نتایج جستجو برای: ethers

تعداد نتایج: 7167  

Journal: :Environmental science & technology 2012
Rebecca M Dickhut Alessandra Cincinelli Michele Cochran Henrik Kylin

Brominated diphenyl ethers (BDE47, 99, 100, and 209) were measured in air, snow and sea ice throughout western Antarctica between 2001 and 2007. BDEs in Antarctic air were predominantly associated with aerosols and were low compared to those in remote regions of the northern hemisphere, except in Marguerite Bay following the fire at Rothera research station in Sept 2001, indicating that this ev...

Journal: :Chemical communications 2011
Christina Efe Ioannis N Lykakis Manolis Stratakis

Gold nanoparticles supported on TiO(2) (~1%) catalyse in high yields the selective cycloisomerisation of aryl propargyl ethers into the corresponding 2H-chromenes, under heterogeneous conditions. 2H,2'H-3,3'-Bichromenes resulting from a catalytic oxidative dimerization pathway are also formed as by-products.

Journal: :Chemical communications 2012
Mayumi Yamamoto Sonoe Nakaoka Yasuyuki Ura Yasutaka Kataoka

A palladium-catalyzed reaction of vinylarenes, allyl ethers, and 1,5-dienes with pinacol proceeded via a selective anti-Markovnikov nucleophilic attack to afford corresponding terminal acetals as major products. The bulkiness of pinacol was found to be critical in controlling the regioselectivity.

Journal: :Sustainable Energy and Fuels 2021

Oxymethylene ethers (OME) as environmentally benign fuels: progress in the design of compounds with tailored properties.

Journal: :Chemico-biological interactions 1987
J E Sinsheimer E Van den Eeckhout B H Hooberman V G Beylin

The Ames procedure with Salmonella typhimurium strain TA100 was used to follow the detoxication by rat liver fractions of two series of aliphatic epoxides. The epoxides employed were 3-chloro-, 3,3-dichloro- and 3,3,3-trichloropropylene oxides and also p-methoxyphenyl-, phenyl- and p-nitrophenylglycidyl ethers. In our procedure with preincubation of the epoxides with rat liver fractions prior t...

Journal: :Toxicology and applied pharmacology 2007
Matthew J Traynor Simon C Wilkinson Faith M Williams

Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. But...

Journal: :Organic & biomolecular chemistry 2006
Edzard M Geertsema Anne Marie Schoevaars Auke Meetsma Ben L Feringa

The concept of bisthioxanthylidene biscrown ethers as potential stereodivergent chiral ligands in asymmetric synthesis is introduced. Substituted bisthioxanthylidenes may be chiral and can exist as stable enantiomers due to their folded structure. As a result, both a right-handed helix (P) and left-handed helix (M) are present in this type of molecule. This offers the unique possibility to cons...

2017
Małgorzata Jóźwiak

The enthalpies of solution of the cyclic ethers 1,4-dioxane, 12-crown-4 and 18-crown-6 in mixtures of ethanol and water have been measured within the whole mole fraction range at T = 298.15 K. The enthalpy of solvation has been calculated. In pure ethanol and pure water, the solvation enthalpy of the investigated cyclic ethers depends linearity on the number of -CH2CH2- groups in the cyclic eth...

2006
Linda S. Birnbaum Elaine A. Cohen Hubal

The use of biomonitoring data holds promise for characterizing exposure and informing risk assessment. Biomonitoring data have been used successfully to track population trends, identify susceptible populations, and provide indications of emerging environmental health issues. However, there remain challenges associated with interpreting biomonitoring data for risk assessment. An international b...

Journal: :Beilstein Journal of Organic Chemistry 2008
Frédéric R Leroux Baptiste Manteau Jean-Pierre Vors Sergiy Pazenok

After nitrogen, fluorine is probably the next most favorite hetero-atom for incorporation into small molecules in life science-oriented research. This review focuses on a particular fluorinated substituent, the trifluoromethoxy group, which is finding increased utility as a substituent in bioactives, but it is still perhaps the least well understood fluorine substituent in currency. The present...

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