Acidolysis of a lignin model: investigation of heterogeneous catalysis using Montmorillonite clay.
The use of heterogeneous conditions involving Montmorillonite K10 clay was investigated as a mild alternative to homogeneous acidolysis of a lignin model. Guaiacyl Dehydrogenation Oligomers (DHOs) synthesized by horseradish peroxidase were selected as starting material. Hydrolysis products were analyzed by gel permeation chromatography and by HPLC/mass spectrometry. Several experimental parameters were studied such as catalyst and substrate concentration, as well as reaction solvent composition in order to minimize high molar mass product formation generated by recombination mechanisms. In both catalytic modes, the best hydrolysis conditions were similar in terms of solvent composition with dioxane/water (90/10, v/v) and catalyst H(+) concentration of about 0.01 mol/L. Although the homogeneous catalysis generated only 28% of low molecular weight (LMW) products (monomers and dimers), clay catalysis generated 35%. In light of the qualitative analysis, both catalytic methods gave the same products, thus supporting similar hydrolysis mechanisms.
Bouxin
Florent
F
UMR FARE, Bât 18-Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France. florent.bouxin@reims.inra.fr
Baumberger
Stéphanie
S
Pollet
Brigitte
B
Haudrechy
Arnaud
A
Renault
Jean-Hugues
JH
Dole
Patrice
P
D000143:Acids / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D002384:Catalysis; D002850:Chromatography, Gel; D002853:Chromatography, Liquid; D006868:Hydrolysis; D008956:Models, Chemical; D021241:Spectrometry, Mass, Electrospray Ionization
D000143:Acids; D001546:Bentonite