JBCS

The point to carry out the distillation cut is between fraction 05 and 06, because in fraction 06 the content of C12 decreases and that of C18 increases. Thus, the distillate would be between 50 and 60% of the total biodiesel used in distillation.

Leaves of Pentacalia desiderabilis (Asteraceae) were extracted using BMImBr and H₂O in a MAE system. Partition with CH₂Cl₂ and fractionation of organic phase afforded four related quinoids (1 - 4). Compounds 1 - 3 displayed activity against Cladosporium sp.

A series of nitroguanidine and 1,1-diamino-2,2-dinitroethene based cyclic energetic materials were designed and their electronic structures, detonation properties and thermal stabilities were fully investigate by density functional theory (DFT).

The presence of the phenolic mediator, 3,4-dihydroxyphenylacetic acid, increased the reaction rate to the phenol red decolorization by a Fenton system.

• Multivariate optimization of analytical methods.
• Silver chromate as coprecipitant copper separation and preconcentration.
• Determination of copper in water samples by FAAS.

Analysis of the correlation between electronic and spectral data of the conformers of new 1,3,4-thiadiazole compounds.

Phytochemical study of the CHCl₃ fraction from EtOH extract of T. hispidula stem led to the isolation of six pure compounds and four mixtures, predominantly triterpenoids and steroids. The CHCl₃ and EtOAc fractions were the most active against Leishmania major promastigotes.

Titanium cooperated with NH₂-UiO-66 has been prepared via post synthesis modifications approach and perform enhanced CO₂ uptake application due to their unprecedented capacity to store small molecules.

We describe a biocompatible nanoparticle system with a magnetic core coated with dextran. The coating was also crosslinked, grafted with amino groups and conjugated with a fluorophore, allowing magnetic resonance contrast action.

The ballpoint pen ink ageing can be used to date questioned documents. One way to evaluate the ageing is the quantification of volatile components as 2-phenoxyethanol. This paper concerned about GC/MS method evaluation of merit figures and the influence of different kinds of paper sheets in the quantification of 2-phenoxyetanol, using Full Factorial Design.

The bees Apis mellifera visit species of Fabaceae. Pollen is acquired in hives and palynological analysis shows the botanical pollen types. The chemical constituents for the Fabaceae pollen bee were identified.

Erythina velutina occurs with chromatic variations in its seeds and flowers on Fernando de Noronha Island. Chemical analysis revealed significant differences in the chemical profile of the essential oils between the red and orange flowers, whereas the fatty acid profile of the red and black seeds was similar.

CPE-scanometry is applied for the determination of Phenylalanine amino acid. The extracted phase was diluted with alkali ethanol and transfered to a special cell. The cells containing the analyte solution were scanned with a scanner, then the color of each cell was analyzed, by software written in Visual Basic (VB 6), to obtain the red, green and blue values.

The graph shown in the figure is inserted in the context of the article, the graph represents the path traveled by green aircraft that cares about the environment, driven by a drop-in biofuel. The aircraft is crossing a sea of biokerosene.

This study evaluated the concentrations of TSP and metals in the air of Ribeirão Preto city. Spatial differences were found between some metals, but seasonal differences were found between TSP and the most of the elements.

Stability and detonation performance of derivatives of Triacetonetriperoxide were investigated. Results show that TATPNO₂ is a candidate of novel high energy density materials.

Compounds from the ethanolic extract of pepper fruit Capsicum baccatum var. pendulum identified by High-Performance Liquid Chromatography (HPLC).

This review presents a critical view of the toxic effects of silver nanoparticles (Ag NPs) on in vitro and in vivo biological models.

Prospects in genetic engineering of enzymes, modules and domains from polyketides megasynthases results in structural diversity on natural products.

This study compared eight simple methods for identification of macrolides residues in canned baby food and an effective extraction method was achieved, using QuEChERS procedure for sample preparation.

Methanator-GC-FID analysis of low level of CO in presence of O₂ need meticulous evaluation. Sample stability and container reusability indicated borosilicate flask with butyl rubber and PTFE/silicone septa sampler as more appropriate for storing GHG and CO samples.

Experimental scheme of the detection of petroleum using oil/water interfaces with an electrochemical approach.

The United Nations has proclaimed 2019 as the International Year of the Periodic Table of Chemical Elements. For that reason, it is considered pertinent to highlight the importance of the periodic system in the scientific and technological development of the chemistry.

Validation of a simple, precise, accurate, rapid and low-cost UV spectrophotometric method for quantification of acetylsalicylic acid in pharmaceutical formulations for experimental activities on teaching laboratories.

Theory of valence resulted from the amalgamation of earlier theories of radicals and types, and was connected with the development of several fundamental aspects of chemistry, such as structural theory, chemical bonding and the periodic table.

In the first decades of the 20^th century, general chemistry textbooks presented the concept of valence in different ways, from classical approaches to the electronic model. Didactic models might include even an analogy with hooks holding atoms together.

Silver bar (front and rear) obtained by the Baron of Eschwege in 1812 from the argentiferous galena (PbS) of the Rio Abaeté sertões - MG.