154 research outputs found
A measurement of D<sup>±</sup><sub>s</sub> -> K<sup>0</sup> K<sup>±</sup> branching ratio and observation of the corresponding semileptonic B<sub>s</sub> decays
No full textSynthesis of bio-plasticizer from epoxidized vegetable oils
No full textInternational @ CDFA+GSC:CPI:LDJInternational audienceIntroductionThe use of renewable resources in the elaboration of various industrial materials and chemical has been recently revitalized because of environmental concerns. Nowadays, vegetable oils constitute one of the most important classes of renewable resources. To substitute the phthalate derivatives that are used at present as plasticizers for PVC, modified vegetables oils were prepared as a new bio plasticizer [1]. Efficient oxirane ring opening of fatty epoxides was performed to synthesis various diesters. Modified oils were characterized. In this paper, we wish to present catalyzed ring opening reaction and effects of esters groups on the PVC plasticisation.Results and discussionWe prepared a range of products via successive ring oxirane opening reaction with a series of acids then esterification of the resulting alcohol with anhydride. The reaction was performed in solvent free conditions and the influence of the catalysts (homogeneous or heterogeneous) in these reactions was evaluated. With this approach symmetric and dissymmetric esters were prepared [2-3].Among the evaluated catalysts, NBu4Cl, TiO2 and Nb2O5 exhibited significant activities for both reactions. Optimisations of the reaction conditions were performed in order to achieve complete conversion. The reaction has been perfomed on G scale. The products were characterized by NMR, GC and TGA and their properties as a bioplasticizer for PVC were evaluated.Fig. 1: Viscoelastic profile of plastisol with modified oils(AcMeSBO : acetylated methyl soyate, BzMeSBO : methyl soyate with benzoate,Ac/CyclohMeSBO : methyl soyate with acetate and cyclohexanoate)Plastisols were prepared by mixing PVC and the fatty ester derivatives (PVC/plasticizers: 2/1 in mass?). The angular frequency used is 6.3 rd/s. The storage modulus G’ was recorded as function of temperature (fig. 1). The temperatures of gelation were almost the same as the standard plasticizer (DINP). Some modified vegetable oils may be good candidates to substitute the phthalate derivative usually added as plasticizer. The influence of the chemical modifications on the properties will be described.ConclusionThis two-step ring opening approach allowed to prepare a range of potential bioplasticizers for PVC starting from vegetable oils. is an interesting method to add new functions on fatty acid esters and it can be applied to the synthesis of PVC bio plasticizers.References[1] R. Stringer, I. Labunska, D. Santillo, J. Siddorn, A. Stephenson, Environ Sci Pollut Res 2000 7,1, 27-36.[2] G. Fogassy, C. Pinel, G. Gelbard, Cat. Commun. 2009 10, 557-560[3]G. Fogassy, P. Ke, F. Figueras, P. Cassagnau, S. Rouzeau, V. Courault, G. Gelbard, C. Pinel, Appl. Catal. A, 2011 393, 1–
Synthesis of bio-plasticizer from epoxidized vegetable oils
No full textInternational @ CDFA+GSC:CPI:LDJInternational audienceIntroductionThe use of renewable resources in the elaboration of various industrial materials and chemical has been recently revitalized because of environmental concerns. Nowadays, vegetable oils constitute one of the most important classes of renewable resources. To substitute the phthalate derivatives that are used at present as plasticizers for PVC, modified vegetables oils were prepared as a new bio plasticizer [1]. Efficient oxirane ring opening of fatty epoxides was performed to synthesis various diesters. Modified oils were characterized. In this paper, we wish to present catalyzed ring opening reaction and effects of esters groups on the PVC plasticisation.Results and discussionWe prepared a range of products via successive ring oxirane opening reaction with a series of acids then esterification of the resulting alcohol with anhydride. The reaction was performed in solvent free conditions and the influence of the catalysts (homogeneous or heterogeneous) in these reactions was evaluated. With this approach symmetric and dissymmetric esters were prepared [2-3].Among the evaluated catalysts, NBu4Cl, TiO2 and Nb2O5 exhibited significant activities for both reactions. Optimisations of the reaction conditions were performed in order to achieve complete conversion. The reaction has been perfomed on G scale. The products were characterized by NMR, GC and TGA and their properties as a bioplasticizer for PVC were evaluated.Fig. 1: Viscoelastic profile of plastisol with modified oils(AcMeSBO : acetylated methyl soyate, BzMeSBO : methyl soyate with benzoate,Ac/CyclohMeSBO : methyl soyate with acetate and cyclohexanoate)Plastisols were prepared by mixing PVC and the fatty ester derivatives (PVC/plasticizers: 2/1 in mass?). The angular frequency used is 6.3 rd/s. The storage modulus G’ was recorded as function of temperature (fig. 1). The temperatures of gelation were almost the same as the standard plasticizer (DINP). Some modified vegetable oils may be good candidates to substitute the phthalate derivative usually added as plasticizer. The influence of the chemical modifications on the properties will be described.ConclusionThis two-step ring opening approach allowed to prepare a range of potential bioplasticizers for PVC starting from vegetable oils. is an interesting method to add new functions on fatty acid esters and it can be applied to the synthesis of PVC bio plasticizers.References[1] R. Stringer, I. Labunska, D. Santillo, J. Siddorn, A. Stephenson, Environ Sci Pollut Res 2000 7,1, 27-36.[2] G. Fogassy, C. Pinel, G. Gelbard, Cat. Commun. 2009 10, 557-560[3]G. Fogassy, P. Ke, F. Figueras, P. Cassagnau, S. Rouzeau, V. Courault, G. Gelbard, C. Pinel, Appl. Catal. A, 2011 393, 1–
Synthesis of bio-plasticizer from epoxidized vegetable oils
No full textInternational @ CDFA+GSC:CPI:LDJInternational audienceIntroductionThe use of renewable resources in the elaboration of various industrial materials and chemical has been recently revitalized because of environmental concerns. Nowadays, vegetable oils constitute one of the most important classes of renewable resources. To substitute the phthalate derivatives that are used at present as plasticizers for PVC, modified vegetables oils were prepared as a new bio plasticizer [1]. Efficient oxirane ring opening of fatty epoxides was performed to synthesis various diesters. Modified oils were characterized. In this paper, we wish to present catalyzed ring opening reaction and effects of esters groups on the PVC plasticisation.Results and discussionWe prepared a range of products via successive ring oxirane opening reaction with a series of acids then esterification of the resulting alcohol with anhydride. The reaction was performed in solvent free conditions and the influence of the catalysts (homogeneous or heterogeneous) in these reactions was evaluated. With this approach symmetric and dissymmetric esters were prepared [2-3].Among the evaluated catalysts, NBu4Cl, TiO2 and Nb2O5 exhibited significant activities for both reactions. Optimisations of the reaction conditions were performed in order to achieve complete conversion. The reaction has been perfomed on G scale. The products were characterized by NMR, GC and TGA and their properties as a bioplasticizer for PVC were evaluated.Fig. 1: Viscoelastic profile of plastisol with modified oils(AcMeSBO : acetylated methyl soyate, BzMeSBO : methyl soyate with benzoate,Ac/CyclohMeSBO : methyl soyate with acetate and cyclohexanoate)Plastisols were prepared by mixing PVC and the fatty ester derivatives (PVC/plasticizers: 2/1 in mass?). The angular frequency used is 6.3 rd/s. The storage modulus G’ was recorded as function of temperature (fig. 1). The temperatures of gelation were almost the same as the standard plasticizer (DINP). Some modified vegetable oils may be good candidates to substitute the phthalate derivative usually added as plasticizer. The influence of the chemical modifications on the properties will be described.ConclusionThis two-step ring opening approach allowed to prepare a range of potential bioplasticizers for PVC starting from vegetable oils. is an interesting method to add new functions on fatty acid esters and it can be applied to the synthesis of PVC bio plasticizers.References[1] R. Stringer, I. Labunska, D. Santillo, J. Siddorn, A. Stephenson, Environ Sci Pollut Res 2000 7,1, 27-36.[2] G. Fogassy, C. Pinel, G. Gelbard, Cat. Commun. 2009 10, 557-560[3]G. Fogassy, P. Ke, F. Figueras, P. Cassagnau, S. Rouzeau, V. Courault, G. Gelbard, C. Pinel, Appl. Catal. A, 2011 393, 1–
Toward Functional PET Imaging of the Spinal Cord
No full textInternational audienceBackground Estimates suggest that approximatively 25% of the world population will be overweight in 2025. Better understanding of the pathophysiology of obesity will help to develop future therapeutics. Serotonin subtype 6 receptors (5-HT 6 ) have been shown to be critically involved in appetite reduction and weight loss. However, it is not known if the pathological cascade triggered by obesity modifies the density of 5-HT 6 receptors in the brain. Methods Influence of diet-induced obesity (DIO) in Wistar rats was explored using MRI (whole-body fat) and PET ([ 18 F]2FNQ1P as a specific 5-HT 6 radiotracer). The primary goal was to monitor the 5-HT 6 receptor density before and after a 10-week diet (DIO group). The secondary goal was to compare 5-HT 6 receptor densities between DIO group, Wistar control diet group, Zucker rats (with genetic obesity) and Zucker lean strain rats. Results Wistar rats fed with high-fat diet showed higher body fat gain than Wistar control diet rats on MRI. [ 18 F]2FNQ1P PET analysis highlighted significant clusters of voxels (located in hippocampus, striatum, cingulate, temporal cortex and brainstem) with increased binding after high-fat diet ( p < 0.05, FWE corrected). Conclusion This study sheds a new light on the influence of high-fat diet on 5-HT 6 receptors. This study also positions [ 18 F]2FNQ1P PET as an innovative tool to explore neuronal consequences of obesity or eating disorder pathophysiology
The failure of hyper-growth firms: a study of the bankruptcy of French SMEs with high growth potential
No full textInternational audienc
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