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Tandem catalysis for the production of alkyl lactates from ketohexoses at moderate temperatures

Orazov, Marat and Davis, Mark E. (2015) Tandem catalysis for the production of alkyl lactates from ketohexoses at moderate temperatures. Proceedings of the National Academy of Sciences, 112 (38). pp. 11777-11782. ISSN 0027-8424. PMCID PMC4586831. doi:10.1073/pnas.1516466112. https://resolver.caltech.edu/CaltechAUTHORS:20150917-135529579

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Abstract

Retro-aldol reactions have been implicated as the limiting steps in catalytic routes to convert biomass-derived hexoses and pentoses into valuable C_2, C_3, and C_4 products such as glycolic acid, lactic acid, 2-hydroxy-3-butenoic acid, 2,4-dihydroxybutanoic acid, and alkyl esters thereof. Due to a lack of efficient retro-aldol catalysts, most previous investigations of catalytic pathways involving these reactions were conducted at high temperatures (≥160 °C). Here, we report moderate-temperature (around 100 °C) retro-aldol reactions of various hexoses in aqueous and alcoholic media with catalysts traditionally known for their capacity to catalyze 1,2-intramolecular carbon shift (1,2-CS) reactions of aldoses, i.e., various molybdenum oxide and molybdate species, nickel(II) diamine complexes, alkali-exchanged stannosilicate molecular sieves, and amorphous TiO_2–SiO_2 coprecipitates. Solid Lewis acid cocatalysts that are known to catalyze 1,2-intramolecular hydride shift (1,2-HS) reactions that enable the formation of α-hydroxy carboxylic acids from tetroses, trioses, and glycolaldehyde, but cannot readily catalyze retro-aldol reactions of hexoses and pentoses at these moderate temperatures, are shown to be compatible with the aforementioned retro-aldol catalysts. The combination of a distinct retro-aldol catalyst with a 1,2-HS catalyst enables lactic acid and alkyl lactate formation from ketohexoses at moderate temperatures (around 100 °C), with yields comparable to best-reported chemocatalytic examples at high temperature conditions (≥160 °C). The use of moderate temperatures enables numerous desirable features such as lower pressure and significantly less catalyst deactivation.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1073/pnas.1516466112DOIArticle
http://www.pnas.org/lookup/suppl/doi:10.1073/pnas.1516466112/-/DCSupplementalPublisherSupporting Information
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4586831/PubMed CentralArticle
ORCID:
AuthorORCID
Davis, Mark E.0000-0001-8294-1477
Additional Information:© 2015 National Academy of Sciences. Freely available online through the PNAS open access option. Contributed by Mark E. Davis, August 19, 2015 (sent for review August 1, 2015). Published online before print September 8, 2015. We thank Dr. Mona Shahgholi (Caltech) for use of GC-MS. This work was financially supported as part of the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-SC0001004. M.O. acknowledges funding from the National Science Foundation Graduate Research Fellowship Program under Grant DGE-1144469. Author contributions: M.O. and M.E.D. designed research; M.O. performed research; M.O. and M.E.D. analyzed data; and M.O. and M.E.D. wrote the paper. The authors declare no conflict of interest. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1516466112/-/DCSupplemental.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0001004
NSF Graduate Research FellowshipDGE-1144469
Subject Keywords:retro-aldol reactions; alkyl lactates; heterogeneous catalysis
Issue or Number:38
PubMed Central ID:PMC4586831
DOI:10.1073/pnas.1516466112
Record Number:CaltechAUTHORS:20150917-135529579
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150917-135529579
Official Citation:Marat Orazov and Mark E. Davis Tandem catalysis for the production of alkyl lactates from ketohexoses at moderate temperatures PNAS 2015 112 (38) 11777-11782; published ahead of print September 8, 2015, doi:10.1073/pnas.1516466112
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60303
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Sep 2015 21:13
Last Modified:10 Nov 2021 22:32

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