depicted that 1mo/L sodium thiocyanate solutions can successfully extract the three metals. Conversely, sodium nitrate solutions at the same concentration are not effective in eluti (mais) ng zinc cyanocomplexes. Based on elution figures, it is proposed that copper and iron can be selectively eluted with nitrate before the zinc, this latter being recovered afterwards with thiocyanate solutions. Both eluants were able to concentrate the cyanocomplexes in solution with a beneficial effect on the subsequent steps of cyanide recycling.

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7

Síntese e caracterização de novos compostos de coordenação de cobre (II) com ligantes não-simétricos N,O-doadores: contribuições para o sítio ativo da galactose oxidase/ Synthesis and characterization of new copper (II) coordination compounds with unsymmetrical N,O-donor ligands: contributions for the galactose oxidase active site

Romanowski, Stela Maris de Moraes; Mangrich, Antonio Sálvio; Neves, Ademir
2001-10-01

Resumo em inglês The reactions of four new unsymmetrical N,O-donor ligands, {H2BBPETEN= [N-(2-hydroxybenzyl) - N,N' - bis(2 methylpyridyl) -N'-(hydroxyethyl) ethylenodiamine], H3BPETEN=[N,N'- bis(2-hydroxybenzyl) -N- (2-methylpyridyl) -N'- (hydroxyethyl) ethylenodiamine], HTPETEN=[N,N,N'- tris(2-methylpyridyl) -N'- (hydroxyethyl) ethylenodiamine] and H3BIMETEN=[N,N'-(2-hydroxybenzyl)-N-(1-methylimidazol-2-il-methyl)-N'- (hydroxyethyl)ethylenodiamine]}, with Cu(II) salts afforded the follo (mais) wing mononuclear compounds: [CuII(HBBPETEN)]ClO4, [CuII(H2BPETEN)]ClO4 , [CuII(HTPETEN)](PF6)2 and [CuII(H2BIMETEN)]ClO4 . All were characterized by EPR, electronic spectroscopy and electrochemistry. The four copper (II) compounds showed interesting electrochemistry properties. All presented an anodic wave that can be attributed to the Cu (I) oxide formation at the electrode surface, or to a Cu0 sediment at the same surface or yet, to Cu(I) -> Cu(II) oxidation process with coupled chemistry reaction, due to their irreversibility. Two of the complexes are described as interesting synthetic models for the active site of the metalloenzyme galactose oxidase.

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8

Isolamento e caracterização ultraestrutural de folículos pré-antrais de vacas da raça Nelore (Bos taurus indicus)/ Isolation and ultrastructural characterization of preantral follicles in the Nelore breed cows (Bos taurus indicus)

Basso, Andréa Cristina; Esper, Cesar Roberto
2002-01-01

Resumo em português Folículos pré-antrais de 41 vacas da raça Nelore foram quantitativa e ultraestruturalmente descritos neste estudo. Uma média de 35.539,20 folículos pré-antrais foram isolados mecanicamente ("Tissue Chopper") por animal. Os folículos foram processados para microscopia eletrônica de transmissão. Os folículos primordiais apresentaram um oócito rodeado por uma camada de células granulosas (CGs) achatadas, com algumas tendendo à forma cuboidal. As demais fases de (mais) desenvolvimento foram classificadas como folículos primários, com uma camada de CGs cuboidais, e secundários, com mais de duas camadas de CGs cuboidais. Os folículos primordiais apresentaram oócito evidente, com núcleo excêntrico e nucléolo bem definido, cercado por regiões de cromatina condensada. As organelas ao redor do núcleo eram, predominantemente, mitocôndrias arredondadas. Folículos em desenvolvimento apresentavam organelas mais dispersas e numerosas, com mitocôndrias alongadas. As comunicações entre o oócito e as CGs mantinham-se por zonas de aderência, "coated pits" e vesículas de endocitose. A zona pelúcida (ZP) começava a aparecer em folículos primários, mostrando microvilos pequenos e vesículas penetrando na ZP. Os folículos secundários apresentavam aglomerados de grânulos corticais em associação a complexos de Golgi. Concluímos que o método mecânico de isolamento fornece quantidades suficientes de folículos pré-antrais de ovários de vacas da raça Nelore e, pela semelhança ultraestrutural com os folículos de outras raças, é possível a utilização dos mesmos protocolos de cultivo que vêm sendo estudados, desde que possibilitem a maturação meiótica dos oócitos. Resumo em inglês Preantral follicles from 41 Nelore breed cows were described quantitative and ultrastructurally in the study. In the average, 35,539.20 preantral follicles were mechanically isolated (Tissue Copper) per animal. Follicles were processed for transmission electron microscopy. Primordial follicles presented an oocyte surrounded by a flattened granulosa cell layer, with some granulosa cells showing cuboidal shape. Other development stages were classified as primary follicles, (mais) with a granulosa cell layer around the oocyte and secondary stages, with oocyte surrounded by two or more cuboidal granulosa cell layer. Primordial follicles showed an evident oocyte, with the nucleus located at an eccentric cytoplasm position and a well-defined nucleolus, with condensed chromatin areas. Organelles were centered at the peri-nuclear area, showing mostly round shaped mitochondria. Follicles under development showed an increasing number of organelles and elongated mitochondria. Adherence zones, coated pits and endocitose vesicles maintained the oocyte-granulosa cell interfaces. The zona pellucida (ZP) appeared in primary follicles, showed small microvilos and many vesicles, which permeated into the ZP. Secondary follicles presented clusters of cortical granules associated to Golgi complexes. In conclusion, the mechanical method provide a sufficient amount of preantral follicles from Nelore breed cows and, due to ultrastructural similarity with follicles from other breed, it is possible to use same protocols of culture, since the oocyte meiotic maturation is kept intact.

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9

Complexação da tetraciclina, da oxitetraciclina e da clortetraciclina com o catião cobre (II). Estudo potenciométrico/ Tetracycline, oxytetracycline and chlortetracycline complexation with copper (II). Potentiometric study

Couto, Cristina M. C. M.; Montenegro, M. Conceição B. S. M.; Reis, Salette
2000-08-01

Resumo em inglês Stability constants of complexes formed by copper (II) with three different tetracyclines (tetracycline, oxytetracycline and chlortetracycline) have been determined potentiometrically with an automatic system in aqueous medium at 25,0 ± 0,2 ºC and I = 0,1 mol L-1 NaNO3. The protonation constants of the three tetracyclines were also determined under the same conditions. The distribution of the complexes was then simulated at therapeutic levels of the drugs.

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10

Avaliação da influência de sulfetos solúveis na complexação do cobre em águas superficiais empregando métodos voltamétricos/ Influence of dissolved sulfides on copper complexation in surface waters using voltammetric methods

Scheffer, Elizabeth W. O.; Grassi, Marco T.
2010-01-01

Resumo em inglês In this work a sulfide quantification protocol using voltammetric methods was developed to evaluate the effect of dissolved sulfides on copper complexation. On the basis of pH, sulfide release from the dissociation of specific metal sulfide complexes can be electrochemically measured and then removed (as H2S) by a N2 purge. Cathodic stripping square wave voltammetry (CSSWV) was conducted to quantify Cu sulfides complexes which dissociate at pH

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11

A "fração argila" dos solos do Estado de São Paulo e seu estudo roentgenográfico

Paiva Neto, J. E. de
1942-01-01

Resumo em inglês In the beginning of this work a brief idea was given on what is understood as "clay", on the scientific methods applied to the study of the matter "clay" as well as on its conception with regard to the edaphic studies. A description is given of the methods of total and natural mechanical analyses which were employed in the agro-geological Department. The work is illustrated by a graphic showing the fractions of the mechanical analysis of the chief great soil types of the (mais) State of São Paulo. The fraction clay is then studied by chemical way in the following sequence : 1.° total chemical analysis, 2.° partial chemical analysis, 3.° chemical analysis of the Helmholz layer and 4.° study of the fixation of the ion Ca+ + in the already mentioned Helmholz layer. The first analysis separates and attacks the hydrated aluminium silicates, the hydrated oxyds of iron and aluminium, manganese, etc. In this analysis the relationship between silica and sesquioxyds was determined. The second type of attack or chemical analysis does not affect the hydrated silicates of aluminium, all others go in dissolution. In this analysis were determined chiefly the sesquioxyds in their free form in the clay complex. For the study of the Helmholz layer, i.e. the determination of changeable ions, solutes of NH4Cl N/l, HNO3 N/5, KCl N/l, etc. were used, percolation of these liquids being made through a layer of air dried soil. The relationship between soil and liquid was always 1:10. In this analysis, principally the cations K+, Ca++, Mg++, Al+ + +, H+ etc. were determined. With such determinations the calculations of the following values were obtained: S = sum of the changeable bases in ME; T = total value in ME of the sorptive power of the complex in each 100 g dried soil at 110° C. and V = percentage of saturation of the complexes with bases. Finally, the qualitative radiographic analysis of the fraction clay was carried out by means of the Debye-Scherrer-Hull method. For these studies the Siemens-Berlin apparatus was used, the transformer of which runs with all0-220 volts 60-cycle alternating current. The bulb has a copper anti-cathode and is fed by a current of 13 m.A. of intensity and the difference of potential is of 30,000, 35,000 and 47,000 volts. The flash of X-rays goes through the nickel filter in order to free it of the b irradiations which are deleterious. In this way, inciding vertically on the preparation, radiations CuK a with l = 1,539 A are obtained. The sensible film used was a Lawe-Film-Agfa, with an exposure going from 11/2 to 2 hours with 35,000 V. The chassis has a diameter of 57 mm. More than 500 radiographs of soil samples were taken, of those proceding from all districts of the State, 79 of which are presented in the present work. With this material the different constituents of the clay minerals contained in our soils were known. Thus, in the soils over the Archean geological formation, kaolinite is represented most frequently and abundantly ; the hydrargillite also appears commonly. The soils over the Glacial formation contain the same representatives and oscillations as those just mentioned. In the Corum-batai formation, quartz is the most important constituent. The Botucatu formation (lava) is that which gave origin to our legitimate red soils ; the mineralogical clay constituents of these soils are : 1.° large amount of hydrated oxyds of iron up to 35% of Fe2O3 for each 100 g of soil at 110° C. ; 2.° hydrargillite and 3.° kaolinite. The amount of the latter in the clay complex ranges between 9 and 25%. The sandy soils existing in the geological formations of lower and upper Baurú bear in their clays the following mineralogical constituents : 1.° kaolinite, 2.° montmorrillonitic type (on the upper Baurú only), 3.° hydrargillite (more common on the lower Baurú) and 4.° quartz, generally, in small percentages. These researches made it evident that the constituents of the clay fraction of our soils commonly have a small sorptive power related to the cations; it follows hence that they do not show a great power of retention of manure with the exception of the montmorrillonitic type.

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