-
Organic & Biomolecular Chemistry Jul 2015Using simple riboflavin related compounds as biomimetic catalysts, catalytic oxidation of various substrates with hydrogen peroxide or molecular oxygen can be performed... (Review)
Review
Using simple riboflavin related compounds as biomimetic catalysts, catalytic oxidation of various substrates with hydrogen peroxide or molecular oxygen can be performed selectively under mild conditions. The principle of these reactions is fundamental and will provide a wide scope for environmentally benign future practical methods.
Topics: Biomimetic Materials; Catalysis; Chemistry Techniques, Synthetic; Dinitrocresols; Hydrogen Peroxide; Organic Chemicals; Oxidation-Reduction; Oxygen
PubMed: 26077635
DOI: 10.1039/c5ob00854a -
Journal of Environmental Monitoring :... Feb 2012In this paper, we discuss the advantages and drawbacks of POCIS (Polar Organic Chemical Integrative Sampler) for the evaluation of river water quality downstream of...
In this paper, we discuss the advantages and drawbacks of POCIS (Polar Organic Chemical Integrative Sampler) for the evaluation of river water quality downstream of wastewater treatment plants. POCIS proved well adapted to sampling alkylphenols and several pharmaceuticals. Concentration factors and the decrease in limits of quantification, compared to grab water sample analyses, were significant except for hormones, β-blockers and bronchodilators. Promising preliminary results obtained in situ on deuterated atenolol used as a performance reference compound need to be confirmed in-lab. This work confirms that POCIS is a valuable tool for monitoring hydrophilic organic molecules in river and wastewaters.
Topics: Environmental Monitoring; Fresh Water; Organic Chemicals; Pharmaceutical Preparations; Waste Disposal, Fluid; Water Pollutants, Chemical
PubMed: 22193508
DOI: 10.1039/c1em10730e -
Journal of the Air & Waste Management... Jun 2007The main objective of this study was to monitor the volatile organic compounds (VOCs) in the stack gas released from organic chemical industrial plants to determine...
The main objective of this study was to monitor the volatile organic compounds (VOCs) in the stack gas released from organic chemical industrial plants to determine emission factors. Samples from 52 stacks, with or without air pollution control devices (APCDs), from seven industrial processes were taken and VOCs measured using U.S. Environmental Protection Agency (EPA) Method 18. These 7 processes, including 26 plants, were the manufacturers of acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), acrylic resin (ACR), vinyl chloride (VC), para-terephthalic acid (PTA), and synthetic fiber (SYF). The results clearly indicate significant variations of emission factors among the various industrial processes, particularly emission factors for those without APCDs. As expected, those with APCDs yield much less emission factors. Regardless of those with or without APCDs, the order of manufacturing processes with regard to VOC emission factors is SYF > ABS > PS >ACR > PTA > PVC > VC. The emission factors for some processes also differ from those in EPA-42 data file. The VOC profiles further indicate that some VOCs are not listed in the U.S. VOC/Particulate Matter Speciation Data System (SPECIATE). The potential O3 formation is determined from the total amount of VOC emitted for each of seven processes. The resultant O3 yield varied from 0.22 (ACR) to 2.33 g O3 g(-1) VOC (PTA). The significance of this O3 yield is discussed.
Topics: Air Pollutants; Chemical Industry; Environmental Monitoring; Industrial Waste; Organic Chemicals; Oxidants, Photochemical; Ozone; Photochemistry; Volatilization
PubMed: 17608005
DOI: 10.3155/1047-3289.57.6.698 -
Environmental Science and Pollution... Jun 2013Polar organic chemical integrative samplers (POCIS) are useful for monitoring a wide range of chemicals, including polar pesticides, in water bodies. However, few...
Polar organic chemical integrative samplers (POCIS) are useful for monitoring a wide range of chemicals, including polar pesticides, in water bodies. However, few calibration data are available, which limits the use of these samplers for time-weighted average concentration measurements in an aquatic medium. This work deals with the laboratory calibration of the pharmaceutical configuration of a polar organic chemical integrative sampler (pharm-POCIS) for calculating the sampling rates of 17 polar pesticides (1.15 ≤ logK(ow) ≤ 3.71) commonly found in water. The experiment, conducted for 21 days in a continuous water flow-through exposure system, showed an integrative accumulation of all studied pesticides for 15 days. Three compounds (metalaxyl, azoxystrobine, and terbuthylazine) remained integrative for the 21-day experiment. The sampling rates measured ranged from 67.9 to 279 mL day(-1) and increased with the hydrophobicity of the pesticides until reaching a plateau where no significant variation in sampling rate is observed when increasing the hydrophobicity.
Topics: Calibration; Chemical Phenomena; Environmental Monitoring; Evaluation Studies as Topic; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Kinetics; Organic Chemicals; Pesticides; Sample Size; Water; Water Pollutants, Chemical
PubMed: 23135754
DOI: 10.1007/s11356-012-1284-3 -
Astrobiology Nov 2016Large bodies, such as the Moon, that have remained relatively unaltered for long periods of time have the potential to preserve a record of organic chemical processes...
Large bodies, such as the Moon, that have remained relatively unaltered for long periods of time have the potential to preserve a record of organic chemical processes from early in the history of the Solar System. A record of volatiles and impactors may be preserved in buried lunar regolith layers that have been capped by protective lava flows. Of particular interest is the possible preservation of prebiotic organic materials delivered by ejected fragments of other bodies, including those originating from the surface of early Earth. Lava flow layers would shield the underlying regolith and any carbon-bearing materials within them from most of the effects of space weathering, but the encapsulated organic materials would still be subject to irradiation before they were buried by regolith formation and capped with lava. We have performed a study to simulate the effects of solar radiation on a variety of organic materials mixed with lunar and meteorite analog substrates. A fluence of ∼3 × 10 protons cm at 4-13 MeV, intended to be representative of solar energetic particles, has little detectable effect on low-molecular-weight (≤C) hydrocarbon structures that can be used to indicate biological activity (biomarkers) or the high-molecular-weight hydrocarbon polymer poly(styrene-co-divinylbenzene), and has little apparent effect on a selection of amino acids (≤C). Inevitably, more lengthy durations of exposure to solar energetic particles may have more deleterious effects, and rapid burial and encapsulation will always be more favorable to organic preservation. Our data indicate that biomarker compounds that may be used to infer biological activity on their parent planet can be relatively resistant to the effects of radiation and may have a high preservation potential in paleoregolith layers on the Moon. Key Words: Radiation-Moon-Regolith-Amino acids-Biomarkers. Astrobiology 16, 900-912.
Topics: Amino Acids; Biomarkers; Extraterrestrial Environment; Gas Chromatography-Mass Spectrometry; Hydrocarbons; Moon; Organic Chemicals; Polymers; Radiation; Solvents
PubMed: 27870583
DOI: 10.1089/ast.2015.1442 -
Environmental Toxicology and Chemistry Sep 2011Predicting the association of contaminants with both particulate and dissolved organic matter is critical in determining the fate and bioavailability of chemicals in...
Predicting the association of contaminants with both particulate and dissolved organic matter is critical in determining the fate and bioavailability of chemicals in environmental risk assessment. To date, the association of a contaminant to particulate organic matter is considered in many multimedia transport models, but the effect of dissolved organic matter is typically ignored due to a lack of either reliable models or experimental data. The partition coefficient to dissolved organic carbon (K(DOC)) may be used to estimate the fraction of a contaminant that is associated with dissolved organic matter. Models relating K(DOC) to the octanol-water partition coefficient (K(OW)) have not been successful for many types of dissolved organic carbon in the environment. Instead, linear solvation energy relationships are proposed to model the association of chemicals with dissolved organic matter. However, more chemically diverse K(DOC) data are needed to produce a more robust model. For humic acid dissolved organic carbon, the linear solvation energy relationship predicts log K(DOC) with a root mean square error of 0.43.
Topics: Benzopyrans; Carbon; Fresh Water; Geologic Sediments; Humic Substances; Models, Chemical; Octanols; Organic Chemicals; Risk Assessment; Water Pollutants, Chemical
PubMed: 21721034
DOI: 10.1002/etc.610 -
Chemical Society Reviews Apr 2007This tutorial review deals with recent advances in the use of phosphine-functionalised polymers in organic synthesis. In the first part of the review, some recent... (Review)
Review
This tutorial review deals with recent advances in the use of phosphine-functionalised polymers in organic synthesis. In the first part of the review, some recent applications of polymer-supported palladium catalysts are reviewed, particularly recyclable catalysts for C-C and C-X bond formation with aryl bromide and chloride substrates. In the second half, novel applications of phosphine-functionalised polymers as reagents, scavengers, organocatalysts and linkers in organic chemistry are presented. Emphasis is placed on the synthesis of biologically active molecules.
Topics: Catalysis; Molecular Structure; Organic Chemicals; Organometallic Compounds; Phosphines; Polymers; Stereoisomerism
PubMed: 17387409
DOI: 10.1039/b603851b -
Environmental Science & Technology Jul 2020Polar organic chemical integrative sampler (POCIS) is a passive sampling device that offers many advantages over traditional discrete sampling methods, but quantitative...
Polar organic chemical integrative sampler (POCIS) is a passive sampling device that offers many advantages over traditional discrete sampling methods, but quantitative time-weighted average (TWA) concentrations rely heavily on the robustness of sampling rates. The effects of changing chemical concentration exposures on POCIS sampling rates and its ability to operate in an integrative regime were investigated for 12 pesticides across a range of environmentally relevant concentrations. In five independent 21-day experiments, POCIS devices were exposed to these compounds at constant concentrations ranging from 3 to 60 μg/L and multiple pulsed concentrations with maximum peaks ranging from 5 to 150 μg/L (TWA concentrations = 3 to 92 μg/L). For the 21-day exposures to constant and pulsed concentrations, there were no significant differences in the POCIS sampling rates between corresponding TWA concentrations. Similarly, there was no significant effect on POCIS ability to operate in an integrative regime. However, loss of linearity was visible for some replicates when exposed to higher pulsed concentrations over an extended period. Modeling and Freundlich isotherms did not predict sorbent saturation, but the extraction and reconstitution protocol likely contributed to atrazine dissolution and subsequent underestimation of sorbed chemical mass when HLB adsorption exceeded 400 μg.
Topics: Atrazine; Environmental Monitoring; Organic Chemicals; Pesticides; Water Pollutants, Chemical
PubMed: 32598138
DOI: 10.1021/acs.est.0c02601 -
Current Medicinal Chemistry 2020In the context of reconsidering the Quantitative Structure-Activity Relationship (QSAR) methods at the economical level, namely the optimization rules of OECD, the... (Review)
Review
In the context of reconsidering the Quantitative Structure-Activity Relationship (QSAR) methods at the economical level, namely the optimization rules of OECD, the present review unfolds the key features of Minimal Sterical, Monte-Carlo and Minimal Topological Difference (MTD) methods, developed for quantitative treatment of the relations between biological activity of organic chemical compounds (drugs, pesticides, and so on) and their structures. The initial Minimal Steric Difference (MSD) is completed by the three-dimensional variant of the MTD method, being the last one referred to here, while the main principles of validating and guiding a viable QSAR method verified by the analytical-automated MTD, thus enlarging the perspectives of understanding the chemical-biological interaction at the level of ligand-receptor sites, cavity, and walls, with a true service to the future adaptive molecular design.
Topics: Binding Sites; Ligands; Organic Chemicals; Quantitative Structure-Activity Relationship
PubMed: 31272345
DOI: 10.2174/0929867326666190704124857 -
Philosophical Transactions. Series A,... Dec 2005Carbonaceous meteorites are fragments of ancient asteroids that have remained relatively unprocessed since the formation of the Solar System. These carbon-rich objects... (Review)
Review
Carbonaceous meteorites are fragments of ancient asteroids that have remained relatively unprocessed since the formation of the Solar System. These carbon-rich objects provide a record of prebiotic chemical evolution and a window on the early Solar System. Many compound classes are present reflecting a rich organic chemical environment during the formation of the planets. Recent theories suggest that similar extraterrestrial organic mixtures may have acted as the starting materials for life on Earth.
Topics: Carbon; Earth, Planet; Evolution, Chemical; Evolution, Planetary; Extraterrestrial Environment; Forecasting; Geology; Meteoroids; Organic Chemicals; Research; Solar System
PubMed: 16286287
DOI: 10.1098/rsta.2005.1670