Dioxane
Mostrando 1-12 de 65 artigos, teses e dissertações.
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1. NANOBIOCATALYTIC SYSTEMS BASED ON LIPASE-Fe3O4 AND CONVENTIONAL SYSTEMS FOR ISONIAZID SYNTHESIS: A COMPARATIVE STUDY
Abstract Superparamagnetic nanomaterials have attracted interest in many areas due to the high saturation magnetization and surface area. For enzyme immobilization, these properties favor the enzyme-support contact during the immobilization reaction and easy separation from the reaction mixture by use of low-cost magnetic processes. Iron oxide magnetic nanop
Braz. J. Chem. Eng.. Publicado em: 2016-09
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2. Synthesis and Characterization of New Copolymer Based Cinnamyl Methacrylate Monomer: Determination of Monomer Reactivity Ratio and Statistical Sequence
AbstractRadical-initiated copolymerization of Cinnamyl methacrylate (CMA) and Ethyl methacrylate (EMA) monomers were carried out at lower conversions (<10%) using 2,2’-azobisisobutyronitrile (AIBN) as initiator, in 1,4-dioxane at 60 °C and nitrogen atmosphere. Structure and composition of copolymers for wide range of monomer feed were determined by Fourie
Mat. Res.. Publicado em: 2015-10
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3. EFFECTS OF SOLVENT, BASE, AND TEMPERATURE IN THE OPTIMISATION OF A NEW CATALYTIC SYSTEM FOR SONOGASHIRA CROSS-COUPLING USING NCP PINCER PALLADACYCLE
The optimisation of a new catalyst system using NCP pincer palladacycle
1 was investigated using the experimental design technique. NCP pincer palladacycle1 was previously investigated in Suzuki-Miyaura and Heck-Mizoroki cross-couplings and found to be a highly efficient catalyst precursor. In this study, the effects of the typeQuím. Nova. Publicado em: 2015-06
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4. Cellulose Sulfuric Acid as an Eco-Friendly Catalyst for Novel Synthesis of Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones
A novel synthesis of a series of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones has been developed from reactions of 1-(5-methyl-1-phenyl-1H-pyrazol-4-yl)-3-arylprop-2-en-1-ones and 7-amino-1,3-disubstituted[1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-ones in dioxane under thermal conditions, using cellulose sulfuric acid as an eco-friendly acid catalyst. The
J. Braz. Chem. Soc.. Publicado em: 2015-05
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5. Caracterização de membranas assimétricas de acetato de celulose produzidas a partir do aproveitamento do resíduo da palha de milho para uso em ultrafiltração
Cellulose acetates (CA) with different degrees of acetylation were synthesized from cellulose extracted from corn stover. Membranes were prepared for the ultrafiltration process with pure polymers and blend form of CA utilizing a dioxane/acetone system. The membranes were characterized according to their transport properties. The blend form materials present
Quím. Nova. Publicado em: 2014-06
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6. Indomethacin solubility estimation in 1,4-dioxane + water mixtures by the extended hildebrand solubility approach
Extended Hildebrand Solubility Approach (EHSA) was successfully applied to evaluate the solubility of Indomethacin in 1,4-dioxane + water mixtures at 298.15 K. An acceptable correlation-performance of EHSA was found by using a regular polynomial model in order four of the W interaction parameter vs. solubility parameter of the mixtures (overall deviation was
Química Nova. Publicado em: 2011-09
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7. Spectrophotometric determination of famotidine using sulphonphthalein dyes
Four new extraction-free spectrophotometric methods have been established for the quantitation of famotidine (FMT). The methods are based on the formation of yellow ion-pair complexes between FMT and four sulphonphthalein dyes viz., bromothymol blue (method A), bromophenol blue (method B), bromocresol purple (method C) and bromocresol green (method D) in dio
Química Nova. Publicado em: 2011
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8. Espectros de duas formas de lignina obtidos por ressonância magnética nuclear.
O conteúdo de lignina pode ser útil na estimativa da digestão da fibra de plantas forrageiras. A determinação quantitativa da lignina pelo método espectrofotométrico pressupõe a existência de um padrão de referência satisfatório. O objetivo deste trabalho foi avaliar, por meio da ressonância magnética nuclear (RMN), duas ligninas, uma extraída
Pesquisa Agropecuária Brasileira. Publicado em: 2011
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9. Effect of porogenic solvent on selective performance of molecularly imprinted polymer for quercetin
Molecularly imprinted polymers (MIP's) for quercetin were successfully synthesized by a thermal polymerization method using quercetin as template molecule, acrylamide as functional monomer and ethylene glycol dimethacrylate as cross-linker in the presence of four different porogenic solvents: 1,4-dioxane, tetrahydrofuran (THF), acetone, and acetonitrile. The
Materials Research. Publicado em: 2009-09
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10. Construção de um calorímetro isotérmico diferencial de alta sensibilidade e baixo custo
The high cost of sensitivity commercial calorimeters may represent an obstacle for many calorimetric research groups. This work describes the construction and calibration of a batch differential heat conduction calorimeter with sample cells volumes of about 400 μL. The calorimeter was built using two small high sensibility square Peltier thermoelectric sens
Química Nova. Publicado em: 2009
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11. Potentiometric studies on nickel(II), copper(II) and zinc(II) metal complexes with new schiff bases containing cyclobutane and thiazole groups in 60% dioxane-water mixture
Neste estudo são investigados potenciometricamente os equilíbrios ácido-base de bases de Schiff contendo ciclobutano e tiazol como grupos funcionais e de seus complexos de cobre(II), níquel(II) e zinco(II) em dioxano-água, 60% em média, a 25,0 ± 0,1 ºC e com I = 0,10 mol L-1 (NaClO4). Os valores das constantes de protonação, logK OH, logK NH(1) e l
Journal of the Brazilian Chemical Society. Publicado em: 2009
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12. Singlet oxygen reactivity in water-rich solvent mixtures
The 3-methylindole (3MI) oxygenation sensitized by psoralen (PSO) has been investigated in 100%, 20% and 5% O2-saturated water/dioxane (H2O/Dx) mixtures. The lowering of the ¹O2* chemical rate when water (k chem∆3MI = 1.4 × 109 M-1 s-1) is replaced by deuterated water (k chem∆3MI = 1.9 × 108 M-1 s-1) suggests that hydrogen abstraction is involved in t
Química Nova. Publicado em: 2008