Physical mixtures of alkali and earth alkali metal carbonates and commercially available zeolites were investigated as solid catalysts for the Knoevenagel condensation. Best results for the model reaction between benzaldehyde and ethyl cyanoacetate were obtained for a 1:4 mixture of Na 2 CO 3 with 4 Å molecular sieves (MS). The effects of the following parameters were investigated: structure of substrate, type and basicity of metal carbonate and zeolite, and temperature. Between 50 and 90°C chemical yields up to >90% were obtained without continuous removal of water and with reasonable catalyst activities and reaction times. Na 2 CO 3 -MS 4 Å proved to be active for the condensation of several aldehydes and ketones with a variety of active methylene components.Résumé : On a évalué la possibilité d'utiliser des mélanges physiques de carbonates de métaux alcalins ou alcalinoterreux et de zéolites commercialement disponibles comme catalyseurs solides pour des condensations de Knoevenagel. Les meilleurs résultats pour la réaction modèle entre le benzaldéhyde et le cyanoacétate d'éthyle ont été obtenus avec un mélange 4:1 de Na 2 CO 3 avec du MS 4 Å. On a étudié les effets des paramètres suivants: structure du substrat; type et basicité du carbonate métallique et du zéolite; température. Entre 50 et 90°C, on a obtenu des rendements chimiques allant jusqu'à plus de 90 % sans nécessité d'enlever l'eau de façon continue, avec des activités catalytiques et des temps de réaction raisonnables. Le mélange Na 2 CO 3 -MS 4 Å s'avère actif pour la condensation de plusieurs aldéhydes et cétones avec une grande variété de composés comportant un méthylène actif.Mots clés : condensation de Knoevenagel, catalyseurs basiques solides, mélanges de zéolite -carbonate de sodium.[Traduit par la Rédaction] Siebenhaar et al. 569

Plywood is widely used in civil construction. Due to the importance of preservation and gluing in bio-composites, this study compares the influence of a chemical treatment with CCA (chromated-copper-arsenate) on Pinus taeda L. wood veneers to produce two plywood types using phenol-formaldehyde (PF) and castor oil-based polyurethane (PU). Four different treatments were performed to analyze both varieties’ physical and mechanical properties. As a result, an improvement in the properties of the treated panels was observed. Lower moisture contents and better interactions caused by less thickness swelling and water absorption were identified in the PU-based plywoods. The treatment with CCA was efficient, improving these properties when they were compared to the reference panels. Most treatments evidenced increases in the modulus of elasticity and modulus of rupture for both adhesives when the CCA treatment was applied to the veneers. Comparing the resins, the PF showed the best values of modulus of elasticity. All treatments met the requirements defined by the Brazilian standard document for the glue line shear.

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