title: Green synthesis of xylan hemicellulose esters.
abstract: The esterification of xylan type hemicelluloses, isolated from birchwood, was carried out firstly in homogeneous conditions using N,N-dimethylformamide (DMF) and lithium chloride (LiCl) in the presence of 4-dimethylaminipyridine (DMAP). The degree of substitution (DS) of xylan acetates ranged between 0.9 and 2.0 as a function of experimental conditions. Due to the problems of toxicity and recycling of DMF, an alternative method of esterification is reported in the second part of this work, performing in the absence of organic solvent and using DMAP or methanesulfonic acid (MSA) as catalysts. Acetylation reaction catalyzed by MSA was developed through an experimental design in order to achieve the highest DS under the mildest conditions. The significant factors and their interactions were identified. The optimization of reaction parameters allowed to obtain a high DS (1.6) and maximal yield (85%). Moreover, the reactivity of propionic and hexanoic anhydrides was evaluated and hydrophobic xylan esters with low degrees of substitution were obtained.
authors: Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON-CNRS), Université de Lyon, 2 Avenue Albert Einstein, 69626 Villeurbanne, France.
authors: Fatima-Zohra
authors: FZ
authors: Belmokaddem
authors: Catherine
authors: C
authors: Pinel
authors: Patrick
authors: P
authors: Huber
authors: Michel
authors: M
authors: Petit-Conil
authors: Denilson Da Silva
authors: Dda S
authors: Perez
mesh_terms: D002236:Carbohydrate Conformation; D004952:Esters / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D055772:Green Chemistry Technology; D011134:Polysaccharides / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D014934:Wood / Q000737:chemistry; D014990:Xylans / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D004952:Esters; D011134:Polysaccharides; D014990:Xylans; C007916:hemicellulose