- Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry
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It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have s
- Mattia Bizzarri, Bruno,Botta, Lorenzo,Pérez-Valverde, Maritza Iveth,Saladino, Raffaele,Di Mauro, Ernesto,García-Ruiz, Juan Manuel
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p. 8126 - 8132
(2018/05/29)
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- Identification of products containing -COOH, -OH, and -C=O in atmospheric oxidation of hydrocarbons
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Atmospheric oxidation of hydrocarbons by hydroxyl radicals and ozone leads to products containing -COOH, -OH, and -C=O functional groups. The high polarity of such compounds precludes direct GC-MS analysis. In addition, many such compounds often exist in a single sample at trace levels. An analytical method has been developed to identify compounds containing one or more functional groups of carbonyl, carboxy, and hydroxy in atmospheric samples. In the method, -C=O groups are derivatized using O-(2,3,4,5,6- pentafluorobenzyl) hydroxy amine (PFBHA), and -COOH and -OH groups are derivatized using a silylation reagent N,O-bis(trimethylsilyl)- trifluoroacetamide (BSTFA). The derivatives are easily resolved by a GC column. The chemical ionization mass spectra of these derivatives exhibit several pseudomolecular ions, allowing unambiguous determination of molecular weights. Functional group identification is accomplished by monitoring the ions in the electron ionization mass spectra that are characteristic of each functional group derivative: m/z 181 for carbonyl and m/z 73 and 75 for carboxyl and hydroxy groups. The method is used to identify products in laboratory studies of ozone oxidation of α-pinene and Δ3-carene. Among products from ozone oxidation of α-pinene, we have detected pinonaldehyde, norpinonaldehyde, pinonic acid, norpinonic acid, C10 hydroxy dicarbonyls, pinic acid, 2,2-dimethyl-3-(formylmethyl)-cyclobutane-formic acid, and a product that has a molecular weight of 156 and contains a C=O and a COOH/OH group. The latter two products have not been reported previously. Δ3- Carene is structurally analogous to α-pinene in that both have an internal unsaturated bond where ozone oxidation takes place. We have also identified the corresponding analogous products, of which all but caronaldehyde are reported for the first time. An analytical method was developed to identify compounds containing one or more functional groups of carbonyl, carboxyl and hydroxyl in atmospheric samples. -C-to-O double bond groups are derivatized using 0-(2,3,4,5,6-pentafluorobenzyl)hydroxyl amine, and -COOH and -OH groups are derivatized using a silylation reagent N,O-bis(trimethylsilyl)-trifluoroacetamide. The derivatives are resolved using a gas chromatography column coupled with mass spectrometry. The method identified products in laboratory studies of ozone oxidation of α-pinene and Δ3-carene.
- Yu, Jianzhen,Flagan, Richard C.,Seinfeld, John H.
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p. 2357 - 2370
(2007/10/03)
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- Diastereoselective synthesis and structural determination of 1,3-dioxolan-4-ones from lactic acid and carbonyl derivatives
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New 1,3-dioxolan-4-ones were prepared by reacting lactic acid with the corresponding ketones.Depending on steric interactions and the cyclization method chosen, a good selectivity was achieved favoring cis or trans diastereomers.Relative stereochemistry and product conformation is discussed on the basis of NMR spectra.Key Words: dioxolanes / chirality transfer / lactic acid / relative stereochemistry
- Ortholand, J. Y.,Greiner, A.
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p. 133 - 142
(2007/10/02)
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- Condensation of Glycolic, Lactic and 2-Hydroxybutanoic Acids during Heating and Identification of the Condensation Products by GLS-MS
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Glycolic, lactic and 2-hydroxybutanoic acids are partly converted to various condensation products during heating.This conversion was studied at 100 deg C and 125 deg C by identifying the trimethylsilylated products consisted of both linear (dimers and trimers) and cyclic (dimers) structures.The influence of the condensation on the recovery and purification of the hydroxy acids by distillation is discussed.
- Alen, Raimo,Sjoestroem, Eero
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p. 633 - 636
(2007/10/02)
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