Electrocarboxylation of chloroacetonitrile mediated by electrogenerated cobalt(I) phenanthroline

The electrocarboxylation of chloroacetonitrilemediated by [Co(II)(phen)3]2+ has been investigated. Cyclic voltammetry studies of [Co(II)(phen)3]2+ have shown that [Co(I)(phen)3]+, an 18 electron complex, activates chloroacetonitrile by an oxidative addition through the loss of a phenanthroline ligand to give [RCo(III)(phen)2Cl]+. The unstable one-electron-reduced complex underwent Co–C bond cleavage. In carbon dioxide saturated solution, CO2 insertion proceeds after reduction of the alkylcobalt complex. A catalytic current is observed which corresponds to the electrocarboxylation of chloroacetonitrile into cyanoacetic acid. Electrolyses confirmed the process and gave faradic yield of 62% in cyanoacetic acid at potentials that are about 0.3 V less cathodic than the one required for Ni(salen)

Observable and unobservable variables in the theory of the equilibrium rate of unemployment, a comparison between France and the United States

This paper confronts, theoretically and empirically, two estimation methods for the Equilibrium Rate of Unemployment (ERU). By introducing observable variables into the TV-NAIRU approach and unobservable variables into the structural approach, we show how these two methods can converge even though their diagnoses differ appreciably in the French case. We considerably improve the econometric and explanatory properties of the French TV-NAIRU model by identifying some of its determinants (interest rates, labour productivity). Moreover, by distinguishing between the concepts of long-term and medium-term ERU, we separate the medium- from the long-term and the observable from the unobservable components of the ERU.

Presentation of the Three-ME model: Multi-sector Macroeconomic Model for the Evaluation of Environmental and Energy policy

This paper presents the structure and the main properties of Three-ME. This new model of the French economy has been especially designed to evaluate the medium and long term impact of environmental and energy policies at the macroeconomic and sector levels. To do so Three-ME combines two important features. Firstly, it has the main characteristics of neo-Keynesian models by assuming a slow adjustment of effective quantities and prices to their notional level. Compared to standard multi-sectors CGEM, this has the advantage to allow for the existence of under-optimum equilibriums such as the presence of involuntary unemployment. Secondly, production and consumption structures are represented with a generalized CES function which allows for the elasticity of substitution to differ between each couple of inputs or goods. This is an improvement compared to the standard approach that uses nested CES functions which has the disadvantage to impose a common elasticity of substitution between the goods located in two different nested structures.neo-Keynesian model, macroeconomic modeling, energy and environmental policy modeling

Lo natural y lo artificial en Aristóteles y Francis Bacon : bases para la tecnología moderna

El poder de la tecnología contemporánea depende de su capacidad para imponerse a lo que la naturaleza ya tiene dado. En términos de la ontología griega clásica, dicha capacidad se puede formular diciendo que la tecnología puede sustituir lo natural por lo artificial. Para entender el significado de esta sustitución, el presente artículo estudia la concepción de lo natural y lo artificial en Aristóteles y en Francis Bacon, y analiza sus diferencias. Con ello se descubren los cambios que el mundo moderno realiza con respecto a la filosofía de la antigüedad, cambios que justifican la creencia contemporánea en el poder de la técnica y que sientan las bases de la tecnología moderna.The power of contemporary technology depends on its ability to override what nature has already given. In terms of classical Greek ontology, such capacity can be formulated saying that technology can replace natural by artificial. To understand the meaning of this substitution, this article examines conception of the natural and the artificial in Aristotle and Francis Bacon, and analyzes their differences. This will discover the changes that the modern world make about the philosophy of antiquity, changes that justify the belief in the power of contemporary technics, and which lay the foundations of modern technology

Point d'arrêt-point d'ouverture Claude Cahun et la photographie de l'objet surréaliste dans Le Coeur de Pic

International audienceCet article explore la contribution de la photographe Claude Cahun au recueil de « poèmes pour les enfants » de Lise Deharme, Le Coeur de Pic (1937). Un examen attentif révèle que le travail d'illustration plus ou moins littéral des poèmes de Deharme s'inscrit dans une réflexion d'ordre artistique et éthique plus large centrée sur la représentation de l'objet domestique. Si le grain photographique participe d'une impression de familiarité, les mises en scène d'objets imaginées par Cahun relèvent, de fait, d'un travail sur la surface qui vise à confronter le spectateur à la relation anémique qu'il entretient avec le monde sensible. Dès lors, la photographie devient le médium d'une recherche du point de contact où il soit possible de mettre en oeuvre ce que Cahun nomme ailleurs « action indirecte », un processus caractérisé par la dialectique du point d'arrêt / point d'ouverture permettant de retrouver le moyen d'intervenir dans le monde. Ce processus, qui souligne une proximité du jeu et de l'expérience, est central dans les expériences artistiques du groupe surréaliste qui culminent avec l'Exposition surréaliste d'objets, fin mai 1936, à la galerie Charles Ratton. De ce point de vue, l'objectif de cet article sera également de situer la contribution de Cahun au Coeur de Pic dans le contexte idéologique du surréalisme et plus largement dans une démarche critique visant à interroger la portée de l'oeuvre au sein des relations de production de son temps. Abstract This article investigates the contribution of photographer Claude Cahun to Lise Deharme's children'

Tot el que veritablement passa em passa a mi

El conte de Borges es presenta a la lectura corn un enigma, un laberint de lectures ¡ d'històries.El conte de Borges es presenta a la lectura corn un enigma, un laberint de lectures ¡ d'històries.El conte de Borges es presenta a la lectura corn un enigma, un laberint de lectures ¡ d'històries

Heidegger y la cuestión de la técnica

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El cosmopolitisme cínic, un precedent del kantià?

En aquest article es compara el cosmopolitisme de Kant amb el cosmopolitisme dels cínics antics. La comparació no és una tesi, és un mètode. L'objectiu és descobrir els elements comuns i també els que no es comparteixen. D'aquesta manera es poden arribar a definir les principals característiques del cosmopolitisme modern. La conclusió més destacada és que, en la modernitat, representada per Kant, la ciutadania del món no és res més que el límit ideal de la ciutadania política.In this article the cosmopolitism of Kant is compared with the old cosmopolitism of the ancient Cynics. The comparison is not a thesis, it is a method. The objective is to discover the common elements and also those that are not shared. This way, the main characteristics of the modern cosmopolitism can be defined. The most outstanding conclusion is that, in the modernity, represented by Kant, the citizenship of the world is not more than the ideal limit of the political citizenship

Electrocarboxylation of chloroacetonitrile by a Cobalt(I) complex of terpyridine

The electrocarboxylation of chloroacetonitrile (NC–CH2–ClRCl) mediated by [CoIIL2]2+ (L = terpyridine) was investigated by cyclic voltammetry. Electrochemical studies under argon atmosphere showed that the monoelectronic reduction of [CoIIL2]2+ yielded a Cobalt(I) complex which after the loss of a terpyridine ligand reacted with chloroacetonitrile. The oxidative addition of chloroacetonitrile on [CoIL]+ gave an alkylCobalt(III) complex [R–CoIIIL]2+ which was reduced into an alkylCobalt(II) complex, highly unstable and decomposed into an alkyl anion and a Cobalt(II) complex. Under carbon dioxide atmosphere, Cobalt(I) complex was shown to be unreactive towards CO2 but CO2 insertion was observed in the alkylCobalt(III) complex [R–CoIIIL] 2+ giving probably a CO2 adduct [R–CoIIIL(CO2)]2+. This adduct presented a strong adsorption at the carbon electrode and was reduced at potential less cathodic than the one of alkylCobalt(III) complex. After reduction, the carboxylate RCO2− (NC–CH2–CO2−) was released and a catalytic bielectronic carboxylation of chloroacetonitrile took place. Controlled potential electrolyses confirmed the catalytic process and gave for cyanoacetic acid faradic yields up to 60% under low overpotential conditions