نتایج جستجو برای: aliphatic carboxylic acids

تعداد نتایج: 276692  

Journal: :Tetrahedron 2021

The photochemical reactivity of acyl azolium salts derived from aliphatic carboxylic acids has been investigated. These species, which serve as models for intermediates generated in N-heterocyclic carbene (NHC) organocatalysis, undergo Norrish type II elimination reactions under irradiation with UVA light analogy to structurally related aromatic ketones. Moreover, efficient Norrish-Yang cycliza...

Journal: :Science 2001
S Pizzarello Y Huang L Becker R J Poreda R A Nieman G Cooper M Williams

The Tagish Lake meteorite fell last year on a frozen lake in Canada and may provide the most pristine material of its kind. Analyses have now shown this carbonaceous chondrite to contain a suite of soluble organic compounds (approximately 100 parts per million) that includes mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic...

2012
Pat Sasso Ken Lynam

A 26-component mix of aliphatic short chain and aromatic alcohols and carboxylic acids was used to evaluate the recently introduced Agilent J&W DB-624UI column to show acceptable peak shape and resolution. The column was compared to non-Agilent 624 phases. Organic acids had reasonable peak width and peak symmetry for a narrow range of volatilities (C3 through C8) on the DB-624UI column, suggest...

2005
ALEXANDER NEAMAN SUSAN L. BRANTLEY

Concentrations of organic acids in prebiotic soils were presumably low, given limitations in abiotic synthesis and the limited lifetimes of organic molecules before the ultraviolet shield developed on early Earth. Prokaryotes, the first landcolonizing organisms, commonly secrete aliphatic carboxylic acids, and, less extensively, secrete aromatic compounds as siderophores and antibiotics. In con...

Journal: :iranian chemical communication 2015
mohammad ali nasseri batol zakerinasab sayyde kamayestani

mn(ii) salen complex immobilized on nano silicagel was prepared by incorporating mn(ii) salen complex into a nanosilica matrix and characterized by tga, xrd, atomic absorption spectroscopy and was successfully applied as catalyst for the oxidation of alcohols. oxidation of a series of alcohols in acetonitrile over immobilized mn(ii) salen complex using tetrabutylammonium peroxymonosulfate (tbao...

Journal: :Geobiology 2011
C Konn D Testemale J Querellou N G Holm J L Charlou

Experiments on hydrothermal degradation of Pyrococcus abyssi biomass were conducted at elevated pressure (40 MPa) over a 200-450 °C temperature range in sapphire reaction cells. Few organic compounds could be detected in the 200 °C experiment. This lack was attributed to an incomplete degradation of P. abyssi cells. On the contrary, a wide range of soluble organic molecules were generated at te...

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