Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) in human breast milk from Colombia: A probabilistic risk assessment approach.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) are ubiquitous environmental contaminants. They were produced in relatively large volumes in the last century and are now subject to long-term monitoring and regulated under the United Nations Stockholm Convention (SC) on persistent organic pollutants (POPs). Though restricted, human exposure is still a concern and in some regions of the globe the information on the health risk is limited. Sixty breast milk samples from nursing mothers were collected between 2014 and 2015, residing in Bogota, Cartagena, and Medellin, which are industrialized cities in Colombia. This is the first comprehensive study to determine the concentrations in breast milk of PBDEs (n = 7), PCBs (n = 29), and OCPs (n = 28) in Colombia. The detection frequency of POPs, including BDE-47, CB-138, CB-153, CB-156, and CB-180, as well as several OCPs such as chloroneb, aldrins, HCHs, DDTs, and heptachlor, was found to be 100% in all samples tested. The mean concentrations of the analyzed legacy POPs were ∑3DDTs (423 ng/g lw) > chloroneb (50.1 ng/g lw) > ∑2permetrins (17.5 ng/g lw) > ∑2aldrins (16.7 ng/g lw) > 29 PCBs (15.04 ng/g lw) > ∑2chlordanes (CHLs) (11.2 ng/g lw) ≈ ∑3endosulfans (11.1 ng/g lw) > ∑2heptachlors (2.43 ng/g lw) > 7PBDEs (2.1 ng/g lw) > ∑4HCHs (0.58 ng/g lw). The results of this study suggest that the concentrations of DDTs were present in breast milk samples from Colombia at levels comparable to those found in previous studies conducted in other countries such as Brazil, Uruguay, Chile, and various Asian countries. The concentrations of PBDE and PCB congeners, as well as many pesticides, were found to be significantly correlated with each other. This suggests that these substances may have similar sources of exposure. The strength of the pair correlation among concentrations of POPs was assessed using Spearman's correlation coefficients, which varied from r = 0.62 for the association between BDE-47 and CB-153, to a high correlation of 0.99 for the correlation between γ-Chlordane and heptachlor. This suggests that these POPs may share similar sources, such as diet. An exposure assessment model obtained by Monte Carlo simulation showed that infants were exposed to low concentrations of POPs with exception of p,p'-DDE and Aldrin, in which 25th, 50th and 95th percentiles were greater than the threshold reference values of non-carcinogenic effects suggested by US-EPA regulations while the 90th percentile of pg TEQ/Kg-bw/day for dl-PCBs was above of the tolerable daily intake (TDI) proposed by the World Health Organization (WHO). Therefore, the health risk of infants exposed to OCPs and dl-PCBs should be exanimated continually through biomonitoring programs in the Colombian population.

Recent Advances in the Microencapsulation of Essential Oils, Lipids, and Compound Lipids through Spray Drying: A Review.

In recent decades, the microcapsules of lipids, compound lipids, and essential oils, have found numerous potential practical applications in food, textiles, agricultural products, as well as pharmaceuticals. This article discusses the encapsulation of fat-soluble vitamins, essential oils, polyunsaturated fatty acids, and structured lipids. Consequently, the compiled information establishes the criteria to better select encapsulating agents as well as combinations of encapsulating agents best suited to the types of active ingredient to be encapsulated. This review shows a trend towards applications in food and pharmacology as well as the increase in research related to microencapsulation by the spray drying of vitamins A and E, as well as fish oil, thanks to its contribution of omega 3 and omega 6. There is also an increase in articles in which spray drying is combined with other encapsulation techniques, or modifications to the conventional spray drying system.

Protection of Mono and Polyunsaturated Fatty Acids from Grapeseed Oil by Spray Drying Using Green Biopolymers as Wall Material.

One of the most common ways to protect oils is microencapsulation, which includes the use of encapsulating agents. Due to the environmental problems facing humanity, this study seeks to combine green biopolymers (microcrystalline cellulose and whey protein isolate) that function as encapsulating agents for grapeseed oil. Grapeseed oil that is obtained from agro-industrial waste has shown health benefits, including cardioprotective, anticancer, antimicrobial, and anti-inflammatory properties. These health benefits have been mainly associated with monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. In this sense, it has been observed that grapeseed oil can be easily modified by environmental factors such as oxygen, high temperatures, and light, showing the instability and easy degradation of grapeseed oil. In this study, grapeseed oil was encapsulated using the spray-drying technique to conserve its lipidic profile. Powder recovery of the grapeseed oil microcapsules ranged from 65% to 70%. The encapsulation efficiency of the microcapsules varied between 80% and 85%. The FTIR analysis showed chemical interactions that demonstrate chemisorption between the grapeseed oil and the encapsulating material, while the SEM micrographs showed a correct encapsulation in a spherical shape. Gas chromatography showed that the lipid profile of grapeseed oil is preserved thanks to microencapsulation. Release tests showed 80% desorption within the first three hours at pH 5.8. Overall, whey protein and microcrystalline cellulose could be used as a wall material to protect grapeseed oil with the potential application of controlled delivery of fatty acids microcapsules.

Comparison by Life-Cycle Assessment of Alternative Processes for Carvone and Verbenone Production.

Verbenone and carvone are allylic monoterpenoid ketones with many applications in the fine chemicals industry that can be obtained, respectively, from the allylic oxidation of α-pinene and limonene over a silica-supported iron hexadecachlorinated phthalocyanine (FePcCl16-NH2-SiO2) catalyst and with t-butyl hydroperoxide (TBHP) as oxidant. As there are no reported analyses of the environmental impacts associated with catalytic transformation of terpenes into value-added products that include the steps associated with synthesis of the catalyst and several options of raw materials in the process, this contribution reports the evaluation of the environmental impacts in the conceptual process to produce verbenone and carvone considering two scenarios (SI-raw-oils and SII-purified-oils). The impact categories were evaluated using ReCiPe and IPCC methods implemented in SimaPro 9.3 software. The environmental impacts in the synthesis of the heterogeneous catalyst FePcCl16-NH2-SiO2 showed that the highest burdens in terms of environmental impact come from the use of fossil fuel energy sources and solvents, which primarily affect human health. The most significant environmental impacts associated with carvone and verbenone production are global warming and fine particulate matter formation, with fewer environmental impacts associated with the process that starts directly from turpentine and orange oils (SI-raw-oils) instead of the previously extracted α-pinene and limonene (SII-purified-oils). As TBHP was identified as a hotspot in the production process of verbenone and carvone, it is necessary to choose a more environmentally friendly and energy-efficient oxidizing agent for the oxidation of turpentine and orange oils.

Polycyclic aromatic hydrocarbons (PAHs) in human breast milk from Colombia: Spatial occurrence, sources and probabilistic risk assessment.

The diet is the main route that polycyclic aromatic hydrocarbons (PAHs) enter the body and measuring breast milk is one of the best ways to understand the maternal body burden and can be passed on to infants. In this study, it was determinate the concentrations of 23 PAHs in 60 milk samples taken from 3 cities in Colombia and to determine the potential routes of exposure and risk to human health. On average, concentration for the ∑PAHs across all locations was 186.6 ng g-1, lipid mass (LM), with city means of 260.1, 175.7, and 123.9 ng g-1 LM for Cartagena, Bogota and Medellin, respectively. Monte Carlo simulations were used to estimate the hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) for infant dietary exposure to PAHs. HQs were below the safe thresholds (HQ = 1) while ILCRs were greater than the reference value equal to 10-6 (mg kg-1day-1). Dietary source assessment indicated that fish is a significant source of PAHs, with mothers that consumed fish at least once per week having ∼2.5 times greater PAH milk concentrations than other groups. While a disparity was also observed among consumers of exclusively marine (∑PAHs 198.5 ng g-1 LM) or freshwater fish (∑PAHs 85.7 ng g-1 LM). However, geographical considerations can be significant in this finding.

Thermodynamics of the Isomerization of Monoterpene Epoxides.

In this contribution, the thermodynamic analysis of α- and ß-pinene epoxide isomerization over Fe and Cu supported on MCM-41 is presented using computational chemistry and group contribution methods (GCMs). Some physical-chemical data (T c, P c, v c, Z c, ω, T b, T fus) and thermodynamic (S°298.15, C p,298.15 °, C v,298.15 °, ΔH f,298.15 °, ΔG f,298.15 °, ΔH vb °, ΔH fus, C pL) properties obtained by different GCMs are reported for several monoterpenes and monoterpenoids, which significantly contribute to the knowledge of the properties of these compounds. Density functional theory (DFT), PBE-D3/6-311G(d,p), was employed for determining the Gibbs free energy and the heat of reaction associated with the transformation of monoterpene epoxides into aldehydes, ketones, and related oxygenated compounds in the presence of different solvents and at several temperatures. The calculations were compared with available data reported and the experimental results of the catalytic reactions. The transformation of α- and ß-pinene epoxides into aldehydes appears to be more spontaneous and favorable than their transformations into alcohols in a wide range of temperatures. These results are in agreement with the experiments over Fe/MCM-41 and Cu/MCM-41, where α-pinene epoxide isomerization yields campholenic aldehyde (50-80% selectivity) as the main product. The 1.7Fe/MCM-41 material was more active in all solvents than 1.3Cu/MCM-41 for both α- and ß-pinene epoxide isomerization. However, perillyl alcohol (20-70% selectivity) was the most favored for the isomerization reaction, except when ethyl acetate was the solvent. Enthalpy and Gibbs free energy of the studied reactions estimated by both GCMs and DFT calculations did not show large differences for most of the reactions at evaluated temperatures.

Influence of molecular structure of oleoresin-derived compounds on flame properties and emissions from laminar flames.

The search for renewable fuels or components which may improve or replace fossil fuels is an important step towards a sustainable future. In particular, the pine oleoresin produced by conifer trees, which is composed by turpentine oil and non-volatile rosin, may be transformed into alternative fuels. In this work, combustion of six molecules which can be obtained from oleoresin either by distillation (i.e., α- and ß-pinene) or by further oxyfunctionalization (nopol, terpineol, myrtenol, and borneol) was studied to assess the potential of pine oleoresin as raw material for biofuels. Emission indices of the main pollutants (carbon monoxide-CO, unburned hydrocarbons-UHC, and nitrogen oxides-NOx) were obtained in non-premixed co-flow laminar flames of the oleoresin-derived molecules blended with n-heptane. The main characteristics of the flames (i.e., temperature and height) were also determined. Significant increase in flame temperature and reduction in CO and UHC emissions with respect to n-heptane were observed with nopol, terpineol, and myrtenol, along an increase in NOx emissions, suggesting an improvement in combustion performance. In addition, differences in emission indices, evidenced for these molecules (even between α- and ß-pinene), suggest the importance of the molecular structure in the combustion reaction.

Turpentine valorization by its oxyfunctionalization to nopol through heterogeneous catalysis.

Turpentine is a mixture of monoterpene hydrocarbons obtained as a by-product in the paper industry. In this contribution we present its transformation process towards an alcohol named nopol, that is an important household product and fragrance raw material. Reaction conditions were established for the oxyfuntionalization of crude turpentine oil over Sn-MCM-41 catalyst for the selective conversion of ß-pinene to nopol. Synthesized materials were characterized by XRD, N2 adsorption, FT-IR, TEM and chemical absorption. The reaction was tested in 2 mL glass reactor with a sample of commercial turpentine with α-pinene (55.5% w/w) and ß-pinene (39.5% w/w) as main components and scaled up into a 100 mL Parr reactor, getting 92% conversion of ß-pinene and a nopol selectivity of 93%. The reusability tests showed that the catalyst can be reused 4 times without loss of activity. The results showed that 86% less solvent and 37.5% less paraformaldehyde can be used with turpentine, compared to the conditions used with ß-pinene for getting similar catalysts activity.

Reaction Mechanism of the Isomerization of Monoterpene Epoxides with Fe3+ as Active Catalytic Specie: A Computational Approach.

The reaction mechanism of the isomerization of α and ß-pinene epoxides with Fe species as catalysts was studied with density functional theory (DFT) calculations and an experimental methodology. ß-pinene epoxide can be isomerized into myrtanal and myrtenol in four steps, while in the case of perillyl alcohol, two additional steps are necessary. On the other hand, high selectivity to myrtanal obtained experimentally can be explained by the number of steps and the kind of the hydrogen transference that is easier for this compound in comparison with myrtenol and perillyl alcohol. A thermodynamic analysis showed that transformation into myrtenol, myrtanal, and perillyl alcohol is spontaneous but transformation into myrtanal is the most favorable. In the case of α-pinene epoxide rearrangement, a mechanistic study was carried out toward the optimization of the possible intermediates. Synthesis of campholenic aldehyde and carveol from α-pinene epoxide was carried out through three steps after the coordination of oxygen to iron, showing that in contrast to carveol formation, campholenic aldehyde synthesis is spontaneous. Analysis of ∇2ρ, the total energy density (H = V + G), and the |V|/G ratio evaluated at the bond critical point of the Fe-O bond showed for both epoxides that such interaction is closed shell instead of covalent. Apparently, α-pinene epoxide can be isomerized faster that ß-pinene epoxide with Fe3+, which is in agreement with previous experimental results. This is the first report where a reaction mechanism of isomerization of monoterpenes epoxides is studied based on very detailed experimental and computational methodologies.

Diseño experimental para determinar el efecto del tamaño del pellet de catalizadores bimetálicos Cu-Ni en la reacción de desplazamiento de agua / Experimental design to determine the effect of the pellet size of bimetallic Cu-Ni catalysts in the water gas shift reaction / Desenho experimental para determinar o efeito do tamanho do pellet de catalisadores bimetálicos de Cu-Ni na reacção de deslocamento de agua

Resumen Se sintetizaron catalizadores bimetálicos de Cu-Ni en relación molar 2-1 en pellets cilíndricos de carbón activado de diferentes diámetros (0,2 cm; 0,3 cm y 0,4 cm) y longitud (0,4 cm y 0,6 cm); se evaluaron en la reacción de desplazamiento de agua a 330 °C y presión atmosférica. Se realizó un diseño experimental para evaluar el efecto de las variables, diámetro y longitud, sobre la conversión del monóxido de carbono. La importancia de los principales factores y sus interacciones se examinaron por medio del análisis de varianza (ANOVA). Los resultados mostraron que tanto el diámetro como la longitud afectan significativamente la conversión del monóxido de carbono. Los resultados de la actividad catalítica, bajo las mejores condiciones de diámetro (0,4 cm) y longitud (0,6 cm) de los pellets, mostraron una conversión del monóxido de carbono del 96%.

Abstract Bimetallic Cu-Ni catalysts were synthesized with molar ratio 2-1 in cylindrical activated carbon pellets of different diameters (0.2 cm, 0.3 cm, and 0.4 cm) and length (0.4 cm and 0.6 cm). They were evaluated in the water gas shift reaction at 330 °C and atmospheric pressure. An experimental design was developed to evaluate the effect of variables, diameter and length of the pellets, over carbon monoxide conversion. The importance of the main factors and their interactions were examined by analysis of variance (ANOVA). The results showed that both diameter and length of the pellets had significant effect on carbon monoxide conversion. The results of the catalytic activity indicated that up to 96% CO conversion was obtained at the optimum characteristic of the pellets, diameter of 0.2 cm and length of 0.6 cm.

Resumo Foram sintetizados catalisadores bimetálicos de Cu-Ni em proporção molar 2-1 sobre pastilhas de carvão ativado de diferentes diâmetros (0,2 cm; 0,3 cm e 0,4 cm) e comprimentos (0,4 cm e 0,6 cm) e foram avaliados na reação de mudança de vapor de agua a 330 °C e pressão atmosférica. Um desenho experimental foi desenvolvido para avaliar o efeito de variáveis, diâmetro e comprimento, na conversão de monóxido de carbono. A importância dos principais fatores e as suas interações foram examinados por análise de variância (ANOVA), os resultados mostraram que tanto o diâmetro e o comprimento afetam significativamente a conversão de monóxido de carbono. Os resultados da atividade catalítica com as melhores condições de diâmetro (0,4 cm) e o comprimento (0,6 cm) das pastilhas mostrou uma conversão de monóxido de carbono de 96%.

Understanding the azeotropic diethyl carbonate-water mixture by structural and energetic characterization of DEC(H2O)(n) heteroclusters.

Diethyl carbonate (DEC) is an oxygenated fuel additive. During its synthesis through a promising green process, a DEC-water azeotrope is formed, which decreases DEC production efficiency in the gas phase. Molecular information about this system is scarce but could be of benefit in understanding (and potentially improving) the synthetic process. Therefore, we report a detailed computational study of the conformers of DEC, and their microsolvation with up to four water molecules, with the goal of understanding the observed 1:3 DEC:H2O molar ratio. The most stable DEC conformers (with mutual energy differences < 1.5 kcal mol(-1)) contribute to the energetic and structural properties of the complexes. An exhaustive stochastic exploration of each potential energy surface of DEC-(H2O)n, (where n = 1, 2, 3, 4) heteroclusters discovered 3, 8, 7, and 4 heterodimers, heterotrimers, heterotetramers, and heteropentamers, respectively, at the MP2/6-311++G(d,p) level of theory. DEC conformers and energies of the most stable structures at each heterocluster size were refined using CCSD(T)/6-311++G(d,p). Energy decomposition, electron density topology, and cooperative effects analyses were carried out to determine the relationship between the geometrical features of the heteroclusters and the non-covalent interaction types responsible for their stabilization. Our findings show that electrostatic and exchange energies are responsible for heterocluster stabilization, and also suggest a mutual weakening among hydrogen bonds when more than three water molecules are present. All described results are complementary and suggest a structural and energetic explanation at the molecular level for the experimental molar ratio of 1:3 (DEC:H2O) for the DEC-water azeotrope.

Effect of the substrate and catalyst chirality on the diastereoselective epoxidation of limonene using Jacobsen-type catalysts.

Chiral and achiral Jacobsen's catalysts in their homogeneous form or immobilized on Al-MCM-41 exhibit similar catalytic activity during diastereoselective epoxidation of limonene when in situ generated dimethyldioxirane is used as oxidizing agent. Experimental observations suggest that not only the catalyst chiral center but also the substrate chiral center participates in the preferential formation of most diastereomers. Remarkable turnover numbers (TON), up to 288, was achieved over the heterogeneous catalysts in comparison to their homogeneous counterparts (TON up to 46). Catalyst leaching rather than catalyst oxidative degradation was identified as the main source of catalyst deactivation during reutilization tests.