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Letter
Self-Terminated Cascade Reactions that Produce Methylbenzaldehydes from Ethanol Takahiko Moteki, Andrew T. Rowley, and David W. Flaherty ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.6b02475 • Publication Date (Web): 28 Sep 2016 Downloaded from http://pubs.acs.org on September 28, 2016
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Self-Terminated Cascade Reactions that Produce Methylbenzaldehydes from Ethanol Takahiko Moteki,†,‡ Andrew T. Rowley,† and David W. Flaherty*,†,‡ † ‡
Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801 Energy Biosciences Institute, University of Illinois Urbana-Champaign, Urbana, IL 61801
ABSTRACT: 2- and 4-Methylbenzaldehyde, useful precursors for phthalic anhydride and terephthalic acid, form by sequential aldol condensations between acetaldehyde and enals and subsequent dehydrocyclization during ethanol upgrading reactions on hydroxyapatite catalysts. Selectivities for methylbenzaldehydes exceed 30% as a result of rapid cyclization reactions and steric protection that hinders further growth. Such pathways compete with a set of alternating condensation and hydrogenation steps, known as the Guerbet reaction, which produces broad distributions of n- and iso-alcohols. The selectivities to C8 aromatic products increase in proportion to the ratio of the acetaldehyde to ethanol concentrations. These reactions provide new pathways for the selective conversion of bioethanol into value-added chemicals. Keywords: tolualdehyde, ethanol upgrading, aldol condensation. dehydrocyclization, hydroxyapatite
Small oxygenates (e.g., acetone, butanol, and ethanol (ABE)) are readily produced from fermentation of biomass (e.g., ethanol or ABE fermentations). Ethanol is unique, because it can be produced with high efficiencies and titers by robust organisms and is easily recovered from fermentation solutions by pervaporation or stripping.1,2 Although ethanol and other small oxygenates are useful fuel additives and chemicals, heavier products with greater value may be formed by catalytic upgrading (e.g., aldol condensation).3,4 This process involves sequences of coupling reactions in order to form heavier products (e.g., C≥8 alcohols), however, a myriad of self- and cross-coupling reactions typically give broad distributions of products and low yields for any given species.5 Such mixtures may be useful as fuels, but it would be desirable to identify pathways and catalysts that convert ethanol into drop-in replacements for large market platform chemicals used to produce durable consumer products. For example, xylenes are a desirable class of building blocks that can be produced from biomass by reactions of dimethyl furan with ethylene,6-8 acrolein9, or isobutanol10, however, the selective production of xylenes or oxygenated xylene derivatives from ethanol has not been demonstrated, to the best of our knowledge. Base catalyzed self-condensation of 2-butenal is known to yield methylbenzaldehydes.11-15 Recently, Resasco showed that MgO and MgO-modified faujasite catalysts convert 2butenal feeds into methylbenzaldehydes and that acetaldehyde-ethanol mixtures give these products with low yields (< 5%).13 Even though small amounts of aromatic species have been observed during the Guerbet reaction of ethanol over calcium hydroxyapatite (Ca-HAP) catalysts,5,16-18 the exact structure of these components and the mechanism of their formation has received little attention.18-24 Notably, significant yields to any specific product are difficult to achieve in aldol
condensation reaction networks, because rates for many selfand cross-condensation reactions are often similar.5 Here, we show that large differences in the rates of competing pathways can be achieved within reaction networks of acetaldehyde-ethanol mixtures on Ca-HAP, and these differences give 2- and 4-methylbenzaldehydes and alcohols (2- and 4-MB=O/–OH, respectively) with carbon selectivities exceeding 30%. Such acetaldehyde-ethanol reactant streams can be produced in situ by use of Cu catalysts to selectively dehydrogenate ethanol. Consequently, this chemistry provides a pathway from bioethanol to renewable and functionalized C8 aromatics that are precursors for phthalic anhydride and (tere)phthalic acid and which are more easily purified than mixtures of similarly structured xylenes.25 Figure 1 shows that linear C4, C6, and C8 enals (2-butenal, 2,4-hexadienal, and 2,4,6-octatrienal, respectively) and C8 aromatics (2- and 4-MB=O/–OH) form by a sequence of condensation reactions with acetaldehyde on Ca-HAP (0.35 kPa C2H4O, 1 kPa C2H5OH, 100 kPa H2, 548 K; Figure S2 shows similar results at 0.56 and 0.85 kPa C2H4O).26 Acetaldehyde is preferentially consumed (approximately 70% at all conversions, Figure S3), which shows that acetaldehyde is the primary reactant in the mixture feed for the sequence of reactions. The value (70%) is close to the molar ratio of reactant necessary for the formation of C8 aromatic alcohols (3 C2H4O and 1 C2H5OH). The selectivities among the products depend strongly on the acetaldehyde conversion: selectivities to 2-butenal decrease monotonically, while those for 2,4-hexadienal and 2,4,6-octatrienal achieve maxima at conversions of 12% and 20%, respectively. These data, together with the product structures, show that these species are formed by initial aldol condensation between two acetaldehyde molecules and two subsequent aldol condensations of acetaldehyde onto the linear
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enal chains. These pathways has been suggested in our previous study using similar reaction condition (see right column of Table 2 in Moteki et al.).5 The products were, however, not identified at that moment.5 The selectivities to 2- and 4MB=O/–OH reach values of 27% and 3%, respectively, at acetaldehyde conversions of nearly 55%. The dominant aromatic products (2-MB=O/–OH) form by electrocyclization of 2,4,6-octatrienal and subsequent dehydrogenation of the cyclic dienal (described below). Subsequent hydrogenation of the carbonyl group of 2-MB=O produces 2-MB-OH (Figure S4), likely by the Meerwein–Ponndorf–Verley (MPV) reaction of 2-MB=O with ethanol (as shown in similar reactions over these Ca-HAP catalysts5), which generates acetaldehyde in situ.
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Figure 2 shows reactant conversion rates for the selfcondensation of acetaldehyde and cross-condensations of acetaldehyde with 2-butenal, 2,4-hexadienal, 2-MB=O, and 4MB=O over Ca-HAP (0.1 kPa reactant, 0.35 kPa C2H4O, 1 kPa C2H5OH, 100 kPa H2, 548 K). Comparisons of these rates directly show that intrinsic differences between the structures of 2-MB=O (the dominant methylbenzaldehyde isomer), 4MB=O, and the acyclic co-reactants make the methylbenzaldehydes a factor of ten (2-MB=O) and four (4-MB=O) times less reactive for nucleophilic attack from acetaldehyde than the other species. Aldol condensation rates of acetaldehyde with 2-MB=O are about one-half the value of that for reaction with 4-MB=O, which shows that the methyl group adjacent to the carbonyl sterically protects 2-MB=O from nucleophilic attack or perhaps reduces the reactivity by electronic effects. Consequently, significant selectivities to C8 aromatics result from both rapid and selective electrocyclization reactions of C8 trienals and the less reactive nature of the aromatic products. These reaction concepts resemble those for the selfcondensation of acetone,4,27 in which sequential reactions create reactive acyclic C9 products (i.e., phorones) that cyclize to form protected products (isophorone and mesitylene) with good yields (30–40%).4,27 Notably, the reaction sequence shown here to produce methylbenzaldehydes (Fig. 1) differs significantly from those that create broad product distributions of primary n- and iso-alcohols from pure ethanol5 and suggest that ethanol can be selectively upgraded to form valuable aromatics by dehydrogenation (to acetaldehyde-ethanol mixtures), aldol condensation, and dehydrocyclization reactions.
Figure 1. Formation of C4–C8 enals (○, 2-butenal; △, 2,4hexadieneal; □, 2,4,6-octatrienal) and C8 aromatic products (red ●, sum of 2-MB=O/–OH; red ▲, sum of 4-MB=O/–OH) as a function of acetaldehyde conversion over Ca-HAP (0.35 kPa C2H4O, 1 kPa C2H5OH, 100 kPa H2, 548 K).26 Dashed lines are included to guide the eye.
The selectivity to C8 aromatics given by this sequence of reactions is striking and reflects the preferential reaction of enals with acetaldehyde (rather than condensation with other aldehydes or enals due to the difficulty of deprotonating the αcarbon of enals), the rapid cyclization of 2,4,6-octatrienal to form 2-MB=O, and the low reactivity of the 2- and 4-MB=O structures for further aldol condensation. Significant selectivities toward C8 aromatics, taken together with small amounts of all C8 and C10 aldehydes, enols, and alcohols (90%), 4-MB products form as well (Figures 1 and S4). The ratio of the 2-MB to 4-MB products (β) increases from 6 to 10 with increasing acetaldehyde conversion (12– 60%, Figure S5), which shows that different reactive intermediates lead to each of these products. Electrocyclization of 2,4,6-octatrienal between the 2- and 7-positions and subsequent dehydrogenation forms 2-MB=O (Scheme 1), however, 4-MB=O cannot form from 2,4,6-octatrienal. 4-MB=O may form either by intermolecular Diels-Alder (DA) or by a nucle-
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ophilic addition (red dashed arrow, Scheme 1) reactions. A DA reaction between 2,4-hexadienal and ethylene or vinyl alcohol, and subsequent dehydrogenation or dehydration would produce 4-MB=O. The C2 co-reactants may be produced in situ by dehydration of ethanol or keto-enol tautomerization of acetaldehyde. However, these species exist at very low concentrations, because stoichiometric Ca-HAP forms little ethylene(? 0 @ A∗ =B 0 C A∗
@ A
D 0
0 C A
(4)
where, A is a constant that reflects the rate constants (6 and 6 ) and the equilibrium constants for adsorption of acetaldehyde and ethanol. The functional dependence of Eq. (4) matches those trends for α shown in Figure 3, which strongly suggests that the selectivity toward C8 aromatic products primarily reflects the ratio of the rate of aldol condensation of 2butenal, via enolization of acetaldehyde and its nucleophilic attack,5,17 to that for hydrogenation of 2-butenal by catalytic hydrogen transfer from ethanol on Ca-HAP surfaces. The reactant pressure dependence of α (Figure 3 and Eq. (4)) explains also selectivities toward hydrogenated products that increase with the extent of acetaldehyde conversion (Figure S6), because these reactions consume acetaldehyde preferentially over ethanol (see above), which leads to values of α that decrease sharply with increasing extent of reaction. It should be noted that, at high ethanol to acetaldehyde ration in the feed (e.g., 0.35 kPa C2H4O, 6.3 kPa C2H5OH), the product selectivity is similar to what obtained via pure ethanol feed.5 The mechanistic insight determined here provides clear guidance for the steps needed to maximize the yield of the C8 aromatic products (i.e., sum of the 2-MB and 4-MB formed). Formation of C8 aromatics require larger relative rates of aldol condensation to hydrogenation, and thus, high ratios of acetaldehyde to ethanol concentration throughout the reactor. Therefore, greater aromatic selectivities can be achieved by introducing feed streams with larger acetaldehyde to ethanol ratios or by using oxide catalysts with inherently greater rate constant ratios (6 ≫ 6 ), which catalyze enolization of acetaldehyde more readily than H-transfer pathways. Table 1 shows that 2-MB and 4-MB can be produced using pure ethanol feed streams by incorporating a highly selective ethanol dehydrogenation catalysts (e.g., Cu-ZnO,30,31 Figure S7) immediately upstream of the Ca-HAP catalyst (Cu|HAP) in order to create acetaldehyde in situ. In the absence of the dehydrogenation catalyst (Table 1, HAP), Ca-HAP produces C4 (55%) and C6 (31%) and larger (C≥8, 14%) alcohols at comparable conversions (52% ethanol conversion) as seen for the Guerbet reaction,5,22,23 because rapid hydrogen transfer reactions saturate the enal products of aldol condensation reactions.5 The addition of Cu-ZnO upstream of the Ca-HAP (Table 1, Cu|HAP) produces near equilibrium yields of acetaldehyde, which subsequently give moderate selectivities to C8
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aromatics (18%) and also increase the selectivity to linear C4 aldehydes and alcohols (65%) (at 34% ethanol conversion). Combining multiple Cu|HAP layers in series can circumvent the single-stage equilibrium limitation for ethanol dehydrogenation (about 40%) and give high ethanol conversions in a single-pass while also improving process heat integration by combining endothermic dehydrogenation and exothermic condensation reactions. A series of four striated Cu|HAP beds (Table 1, 4 × Cu|HAP, the reactor set-up is shown in Figure S1) triples the C≥4 products yield (from 21% to 58%) and maintains similar selectivities toward obtained with a single Cu|HAP bed. C4 alcohols and aldehydes (1-butanol, 2-butenal, crotyl alcohol, and butyraldehyde) comprise nearly 65% of the products (Table 1, 4 × Cu|HAP), and these linear C4 species can be selectively hydrogenated to form 1-butanol. 1-Butanol and the 2- and 4-MB products would be separated by crystallization. Thus, sequential ethanol dehydrogenation and aldehyde-enal condensation and dehydrocyclization reactions give significant selectivities to mixtures of easily separated commodity chemicals. While these results provide proof-ofconcept for C8 aromatics and 1-butanol production from ethanol reactant streams, however, further optimization is needed to improve yields, especially of aromatics. In summary, 2-MB=O and 4-MB=O forms from acetaldehyde and ethanol mixtures, which can be obtained by ex situ or in situ dehydrogenation of ethanol. Direct detection of a number of highly reactive enal, dienal, and trienal intermediates shows that sequential aldol condensations, electrocyclization, and dehydrogenation steps form effectively self-terminated C8 aromatic structures. The majority of the aromatics consists of 2-MB=O and 2-MB‒OH and a much smaller amount of 4MB=O and 4=MB‒OH, however, the ratio of these two isomers changes with conversion indicating the presence of several parallel reaction pathways. Further investigation is required to determine the mechanisms and reaction pathways that form the 4-MB=O product. Overall, these findings introduce a promising new strategy to convert bioethanol selectively into higher value commodity chemicals such as precursors for phthalic anhydride, terephthalic acid, and 1-butanol.
AUTHOR INFORMATION Corresponding Author *
[email protected] Notes The authors declare no competing financial interest.
ASSOCIATED CONTENT Supporting Information. The Supporting Information is available free of charge on the ACS Publications website at http://pubs.acs.org.
Experimental procedures; (PDF)ACKNOWLEDGMENT
Figures
S1-S9
The authors gratefully acknowledge Mark Triezenberg, Malek Ibrahim, and Megan Witzke for their help synthesizing Cu-ZnO. TM acknowledges helpful discussion with Daniel Bregante and DWF acknowledges helpful conversations with Dr. Damien Guironnet. This work was financially supported by the Energy Biosciences Institute (EBI) at the University of Illinois. This work
was carried out in part in the Frederick Seitz Materials Research Laboratory, University of Illinois.
REFERENCES (1) Hamelinck, C. N.; van Hooijdonk, G.; Faaij, A. P. C. Biomass Bioenergy 2005, 28, 384−410. (2) Angelici, C.; Weckhuysen, B. M.; Bruijnincx, P. C. A. Chemsuschem 2013, 6, 1595−1614. (3) Anbarasan, P.; Baer, Z. C.; Sreekumar, S.; Gross, E.; Binder, J. B.; Blanch, H. W.; Clark, D. S.; Toste, F. D. Nature 2012, 491, 235−239. (4) Wu, L.; Moteki, T.; Gokhale, A. A.; Flaherty, D. W.; Toste, F. D. Chem 2016, 1, 32−58. (5) Moteki, T.; Flaherty, D. W. ACS Catal. 2016, 6, 4170−4183. (6) Williams, C. L.; Chang, C.-C.; Phuong, D.; Nikbin, N.; Caratzoulas, S.; Vlachos, D. G.; Lobo, R. F.; Fan, W.; Dauenhauer, P. J. ACS Catal. 2012, 2, 935−939. (7) Nikbin, N.; Do, P. T.; Caratzoulas, S.; Lobo, R. F.; Dauenhauer, P. J.; Vlachos, D. G. J. Catal. 2013, 297, 35−43. (8) Brandvold, T. A. U.S. Patent US8,314,267B2, November 20, 2012. (9) Shiramizu, M.; Toste, F. D. Chem., Eur. J. 2011, 17, 12452−12457. (10) Peters, M. W.; Taylor, J. D.; Jenni, M.; Manzer, L. E.; Henton, D. E. U.S. Patent US2011/0087000A1, April 14, 2011. (11) McIntosh, J. M.; Khalil, H.; Pillon, D. W. J. Org. Chem. 1980, 45, 3436−3439. (12) Kurokawa, H.; Yanai, M.; Ohshima, M.-a.; Miura, H. React. Kinet., Mech. Catal. 2012, 105, 401−412. (13) Zhang, L.; Pham, T. N.; Faria, J.; Santhanaraj, D.; Sooknoi, T.; Tan, Q.; Zhao, Z.; Resasco, D. E. ChemSusChem 2016, 9, 736−748. (14) Hong, B.-C.; Tseng, H.-C.; Chen, S.-H. Tetrahedron 2007, 63, 2840−2850. (15) Weimann, J.; Lacroix, P. Bull. Soc. Chim. Fr. 1961, 2257−2269. (16) Tsuchida, T.; Kubo, J.; Yoshioka, T.; Sakuma, S.; Takeguchi, T.; Ueda, W. J. Catal. 2008, 259, 183−189. (17) Tsuchida, T.; Sakuma, S.; Takeguchi, T.; Ueda, W. Ind. Eng. Chem. Res. 2006, 45, 8634−8642. (18) Ogo, S.; Onda, A.; Yanagisawa, K. Appl. Catal., A 2011, 402, 188−195. (19) Ogo, S.; Onda, A.; Iwasa, Y.; Hara, K.; Fukuoka, A.; Yanagisawa, K. J. Catal. 2012, 296, 24−30. (20) Hanspal, S.; Young, Z. D.; Shou, H.; Davis, R. J. ACS Catal. 2015, 5, 1737−1746. (21) Ho, C. R.; Shylesh, S.; Bell, A. T. ACS Catal. 2016, 6, 939−948. (22) Gabriëls, D.; Hernández, W. Y.; Sels, B.; Voort, P. V. D.; Verberckmoes, A. Catal. Sci. Technol. 2015, 5, 3876−3902. (23) Kozlowski, J. T.; Davis, R. J. ACS Catal. 2013, 3, 1588−1600. (24) Young, Z. D.; Hanspal, S.; Davis, R. J. ACS Catal. 2016, 6, 3193−3202. (25) Nikolov, V.; Klissurski, D.; Anastasov, A. Catal. Rev. 1991, 33, 319−374. (26) Acyclic aldehydes and alcohols (predominantly linear C4 species) account for the residual selectivity at each acetaldehyde conversion. (27) Salvapati, G. S.; Ramanamurty, K. V.; Janardanarao, M. J. Mol. Catal. 1989, 54, 9−30. (28) Obtained by density functional theory (DFT) calculation performed using B3LYP functional/6-31G(d,p) basis sets. The Gaussian 09 package was used to undertake the molecular orbital theory calculations. (29) In Eq. (2), all C≥6 hydrogenated products are counted as products of hydrogenation event for 2-butenal. This treatment may contain some unavoidable inaccuracy, because C≥6 hydrogenated products (e.g., 1-hexanol) may form by two pathways (i.e., aldol condensation
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to C6 dienal and subsequent hydrogenation or hydrogenation of 2butenal and subsequent aldol condensation). The contribution of C≥6 products is, however, less than 20% among hydrogenated products and error within this value would not change the conclusions (Figure 3).
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(30) Jiménez-Gómez, C. P.; Cecilia, J. A.; Durán-Martín, D.; Moreno-Tost, R.; Santamaría-González, J.; Mérida-Robles, J.; Mariscal, R.; Maireles-Torres, P. J. Catal. 2016, 336, 107−115. (31) Witzke, M. E.; Dietrich, P.; Ibrahim, M. Y. S.; Al-Bardan, K.; Triezenberg, M. D.; Flaherty, D. W. to be submitted
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