Catalytic Processes Directed Towards Lignin
Derived Commodity Chemicals for Polymer
Synthesis
Xiaojuan Zhou, Pradeep Agrawal and
Christopher W. Jones
Georgia Institute of Technology
School of Chemical & Biomolecular Engineering
Atlanta, GA 30332
IPST Members Meeting
Wednesday, April 11, 2012
• Mariefel Valenzuela Olarte
• Xiaojuan Zhou
• Previous work: catalytic phenol hydrogenation – fuels
• Current work: catalytic phenol hydrogenation -
chemicals
Outline
Mariefel Valenzuela Olarte
University of the Philippines, Los Baños
B.S. Chemical Engineering, 2001
Georgia Institute of Technology
M.S. Paper Science and Engineering, 2006
Thesis Title: “Batch Aqueous-phase Reforming
of Woody Biomass”
Georgia Institute of Technology
Ph.D. Chemical Engineering, 2011 “Depolymerization of Lignin and
Catalytic Hydrogenation of
Lignin-derived Model Compounds”
Current: Research Engineer, Catalytic Biorefining,
Pacific Northwest National Laboratory, Richland, WA.
Xiaojuan (Roxy) Zhou
Zhejiang University
•2007-2008
•Major: Material Science and
Engineering
Miami University (Oxford)
•2008-2011
•Major: Chemical Engineering with
concentration in Paper Science
•Degree: B.S. in Engineering
Motivation
OH
Pt/Zeolite
H2 (4 MPa), 473 K
Hydrogenation/Hydrogenolysis
+
Hydrogenation/Hydrogenolysis& Coupling
Bifunctional Catalysis
Most hydrodeoxygenation studies have focused on sulfided CoMo and NiMo-based
catalysts.
A significant fraction of fast pyrolysis and other bio-oils is a mixture of phenol
compounds (20~30%).
However, most of the phenolic fragments will be 6-9 carbons in mass, and after
deoxygenation and ring saturation, the hydrocarbons formed will be of lower molecular
weight and thus of only moderate value as a fuel.
To this end, an important goal in biomass upgrading is often molecular weight
enhancement, producing molecules of appropriate molecular weight for use as gasoline
or diesel fuels.
Experimental:
Preparation of catalysts
Impregnation of the solution of Pt(NH3)4(NO3)2 onto Y zeolites
Calcination: 500 oC for 4 in air.
Catalytic activity measurement
Continuous fixed bed reactor
Reduction: H2 flow (50 ml/min; atmospheric pressure), 500 oC for 1h (b =1 oC/min).
Temperature = 473 - 523 K
H2 pressure = 40 bar
WHSV = 5 - 20 h-1
H2 flow rate = 50 ml/min
Product analysis: On-line GC equipped with FID and TCD, GC/MS
Characterization of catalyst
XRD, H2 chemisorption, N2 physisorption, 27Al NMR, TGA, FT-IR
Products identified using GC/MS
O
OH
OH
Major products
Minor products
Trace
O
OH
O OH
OH
O HO
OO
OHOH
OHOH
Major products
Minor products
Trace
O
OH
O OH
OH
O HO
( < 0.5%)
( 60 ~ 95%) ( ~ 8%) ( ~ 15%)
( ~ 5%) ( ~ 5%) ( ~ 1%) ( ~ 3%) ( ~ 1%) ( ~ 1%)
* Parentheses show the maximum selectivity
Products were identified by Shimadzu GC/MS and Varian GC/MS.
0 20 40 60 80 100
0
5
10
15
20
25
30
Methyl cyclopentane
Benzene
Cyclohexane
Cyclohexene
Cyclohexanone
Cyclohexanol
Conversion of phenol (%)
Sele
cti
vit
y (
%)
0
20
40
60
80
100
Sele
ctiv
ity (%
)
Temperature, 473 K; H2 pressure, 4.0 MPa; Catalyst loading, 100 mg; Catalyst, 0.5 wt% Pt/HY
(SiO2/Al2O3 = 12), WHSV, 5-20 h-1; H2O content, 5 wt%.
Monocyclic Product Selectivity versus Phenol Conversion
Reaction pathway of phenol to monocyclics
OH
2H2
OH
H2
OH
H+ H2
O
-H2O
H2
H2H2H2
Reaction pathway of phenol to monocyclics in the catalytic hydrogenation treatment.
Phenol appears to be hydrogenated to cyclohexenol as an intermediate product in the initial steps,
and then this species is rapidly converted to cyclohexanol and/or cyclohexanone through two parallel
pathways.
Hong et al., Chem. Commun. 2010, 46, 1038;
0 20 40 60 80 100
0
1
2
3
4
5
6
Se
lec
tiv
ity (
%)
Conversion of phenol (%)
Cychlopentyl Methyl cyclohexane
Bicyclohexyl
2-Cyclohexyl cyclohexanone
2-Cyclohexyl phenol
4-Cyclohexyl phenol
Tricyclohexyl
Temperature, 473 K; H2 pressure, 4.0 MPa; Catalyst loading, 100 mg; Catalyst, 0.5 wt% Pt/HY
(SiO2/Al2O3 = 12), WHSV, 5-20 h-1; H2O content, 5 wt%.
Bycyclic Product Selectivity versus Phenol Conversion
OH
OH
O
OH
OO
OH
H+
H+
H2
2H2
O
2H2
2H2
3H2
Proposed reaction pathway of phenol to bicyclics in the catalytic hydrogenation reaction
Reaction pathway of phenol to bicyclics
Cyclohexyl phenol formation is dominant in the presence of cyclohexanol as an alkylating agent
2-cyclohexyl cyclohexanone can be produced from cyclohexanone by aldol condensation over the
acidic zeolite
Kallury, et al., Can. J. Chem., 1984, 62, 2540; Anand et al.,Catal. Lett., 2002, 81, 241–246; 2002, 81, 33.
Xu et al., J. Am. Chem. Soc., 1994, 116, 1962;
J. Huang, W. Long, P. K. Agrawal and C. W. Jones, J. Phys.Chem. C, 2009,
113, 16702.
0.0 0.2 0.4 0.6 0.8 1.00
50
100
150
200
250
300
N2 a
ds
orb
ed
(m
l/g
, S
TP
)
Relative Pressure (P/Po)
0h
1h
5h
8h
10h
Reaction conditions: Temperature, 473 K; H2
pressure, 40 bar; Catalyst loading, 100 mg; Catalyst,
0.5 wt% Pt/HY (SiO2/Al2O3 = 12); WHSV, 5 h-1; H2O
content, 10 wt%.
0 2 4 6 8 100
20
40
60
80
100
Co
nv
ers
ion
of
ph
en
ol (%
)
Time-on-stream (h)
Conversion of phenol
Samples were pretreated in vacuum at 473 K for 12 hr
N2 adsorption over spent catalysts with different on-stream times
Sample SBET (m2/g) TPV (cm3/g) Vmicro
(cm3/g) Vol* (cm3/g)
0 h 764 0.44 0.24 200
1 h 240 0.17 0.07 64
5 h 109 0.11 0.03 28
8 h 55 0.09 0.01 15
10 h 50 0.08 0.01 13
Summary
• Pt-HY catalyst effectively hydrogenates phenol to produce saturated
hydrocarbons.
• Hydrogen use significant (high P); catalyst expensive (Pt).
• Catalyst deactivates due to coking – stability too limited for practical use.
• Bicyclic products in good molecular weight regime for fuels, cyclohexane
of limited value.
Recent Work: Slow Deactivation, Tune Product Selectivity
• Replace Pt with Ni (lower metal cost)
• Replace microporous zeolite with large pore, mesocellular foam
(improved transport, lower acid strength, less impact of carbon
deactivation)
• Experiment with reactor configuration:
-- bifunctional catalysts
-- intermixed acid and hydrogenation catalysis
-- dual beds - acid and hydrogenation catalysis
• Ni/SiO2 is a known catalyst for phenol hydrogenation.
Shin, E. J.; Keane, M. A., Ind. Eng. Chem. Res. 2000, 39, 883-892.
Pina, G.; Louis, C.; Keane, M. A., Phys. Chem. Chem. Phys. 2003, 5 , 1924-1931;
Mahata, N.; Raghavan, K. V.; Vishwanathan, V.; Keane, M. A. React. Kinet. Catal. Lett. 2001, 72, 297-302;
Shin, E. J.; Keane, M. A., Appl. Catal. B. Env. 1998, 18, 241-250.
Mesocellular foams (MCF): hydrothermally-synthesized mesoporous
silicates* formed by adding a swelling agent (1,3,5-trimethylbenzene) to
the surfactant-templated SBA-15 synthesis mix
Progression of morphological transition of P-123-templated materials as TMB content is increased
Because of the pore expansion, a
higher surface area is achieved
promising support for catalysts
dealing with large molecules
as substrate, such as fatty
acids and possibly lignin
Lettow, et. al. Langmuir 2000, 16, 8291-8295.
Liu, et. al. Catal. Lett. 2008, 125, 62-68.
Silica and Aluminosilicate Mesocellular Foams
Conditions:
NiMCF, 6.7 bar , 200 oC, 5 h-1 sv,
100 mg catalyst, 10% H2O,
Ni-MCF:
Main product: cyclohexanol
Still complete
conversion of phenol in
15 hrs with 80% less H2
Ni-MCF as a Hydrogenation Catalyst
No deactivation over 16 hrs.
(a) Single Bed – single catalyst type
(b) Sequential Beds (c) Single Bed – physical mixture
Control Reaction Selectivity by Catalyst Configuration
Control Reaction Selectivity by Catalyst Configuration
200°C, 100 psig H2 , WSHV = 5hr-1
Selectivity Phenol
Conversion
Reactant Reactor
pressure Catalyst Major product
after 4
hours
after 15
hours
after 4
hours
after 15
hours
Aqueous phenol
(10% water)
100 psig
(6.7 bars)
NiMCF Cyclohexanol 82 90.5 100 100
HY no reaction
AlMCF no reaction
NiMCF-HY
sequential beds Cyclohexene 91.9 93.8 100 100
NiMCF/HY
mixed bed Cyclohexane 98.7 98.7 100 100
NiMCF-AlMCF
sequential beds Cyclohexene 91.7 98.4 100 100
NiMCF/AlMCF
mixed beds Cyclohexane 98.6 98.7 100 100
Control Reaction Selectivity by Catalyst Configuration
200°C, 100 psig H2 , WSHV = 5hr-1
Selectivity Phenol
Conversion
Configuration Reactor
pressure Catalyst Major product
after 4
hours
after 15
hours
after 4
hours
after 15
hours
100 psig
(6.7 bars)
NiMCF Cyclohexanol 82 90.5 100 100
HY no reaction
AlMCF no reaction
NiMCF-HY
sequential beds Cyclohexene 91.9 93.8 100 100
NiMCF/HY
mixed bed Cyclohexane 98.7 98.7 100 100
NiMCF-AlMCF
sequential beds Cyclohexene 91.7 98.4 100 100
NiMCF/AlMCF
mixed beds Cyclohexane 98.6 98.7 100 100
Control Reaction Selectivity by Catalyst Configuration
200°C, 100 psig H2 , WSHV = 5hr-1
Selectivity Phenol
Conversion
Configuration Reactor
pressure Catalyst Major product
after 4
hours
after 15
hours
after 4
hours
after 15
hours
100 psig
(6.7 bars)
NiMCF Cyclohexanol 82 90.5 100 100
HY no reaction
AlMCF no reaction
NiMCF-HY
sequential beds Cyclohexene 91.9 93.8 100 100
NiMCF/HY
mixed bed Cyclohexane 98.7 98.7 100 100
NiMCF-AlMCF
sequential beds Cyclohexene 91.7 98.4 100 100
NiMCF/AlMCF
mixed beds Cyclohexane 98.6 98.7 100 100
Control Reaction Selectivity by Catalyst Configuration
200°C, 100 psig H2 , WSHV = 5hr-1
Selectivity Phenol
Conversion
Reactant Reactor
pressure Catalyst Major product
after 4
hours
after 15
hours
after 4
hours
after 15
hours
Aqueous phenol
(10% water)
100 psig
(6.7 bars)
NiMCF Cyclohexanol 82 90.5 100 100
HY no reaction
AlMCF no reaction
NiMCF-HY
sequential beds Cyclohexene 91.9 93.8 100 100
NiMCF/HY
mixed bed Cyclohexane 98.7 98.7 100 100
NiMCF-AlMCF
sequential beds Cyclohexene 91.7 98.4 100 100
NiMCF/AlMCF
mixed beds Cyclohexane 98.6 98.7 100 100
• High selectivities and yields of olefin, alcohol and alkane by adjusting
catalyst configuration with no deactivation over 16 hrs.
Summary
• Ni-MCF, combined with acidic catalysts such as H-Al-MCF or HY, can
be used to give high yields and selectivities of cyclohexanol,
cyclohexane or cyclohexene.
Summary
• Ni-MCF, combined with acidic catalysts such as H-Al-MCF or HY, can
be used to give high yields and selectivities of cyclohexanol,
cyclohexane or cyclohexene.
New Project
• Tune catalyst and reactor configuration to produce high yields of
cyclohexanols/cyclohexanones from mixed lignin-derived phenol
streams.
• Investigate utility of lignin-derived cyclohexanols/cyclohexanones as
components of renewable nylon polymers.
Nylon 6 Precursors from Lignin Fragments by Catalytic Hydrogenation
Traditional Nylon 6 synthesis
selective
catalytic
hydrogenation
Proposed work Schedule:
Year 1: Recruit student, use existing infrastructure (high pressure flow
reactor) to study individual model compounds (phenol, catechol, guaiacol,
4-ethylguaiacol). Start with Ni/NiO/SiO2 catalyst.
Years 2-3: Tune catalyst structure and reaction conditions to target
monomeric cyclohexanols.
Year 4: Evaluate blending model compounds as simulated mixed phenol
feedstock in catalytic experiments.
Questions –
Primary: can we control hydrogenation selectivity of mulitiply-substituted
phenols? [85% catalysis and reaction engineering]
Secondary: if yes, can we make Nylon 6 from said precursors? What are
properties of nylons? [15% polymer science]
Nylon 6 Precursors from Lignin Fragments by Catalytic Hydrogenation
Research Support: This Work
Also thanked for financial support: