ChemSusChem
10.1002/cssc.201802497
COMMUNICATION
As already mentioned, solvolysis alone is expected to afford Acknowledgements
around 20% conversion to monophenolic compounds. Therefore,
the observed 34 wt% yield of monophenolics obtained from birch
fractionation cannot be explained by only stabilization reactions of
the released monolignols by the cobalt catalyst.
This work was supported by the Swedish Energy Agency.
Keywords: biomass fractionation • birch wood • cobalt •
To gain more insight into the role of the cobalt catalyst, we studied
the effect of Co-phen/C on the transfer hydrogenolysis of 5 in the
presence of formic acid. Compared to using formic acid alone, the
catalyst increased the yield of monophenolic compounds
dramatically and shifted the product distribution giving 11 along
with 9 and 10 (Table 2, entry 4). The hydrogenolysis activity of the
Co-phen/C catalyst was further studied using model compound 8.
This compound cannot undergo acid-catalyzed transformations to
give aldehyde 9.[29] Therefore, compound 8, is relevant to use in
order to study whether a catalyst can perform C–O bond cleavage
via a transfer hydrogenolysis reaction. The reaction of 8 was
remarkably selective giving 12 and syringol 10 as main products
heterogeneous catalysis • lignin
[
[
1]
2]
M. V. Galkin, J. S. M. Samec, ChemSusChem 2016, 9, 1544–1558.
R. Rinaldi, R. Jastrzebski, M. T. Clough, J. Ralph, M. Kennema, P. C.
A. Bruijnincx, B. M. Weckhuysen, Angew. Chem. Int. Ed. 2016, 55,
8164–8215.
[3]
T. Renders, S. Van den Bosch, S.-F. Koelewijn, W. Schutyser, B. F.
Sels, Energy Env. Sci 2017, 10, 1551–1557.
[4]
5]
[6]
Z. Sun, B. Fridrich, A. de Santi, S. Elangovan, K. Barta, Chem. Rev.
2018, 118, 614–678.
[
W. Schutyser, T. Renders, S. Van den Bosch, S.-F. Koelewijn, G. T.
Beckham, B. F. Sels, Chem. Soc. Rev. 2018, 47, 852–908.
M. Zaheer, R. Kempe, ACS Catal. 2015, 5, 1675–1684.
P. J. Deuss, K. Barta, Coord. Chem. Rev. 2016, 306, 510–532.
Q. Song, F. Wang, J. Cai, Y. Wang, J. Zhang, W. Yu, J. Xu, Energy
Environ. Sci. 2013, 6, 994.
[7]
8]
[
[9]
F. Schüth, in Catal. Hydrog. Biomass Valorization (Ed.: R. Rinaldi),
Royal Society Of Chemistry, 2015, pp. 1–13.
(
Table 2, entry 5). Indeed, full conversion of 8 and excellent
selectivity were also achieved using sodium formate as hydrogen
donor (Table S3, entry 2), showing that the catalyst is able to
employ both formic acid and formate as hydrogen donors. These
experiments indicate that formic acid promotes solvolysis to
liberate reactive monomers and lignin fragments from the wood.
[
10]
P. Ferrini, R. Rinaldi, Angew. Chem. - Int. Ed. 2014, 53, 8634–8639.
M. V Galkin, A. T. Smit, E. Subbotina, K. A. Artemenko, J. Bergquist,
W. J. J. Huijgen, J. S. M. Samec, ChemSusChem 2016, 9, 3280–
[11]
3287.
[12]
I. Kumaniaev, E. Subbotina, J. Sävmarker, M. Larhed, M. V. Galkin, J.
S. M. Samec, Green Chem. 2017, 19, 5767–5771.
Z. Cao, M. Dierks, M. T. Clough, I. B. Daltro de Castro, R. Rinaldi,
Joule 2018, 2, 1118–1133.
J. P. Lange, Angew. Chem. - Int. Ed. 2015, 54, 13187–13197.
L. He, F. Weniger, H. Neumann, M. Beller, Angew. Chem. - Int. Ed.
[
13]
14]
The catalyst Co-phen/C thus performs reductive cleavage of
lignin fragments/oligomers provided by organosolv pulping and at
the same time plays a key role in the stabilization of the reactive
monomers by catalyzing transfer hydrogenolysis/hydrogenation
reactions (Table 2). Both of these two actions leads to further
increase the yield of monophenolic compounds.[1,12,30]
[
[15]
2016, 55, 12582–12594.
[16]
R. V Jagadeesh, T. Stemmler, A. Surkus, M. Bauer, M. Pohl, J.
Radnik, K. Junge, H. Junge, A. Brückner, M. Beller, Nat. Protoc. 2015,
10, 916–926.
F. A. Westerhaus, R. V. Jagadeesh, G. Wienhöfer, M.-M. Pohl, J.
Radnik, A.-E. Surkus, J. Rabeah, K. Junge, H. Junge, M. Nielsen, et
al., Nat. Chem. 2013, 5, 537–543.
R. V Jagadeesh, H. Junge, M. Pohl, J. Radnik, A. Brückner, M. Beller,
J. Am. Chem. Soc. 2013, 135, 10776–10782.
C. Tang, A. E. Surkus, F. Chen, M. M. Pohl, G. Agostini, M.
Schneider, H. Junge, M. Beller, Angew. Chem. - Int. Ed. 2017, 56,
[17]
We were able to recycle the catalyst 3 times with negligible loss
of efficiency (yield dropped from >95% to 92%, Figure S6).
[
18]
19]
[
Catalytic reductive fractionation of lignocellulose using
heterogeneous cobalt catalyst yields up to 34 wt% of
lignin-derived monophenolic compounds. Formic acid/formate
were used as hydrogen donors. The role of the cobalt catalyst is
to both stabilize reactive monomers from solvolysis as well as to
reductively cleave oligomers of lignin by hydrogenation and
hydrogenolysis reaction.
16616–16620.
[20]
[21]
[22]
[23]
[24]
[25]
Y. L. Ren, M. Tian, X. Z. Tian, Q. Wang, H. Shang, J. Wang, Z. C.
Zhang, Catal. Commun. 2014, 52, 36–39.
X. Liu, W. Jia, G. Xu, Y. Zhang, Y. Fu, ACS Sustain. Chem. Eng.
2017, 5, 8594–8601.
C. Canevali, M. Orlandi, L. Pardi, B. Rindone, R. Scotti, J. Sipila, F.
Morazzoni, J. Chem. Soc. Dalton Trans. 2002, 3007–3014.
H. Yang, R. Nie, W. Xia, X. Yu, D. Jin, X. Lu, D. Zhou, Q. Xia, Green
Chem 2017, 19, 5714–5722.
Z. Wei, J. Wang, S. Mao, D. Su, H. Jin, Y. Wang, F. Xu, H. Li, Y.
Wang, ACS Catal. 2015, 5, 4783–4789.
L. Liu, P. Concepción, A. Corma, J. Catal. 2016, 340, 1–9.
D. Hulicova-Jurcakova, M. Seredych, G. Q. Lu, T. J. Bandosz, Adv.
Funct. Mater. 2009, 19, 438–447.
J. Casanovas, J. M. Ricart, J. Rubio, F. Illas, J. M. Jiménez-Mateos, J.
Am. Chem. Soc. 1996, 118, 8071–8076.
T. Renders, S. Van Den Bosch, T. Vangeel, T. Ennaert, S. Koelewijn,
G. Van Den Bossche, C. M. Courtin, W. Schutyser, B. F. Sels, ACS
Sustain. Chem. Eng. 2016, 4, 6894–6904.
J. D. Nguyen, B. S. Matsuura, C. R. J. Stephenson, J. Am. Chem.
Soc. 2014, 136, 1218–1221.
Experimental Section
[26]
27]
[28]
[
In a typical reaction, birch sawdust (200 mg, sieved ≤250 µm), catalyst
(30 mg, 1 mol% Co), EtOH (3 mL), DI water (3 mL) and hydrogen donor
were measured into the reactor equipped with a magnetic stirring bar. The
mixture was bubbled with Ar for 5 min, sealed, placed in preheated oil bath
and stirred at 500 rpm. After the desired time, the reactor was removed
from oil bath and cooled to RT. The mixture was poured onto filter paper
and washed with EtOH/water (3x5 mL), water (5 mL) and acetone (5 mL).
[29]
[30]
M. V. Galkin, J. S. M. Samec, ChemSusChem 2014, 7, 2154–2158.
4
mg of tetracosane was added to the filtrate as GC standard. The
combined filtrates were evaporated in vacuo to give a mixture of lignin oil
and aqueous solution of hemicelluloses. Lignin oil was separated by
liquid‒liquid extraction using DCM‒water. The organic phase was dried
using Na
The solid residue comprising pulp and catalyst were dried overnight at
0 °C.
2 4
SO , evaporated in vacuo and dried for 2 h under high vacuum.
5
This article is protected by copyright. All rights reserved.