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Xylose Isomerization with Zeolites in a Two‐Step Alcohol–Water Process
Author(s) -
Paniagua Marta,
Saravanamurugan Shunmugavel,
MelianRodriguez Mayra,
Melero Juan A.,
Riisager Anders
Publication year - 2015
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201402965
Subject(s) - chemistry , xylose , isomerization , catalysis , zeolite , methanol , yield (engineering) , pyridine , mordenite , lewis acids and bases , hydrolysis , organic chemistry , alcohol , materials science , fermentation , metallurgy
Isomerization of xylose to xylulose was efficiently catalyzed by large‐pore zeolites in a two‐step methanol–water process that enhanced the product yield significantly. The reaction pathway involves xylose isomerization to xylulose, which, in part, subsequently reacts with methanol to form methyl xyluloside (step 1) followed by hydrolysis after water addition to form additional xylulose (step 2). NMR spectroscopy studies performed with 13 C‐labeled xylose confirmed the proposed reaction pathway. The most active catalyst examined was zeolite Y, which proved more active than zeolite beta, ZSM‐5, and mordenite. The yield of xylulose obtained over H‐USY (Si/Al=6) after 1 h of reaction at 100 °C was 39 %. After water hydrolysis in the second reaction step, the yield increased to 47 %. Results obtained from pyridine adsorption studies confirm that H‐USY (6) is a catalyst that combines Brønsted and Lewis acid sites, and isomerizes xylose in alcohol media to form xylulose at low temperature. The applied zeolites are commercially available; do not contain any auxiliary tetravalent metals, for example, tin, titanium, or zirconium; isomerize xylose efficiently; are easy to regenerate; and are prone to recycling.