TY - JOUR
T1 - Towards quantitative catalytic lignin depolymerization
AU - Roberts, Virginia M.
AU - Stein, Valentin
AU - Reiner, Thomas
AU - Lemonidou, Angeliki
AU - Li, Xuebing
AU - Lercher, Johannes A.
PY - 2011/5/16
Y1 - 2011/5/16
N2 - The products of base-catalyzed liquid-phase hydrolysis of lignin depend markedly on the operating conditions. By varying temperature, pressure, catalyst concentration, and residence time, the yield of monomers and oligomers from depolymerized lignin can be adjusted. It is shown that monomers of phenolic derivatives are the only primary products of base-catalyzed hydrolysis and that oligomers form as secondary products. Oligomerization and polymerization of these highly reactive products, however, limit the amount of obtainable product oil containing low-molecular-weight phenolic products. Therefore, inhibition of concurrent oligomerization and polymerization reactions during hydrothermal lignin depolymerization is important to enhance product yields. Applying boric acid as a capping agent to suppress addition and condensation reactions of initially formed products is presented as a successful approach in this direction. Combination of base-catalyzed lignin hydrolysis with addition of boric acid protecting agent shifts the product distribution to lower molecular weight compounds and increases product yields beyond 85%.
AB - The products of base-catalyzed liquid-phase hydrolysis of lignin depend markedly on the operating conditions. By varying temperature, pressure, catalyst concentration, and residence time, the yield of monomers and oligomers from depolymerized lignin can be adjusted. It is shown that monomers of phenolic derivatives are the only primary products of base-catalyzed hydrolysis and that oligomers form as secondary products. Oligomerization and polymerization of these highly reactive products, however, limit the amount of obtainable product oil containing low-molecular-weight phenolic products. Therefore, inhibition of concurrent oligomerization and polymerization reactions during hydrothermal lignin depolymerization is important to enhance product yields. Applying boric acid as a capping agent to suppress addition and condensation reactions of initially formed products is presented as a successful approach in this direction. Combination of base-catalyzed lignin hydrolysis with addition of boric acid protecting agent shifts the product distribution to lower molecular weight compounds and increases product yields beyond 85%.
KW - borates
KW - catalytic depolymerization
KW - hydrolysis
KW - lignin
KW - renewable resources
UR - http://www.scopus.com/inward/record.url?scp=79955754674&partnerID=8YFLogxK
U2 - 10.1002/chem.201002438
DO - 10.1002/chem.201002438
M3 - Article
AN - SCOPUS:79955754674
SN - 0947-6539
VL - 17
SP - 5939
EP - 5948
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 21
ER -