Search results for "Organo"
showing 10 items of 1460 documents
Towards the design of organocatalysts for nerve agents remediation: The case of the active hydrolysis of DCNP (a Tabun mimic) catalyzed by simple ami…
2015
We report herein a study of the hydrolysis of Tabun mimic DCNP in the presence of different amines, aminoalcohols and glycols as potential suitable organocatalysts for DCNP degradation. Experiments were performed in CD3CN in the presence of 5% D2O, which is a suitable solvent mixture to follow the DCNP hydrolysis. These studies allowed the definition of different DCNP depletion paths, resulting in the formation of diethylphosphoric acid, tetraethylpyrophosphate and phosphoramide species as final products. Without organocatalysts, DCNP hydrolysis occurred mainly via an autocatalysis path. Addition of tertiary amines in sub-stoichiometric amounts largely enhanced DCNP depletion whereas non-te…
The overproduction of 2,4-DTBP accompanying to the lack of available form of phosphorus during the biodegradative utilization of aminophosphonates by…
2014
Although information about the ability of some filamentous fungi to biodegrade organophosphonates is available, the knowledge about accompanying changes in fungal metabolism is very limited. The aim of our study was to determine the utilization of the chosen, structurally diverse aminophosphonates by Aspergillus terreus (Thom), in the context of the behaviour of this fungus while growing in unfavourable conditions, namely the lack of easily available phosphates. We found that all the studied compounds were utilized by fungus as nutritive sources of phosphorus, however, their effect on the production of fungal biomass depended on their structure. We also observed an interesting change in the…
Comparative electrochemical treatments of two chlorinated aliphatic hydrocarbons. Time course of the main reaction by-products.
2011
The chlorinated aliphatic hydrocarbons conjugate toxicity with high chemical stability, bioaccumulation and long-range diffusivity. Chloroethanes are particularly ubiquitous in the industry and in household products, and their entry to the environment may entail potential risks for the living beings. At present, the US Environmental Protection Agency is carrying out the Endocrine Disruptor Screening Program (EDSP), where 1,2-dichloroethane (DCA) and 1,1,2,2-tetrachloroethane (TCA) are considered as priorities for their potential effects on the endocrine system. DCA is also found in the list of priority substances drawn up by the European Commission. To avoid the release of chloroethanes int…
Chloroterpenes and other organochlorines in Baltic, Finnish and Arctic wildlife
1991
Abstract Chloroterpene mixtures were analyzed as toxaphene (TOX) in Baltic, Finnish and Arctic fish, seal and bird samples together with DDT residues, hexachlorocyclohexanes (HCH), hexachlorobenzene (HCBz), chlordanes, hexachloronaphthalenes (HxCN), PCBs, PCDDs and PCDFs. TOX was found to be the most globally (evenly) distributed organochlorine compound in Scandinavia, thus far. TOX seemed to bioaccumulate significantly in fish but not in predatory birds in Finland.
Phosphotransferase properties of human erythrocyte phosphoglycolate phosphatase.
1982
Abstract 1. 1. Human erythrocyte phosphoglycolate phosphatase (PGP) (EC 3.1.3.18) shows transferase properties. Using p -nitrophenylphosphate ( p -NPP) as substrate, methanol, at a concentration of 4.9 M. was the most efficient phosphate acceptor tested (60% phosphate transfer). 2. 2. The branched alcohols i -propanol and i -butanol accept the phosphate better than the unbranched compounds. The acceptor potency is methanol > ethanol > i -propanol > n -propanol > i -butanol > n -butanol. 3. 3. The relative transferase activity could be demonstrated to be independent of substrate concentration, pH. and the inhibitory effect of NaF at 2 and 4 mM. 4. 4. POP shows no transferase activity towards…
ChemInform Abstract: Organocatalytic Enantioselective Friedel-Crafts Alkylation of 1-Naphthol Derivatives and Activated Phenols with Ethyl Trifluorop…
2016
Financial support from the MINECO [Gobierno de Espana and FEDER (EU)] (CTQ2013-47949-P) and from Generalitat Valenciana (ISIC2012/001) is gratefully acknowledged. M.M.-M. thanks the Universitat de Valencia for a predoctoral grant. C. V. thanks MINECO for JdC contract. Access to NMR and MS facilities from the Servei central de support a la investigacio experimental (SCSIE)-UV is also acknowledged.
Ethylene and phenylene bridged polysilsesquioxanes functionalized by amine and thiol groups as adsorbents of volatile organic compounds
2007
Abstract Ethylene and phenylene bridged polysilsesquioxane xerogels having amine and thiol groups attached to the surface have been obtained by the sol–gel method from 1,2-bis(triethoxysilyl)ethane or 1,4-bis(triethoxysilyl)benzene and functionalized silanes in the presence of an ammonium fluoride catalyst in an ethanol solution. The synthesized samples have a porous structure (700–850 m2/g) and a high content of functional groups (1.4–1.9 mmol/g). The obtained porous bridged polysilsesquioxanes exhibit a considerable affinity for adsorbing several organic compounds (n-hexane, n-heptane, benzene, cyclohexane, acetonitrile and triethylamine) from the gas phase. The sample with an ethylene br…
Titanium and vanadium catalysts with oxazoline ligands for ethylene-norbornene (co)polymerization
2018
A series of catalysts, (Py-ox)TiCl4, (Py-box)TiCl4, (Py-ox)VCl3, (Py-box)VCl3, SIL/(Py-ox)VCl3, SIL/(Py-box)VCl3, with 2-(1,3-oxazolin-2-yl)pyridine (Py-ox) and 2,6-bis(1,3-oxazolin-2-yl)pyridine (Py-box) ligands, silica support modified by 1-[3-(triethoxysilyl)propyl]pyridinium ethylchloroaluminate ionic liquid (SIL), activated by AlEt2Cl, AlEtCl2, and methylaluminoxane (MMAO) were studied in ethylene polymerization and ethylene-norbornene copolymerization. Single-crystal X-ray diffraction is given for both Py-ox and Py-box. The complexation was confirmed by NMR and ESI-MS methods. All complexes were found to be active in ethylene polymerization with better performance of the vanadium cata…
Counterintuitive Mechanisms of the Addition of Hydrogen and Simple Olefins to Heavy Group 13 Alkene Analogues
2013
The mechanism of the reaction of olefins and hydrogen with dimetallenes ArMMAr (Ar = aromatic group; M = Al or Ga) was studied by density functional theory calculations and experimental methods. The digallenes, for which the most experimental data are available, are extensively dissociated to gallanediyl monomers, :GaAr, in hydrocarbon solution, but the calculations and experimental data showed also that they react with simple olefins, such as ethylene, as intact ArGaGaAr dimers via stepwise [2 + 2 + 2] cycloadditions due to their considerably lower activation barriers vis-à-vis the gallanediyl monomers, :GaAr. This pathway was preferred over the [2 + 2] cycloaddition of olefin to monomeric…
A morphogenetic role for ethylene in hypocotyl cultures of Digitalis obscura L.
1985
The effect of exogenously applied ethylene on organogenesis in Digitalis obscura L. hypocotyls cultured in vitro was studied. Interactions of this gas with other growth regulators was also tested. Ethylene by itself only promoted root formation. Shoot regeneration was obtained in presence of indoleacetic acid and kinetin. The addition of ethylene (10 ppm) increased the caulogenetic action of this medium; higher concentrations than 10 ppm reduced this response. Kinetin alone did not promote organogenesis and nullified the promotive effect of ethylene on rhizogenesis.