A New Catalytic Pathway for the Production of Bio-based 1,5-Pentanediol - Kevin J. Barnett, Kefeng Huang, and George W. Huber
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A New Catalytic Pathway for the Production
of Bio-based 1,5-Pentanediol
Kevin J. Barnett, Kefeng Huang, and George W. Huber
[ kjbarnett@pyranco.com ]
MI Forest Bioeconomy Conference
February 12, 2019
Chemicals from
Biomass
▪ Oxidizing petroleum to chemicals can
be difficult and costly
Reduction
Oxidation
▪ Alternative: selectively reduce oxygenated
biomass
▪ Cost-competitive with petroleum due to high
cost of chemicals
▪ Renewably replace portion of oil end-use
2
α,ω-Diols from
Biomass Xylose (C5)
1,4-butanediol (1,4-BD)
▪ α,ω-diols are aliphatic carbon chains with
~2000 kton/yr
terminal alcohol groups Glucose (C6)
C5 Derived
C6 Derived
▪ End uses: polyurethanes, coatings, acrylates,
adhesives, 1,5-pentanediol
polyesters, and(1,5-PD)
plasticizers
~3 kton/yr
▪ High value: ~ $1500-4500 per MT
1,6-hexanediol (1,6-HD)
~130 kton/yr
3
C4-C6 α,ω-Diols Production and Market
Adipic Acid
Dicarboxylic Paints
$7B/yr Global Market acid
7% CAGR
(α,ω-diols)
Coatings
1,4-BD
Polyester
1,5-PD polyols
1,6-HD
Plastics
1,4-butanediol (1,4-BD)
$1600-3300/ton
1,5-pentanediol (1,5-PD)
$6000/ton $2000/ton Adhesives
1,6-hexanediol (1,6-HD)
$3000-4700/ton 4
Biomass to C5 and C6 α,ω-Diols
Biomass
Furfural
C5 Route 1,5-Pentanediol
Lignocellulosic
Biomass GVL H2 H2
recycle
Xylose
GVL/Water GVL/W H2O
R1
H2SO4 Extraction Dehydration H2 recycle purge
H2 recycle purge purge
Lignin to 1,5-PDO
SEP R2 THFA R3 DHP R4 2-HY-THP R5 PDO
Drying SEP Water
Water Process Heat Hydrogenation DEH HDR HYD
By-products
Cellulose Furfural
H2
R6 THF
C6 Route
H2SO4 H2
Dehydration recycle
H2 recycle H2 recycle
purge purge
LGO+HMF HDO precursors purge
1,6-HDO
LGO R7 R8 Solvent R9
SEP removal SEP Waste Water
HMF Hydrogenation HYD HYD
By-products
Levoglucosenol
THFDM
THFDM
THFDM
By-products
(purification to remove
acids)
Levoglucosenone 1,6-Hexanediol 5
▪ Process combines biomass
fractionation with chemical
production
▪ >80% of the initial wood
converted to products:
1. High purity cellulose
2. Furfural
3. High purity lignin
4. Acetic acid
5. Formic acid
6. Levulinic acid
▪ >$500 revenues per MT of
wood
▪ High biomass loading
20-30 wt%
6
Xylose Dehydration – Water vs. GVL
Key advantages of GVL
Increased reactivity of mineral acids:
Hydrolysis reaction rates (100 X vs. water)
Dehydration reaction rates (30 X vs. water)
7
Slide courtesy of David Martin-Alonso
Technilogical Advantages of GVL Process
Commercial process GVL process
Process Semi-continuous Continuous
Yield 35-55 % 95 %
Feedstock Corn cobs Xylose
Time 3-5 hours 30-60 seconds
Sulfuric acid 0.55 0.075
(ton/ton furfural)
Temperature 170-200°C 225 °C/
/pressure /5-10 atm 20 atm
Furfural concentration (wt%) 5
(25-50 wt% respect to water)
Steam (ton/ton furfural) 60 4
Slide courtesy of David Martin-Alonso 8
1,5-PD Production from Biomass
▪ Direct Hydrogenolysis Approach:
Hydrogenolysis over bimetallic, noble-metal catalysts (i.e. RhRe)1,2
• Uneconomical due to high catalyst costs
1 M. Chia et al. J. Am. Chem. Soc. 2011, 133, 12675–89.
2 Y. Nakagawa et al. Catal. Today 2012, 195, 136–143.
▪ New Approach: 3-step Dehydration-Hydration-Hydrogenation (DHH) pathway
3L. E. Schniepp, H. H. Geller, J. Am.
• Previously attempted by Geller et. al in 19463 Chem. Soc. 1946, 68, 1646–1648. 9
DHH pathway for 1,5-PD production
• Brentzel et. al. Chemicals from Biomass: Combining Ring-Opening Tautomerization
and Hydrogenation Reactions to Produce 1,5-Pentanediol from Furfural.
ChemSusChem 2017.10, 1351-1355.
• Huang et al. Conversion of Furfural to 1,5-Pentanediol: Process Synthesis and
Analysis. ACS Sustainable Chemistry and Engineering. 2017. 5 (6), 4699-4706.
• Huang et al. Improving Economics of Lignocellulosic Biofuels: An Integrated
Strategy for Coproducing 1,5-Pentanediol and Ethanol. 2017. In revision.
New pathway
MSP $2,436
MSP
THFA feedstock costs
Costs
Utility & Electricity costs
hydrogenolysis
Catalyst costs
MSP $4,090
pathway
Direct
Capital costs
Fixed operating costs
Costs
Other raw material costs
0 600 1200 1800 2400 3000 3600 4200
Costs and MSPs ($/ton 1,5-PDO)
• Production Cost of DHH pathway is 6.6 times lower (excluding feedstock)
• Catalyst cost of DHH pathway is 51 times lower 10THFA DEHYDRATION
11THFA Dehydration to Dihydropyran
▪ THFA dehydrated over metal-oxides in vapor phase
▪ Catalyst regenerated with 500˚C calcination step
▪ Catalyst nearly completely regenerable
• Only 2.5% loss in activity from Cycle 3 to Cycle 4
▪ 90% DHP Yields achieved at high conversion
12DHH Pathway Advantages Reactant Product
Concentration Yield
▪ Step 1: THFA Dehydration
• Low-cost metal-oxide catalysts Up to 100% 90%
• Catalyst regenerable
13DIHYDROPYRAN HYDRATION
14DHP Hydrates to 1,5-PD precursors in >99% Yields
▪ DHP hydrated in water with no catalyst added
2-phase Batch Reaction
2-HY-THP Yield 5-tetrahydropyranyloxy- 2-tetrahydropyranyl
Temperature Reaction pentanal Yield ether Yield
Overall Yield
( ͦ C) Time (h)
70 4 84.5% 5.3% 1.9% 91.7%
100 4 92.0% 6.6% 1.2% 99.8%
130 4 89.5% 6.4% 1.0% 96.9%
160 4 65.4% 4.2% 1.3% 70.9%
15Why does DHP so readily hydrate?
▪ DHP hydration rates >> cyclohexene hydration rates
▪ Hypothesis: due to formation of stable oxocarbenium transition state
Cyclohexene Mechanism
2˚ Carbocation
Dihydropyran Mechanism
Oxocarbenium
16Why does DHP so readily hydrate?
5 orders of magnitude difference
3˚ Carbocation
Oxocarbenium
2˚ Carbocation Transition State
A variety of unsaturated compounds were tested with HZSM5 in an attempt
to observe trend between transition state stability and hydration rate
2˚ Carbocation 3˚Carbocation Oxocarbenium 17DHH Pathway Advantages Reactant Product
Concentration Yield
▪ Step 1: THFA Dehydration
• Low-cost metal-oxide catalysts Up to 100% 90%
• Catalyst regenerable
▪ Step 2: DHP Hydration: Autocatalytic
• DHP hydrates with no catalyst
• Rate increased by in situ formation of acids Up to 50% 98%
• DHP readily hydrates due to stable transition state
182-HY-THP HYDROGENATION
19Ring-opening Tautomerization of 2-HY-THP into
5-hydroxyvaleraldehyde: NMR Studies
24˚C
• Variable temperature quantitative 13C 80˚C
NMR studies confirm the existence of
5-hydroxyvaleraldehyde (5HVal)
• Higher concentrations of 5HVal are
observed at elevated temperatures
- Tautomerization reaction is endothermic
20Ring-opening Tautomerization of 2-HY-THP into
5-hydroxyvaleraldehyde: NMR Studies
• Variable temperature quantitative 13C
NMR studies confirm the existence of
5-hydroxyvaleraldehyde (5HVal)
• Higher concentrations of 5HVal are
observed at elevated temperatures
- Tautomerization reaction is endothermic
21Tautomerization vs. Hydrogenolysis
▪ Direct Hydrogenolysis Approach:
Hydrogenolysis over bimetallic, noble-metal catalysts (i.e. RhRe)
▪ New Approach: Ring-opening tautomerization and hydrogenation
Noble metal bimetallics not
required for hydrogenation
O OH
Hemiacetal groups can homogeneously Hydrogenation rate >80x
tautomerize to their ring-opened form faster than hydrogenolysis 22DHH Pathway Advantages Reactant Product
Concentration Yield
▪ Step 1: THFA Dehydration
• Low-cost metal-oxide catalysts Up to 100% 90%
87% Overall Yield
• Catalyst regenerable
▪ Step 2: DHP Hydration: Autocatalytic
• DHP hydrates with no catalyst
• Rate increased by in situ formation of acids Up to 50% 98%
• DHP readily hydrates due to stable transition state
▪ Step 3: 2-HY-THP Hydrogenation
• Tautomerization of 2-HY-THP to aldehyde
• Lower-cost, monometallic catalysts Up to 50% 99%
23Conclusions ▪ DHH pathway: 51x lower catalyst cost for 1,5-PDO from bio-derived furfural ▪ Ring-opening tautomerization allows for high hydrogenation rates over lower- cost monometallic catalysts ▪ 1,5-PD minimum selling price
Key Takeway
Inherent chemical functionalities of biomass-derived molecules can
be advantaged to increase efficiencies and lower costs of bio-based
processes compared to petroleum-based process
25Kevin Barnett kjbarnett@pyranco.com
1,5-PD is produced from dicarboxylic acid as
byproduct of caprolactam
“KA Oil”
1,6-HD synthesized via oxidation of KA oil
to adipic acid with nitric acid catalyst
Cu2+, NH4VO3
50-60% HNO3C4-C6 α,ω-Diols Production and Market
Adipic Acid
Dicarboxylic Paints
$7B/yr Global Market acid
7% CAGR
(α,ω-diols)
Coatings
1,4-BD
Polyester
1,5-PD polyols
1,6-HD
Plastics
1,4-butanediol (1,4-BD)
$1600-3300/ton
1,5-pentanediol (1,5-PD)
$6000/ton $2000/ton Adhesives
1,6-hexanediol (1,6-HD)
$3000-4700/ton 28Chemicals from
Biomass
▪ Oxidizing petroleum to chemicals can
be difficult and costly
Reduction
Oxidation
▪ Alternative: selectively reduce oxygenated
biomass
▪ Cost-competitive with petroleum due to high
cost of chemicals
▪ Renewably replace portion of oil end-use
29α,ω-Diols from
Biomass
▪ α,ω-diols are aliphatic carbon chains with
terminal alcohol groups
Reduction
Oxidation
▪ End uses: polyurethanes, polyester polyols
paints, coatings, adhesives, and plastics
▪ High value: ~ $1500-4500 per MT
30α,ω-Diols from
Biomass Xylose (C5)
1,4-butanediol (1,4-BD)
~2000 kton/yr
Glucose (C6)
C5 Derived
C6 Derived
1,5-pentanediol (1,5-PD)
~3 kton/yr
1,6-hexanediol (1,6-HD)
~130 kton/yr
31pH decreases during DHP hydration
▪ DHP hydrated in water with no catalyst added
2-phase Batch Reaction
Visibly more solids
formation at higher
temperatures
pH~3.4 for all conditions tested
Indicative of
carboxylic acid formation
Reaction Conditions: P=250 psi He, Feed=20wt% DHP/H2O
32DHP Hydration is Autocatalytic
▪ Hydration performed in batch reactor with
two different solvents:
1) Pure DI water
2) 50% DI water + 50% reaction
filtrate from 200 ˚C hydration
▪ Acidic species formed during 200˚C
hydration
▪ 2-HY-THP yields increased 4x when
reaction product introduced
▪ Further evidence for autocatalytic hydrationDHP Hydration is Autocatalytic
▪ Performed DHP hydration at low
temperatures to study initiation
period of reaction
▪ Reaction rate doubles after 4h due
to increase in solution acidity
▪ Small amount of acidic species
(likely 5-hydroxyvaleric acid) form
▪ Initiation period very short!
Occurs atAcidic solid coke autocatalyzes
DHP hydration in flow reactor
2-HY-THP/H2O
(To hydrogenation)
75˚C Inert glass
beads
DHP H2O
▪ DHP hydration over inert glass beads performed in continuous flow reactor 11Acidic solid coke autocatalyzes
DHP hydration in flow reactor
2-HY-THP/H2O
(To hydrogenation)
100˚C
75˚C Inert glass
beads
DHP H2O
▪ Increased acidic coke formation at higher temperature increases hydration rate 12Acidic solid coke autocatalyzes
DHP hydration in flow reactor
2-HY-THP/H2O
(To hydrogenation)
140˚C
100˚C
75˚C Inert glass
beads
DHP H2O
▪ Increased acidic coke formation at higher temperature increases hydration rate 13Acidic solid coke autocatalyzes
DHP hydration in flow reactor
2-HY-THP/H2O
(To hydrogenation)
140˚C
100˚C
75˚C Inert glass
beads
60˚C
DHP H2O
▪ Increased acidic coke formation at higher temperature increases hydration rate 14Non-catalytic DHP Hydration – High T “Activation”
Temperature increased to
140°C for ~24h ▪ Goal: attempt to increase rate by forming
“active coke” at high temperature (140C)
▪ Experiment: Start at 75C -> go to 140C for
24h -> go back to 75C to observe increased
rate
75C
140C 0.037 mL/min
Temp: 75C
Flowrate: 0.037 mL/min
0.23 mL/min ▪ At 140C, activity increased by ~6.5x
▪ Cooling back to 75C only resulted in 37% rate
increase: not permanent activity increase
39Non-catalytic DHP Hydration – High T “Activation”
▪ Hypothesis: both soluble and insoluble humins – need to dry reactor to form solid coke in reactor
▪ Experiment: Start at 75C -> go to 140C for 24h -> dry reactor -> return to 75C to observe increased rate
▪ Cooling back to 75C resulted in 144% rate increase: 4x higher increase than w/o drying step
40
▪ At 100˚C with 2 drying steps, activity was increased >650% to complete conversionSolid-acid Catalyzed DHP Hydration
▪ Goal: Improve hydration rates by using solid acid catalysts
▪ Solid acid catalysts screened for DHP hydration in batch reactors:
No activity contribution
from autocatalytic hydration
Reaction Conditions:
T=50˚C, P=500psi Ar,
Feed=0.5wt% DHP/H2O,
Reaction Time=1h
(a) Ronen et. al (2011) (b) Ning Li et. al (2011) (c) Yu-Ting et. al. (2012) (d) Present Work *Amberlyst-70 acid site density
▪ Solid acids show high activity at condition where autocatalytic hydration does not occur
▪ Hydration rates correlate with Brønsted site density 41Solid-acid Catalyzed DHP Hydration
▪ Goal: Improve hydration rates by using solid acid catalysts
▪ Solid acid catalysts screened for DHP hydration in batch reactors:
Catalyst Reaction Rate (μmol/gcat-min) Bronsted site TOF (s-1)
No Catalyst 0 - No activity contribution
from autocatalytic hydration
γ-Al2O3 4 0.00038
HZSM5 2822 0.115
Amberlyst-70 26017 0.152
▪ Solid acids show high activity at condition where autocatalytic hydration does not occur
▪ Hydration rates correlate with Brønsted site density 42HZSM5 is stable for DHP hydration for 20wt% Feed
2-HY-THP/H2O
(To hydrogenation)
T: 70˚C
HZSM5 P: 900psi Argon
Feed: 20wt% DHP/H2O
DHP H2O
▪ Slight deactivation at 100% conversion likely to due coke
▪ Hydrothermally stable at 40-50% conversion
▪ High pressures (900psi) critical to improved HZSM5 stability 43HZSM5 is stable for DHP hydration for 50wt% Feed
2-HY-THP/H2O
(To hydrogenation)
T: 70˚C
HZSM5 P: 900psi Argon
Feed: 50wt% DHP/H2O
DHP H2O
▪ Hydrothermally stable at 40-50% conversion
▪ High pressures (900psi) critical to improved HZSM5 stability
44Combined Hydration-Hydrogenation: DHP to 1,5-PD
1,5-PD/H2O
Ru/C
(hydrogenation)
HZSM5
(hydration)
DHP H2O
Reaction Conditions: Reaction Conditions: 45
T=100˚C, P=500psi, Feed=0.5wt% DHP/H2O, Reaction Time=2h T=70˚C, P=500psi, Feed=20wt% DHP/H2O, mass Ru/C=0.75g, mass HZSM5=0.5gProbe Molecule Hydration
5 orders of magnitude difference
3˚ Carbocation
Oxocarbenium
2˚ Carbocation Transition State
2˚ Carbocation 3˚ Carbocation Oxocarbenium
46Why does DHP so readily hydrate?
▪ Hydration rates plotted versus transition state
Gibbs energy of formation (ΔG) for each molecule tested
ΔG
ΔG
232-HY-THP and Dimers convert to
1,5-pentanediol at ~100% Yields
▪ 2-HY-THP product (including dimers) from DHP hydration step directly
subjected to hydrogenation without purification
+ Dimers
Reaction Conditions: Feed=20wt% 2-HY-THP/H2O, Catalyst=1% Ru/TiO2, T=120˚C, P=650psi H2
▪ Dimers increase at low conversion due to shift in equilibrium
▪ 97% 1,5-PD yields achieved at complete conversion 482-HY-THP and Dimers convert to
1,5-pentanediol at ~100% Yields
+ Dimers
Reaction Conditions: Feed=20wt% 2-HY-THP/H2O, Catalyst=1% Ru/TiO2, T=120C̊, P=650psi H2
▪ Dimers increase at low conversion due to shift in equilibrium
▪ 97% 1,5-PD yields achieved at complete conversion 492-HY-THP Hydrogenation over Pt Catalysts
2-HY-THP
2-HY-THP Conversion # of sites
Catalyst Pretreatment Conversion rate TOF (1/min)
rate (mmol/g_Pt/min) (umol/g)
(mmol/g/min)
0.59wt% Pt/H-ZSM5
ER @300C & IR@200C 1.8 314 5.54 329
(Impregnation)
5wt% Pt/SiO2 (Insoo) Reduction @200C 0.3 6.1 38 8
0.2Fe-Pt/SiO2 Reduction @200C 8.5 171 20.8 410
Reaction conditions: 120C, P: 35 bar H2, feed: 10wt% 2-HY-THP/H2O.
▪ Pt/HZSM5 catalysts give very high 2-HY-THP hydrogenation rates
[1] Chem. Commun., 2013, 49, 10355Pt/HZSM5 stable for 170h TOS
50 Feed added Feed added
40
Conversion (%)
30
Reaction conditions: Catalyst mass:
20 11.5mg, 120C, P: 30 bar H2, feed:
10wt% 2-HY-THP/H2O
10
0
0 50 100 150 200
TOS (h)
▪ 0.59% Pt/HZSM5 very stable over 170 h time-on-stream
▪ Decrease in catalyst cost due to less noble metal (low Pt loading and high rates)1,5-pentanediol Formed via
Hydrogenation of 5-HY-Val
▪ Study the rate of ring-opening relative
to hydrogenation by using step changes
of H2 pressure with the in situ ATR-FTIR
▪ Monitor the C=O absorbance of 5-HY-
Val throughout the course of reaction
FTIR Probe 521,5-pentanediol Formed via
Hydrogenation of 5-HY-Val
0.12
5-Hydroxyvaleraldehyde IR
0.1 300 psi H2
0 psi H2
0.08
Abs. Units
▪ Ring-opening reaction is quasi- 0.06
equilibrated relative to hydrogenation 0.04
0.02
▪ Hydrogenation of 5HVal aldehyde
0
rate-determining step
0 100 200 300
Time (min)
53Ring-opening Tautomerization of 2-HY-THP into
5-hydroxyvaleraldehyde: NMR Studies
24˚C
• Variable temperature quantitative 13C 80C̊
NMR studies confirm the existence of
5-hydroxyvaleraldehyde (5HVal)
• Higher concentrations of 5HVal are
observed at elevated temperatures
- Tautomerization reaction is endothermic
54Tautomerization vs. Hydrogenolysis
▪ Conventional Approach: Hydrogenolysis over bimetallic, noble-metal
catalysts (i.e. RhRe)
▪ New Approach: Ring-opening tautomerization and hydrogenation
Noble metal bimetallics not
required for hydrogenation
O OH
Hemiacetal groups can homogeneously Hydrogenation rate >80x
tautomerize to their ring-opened form faster than hydrogenolysis 55Tautomerization of C4-C6 Cyclic Hemiacetals
C4
Cyclic Hemiacetal
2-hydroxy-tetrahydrofuran 4-hydroxy-butanal
Aldehyde
(2-HY-THF) (4-HY-Butanal)
C5
2-hydroxy-tetrahydropyran 5-hydroxy-valeraldehyde
(2-HY-THP) (5-HY-Val)
C6
6-hydroxy-hexanal
2-oxepanol (6-HY-Hexanal) 56You can also read
