A New Catalytic Pathway for the Production of Bio-based 1,5-Pentanediol

Transcription

1 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

2 Oxidation Chemicals from Biomass Oxidizing petroleum to chemicals can be difficult and costly Alternative: selectively reduce oxygenated biomass Cost-competitive with petroleum due to high cost of chemicals Renewably replace portion of oil end-use Reduction 2

3 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 End uses: polyurethanes, coatings, acrylates, adhesives, 1,5-pentanediol polyesters, and (1,5-PD) plasticizers ~3 kton/yr High value: ~ $ per MT C5 Derived C6 Derived Glucose (C6) ~130 kton/yr 1,6-hexanediol (1,6-HD) 3

4 C4-C6 α,ω-diols Production and Market $7B/yr Global Market 7% CAGR (α,ω-diols) 1,4-BD 1,5-PD 1,6-HD 1,4-butanediol (1,4-BD) Dicarboxylic acid Polyester polyols $ /ton Adipic Acid Paints Coatings Plastics 1,5-pentanediol (1,5-PD) $6000/ton $2000/ton Adhesives 1,6-hexanediol (1,6-HD) $ /ton 4

5 THFDM Levoglucosenol THFDM THFDM Xylose Biomass Biomass to C5 and C6 α,ω-diols Lignocellulosic Biomass Furfural GVL recycle H 2 C5 Route H 2 1,5-Pentanediol GVL/Water H 2 SO 4 Cellulose GVL/W Extraction Drying Water R1 Dehydration Lignin to Process Heat SEP Furfural H 2 recycle purge R2 THFA Hydrogenation R3 DEH DHP H 2 O R4 HDR 2-HY-THP H 2 recycle R5 HYD purge PDO SEP purge 1,5-PDO Water By-products H 2 SO 4 LGO+HMF R6 Dehydration SEP H 2 LGO HMF H 2 recycle R7 Hydrogenation R8 HYD THF recycle purge Solvent removal H 2 C6 Route H 2 recycle purge HDO precursors R9 HYD SEP purge 1,6-HDO Waste Water By-products By-products (purification to remove acids) Levoglucosenone 1,6-Hexanediol 5

6 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 wt% 6

7 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) Slide courtesy of David Martin-Alonso 7

8 Technilogical Advantages of GVL Process Commercial process GVL process Process Semi-continuous Continuous Yield % 95 % Feedstock Corn cobs Xylose Time 3-5 hours seconds Sulfuric acid (ton/ton furfural) Temperature /pressure C /5-10 atm 225 C/ 20 atm Furfural concentration (wt%) < 3 > 5 (25-50 wt% respect to water) Steam (ton/ton furfural) 60 4 Slide courtesy of David Martin-Alonso 8

9 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, Y. Nakagawa et al. Catal. Today 2012, 195, New Approach: 3-step Dehydration-Hydration-Hydrogenation (DHH) pathway Previously attempted by Geller et. al in L. E. Schniepp, H. H. Geller, J. Am. Chem. Soc. 1946, 68,

10 DHH pathway for 1,5-PD production Direct hydrogenolysis pathway New pathway Brentzel et. al. Chemicals from Biomass: Combining Ring-Opening Tautomerization and Hydrogenation Reactions to Produce 1,5-Pentanediol from Furfural. ChemSusChem , Huang et al. Conversion of Furfural to 1,5-Pentanediol: Process Synthesis and Analysis. ACS Sustainable Chemistry and Engineering (6), Huang et al. Improving Economics of Lignocellulosic Biofuels: An Integrated Strategy for Coproducing 1,5-Pentanediol and Ethanol In revision. MSP Costs MSP Costs $2,436 $4, Costs and MSPs ($/ton 1,5-PDO) MSP THFA feedstock costs Utility & Electricity costs Catalyst costs Capital costs Fixed operating costs Other raw material costs Production Cost of DHH pathway is 6.6 times lower (excluding feedstock) Catalyst cost of DHH pathway is 51 times lower 10

11 THFA DEHYDRATION 11

12 THFA 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 12

13 DHH Pathway Advantages Step 1: THFA Dehydration Low-cost metal-oxide catalysts Catalyst regenerable Reactant Concentration Up to 100% Product Yield 90% 13

14 DIHYDROPYRAN HYDRATION 14

15 DHP Hydrates to 1,5-PD precursors in >99% Yields DHP hydrated in water with no catalyst added 2-phase Batch Reaction Temperature ( C) Reaction Time (h) 2-HY-THP Yield 5-tetrahydropyranyloxypentanal Yield 2-tetrahydropyranyl ether Yield Overall Yield % 5.3% 1.9% 91.7% % 6.6% 1.2% 99.8% % 6.4% 1.0% 96.9% % 4.2% 1.3% 70.9% 15

16 Why 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 16

17 Why does DHP so readily hydrate? 5 orders of magnitude difference 3 Carbocation 2 Carbocation Oxocarbenium 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 17

18 DHH Pathway Advantages Step 1: THFA Dehydration Low-cost metal-oxide catalysts Catalyst regenerable Step 2: DHP Hydration: Autocatalytic DHP hydrates with no catalyst Rate increased by in situ formation of acids DHP readily hydrates due to stable transition state Reactant Concentration Up to 100% Up to 50% Product Yield 90% 98% 18

19 2-HY-THP HYDROGENATION 19

20 Ring-opening Tautomerization of 2-HY-THP into 5-hydroxyvaleraldehyde: NMR Studies 24 C Variable temperature quantitative 13 C NMR studies confirm the existence of 5-hydroxyvaleraldehyde (5HVal) 80 C Higher concentrations of 5HVal are observed at elevated temperatures - Tautomerization reaction is endothermic 20

21 Ring-opening Tautomerization of 2-HY-THP into 5-hydroxyvaleraldehyde: NMR Studies Variable temperature quantitative 13 C NMR studies confirm the existence of 5-hydroxyvaleraldehyde (5HVal) Higher concentrations of 5HVal are observed at elevated temperatures - Tautomerization reaction is endothermic 21

22 Tautomerization 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 tautomerize to their ring-opened form Hydrogenation rate >80x faster than hydrogenolysis 22

23 DHH Pathway Advantages Step 1: THFA Dehydration Low-cost metal-oxide catalysts Catalyst regenerable Step 2: DHP Hydration: Autocatalytic DHP hydrates with no catalyst Rate increased by in situ formation of acids 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 Reactant Concentration Up to 100% Up to 50% Up to 50% Product Yield 90% 98% 99% 87% Overall Yield 23

24 Conclusions DHH pathway: 51x lower catalyst cost for 1,5-PDO from bio-derived furfural Ring-opening tautomerization allows for high hydrogenation rates over lowercost monometallic catalysts 1,5-PD minimum selling price <$2000/ton from furfural Current 1,5-PD price = $6000 Historic 1,6-HD price = $

25 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 25

26 Kevin Barnett

27 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 Cu 2+, NH 4 VO % HNO 3

28 C4-C6 α,ω-diols Production and Market $7B/yr Global Market 7% CAGR (α,ω-diols) 1,4-BD 1,5-PD 1,6-HD 1,4-butanediol (1,4-BD) Dicarboxylic acid Polyester polyols $ /ton Adipic Acid Paints Coatings Plastics 1,5-pentanediol (1,5-PD) $6000/ton $2000/ton Adhesives 1,6-hexanediol (1,6-HD) $ /ton 28

29 Oxidation Chemicals from Biomass Oxidizing petroleum to chemicals can be difficult and costly Alternative: selectively reduce oxygenated biomass Cost-competitive with petroleum due to high cost of chemicals Renewably replace portion of oil end-use Reduction 29

30 Oxidation α,ω-diols from Biomass α,ω-diols are aliphatic carbon chains with terminal alcohol groups End uses: polyurethanes, polyester polyols paints, coatings, adhesives, and plastics High value: ~ $ per MT Reduction 30

31 α,ω-diols from Biomass Xylose (C5) 1,4-butanediol (1,4-BD) ~2000 kton/yr ~3 kton/yr 1,5-pentanediol (1,5-PD) C5 Derived C6 Derived Glucose (C6) 1,6-hexanediol (1,6-HD) ~130 kton/yr 31

32 ph 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/H 2 O 32

33 DHP 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 hydration

34 DHP 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 at <1% conversions 15

35 Acidic solid coke autocatalyzes DHP hydration in flow reactor 2-HY-THP/H 2 O (To hydrogenation) 75 C Inert glass beads DHP H 2 O DHP hydration over inert glass beads performed in continuous flow reactor 11

36 Acidic solid coke autocatalyzes DHP hydration in flow reactor 2-HY-THP/H 2 O (To hydrogenation) 100 C 75 C Inert glass beads DHP H 2 O Increased acidic coke formation at higher temperature increases hydration rate 12

37 Acidic solid coke autocatalyzes DHP hydration in flow reactor 140 C 100 C 2-HY-THP/H 2 O (To hydrogenation) 75 C Inert glass beads DHP H 2 O Increased acidic coke formation at higher temperature increases hydration rate 13

38 Acidic solid coke autocatalyzes DHP hydration in flow reactor 140 C 100 C 2-HY-THP/H 2 O (To hydrogenation) 75 C Inert glass beads 60 C DHP H 2 O Increased acidic coke formation at higher temperature increases hydration rate 14

39 Non-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 Temp: 75C Flowrate: ml/min 140C 0.23 ml/min 75C ml/min At 140C, activity increased by ~6.5x Cooling back to 75C only resulted in 37% rate increase: not permanent activity increase 39

40 Non-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 At 100 C with 2 drying steps, activity was increased >650% to complete conversion 40

41 Solid-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 41

42 Solid-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 - γ-al2o HZSM Amberlyst No activity contribution from autocatalytic hydration Solid acids show high activity at condition where autocatalytic hydration does not occur Hydration rates correlate with Brønsted site density 42

43 HZSM5 is stable for DHP hydration for 20wt% Feed 2-HY-THP/H 2 O (To hydrogenation) HZSM5 T: 70 C P: 900psi Argon Feed: 20wt% DHP/H 2 O Slight deactivation at 100% conversion likely to due coke Hydrothermally stable at 40-50% conversion DHP H 2 O High pressures (900psi) critical to improved HZSM5 stability 43

44 HZSM5 is stable for DHP hydration for 50wt% Feed 2-HY-THP/H 2 O (To hydrogenation) HZSM5 T: 70 C P: 900psi Argon Feed: 50wt% DHP/H 2 O DHP H 2 O Hydrothermally stable at 40-50% conversion High pressures (900psi) critical to improved HZSM5 stability 44

45 Combined Hydration-Hydrogenation: DHP to 1,5-PD 1,5-PD/H 2 O Ru/C (hydrogenation) HZSM5 (hydration) DHP H 2 O eaction Conditions: =100 C, P=500psi, Feed=0.5wt% DHP/H2O, Reaction Time=2h Reaction Conditions: 45 T=70 C, P=500psi, Feed=20wt% DHP/H2O, mass Ru/C=0.75g, mass HZSM5=0.5g

46 Probe Molecule Hydration 5 orders of magnitude difference 3 Carbocation 2 Carbocation Oxocarbenium Transition State 46 2 Carbocation 3 Carbocation Oxocarbenium

47 Why does DHP so readily hydrate? Hydration rates plotted versus transition state Gibbs energy of formation (ΔG) for each molecule tested ΔG ΔG 23

48 2-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/H 2 O, Catalyst=1% Ru/TiO2, T=120 C, P=650psi H 2 Dimers increase at low conversion due to shift in equilibrium 97% 1,5-PD yields achieved at complete conversion 48

49 2-HY-THP and Dimers convert to 1,5-pentanediol at ~100% Yields + Dimers Reaction Conditions: Feed=20wt% 2-HY-THP/H 2 O, 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 49

50 2-HY-THP Hydrogenation over Pt Catalysts Catalyst 0.59wt% Pt/H-ZSM5 (Impregnation) Pretreatment 2-HY-THP Conversion rate (mmol/g/min) 2-HY-THP Conversion rate (mmol/g_pt/min) # of sites (umol/g) TOF (1/min) & IR@200C wt% Pt/SiO 2 (Insoo) Fe-Pt/SiO Reaction conditions: 120C, P: 35 bar H 2, feed: 10wt% 2-HY-THP/H 2 O. Pt/HZSM5 catalysts give very high 2-HY-THP hydrogenation rates [1] Chem. Commun., 2013, 49, 10355

51 Conversion (%) Pt/HZSM5 stable for 170h TOS Feed added Feed added TOS (h) Reaction conditions: Catalyst mass: 11.5mg, 120C, P: 30 bar H 2, feed: 10wt% 2-HY-THP/H 2 O 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)

52 1,5-pentanediol Formed via Hydrogenation of 5-HY-Val Study the rate of ring-opening relative to hydrogenation by using step changes of H 2 pressure with the in situ ATR-FTIR Monitor the C=O absorbance of 5-HY- Val throughout the course of reaction FTIR Probe 52

53 5-Hydroxyvaleraldehyde IR Abs. Units 1,5-pentanediol Formed via Hydrogenation of 5-HY-Val Ring-opening reaction is quasiequilibrated relative to hydrogenation Hydrogenation of 5HVal aldehyde rate-determining step psi H 2 0 psi H Time (min) 53

54 Ring-opening Tautomerization of 2-HY-THP into 5-hydroxyvaleraldehyde: NMR Studies 24 C Variable temperature quantitative 13 C NMR studies confirm the existence of 5-hydroxyvaleraldehyde (5HVal) 80 C Higher concentrations of 5HVal are observed at elevated temperatures - Tautomerization reaction is endothermic 54

55 Tautomerization 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 tautomerize to their ring-opened form Hydrogenation rate >80x faster than hydrogenolysis 55

56 Cyclic Hemiacetal Tautomerization of C4-C6 Cyclic Hemiacetals C4 2-hydroxy-tetrahydrofuran (2-HY-THF) 2-hydroxy-tetrahydropyran (2-HY-THP) C5 C6 4-hydroxy-butanal (4-HY-Butanal) 5-hydroxy-valeraldehyde (5-HY-Val) Aldehyde 2-oxepanol 6-hydroxy-hexanal (6-HY-Hexanal) 56