C. Filliatre

Analysis of the variation of the essential oil composition of Eucalyptus globulus Labill. from Portugal using multivariate statistical analysis

Abstract Samples of Eucalyptus globulus Labill. subsp. globulus essential oil obtained from trees of different ages, growing in maritime and inland Portuguese regions, collected in May and November periods (1991–1992), were submitted to quantitative analysis. The results obtained were interpreted using principal component analysis and cluster analysis, considering the 25 abundantly found compounds. These compounds were grouped according to their variation patterns, leading to the definition of five groups, four of which have shown to be significant in the differentiation of young and adult leaves. Young leaves, when compared to adult leaves, were found to have higher oil yields, with lower percentage of group II (in which 1,8-cineole is included) and III compounds and higher percentages of compounds from groups I and IV. Variations in the oil composition due to season and geographic localisation were found not to be significant.

Determinations cinetiques par microcalorimetrie differentielle en programmation de temperature. I. Considerations generales sur l'appareillage et les reactions de decomposition d'amorceurs radicalaires en solution

Abstract Kinetic parameters of decompositions of free-radical initiators can be determined by differential scanning microcalorimetry. A conduction microcalorimeter fitted with an inertia corrector can be used. A critical survey of the apparatus used and of the reactions studied has determined the working under which the measures must be carried out.

Determinations cinetiques par microcalorimetrie differentielle en programmation de temperature. X. Decompositions simultanees spontanee et induite du peroxyde de benzoyle en solution

Abstract The kinetics of the thermal decomposition of benzoyl peroxide in dibutyl phthalate solvent were studied by differential scanning microcalorimetry. Mathematical treatment of the enthalpimetric curves obtained for several different initial concentrations led to as an experimental rate law. From the kinetic studies and analysis of the products of some isothermal decompositions a reaction mechanism was proposed. Both spontaneous and radical induced decompositions were found to occur; their rate constants and activation parameters were easily computed from the results of the non-isothermal kinetic determinations.

Delta-pyrone`ne : Epoxydation se´lective et acce`s aux cyclocitrals

Abstract: The selective obtention of epoxides from delta-pyronene has been realized using a peracid and a cyclodehydrohalogenation reaction. The isomerization of an epoxidic isomer with Lewis and protonic acids and on active alumina has been studied leading to cyclocitrals.

Determinations cinetiques par microcalorimetrie differentielle en programmation de temperature. IX. thermolyses de perbenzoates de t-butyle p-substitues. Parametres cinetiques et d'activation

Abstract Kinetic and activation parameters of thermolysis in several solvents are compared. The free activation enthalpy is taken as a specific characteristic of the thermal stability; it is then applied to “evaluate” the influence of aromatic ring substituents. A symbatic variation in the case of the activation energy and the pre-exponential factor of the Arrhenius relation as well as in that of the activation enthalpy and entropy are found. The significance of the corresponding kinetic compensation effect is discussed as well as that of the isokinetic temperature of the thermolysis of p -substituted peroxybenzoates.

Determinations cinetiques par microcalorimetrie differentielle en programmation de temperature. II. Influence de la variation de la sensibilite du calorimetre avec la temperature sur les valeurs trouvees pour les constantes de vitesse et les enthalpies de reaction

Abstract The variation with temperature of the sensitivity of a “Thermanalyse” microcalorimeter has been determined using the electrical calibration system of the apparatus. From the results, a method for the correction of the differential scanning microcalorimetric diagrams has been developed. The influence on the determination of the rate constants during kinetic studies of the decompositions of free radical initiators and on enthalpy measurements has been studied.

Determinations cinetiques par microcalorimetrie differentielle en programmation de temperature. III. Probleme de la non correspondance entre temperatures mesurees et constantes de vitesse

Abstract Rate constants of the free radical decomposition of AIBN have been determinated in different solvents using a differential scanning microcalorimeter at several temperature programmes. They seem to depend on the heating rate; but this is explained by the existence of a difference in temperature between the studied solution and the position at which θ is measured. At low heating rate, there is agreement between real and measured temperatures and, thus, fair correspondence between rate constants and temperatures observed.

Determinations cinetiques par microcalorimetrie differentielle en programmation de temperature. VII. thermolyses de perbenzoates de t-butyle p-substitues. Influence des substituants

Abstract Kinetic studies performed by differential scanning microcalorimetry show that the stability of t -butyl p -substituted peroxybenzoates is slightly influenced by the electronic effects of substituents. No simple correlation is found between ln k r and σ.

Determinations cinetiques par microcalorimetrie differentielle en programmation de temperature. VI. Thermolyse d'azo-1,1′-(cyano-1 cyclanes) dans differents solvants

Abstract Bis-azo-cyanocyclo-pentane, -hexane and -heptane are prepared and the kinetics of their thermolysis in several solvents are studied by differential scanning microcalorimetry. Unlike activation enthalpy and entropy, activation free enthalpy does not depend on solvent. Moreover its variation with temperature is quite small in each kinetic study temperature range. Thus ΔG# is given as an intrinsic stability characteristic of azo-nitriles. “Kinetic compensation effect” between ΔS# and ΔH# is discussed.

Synthesis of Some New Benzylic Ethers from 1,8-Cineole with Antimicrobial Activity

Summary. The synthesis and structural characterization of several benzylic derivatives of 3-exo-hydroxy-1,8-cineole is described. The new compounds show antimicrobial activity against Cladosporium cucumerinum, Staphylococcus aureus, Mycobacterium smegmatis, Pseudomonas aeruginosa, and Candida albicans.Zusammenfassung. Die Synthese und strukturelle Charakterisierung einiger Benzylderivate des 3-exo-Hydroxy-1,8-cineols werden beschrieben. Die neuen Verbindungen zeigen antimikrobielle Aktivität gegen Cladosporium cucumerinum, Staphylococcus aureus, Mycobacterium smegmatis, Pseudomonas aeruginosa und Candida albicans.