28 documents found, page 1 of 3

Oxigênio no contexto da COVID-19: o que sabemos sobre a molécula que respiramos...

OXYGEN IN THE COVID-19 CONTEXT: WHAT WE KNOW ABOUT THE MOLECULE WE BREATHE AND THE CENTRAL ROLE OF CHEMISTRY. In this work, the role of chemistry in the coronavirus disease 2019 (COVID-19) pandemic is highlighted through the medical oxygen supply crises in Brazil, as an example of oxygen utility in health. Starting from oxygen chemical characterization, the oxygen cycle in nature is discussed to show how oxygen...

EXTRAÇÃO DO PARACETAMOL E ANÁLISE DA DISPERSÃO DA MASSA DE COMPRIMIDOS: COMPARA...

Medicines are employed in undergraduate courses as motivational strategy. The experiment herein developed compares the extraction of paracetamol from generic and brand name drugs. Tablets were used from two commercial sources purchased from local drugstores. Twenty tablets of each drug type were individually weighed to average weight analysis and mass dispersion was statistically analyzed in simulating of quali...

COBRE: PRODUÇÃO INDUSTRIAL E APLICAÇÕES

This article is dedicated to element copper in honor to International Year of the Periodic Table celebrated in 2019. Copper is one of the oldest discovered chemical elements and manipulated by human being. In this sense, aspects about the element copper and its importance in different areas are described, from its mineral exploration through its processing and applications. Inorganic aspects such as structure o...

CLORAÇÃO MECANOQUÍMICA DA ACETANILIDA

We described herein a solvent-free synthesis of 4-chloroacetanilide both under hand grinding and mechanical grinding of stoichiometric amounts of acetanilide with trichloroisocyanuric acid. The synthetic approach was developed in the context of undergraduate organic chemistry and is the greener preparation of this compound already described.

EXPERIMENTO COM ABACATE, BORRA DE CAFÉ, LICURI E LEITE DE COCO PARA EXTRAÇÃO DE...

An undergraduate organic chemistry experiment for oil extraction and biodiesel production using alternative biomass was developed, whereby oils of avocado, coconut and spent coffee grounds were obtained and submitted to transesterification reaction with CH3OH under NaOH catalysis. Avocado and coffee oils were obtained by typical extraction and coconut oil was obtained through water evaporation of coconut milk i...

TOPOLOGIA UNIFICADA DOS ORBITAIS MOLECULARES DE FRONTEIRA PARA EXPLICAR REAÇÕES...

In this work is proposed a didactic alternative vision to teach pericyclic reactions. To this end, they were classified according to the connectivity of reactants systems, as connected atom reactions (CAR) and the other possibility, as not connected atom reactions (NOCAR). Electrocyclic reactions and sigmatropic rearrangements are examples of CAR categorization, and the cycloadditions being NOCAR. With these tw...

TOPOLOGIA DOS ORBITAIS MOLECULARES DE POLIENOS PARA DEDUZIR ENERGIAS RELATIVAS ...

A didactic alternative approach is proposed for deducing the molecular orbital topology of acyclic and cyclic polyenes and then evaluating their bonding, antibonding, and nonbonding character. The relative energies of molecular orbitals of neutral molecules and ions were described, in addition to the orbital degeneracy to cyclic conjugated polyenes, and the method deduce correctly the relative stability of poly...

ALÉM DA CAIPIRINHA: CACHAÇA COMO SOLVENTE PARA SÍNTESE ORGÂNICA E EXTRAÇÃO DE P...

Cachaça (brazilian sugarcane spirit) was applied for the first time as an alternative solvent in undergraduate experiments of organics synthesis, and natural dye extraction. The classical Claisen-Schmidt condensation of benzaldehyde with acetophenone and with acetone were employed to demonstrate the cachaça viability as solvent. Cachaça was also the recrystallization solvent of obtained benzalacetophenone and d...

Eco-Friendly, Catalyst and Solvent-Free, Synthesis of Acetanilides and N-Benzot...

An expeditious and green synthesis of acetamides in a solvent-free simple way is described, without catalyst or additives, and in good yield by an instantaneous reaction of anilines or 2-aminothiazoles and acetic anhydride without external heating, and with simple purification. Sixteen substituted acetanilides and four N-benzothiazole-2-yl-acetamides were formed, but aliphatic amines of low molecular weight wer...

ACETANILIDA: SÍNTESE VERDE SEM SOLVENTE