The electroreduction of trichlorofluoromethane (CFC 11) on lead cathodes, in combination with a hydrogen diffusion anode in an undivided cell using methanol‐water mixtures at 15°C, was studied by constant‐current electrolyses, chronocoulometry, gas chromatography, scanning electron microscopy, inductively coupled plasma, and energy dispersive X‐ray microanalyses. The base electrolyte was a CFC‐saturated methanol (70 vol %)‐water mixture containing 0.75 mol dm−3 NH4normalCl . In this solution, and also with the addition of Cu2+ or tetrabutylammonium perchlorate, the current efficiency for the CFC 11 electroreduction was about 96%. When PdCl2 was added to the base solution, Pd black was electrodeposited on Pb and the current efficiency decreased with time up to about 80% (smaller for MeOH concentrations less than or equal to 60 vol %). The current efficiencies found for additions of Fe3+ , Al3+ , or Zn2+ were also smaller. Under all conditions, the gas volume collected from the cathode increased with time, and dichlorofluoromethane was the main product in the gas and in the liquid. The use of electrodeposited Pd black on the cathode slightly favored the formation of fluoromethane compared to chlorofluoromethane, in particular at 200 mA cm−2 . The mechanism of the process, the effect of the cations employed, and the possibilities to increase the extent of CFC 11 electrodechlorination are discussed. © 2000 The Electrochemical Society. All rights reserved.

In this work, the efficiency and product formation in the electroreduction of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC 113) to obtain completely dechlorinated products has been studied using constant-current electrolysis at different current densities, gas chromatography, scanning electron microscopy, and energy dispersive x-ray. While chlorotrifluoroethene was the main product obtained from CFC 113 in MeOH-water solutions containing NH 4 C1, different and suitable conditions which lead to its complete dechlorination are described in this paper. In the presence of small amounts of Pd 2+ in solution, a very thin film of Pd black was electrodeposited on the Pb cathode and the efficiency of the CFC 113 electroreduction was about 98%. The efficiency was much smaller and the product composition very different in the absence of Pd 2+ in solution, even in the presence of Pd black electrodeposited on the cathode. In the presence of Pd 2+ , the main products in the gas phase were difluoroethene and trifluoroethene. Small amounts of 1,2-dichloro-1,1,2-trifluoroethane, chlorotrifluoroethene, difluoroethane, and fluroethane were also present in the gas phase. The liquid composition was enriched in the less volatile compounds. A possible reaction pathway involving the removal of halides by successive reactions is discussed. The anode employed in these experiments was a thin Pd foil with electrodeposited Pd black, which permitted hydrogen diffusion and its further oxidation to H + . Because of this reaction, contamination of the workingelectrolyte by other oxidation products such as C12 or MeOH derivatives were avoided. This system allows new electrosynthetic processes along with CFC electrodegradation.

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The current density response of H2-fed (1 atm) Pd foil anodes in MeOH-water mixtures has been studied by current vs. voltage measurements and scanning electron microscopy. The current density response of different hydrogen-diffusion anodes, based on 25 p.m thick Pd foils coated on both sides with electrodeposited Pd black, has been tested for aqueous and MeOH (70% volume per volume)-water mixtures containing NH4C1 at concentrations near saturation. The anode current density response increased with temperature, but decreased in the presence of MeOH in the electrolyte. The best anode current density response was obtained with Pd black electrodeposited at 50°C and current densities about -15 mA cm2 in acid (i.e., with 40 g dm3 NH4C1 and set to pH 0 with HC1) with 2% PdCl2. In this case, quasi-stationary current densities ca. 50 mA cm2, with hydrogen oxidation efficiency of 100%, in MeOH-water mixtures containing 1 mol dm3 NH4C1 at 20°C were obtained. A possible mechanism of the process is discussed.

Resumen: Se analiza cómo y en qué grado se aplica el modelo RDF en las principales colecciones digitales españolas de materiales patrimoniales. Se introduce este modelo y también las iniciativas de Datos Abiertos y Datos Enlazados. A continuación se examinan 51 repositorios digitales y de cada uno de ellos se determina si expresan sus registros en RDF, ofrecen un punto de consulta SPARQL consultable por agentes externos y si usan referencias como valor de las propiedades. A partir de los resultados se describen los modelos EDM de Europeana y OntoWeb. Se concluye que la aplicación de RDF es desigual, demasiado condicionada al uso de aplicaciones que convierten automáticamente los registros en tripletas RDF, que se dan pocos puntos SPARQL para la consulta externa y que el empleo de referencias se vincula al uso de aplicaciones con diferentes modelos: EDM u OntoWeb. Se recomienda que las colecciones han de enriquecer sus datos y determinar niveles de agregación de los datos RDF generados para difundirse, hacerse accesibles y adaptarse a la web semántica.Palabras clave: RDF; modelos de datos; repositorios patrimoniales; consulta SPARQL; referencias; URI; Europeana Data Model; OntoWeb; datos abiertos; datos enlazados. Implementation of the RDF data model in digital collections of Spanish libraries, archives and museumsAbstract: The article discusses how and to what extent the RDF data model is applied in major Spanish digital collections of heritage materials. This model, as well as Open Data and Linked Data initiatives, are introduced. Fifty-one digital repositories were analysed to determine whether they expressed their records in RDF, offered SPARQL query points searchable by external agents, and used references as property values. The Europeana EDM and OntoWeb models are also described. It is concluded that the use of RDF is unequal and excessively conditioned by the use of applications that automatically convert records into RDF triples. Few of the collections analysed give SPARQL points for external queries. Also, the use of references is linked to applications using different models: EDM or OntoWeb. Collections should enrich their data and define aggregation levels for generated RDF data in order to be disseminated, made accessible, and adapted to the semantic web.