The essential oil (EO) of plants of the Myrtaceae family has diverse chemical composition and several applications. However, data on the oil yield, its composition, and its complete chemistry are still unavailable for some species belonging to this family, such as Myrcia eximia DC. In this study, the chemical compositions of the EOs of Myrcia eximia were evaluated by using gas chromatography (GC) alone and gas chromatography coupled with mass spectrometry (GC–MS). Samples for both evaluations were collected from the city of Magalhães Barata, State of Pará, Brazil, in 2017 and 2018. For the plant material collected in 2017, EO was obtained by hydrodistillation (HD) only, while, for the material collected in 2018, EO was obtained by hydrodistillation and steam distillation (SD), in order to evaluate the differences in chemical composition and mass yield of the EO. The yields of (E)-caryophyllene were 15.71% and 20.0% for the samples collected by HD in 2017 and 2018, respectively, while the yield was 15.0% for the sample collected by SD in 2018. Hexanal was found to be the major constituent in the EO obtained by HD, with yield of up to 26.09%. The oil yields reached 0.08% by using SD, and 0.01% and 0.36% for the samples collected in 2017 and 2018, respectively, using HD. The results of this study provide new information about the mass yield and chemical composition of Myrcia eximia DC, and they can add value and income to traditional populations, as well as facilitate the preservation of this species.

The control of invasive plants is still carried out with the use of synthetic chemical agents that may present high toxicity and, consequently, be harmful to humans and animals. In Brazil, especially in the Amazon, small producers use this kind of technique in a rustic way, with brushcutters or fire. In this sense, the search for natural agents with bioherbicide potential becomes necessary. Examples of these agents are the essential oils that over the years have been shown to be a viable alternative to weed control. Thus, this review aims to show the potentially phytotoxic activity of allelochemicals present in essential oils of different aromatic plants.

This chapter describes the use of carbon dioxide at high pressures as an alternative for the extraction of bioactive compounds in a more sustainable way, addressing some of its physicochemical properties, such as pressure, temperature, density, solvation, selectivity, and its interaction with the solute when modified by other solvents such as ethanol and water. This extraction process is considered chemically “green,” when compared to conventional extraction processes using toxic organic solvents.

This chapter reviews plant-based fatty acids as well as their methods of production, applications in the industry, and benefits in treatments of cardiovascular and cerebral diseases, besides being a source of food. The fatty acids obtained from vegetable matrices have been acting as alternatives to the use of lipids of animal origin, due to their limitation in relation to the increase in demand. Thus, plants have been investigated in order to act as sources of fatty acids and assist in the supply of such demands. Vegetable oils represent not only an economical alternative but also a beneficial source of human health.

Of African origin and with an estimated world production of 6.85 million tons, palm kernel oil contributes about 3% of the total world production of oils and fats. With such production, the world waste generation was about 10,026 × 103 tons in 2017, which represents an important environment issue. The present work aimed to review the literature on the main methods of extraction, applications, and future perspectives of Elaeis guineensis Jacq., with emphasis on its seed: palm kernel. Regarding its main applications, biodiesel production was highlighted, since the biomass generated can be used as a substitute for fossil fuels in energy production. Key words: Elaeis guineensis Jacq., palm kernel, extraction of vegetable oils, biodiesel.

In this work, the adsorption of benzene, toluene and p-xylene on activated carbon was verified through a computer simulation. A carbon model was used as the work basis. Several steps were completed from the modeling of the carbon structures and pollutants to simulations of molecular dynamics. After analyzing the results, it was found that the groups: ether, lactone and carbonyl (ketone) present in the carbon structure provided acidic character and due to this fact, and the carbon's complex network of micropores, the adsorption became viable. This study corroborates the present understanding on this type of phenomenon.