Chemical Reactions
Mostrando 1-12 de 790 artigos, teses e dissertações.
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1. Sustainable and Reusable Sulfonic Acid-Functionalized Task-Specific Ionic Liquid Catalysts for Multicomponent Reactions. A Review
Improvements in Sustainable Organic Synthesis are usually related to the investigation of less hazardous, non-corrosive and renewable materials, as well as waste prevention, energy efficiency, solvent-free reactions, and the development of efficient reusable catalysts. In this context, multicomponent reactions emerged as important strategies for the rapid an
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. PEDRO DE ALCANTARA LISBOA, QUÍMICO BRASILEIRO DO SÉCULO XIX
The subject of the present article is a Brazilian chemist who lived and worked in the nineteenth century and who is hardly known today. He was the first person in Brazil, still in the first half of the nineteenth century, to write chemical equations in the description of actual reactions, and also the first to use equations in order to perform stoichiometric
Química Nova. Publicado em: 2022
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3. ESTUDO TEÓRICO E EXPERIMENTAL DE ESTRUTURA E REATIVIDADE RELACIONADO AO METABOLISMO E TOXICIDADE DO PARACETAMOL
An experimental and theoretical approach on oxidative metabolism of paracetamol was applied for the pharmaceutical chemistry learning. Classical reactions, functional group identification, structural parameter, and chemical reactivity using frontier orbitals and Fukui index were used explaining the main products between N-acetyl-p-benzosemiquinone (NAPQI) an
Química Nova. Publicado em: 2022
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4. Household Infrared Technology as an Energy-Efficient Approach to Achieve C-Cπ Bond Construction Reactions
We examined the ability of short-wave infrared (IR) light in the λ1.5-3.0 μm region of the infrared emission spectrum to accomplish C-Cπ bond construction reaction between π-excessive azaheteroaromatic and different carbonyl substrates supported on a bentonitic clay catalyst in solventless condition via a three-component condensation reaction. Preliminar
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. NMR Relaxometry Applied to Chemical Studies of Paramagnetic Metal Cation Complexes: Fundamentals and Applications
Low field time-domain nuclear magnetic resonance (TD-NMR) relaxometry of paramagnetic metal cations (PMC) has been widely used to study and improve contrast agents for magnetic resonance imaging (MRI). However, despite its remarkable potential, TD-NMR is rarely used to study PMC complexes, and coordination compounds in non-biomedical application. Therefore,
Journal of the Brazilian Chemical Society. Publicado em: 2022
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6. CLASSIFICAÇÃO DAS SUBSTÂNCIAS QUÍMICAS: UM CONCEITO POUCO EXPLORADO NA EDUCAÇÃO QUÍMICA
The classification of chemical substances is a concept little explored in Chemistry teaching literature and in Chemistry textbooks at higher and secondary levels. The aim of this paper is to discuss theoretically the importance and contributions of this concept for teaching and learning Chemistry. The History of Chemistry reveals that the chemical criteria f
Quím. Nova. Publicado em: 2021-04
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7. MODIFICAÇÃO QUÍMICA DO POLIPROPILENO ATRAVÉS DA INTRODUÇÃO DE GRUPOS SULFÔNICOS PARA APLICAÇÃO COMO CATALISADOR EM REAÇÕES DE ESTERIFICAÇÃO
In this work, the chemical modification of pristine polypropylene was carried out through sulfonation reactions with concentrated sulfuric acid (PPS1) and fuming sulfuric acid (PPS2), for production of heterogeneous catalysts used in esterification reactions. Fourier transform infrared spectroscopy, elemental analysis, degree of substitution and ion exchange
Quím. Nova. Publicado em: 2021-04
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8. Efeitos do Hydrosalpinx no Falho de Implantação Endometrial: Avaliar a salpingectomia nas mulheres em curso de Fertilização in vitro
Abstract Hydrosalpinx is a disease characterized by the obstruction of the salpinx, with progressive accumulation in the shape of a fluid-filled sac at the distal part of the tuba uterina, and closed to the ovary. Women with hydrosalpinges have lower implantation and pregnancy rates due to a combination of mechanical and chemical factors thought to disrupt t
Rev. Bras. Ginecol. Obstet.. Publicado em: 2021-04
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9. IMIDAZOL E CATÁLISE: UM PAR PERFEITO
The imidazole (IMZ) ring presents several chemical properties that turns it into a versatile acid-basic/nucleophilic catalyst. The discovery of the biological properties of histidine (amino acid with IMZ ring) instigates the study of this class of compounds. It is found in nature in several enzymes such as chymotrypsin and RNAses due to these properties. Thi
Quím. Nova. Publicado em: 2021-03
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10. ORBITALS IN GENERAL CHEMISTRY, PART III: CONSEQUENCES FOR TEACHING
In Part III of this series, we undertake a critique of the nature of application of orbitals to describe or to explain the structure and the binding within molecules and materials. Teaching orbitals in introductory chemistry presents five dilemmas that cannot be easily resolved. We thus conclude, based on mathematical realties, that orbitals are not essentia
Quím. Nova. Publicado em: 2021-03
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11. COVID-19 in Brazil: A Message to the World
In Part III of this series, we undertake a critique of the nature of application of orbitals to describe or to explain the structure and the binding within molecules and materials. Teaching orbitals in introductory chemistry presents five dilemmas that cannot be easily resolved. We thus conclude, based on mathematical realties, that orbitals are not essentia
Rev. Bras. Ginecol. Obstet.. Publicado em: 2021-03
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12. Unified comprehension of the kinetics of isothermal ceramic processes under field-free and resonant wave-field conditions
Abstract This paper proposes a unified comprehension of the isothermal ceramic process kinetics stemming from mesoscopic irreversible thermodynamics. Accordingly, a unified process kinetic equation (UPKE) is derived, which predicts that the global isothermal process rate of any ceramic process is, in general, nonlinearly related both to its activation energy
Cerâmica. Publicado em: 2021-03