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

Thanks to:

IPST and IPST member companies.

Research Support: This Work

Also thanked for financial support: