Synthesis of new diesters of 1,4:3,6-dianhydro-d-glucitol by esterification with fatty acid chlorides

International audienceA new series of esters was prepared by esterification of 1,4:3,6-dianhydro-o-glucitol with long chain fatty acid chlorides. The experimental conditions prevented thermal degradation of the sugar and led to diesters with a high degree of purity. The final products were readily isolated and characterized by IR and NMR. Molecular modelling confirmed that the exo and endo configurations of the o-alkyl groups of the diesters of isosorbide were retained. This work reports a novel synthesis of diesters of natural origin which shows promise in environmentally sensitive applications, such as phytosanitory adjuvants, requiring biodegradable materials as replacements for fossil-derived products

Collezionismo e commercio di arte islamica tra Otto e Novecento. L\u2019Italia e il contesto internazionale

Il lavoro offre un\u2019indagine sul collezionismo e commercio di arte islamica in Italia tra Otto e Novecento. Esso evidenzia l\u2019importanza del ruolo svolto dalla penisola che, mediante i suoi antiquari, ha alimentato il mercato artistico internazionale, rifornendo alcuni grandi collezionisti e contribuendo alla formazione delle raccolte dei musei stranier

Impact des lubrifiants sur l’environnement. Une alternative : les biolubrifiants

National audienceDifférents tests de laboratoire peuvent être utilisés pour caractériser le devenir des lubrifiants dans l’environnement. Après avoir expliqué en quoi consistent ces tests, et quelles sont leurs limites d’interprétation, l’auteur présente les principaux résultats obtenus en étudiant la dégradation de différentes catégories de lubrifiants et leur écotoxicité, dans le cadre d’un protocole expérimental

Impact des lubrifiants sur l’environnement. Une alternative : les biolubrifiants

Différents tests de laboratoire peuvent être utilisés pour caractériser le devenir des lubrifiants dans l’environnement. Après avoir expliqué en quoi consistent ces tests, et quelles sont leurs limites d’interprétation, l’auteur présente les principaux résultats obtenus en étudiant la dégradation de différentes catégories de lubrifiants et leur écotoxicité, dans le cadre d’un protocole expérimental

Huile adjuvante : devenir des esters méthyliques dans le sol

International audienceThe fate of vegetal oil, ofeic acid methyl ester, in soil was investigated and compared ta that of a minerai oil. Experiments were both carried out in laboratory conditions (sol/ columns or lysimeters) and in field conditions. A microbiology study was performed using the same soil. Vegetal and mineral oils were applied an soil of lysimeter or field ot the phytosanitary application dose. Migration and primary degradation profiles of the oils and their metabolites were determined during a period of 120 days by gas chromatography analysis. Results showed a total degradation of the vegetal oil and its metabofites after 60 days whereas mineral oil required 90 days. A microbiology study was performed to identify some micro-organisms of the soi! and to evaluate ecotoxicity effects of the oils. Vegetal oil was revea/ed ta be Jess taxie thon minerai oil even at high concentration. The high biodegradability of the vegetal ester in soil was confirmed as well as their environmental qualities

Un nouveau test d’évaluation de la biodégradabilité dans le sol -- Travaux de normalisation en cours

Biodégradabilité primaire (disparition d’un composé parent), biodégradabilité ultime (stade terminal de la transformation du composé), écotoxicité, bio‐acc umulation autant d’outils à notre disposition pour évaluer l’impact environnemental des composés chimiques. Néanmoins, les problématiques ne sont pas les mêmes en milieu aqueux et en milieu sol. Le travail présenté dans cet article compare et cherche les c orrespondances entre les comportements dans les deux milieux pour valider un nouveau test d’évaluation de la biodégradabilité aérobie ultime des composés organiques en milieu sol. Primary biodegradability (analysis of disappearance of original compounds), ultimate biodegradability (complete mineralisation of organic material), ecotoxicity and bio-storage tests so many tools to assess the impact of chemicals on the environment. However, environmental hazards of organic compounds differ in aqueous and in soil medium. This article compares the chemical behaviour in both media in order to set up a new ultimate biodegradability test in soil

Ecotoxicity and biodegradability in soil and aqueous media of lubricants used in forestry applications

The work presented in this article focuses on the environmental impact of hydraulic fluids used in forestry. Migration and biodegradability of three biolubricants and a mineral lubricant were monitored in two forest soils and in a liquid medium. These studies proved that biolubricants were easily degradable products and showed ultimate biodegradability rates significantly higher than those of the fluid of mineral origin, specially in a soil environment. This superiority was even greater when fluid behaviour was observed after 1000 h of use. Ecotoxicity test enabled the classification and comparison of biolubricants and showed that toxicity levels of the biolubricants were never high however, even after use, as compared to petroleum-based fluid

Glycolipid self-assembly: micellar structure

Small-angle scattering is used to investigate a typical glycolipid micelle structure in conjunction with NMR determination of sugar cycle conformation. It is shown that the ellipsoidal shape of the micelle originates from two constraints: sugar rings perpendicular to the interface induce a limited area at the chain-head interface. Together with the bulky hydrated heads, this imposes an ellipsoidal shape

Lubrifiants et environnement

As figures show, volumes of lost lubricants in Europe like in most of industrial countries represent a threat for the environment and for the human health. Numerous activity fields are concerned through equipment involved in transports, in construction, in mechanical industry, in forest harvesting or in agriculture… The spread of lubricants in the environment affects different parts of the natural medium (soils, underground waters, rivers…), which explains the difficulty to select analytic methods assessing the real environmental impact of these products. The most usual analyses provides degradation rates of the substance in contact with microorganisms, doses of non-toxicity or measures regarding to the oxygenation rate of waters. It is important to select the most adapted method according to the context. For a few years, vegetable based lubricants have been considered as a reliable solution to combine technical performances and ecocompatibility characteristics. These meet criteria defined in ecolabels or other classifications concerning several categories of biolubricants. National and european programs aiming at technology transfer allowed to measure and compare the ultimate biodegradability in liquid and in soil for hydraulic fluids. The results obtained show an environmental gain for biolubricants included after a 1,000 hours operation period

Huile adjuvante : devenir des esters méthyliques dans le sol

The fate of vegetal oil, ofeic acid methyl ester, in soif was investigated and compared ta that of a minerai oil. Experiments were bath carried out in laboratory conditions (soi/ columns or lysimeters) and in field conditions. A microbiology study was performed using the same soi/. Vegetal and minerai oils were applied an soi/ of lysimeter or field ot the phytosanitary application dose. Migration and primary degradation profiles of the oils and their metabolites were determined during a period of 120 days by gas chromatography analysis. Results showed a total degradation of the vegetal oil and its metabofites after 60 days whereas minerai oil required 90 days. A microbiology study was performed to identify some micro-organisms of the soi! and to evaluate ecotoxicity effects of the oils. Vegetal oil was revea/ed ta be Jess taxie thon minerai oil even at high concentration. The high biodegradability of the vegetal ester in soi/ was confirmed as we/1 os their environmental qua'Jities