Oxygenated Fuel from Bio-oil via Methylation of Acids and Phenolics Suh-Jane Lee, Evgueni Polikarpov, Huamin Wang and Karl Albrecht Chemical and Biological Process Development Group Pacific Northwest National Laboratory 902 Battelle Blvd., Richland, WA 99352, USA 1 Background The Co-Optimization of Fuels and Engines (Co-Optima) project is a collaborative project between national labs, universities and industry to develop new fuels and engine architectures in tandem to maximize performance and carbon efficiency with low GHGs emission. Objectives for Future Fuels: 1. Reduce petroleum consumption 2. Improve fuel economy 3. Decrease pollutants and GHG emission 4. Accelerate the speed of advanced biofuel deployment 2 Future Fuels-Oxygenated Fuel 1. Advantages a. No need for addition of hydrogen to remove oxygen during upgrading process b. Atom efficiency without loss of oxygen c. Enhance Octane Number 2. Market interests: “Industry is experiencing an Octane lovefest; Petroleum marketers have talked about higher octane demand for future fuels.” -Ron Lamberty in the April, 2016 issue of EPM 3. Aryl ethers are particularly effective anti-knock additives for gasolines. Dolhyj et al. USA Patent 4,412,847, 1983“ Motor Fuel Additive” Compound RON MON AKI (R+M)/2 n-Octane -20 n-Heptane 0 0 0 n-hexane 25 26.0 26 n-pentane 62 61.9 62 ethanol 107 n-butanol 92 71 83 Methyl acetate >120 Anisole 103 Methyl acetate as a component octane commercial gasoline by Amirkhanow K. Sh. and Kislitsyn, A. A. Oil and Gas Business, 2014, 1, 178-192 3 Esters and Aryl Ethers from Bio-oil? 1. Advantage: Bio-oil is rich in acid and phenolics, a mixture of 30% water, 10% acids , 20% aldehydes/ketones, 15% alcohols and 30% phenolics and other H OH O O miscellaneous compounds. O O O O OH O O 3-methyl- HO O furfural O O OH O HO O O H 2(3H)-furanone OH furan O acetaldehyde methyl formate formic acid O levoglucosan O acetic acid OH 5-hydroxymethylfurfural O O H H hydroxyacetaldehyde O OH O O OH 2-methylcyclopent- O O O methanol water acetone 2-en-1-one 5-methylfurfural furfuryl alcohol furan-2(5H oxygenates and water )-one Light 5-methylfuran-2(3H)-one (not suitable as fuels) OH HO O OH Sugar-derived products phenol HO 4-methyl guaiacol HO HO O O OH OH hydroquinone O coumaryl HO HO syringol isoeugenol alcohol O O HO O O O eugenol OH vanillin OH HO OH O HO OH coniferyl alcohol O O O O 4-vinylsyringol p-vinyl guaiacol 4-propenyl syringol HO resorcinol OH HO OH OH O OH O sinapyl alcohol catechol 4-vinyl phenol 2-methoxyphenol 2. Challenge: Lignin-derived products Two individual chemistries will be conducted in a complicated mixture • Carboxylic acids to esters • Phenolics to aryl ethers 4 Technical Approaches 1. Conversion of carboxylic acids to esters using an acid catalyst and alcohols O O + acid ROH OH catalyst OR 2. Conversion of phenolics to aryl ethers using a methylation agent via O-alkylation OH OR MR base + Methylation o catalyst MR= ROH, > 400 C reagent o DMC, ~160 C OH OC2H5 O + acid cat. o OC2H5 160 C Sarmah, B. and Srivastava, R. Sustainable Chem. Eng. 2015, 3, 210-215 5 First Attempt: One Pot Methylation of Acid and Phenol OH OCH3 O O + Acid cat. Acid cat. CH3OH OH OCH3 + What are yields of methyl acetate and anisole? OH OCH3 O O + 45 + zeolite Beta CH3OH 2 + 1 160o 6h OH C, OCH3 ~70.7% ~4.5% 1. Reaction equilibrium likely 2. Esterification rate >> Etherification rate 6 Different Ratio of Acids & Phenols with Methanol OH OCH3 O O O + CH OH + zeolite Beta 3 + OH 160o 6h OCH3 C, OCH3 Anisole from Methanol / acetic acid / phenol 120 100 80 % 60 phenol conversion 40 anisole selectivity 20 0 0.00 0.50 1.00 1.50 2.00 2.50 ratio of phenol / acetic acid ( methyl acetate ) 1. Poor yield of anisole 2. Can we improve anisole yield? 7 Methylation of Phenol with Methyl Acetate O OH O OCH3 O O + Zeolite Beta H3C OCH3 + o + H C OH CH 170 C/400 psi 3 + 3OH Results of methyl acetate and phenol reaction MA/Ph = 4:1 MA/Ph = 25:1 Conversion of Phenol 38.30% 37.90% Selectivity of Anisole 89.40% 94.30% Apparently zero order in phenol 8 Alkyl Ester Reactions with Phenol Comparison of Alkyl Acetate H O + H+ O 100 R R 80 O O 60 phenol conversion % % 40 aryl ether selectivity % H 20 O 0 methyl acetate ethyl acetate t-butyl acetate H3C O R Sarmah, B. and Srivastava, R. Sustainable Chem. Eng. 2015, 3, 210-215 R R R OH O O H - + H Stability of carbocation: t-butyl > ethyl> methyl 9 Second Attempt: Two step methylation Step 1: O O MeOH + acid cat. OH OCH3 Step 2: OH OCH3 O MeOH + cat. base + + H3CO OCH3 DMC CO2 Methylation of Phenol and Its Derivatives with Dimethyl Carbonate in the Presence of Mn2(CO)10, W(CO)6, and Co2(CO)8 2013 R. I. Khusnutdinov, N. A. Shchadneva, and Yu. Yu. Mayakova 10 Methylation Validation with Model Compounds OH OH OCH3 OCH3 O H 3CO + K2CO3 H3CO 160oC H3CO OCH3 1 1 2.5 85% 89% 11 What happens to methyl acetate in the system with a base catalyst? OH OCH3 O O CO2 2 + K2CO3 OCH3 1 + 1.5 H CO OCH o + 3 3 160 C, 400psi CH3OH Base ? O Analysis result Phenol conversion 98.80% OH Anisole selectivity 100% + Methyl acetate no signification change CH3OH Acetic acid below detection limit 12 Liquid-Liquid Extraction: Target Carboxylic Acid and Phenol Comparison of Extractants: Cyanex vs. EtOAc vs. MtBE 120.0% 100.0% 80.0% 60.0% % Dry base % Dry 40.0% Cyanex EtOAc 20.0% MtBE 0.0% 1. Cyanex is an excellent extractant but it is difficult to recover chemicals 2. EtOAc extracts more carbon but carries more water and sugars with less acid 3. MtBE was chosen as the extactant due to low BP, better acid recovery, and less sugar extracted 13 Liquid-Liquid Extraction: Can a H2O wash remove sugar and heavy lignin fragments? Water MtBE w-MtBE Bio-oil x 3 Water x 2 MtBE - MtBE soluble soluble ext. MtBE d-MtBE x 2 MtBE soluble -MtBE ext. Direct vs Indirect MtBE extraction Acidity of Extracted Liquid 40 100.0% 80.0% 30 d-MtBE 60.0% d-MtBE 20 w-MtBE 40.0% w-MtBE % Dry base Dry % % Recovery Recovery % 10 20.0% 0 0.0% Mass Sugar Acids Phenols TAN CAN PAN 14 Characterization of Liquid Extraction by 13C NMR 45 40 35 30 25 20 Feed 15 d-MtBE extracted 10 % Carbon Number % Carbon 5 w-MtBE extracted 0 w-MtBE d-MtBE 15 Methylation of acids and phenols in bio-oil Step 1 O zeolite Beta 10 CH OH + Acetic Acid in Bio-oil H O wash / MtBE exttracted) 3 ( 2 o 130 C, 400psi OCH3 Conversion of Acetic Acid = 92% Selectivity of Methylactate = 82% Step 2 OCH3 O K CO 1.5 DMC + Phenol in Product of Step 1 2 3 o OCH + (Phenolics) 170 C, 400psi 3 Conversion of Phenol = 33% Selectivity of anisole = 20% The concentrations of acetic acid and phenol in bio-oil were determined by CAN and PAN. 16 GC/MS Spectra of Methylation of Phenolics in Bio-oil Product benzene - benzene methyl - Tirmethoxy Trimethoxy Dimethoxy benzene Dimethoxy Abundance TIC: DMBS-2-F_A.D\data.ms 3000000 2900000 2800000 2700000 2600000 2500000 2400000 2300000 2200000 2100000 2000000 Feed 1900000 1800000 1700000 phenol Dimethoxy 1600000 1500000 1400000 1300000 1200000 1100000 1000000 900000 800000 700000 600000 500000 400000 300000 200000 17 100000 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 55.00 Time--> Summary 1. Both esters and aryl ethers are potential fuel additives due to their high RON 2. Esters and aryl ethers could be produced from bio-oil, but the chemistry to produce them is not suited for a single step 3. We have demonstrated the two steps of methylation of carboxylic acid and phenol using model compounds. 4. Liquid-Liquid extraction of bio-oil is an effective way to remove sugars 5. The sequential production of esters and aryl ethers from bio-oil is challenging. 1. Esterification of the acids is straight forward and goes at high yield 2. Etherification of phenolics is challenging due to the presence of water 18 Acknowledgements: Funding from the U.S. Department of Energy through the Bioenergy Technologies Office Analytical Assistance: Teresa Lemmon Marie Swita 19 .