DMSO Molecule as Ancillary Ligand in Ru-Based Catalysts for Ring Opening Metathesis Polymerization

A polimerização via metátese por abertura de anel (ROMP) de norborneno (NBE) ocorre em presença do complexo fac-[RuCl 2 (S-DMSO) 3 (O-DMSO)] e etildiazoacetato (5 µL), onde DMSO é dimetilsulfóxido coordenado pelo átomo de enxofre ou de oxigênio. O rendimento é 62% (PDI = 1,64) à temperatura ambiente por 5 min e 88% (PDI = 1,93) a 50 ºC por 30 min, com [NBE]/ [Ru] = 516 em CHCl 3 . Na presença de NBu 4 ClO 4 o rendimento é 90% (PDI = 1,64) à temperatura ambiente por 5 min. O complexo é praticamente inativo quando uma ou duas moléculas de DMSO são substituídas por piridina, imidazol, 2-metil-imidazol ou benzoimidazol. A formação in situ da espécie catalítica e os comportamentos das moléculas de DMSO como ligantes ancilares nas reatividades dos complexos de Ru II são discutidas nesse trabalho. The ring-opening metathesis polymerization (ROMP) of norbornene (NBE) occurs in the presence of the fac-[RuC

ADSORÇÃO DO CORANTE TÊXTIL AZUL REMAZOL POR PECÍOLO DE BURITI (Mauritia flexuosa L.f.)

No presente trabalho foi investigada a remoção do corante azul remazol usando como adsorvente o pecíolo do buriti. A partir do espectro de infravermelho, foram identificados os principais grupos funcionais do adsorvente. O comprimento de onda de máxima absorção (λmáx) do corante foi obtido por espectrofotometria na região do UV-visível foi 595nm. O pH no ponto de carga zero do adsorvente foi estimado graficamente em torno de 4,6. Foram investigados alguns parâmetros tais como: a influência do pH, o tempo de contato e a concentração do corante. A capacidade de adsorção do corante é maior em pH's mais baixos. Os modelos cinéticos de adsorção que apresentaram os melhores ajustes foram os de pseudossegunda ordem para a menor concentração (R2 ≈ 93%) e Elovich para as concentrações de 400 e 800 mg.L-1 (R2 ≈ 97%). Os modelos isotérmicos utilizados foram os de Freundlich, Sips e Multicamada. Os modelos de Sips e Multicamada foram os que ajustaram melhor os dados de equilíbrio (R2 > 96%). A quantidade máxima adsorvida estimada pelo modelo de Sips foi 33 mg.g-1. Essa capacidade de adsorção relativamente alta torna o pecíolo do buriti um adsorvente com potencial para remover corantes.Palavras-chave: Pecíolo de buriti (Mauritia flexuosa L.f.). Adsorção. Corantes têxteis.ADSORPTION OF BLUE TEXTILE DYE REMAZOL FOR BURITI PETIOLE (Mauritia flexuosa Lf)Abstract: In the present study was investigated the removal of Remazol Blue dye using as adsorbent buriti petiole. From the IR spectrum. the main functional groups of the adsorbent were identified. The wavelength of maximum absorption (λmáx) of the dye was obtained by spectrophotometric in the UV-visible was 595 nm. The pH at the point of zero charge of the adsorbent was estimated graphically at 4,6. Were investigated Some parameters were investigated such as: the influence of pH, the contact time and the concentration of the dye. The adsorption capacity of the dye is higher in lower pH's. The adsorption kinetic models that showed the best fits were the pseudo-second order for the lower concentration (R2 ≈ 93%) and Elovich for  concentrations of 400 and 800 mg.L-1 (R2 ≈ 97%). The isotherm models used were those of Freundlich, Sips and Multilayer. Sips and Multilayer models were best fitted the equilibrium data (R2 > 96%). The maximum amount adsorbed estimated by Sips model was 33 mg.g-1. That relatively high adsorption capacity makes the buriti petiole a potential adsorbent to remove dyes.Keywords: Buriti petiole (Mauritia flexuosa L.f.). Adsorption. Textile dyes.ADSORCIÓN DEL COLORANTE TEXTIL AZUL REMAZOL POR EL PECÍOLO DE BURITI (Mauritia flexuosa L.f.)Resumen: En el presente trabajo fue investigada la retirada del colorante azul remazol usando como adsorbente el peciolo del buriti. Através del espectro infrarrojo se identificaron los principales grupos funcionales del adsorbente. La longitud de onda de absorción máxima (λmáx ) del colorante se obtuvo por espectrofotometria en UV-Visible en 595nm. El pH en el punto de carga cero del adsorbente foi aproximado graficamente en 4,6. Fueron investigados la influencia del pH, tiempo de contacto y la concentración del colorante. La capacidade de adsorción del colorante es mayor en pH's mas bajos. Los modelos cinéticos de adsorción que presentaron los mejores ajustes fueron los de pseudo-segundo orden para la menor concentración (R2 ≈ 93%) e Elovich para las concentraciones de 400 y 800 mg.L-1 (R2 ≈ 97%). Los modelos isotérmicos utilizados fueron los de Freundlich, Sips y de Multicapas. Los modelos de Sips y de Multicapas fueron los que adecuaron mejor los datos del equilibrio (R2 > 96%). La cantidad máxima adsorbida calculada por el modelo de Sips fue de 33 mg.g-1. Esta capacidad relativamente alta de adsorción define al peciolo del buriti como un adsorbente con potencial para retirar colorantes.Keywords: Peciolo de buriti (Mauritia flexuosa L.f.). Adsorción. Colorantes téxtiles

DMSO molecule as ancillary ligand in Ru-based catalysts for ring opening metathesis polymerization

The ring-opening metathesis polymerization (ROMP) of norbornene (NBE) occurs in the presence of the fac-[RuCl2(S-DMSO)3(O-DMSO)] complex and ethyldiazoacetate (5 μL), where DMSO is S- or O-bonded dimethylsulfoxide. The yield is 62% (PDI = 1.64) at room temperature for 5 min and 88% (PDI = 1.93) at 50 ºC for 30 min, with [NBE]/[Ru] = 516 in CHCl3. The yield is 90% (PDI = 1.64) in the presence of NBu4ClO4 at room temperature for 5 min. The complex is practically inactive when one or two molecules of DMSO are replaced by pyridine, imidazole, 2-methyl-imidazole or benzimidazole. The in situ formation of the catalytic species and the behavior of the DMSO molecules as ancillary ligands in the reactivity of the RuII complexes are discussed

Metátese de olefinas no Brasil: "Brazil is romping it!"

Some aspects of the olefin metathesis reactions are summarized here (types of reactions, mechanism and catalysts). In particular, the research groups that have been working on this chemistry in Brazil are presented. The main goal of this paper is to make this type of reaction more widely known in the Brazilian chemical community

New Chemical Organic Anhydride Immobilization Process Used on Banana Pseudostems: A Biopolymer for Cation Removal

Maleic and phthalic anhydrides were chemically incorporated onto the banana pseudostem biopolymeric structure through reaction without solvent at the fusion temperatures of the reagents. The new biomaterials showed unequivocal success for these proposed reactions and demonstrated abilities to remove cations from aqueous solutions. Phthalic anhydride pendant chains bonded to biopolymeric structure showed high performance for cation sorption at short times, 60–180 min, to give the maximum sorption capacities of 0.52, 0.54, and 0.59 mmol g^–1 for copper, cobalt, and nickel, respectively. Identically, maleic anhydride chains gave 0.27, 0.32, and 0.20 mmol g^–1 for the same sequence of cations. The equilibrium data were best represented by the Langmuir model in a linear regression and by the Freundlich model in nonlinear regression procedures. These new biopolymers are promising for ecosystem remediation with advantages in using biopolymers based on a natural, cheap, and abundant raw biomaterial

New Chemical Organic Anhydride Immobilization Process Used on Banana Pseudostems: A Biopolymer for Cation Removal

Maleic and phthalic anhydrides were chemically incorporated onto the banana pseudostem biopolymeric structure through reaction without solvent at the fusion temperatures of the reagents. The new biomaterials showed unequivocal success for these proposed reactions and demonstrated abilities to remove cations from aqueous solutions. Phthalic anhydride pendant chains bonded to biopolymeric structure showed high performance for cation sorption at short times, 60–180 min, to give the maximum sorption capacities of 0.52, 0.54, and 0.59 mmol g^–1 for copper, cobalt, and nickel, respectively. Identically, maleic anhydride chains gave 0.27, 0.32, and 0.20 mmol g^–1 for the same sequence of cations. The equilibrium data were best represented by the Langmuir model in a linear regression and by the Freundlich model in nonlinear regression procedures. These new biopolymers are promising for ecosystem remediation with advantages in using biopolymers based on a natural, cheap, and abundant raw biomaterial

New Chemical Organic Anhydride Immobilization Process Used on Banana Pseudostems: A Biopolymer for Cation Removal

Maleic and phthalic anhydrides were chemically incorporated onto the banana pseudostem biopolymeric structure through reaction without solvent at the fusion temperatures of the reagents. The new biomaterials showed unequivocal success for these proposed reactions and demonstrated abilities to remove cations from aqueous solutions. Phthalic anhydride pendant chains bonded to biopolymeric structure showed high performance for cation sorption at short times, 60–180 min, to give the maximum sorption capacities of 0.52, 0.54, and 0.59 mmol g^–1 for copper, cobalt, and nickel, respectively. Identically, maleic anhydride chains gave 0.27, 0.32, and 0.20 mmol g^–1 for the same sequence of cations. The equilibrium data were best represented by the Langmuir model in a linear regression and by the Freundlich model in nonlinear regression procedures. These new biopolymers are promising for ecosystem remediation with advantages in using biopolymers based on a natural, cheap, and abundant raw biomaterial

New Chemical Organic Anhydride Immobilization Process Used on Banana Pseudostems: A Biopolymer for Cation Removal

Maleic and phthalic anhydrides were chemically incorporated onto the banana pseudostem biopolymeric structure through reaction without solvent at the fusion temperatures of the reagents. The new biomaterials showed unequivocal success for these proposed reactions and demonstrated abilities to remove cations from aqueous solutions. Phthalic anhydride pendant chains bonded to biopolymeric structure showed high performance for cation sorption at short times, 60–180 min, to give the maximum sorption capacities of 0.52, 0.54, and 0.59 mmol g^–1 for copper, cobalt, and nickel, respectively. Identically, maleic anhydride chains gave 0.27, 0.32, and 0.20 mmol g^–1 for the same sequence of cations. The equilibrium data were best represented by the Langmuir model in a linear regression and by the Freundlich model in nonlinear regression procedures. These new biopolymers are promising for ecosystem remediation with advantages in using biopolymers based on a natural, cheap, and abundant raw biomaterial