Exploration de la technique d' ionisation MAB (Metastable Atom Bombardment) dans le cadre de l' analyse de composés de l' industrie pétrochimique

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Suitable gradient conditions for the separation of bio-oils samples in RPLC X RPLC

communication par afficheInternational audienc

Hydrothermal conversion of glucose in a batch reactor. A detailed study of an experimental key-parameter : the heating time

n this study, conversions of an aqueous solution of glucose (2 wt%) were performed at 370 °C and 25 MPa in subcritical water during different heating times. The original batch reactor used for this study allowed the introduction of the glucose solution directly in the hot and compressed aqueous medium. In this work, an original analytical approach combining chromatographic (SEC, GC, HPLC) and mass spectrometric techniques (FT-ICR/MS) has been also developed in order to provide more information about the chemical and molecular weights polydispersity of the products. From our experiments, it has been shown that the glucose conversion occurs via a complex reaction pathway implying competitive fragmentation and condensation reactions. Yields of product resulting from condensation reactions can be limited mainly by both short heating time and reaction time

Hydrothermal conversion of Lignin compounds. A detailled study of fragmentation and condensation reaction pathways

The hydrothermal conversion takes advantage of the singular physico-properties of the hot and compressed water which can be considered as a green solvent. The hydrothermal conversions of an alkali lignin and of phenolic model compounds (vanillin, monobenzone, 2,2′-biphenol) have been studied at 370 and 390 °C, at 25 MPa between 5 and 40 min. Polydispersity of products in term of both chemical structures and molecular weights has been characterized through a new analytical approach combining chromatographic (GC) and spectrometric techniques (Fourier transform ion cyclotron mass spectrometry FT-ICR/MS, NMR). From our experiments, it is clear that lignin conversion occurs via a complex reaction pathway where competitive fragmentation and condensation reactions occur. An original reaction pathway has been suggested from the main emphasized reactions

Correspondence Between Structure and Reactivity During Hydrothermal Conversion of Lignocellulosic Macromolecules

In this study, reaction pathway of a woody biomass under hydrothermal conditions is investigated in order to further understand reactions that occur during the thermochemical liquefaction of a lignocellulosic biomass. A multitechnique analytical approach combining chromatographic and spectroscopic techniques has been developed in order to characterize both chemical structure and molecular weight of the products. From our experiments, we can assume that the holocellulosic and the ligneous fractions of biomass have different reactivity under hydrothermal condition. Although hydrothermal conversion of holocellulose and lignin occur both according to a complex pathway composed of competitive fragmentation and condensation reactions, holocellulose reacts first by total fragmentation to low molecular weight compounds followed by the condensation of the fragment to heavy molecular weight compounds, whereas lignin reacts essentially by partial depolymerisation. Since compounds produced from both the holocellulosic and the ligneous fraction are together in the reaction medium then they condense each other during the conversion of lignocellulosic material