Encres anciennes: l'encre ferro-gallique

in L'analyse chimique, outil des experts (2012, October 11)

Influence of the water content in the synthesis of fructose laurate by immobilized lipase B of Candida antarctica (Novozym 435)

in Bulletin de la Société Royale des Sciences de Liège (2012), 81(2012), 82-89

New synthesis conditions for a direct esterification of fructose by lauric acid with Novozym 435 as a catalyst are reported in this paper. With these new conditions, a conversion rate of 72% was achieved ... [more ▼]

New synthesis conditions for a direct esterification of fructose by lauric acid with Novozym 435 as a catalyst are reported in this paper. With these new conditions, a conversion rate of 72% was achieved, which is almost the same value as in the case of transesterification where no water as by-product is produced (74.6 %). The conversion rate of these reactions can be modeled as a function of the initial water content by a three-parameter power law for the esterification and by an exponential law for the transesterification. The influence of the water content on the mono over di-ester ratio will also be discussed to a lesser extent. [less ▲]

La Soudière des Trois Lucs (Marseille) - Etudes historiques et fouilles préliminaires

in Atelier du CRH (L') (2012), (09 Varia), 1-29

The supplying of vegetable soda was interrupted in 1808 after Napoleon’s army had entered Spain. Therefore, (artificial) soda factories using Nicolas Leblanc’s patent from 1791 opened mainly in Paris ... [more ▼]

The supplying of vegetable soda was interrupted in 1808 after Napoleon’s army had entered Spain. Therefore, (artificial) soda factories using Nicolas Leblanc’s patent from 1791 opened mainly in Paris, Rouen and Marseille between June 1808 and the end of 1810. In Marseille, one of these factories was set up in 1810 in the district called Les Trois Lucs. Thanks to everything that could have been discovered, it was perfectly located, thus allowing the preliminary excavations. [less ▲]

La soudière des Trois-Lucs (Marseille) - Étude historique

in Provence Généalogie (2011), (160), 26-33

L'article décrit les recherches historiques sur une soudière du 19e siècle aux 3 Lucs à Marseille afin de la localiser avec précision et peut être trouver des ruines. Des informations supplémentaires et ... [more ▼]

L'article décrit les recherches historiques sur une soudière du 19e siècle aux 3 Lucs à Marseille afin de la localiser avec précision et peut être trouver des ruines. Des informations supplémentaires et des corrections ont été apporté par rapport à l'article de 2010. [less ▲]

Quantum Chemistry Lab at Home: A Microsoft Windows Alternative

in Journal of Chemical Education (2009), 86(5), 567

Nouveaux marqueurs de pH utilisables en RMN du 31P : étude de la relaxation longitudinale en fonction de la structure chimique, de la température, du pH et du milieu biologique

in Comptes Rendus Chimie (2008), 11(4-5), 541-552

New uncharged a-aminophosphonates derived from diethyl(2-methylpyrrolidin-2-yl) phosphonate were synthesized by nucleophilic addition of dialkylphosphites on 2-methyl-1-pyrroline. These compounds were ... [more ▼]

New uncharged a-aminophosphonates derived from diethyl(2-methylpyrrolidin-2-yl) phosphonate were synthesized by nucleophilic addition of dialkylphosphites on 2-methyl-1-pyrroline. These compounds were intended as enhanced 31P-NMR pH probes in biological systems. Compared to standard pH markers such as inorganic phosphate or methylphosphonate, they demonstrated in vitro low acidic pKa values (6.6 < pKa < 7.0), resonance peaks ranging from 21 to 35 ppm, distinct from those of phosphorylated metabolites, and 3e4 times as sensitive (9.2 < Ddab < 9.9 ppm) as usual markers, such as inorganic phosphate or methylphosphonate. The detailed synthetic procedures for three representative new pH probes, which were non-toxic (in the mM range) in rat isolated heart preparations, was reported. In a larger series of 27 structurally related a-aminophosphonates, 1/T1 (31P) values were given in different conditions of milieu, temperature and pH. The data support unique features for these compounds to reveal acidic cellular compartments. [less ▲]

Synthesis of New Tetraethyl(N-alkyl-1-aminoethan-1,1-diyl)bisphosphonates and ESR Analysis of Chemical Exchange of Derived Nitroxides of Acyclic Aminobisphosphonates.

in Phosphorus, Sulfur & Silicon & the Related Elements (2007), 182(10), 2359-2369

The synthesis and the full characterization of two new linear bisphosphonates(tetraethyl(N-tert-butyl-1-aminoethan-1,1-diyl)bisphosphonate and tetraethyl(Nsec-butyl-1-aminoethan-1,1-diyl)bisphosphonate ... [more ▼]

The synthesis and the full characterization of two new linear bisphosphonates(tetraethyl(N-tert-butyl-1-aminoethan-1,1-diyl)bisphosphonate and tetraethyl(Nsec-butyl-1-aminoethan-1,1-diyl)bisphosphonate), and the first analysis of the ESR spectra of the corresponding nitroxides is reported. The preliminary results of theoretical calculations on model compounds suggest a small B0 (in the McConnell equation). The results of bisphosphonate ester and bisphosphonic acid are similar. The discrepancies of P coupling for the diphosphorus compound stems from B2 that is different when the dihedral angle is larger than 90◦. [less ▲]

Large phosphorus hyperfine coupling as a sensitive tool for studying molecular dynamics : ESR and Molecular Mechanics studies of ring interconversion in cis-2,5-diphosphoryl-2,5-dimethyl-pyrrolidinoxyl radical

in Journal of Physical Chemistry A (2003), 107(19), 3851-3857

ESR spectra of cis- and trans-â-diphosphorylated pyrrolidine-N-oxyl radicals, c-1 and t-1, were studied in liquid and frozen solution. The expected 1:2:1 triplet (aP (2)) of the 1:1:1 triplet (aN) was ... [more ▼]

ESR spectra of cis- and trans-â-diphosphorylated pyrrolidine-N-oxyl radicals, c-1 and t-1, were studied in liquid and frozen solution. The expected 1:2:1 triplet (aP (2)) of the 1:1:1 triplet (aN) was observed for t-1; however, for c-1, the inner lines of the 1:2:1 triplet showed a dramatic broadening characteristic of chemical exchange between two equivalent conformations. Owing to the large difference in the hyperfine splitting constants (hfsc) of the exchanging phosphorus (¢aP 21 G), the coalescence temperature was unusually high (193 K, in n-pentane), and the potential barrier for ring interconversion (10.5 kJ mol-1) was easily obtained from the temperature dependence of the exchange rate. This value was in very good agreement with the value obtained for an empirical pseudorotational potential (11 kJ mol-1) that was adjusted to fit the temperature dependence of the phosphorus hfsc. For c-1, molecular mechanics calculations gave similar characteristics for the pseudorotational potential and indicated the existence of two identical minima with distorted geometries lying between 3T4 and 3E or 4T3 and E3. For t-1, only the 3T4 conformer was found to be significantly populated. Frozen solution spectra showed that the phosphorus hfsc anisotropy is higher when the C-P bond is pseudoaxial; this result can be explained by a geometry-dependent delocalization of the unpaired electron into the phosphorus 3p orbitals. [less ▲]

Control of the Radical Polymerization by 2,2,15,15-tetramethyl-1-aza-4,7,10,13-tetraoxacyclopentadecan-1-oxyl and its Sodium Salt

in Macromolecular Chemistry and Physics (2002), 203(12), 1790-1796

The control of the radical polymerization of styrene by 2,2,15,15-tetramethyl-1-aza-4,7,10,13-tetraoxacyclopentadecan-1-oxyl is reported here in bulk at 90 °C, 120 °C and in miniemulsion. Similarly, the ... [more ▼]

The control of the radical polymerization of styrene by 2,2,15,15-tetramethyl-1-aza-4,7,10,13-tetraoxacyclopentadecan-1-oxyl is reported here in bulk at 90 °C, 120 °C and in miniemulsion. Similarly, the control by its sodium complex is reported in bulk at 90 °C. [less ▲]

Synthesis of 2-Diethoxyphosphoryl-2-Methyl-5-Phenyl-3,4-Dihydro-2H-Pyrrole-1-Oxide (DEPMPO-Ph): a New Radical Spin-Trap

in Symposium Drug Discovery Strategies: from Leads to Drugs (2001, November 16)

The synthesis of a new radical spin trap is presented here: the 2-Diethoxyphosphoryl-2-Methyl-5-Phenyl-3,4-Dihydro-2H-Pyrrole-1-Oxide (DEPMPO-Ph)