Ketones

Hwang, Yng-Long; Bedard, Thomas C.

doi:10.1002/0471238961.1105201502180109.a01.pub2

Cited by 7 publications

(4 citation statements)

References 72 publications

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“…These compounds can take the form of short-chain acids produced via mixed culture fermentation, or long-chain fatty acids produced via fatty acid biosynthesis . Short-chain carboxylic acids can be converted to a variety of industrially relevant ketones using chemical catalysis . Long-chain fatty acids are an attractive feedstock because they can be produced in varying carbon chain lengths .…”

Section: Biobased Platformsmentioning

confidence: 99%

Bridging the Chemical and Biological Catalysis Gap: Challenges and Outlooks for Producing Sustainable Chemicals

et al. 2014

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Recent advances in metabolic engineering have allowed for the production of a wide array of molecules via biocatalytic routes. The high selectivity of biocatalysis to remove functionality from biomass can be used to produce platform molecules that are suitable for subsequent upgrading over heterogeneous catalysts. Accordingly, the more robust continuous processing allowed by chemical catalysis could be leveraged to upgrade biologically derived platform molecules to produce direct or functional replacements for petroleum products. Herein, we highlight recent results that utilize a combination of chemical and biological catalysis, and using the perspective of heterogeneous chemical catalysis, we identify challenges that need to be addressed to bridge the gap between the two catalytic approaches. Specifically, studies are required to address the effects on catalyst performance of impurities that originate during bioprocessing. In addition, new generations of heterogeneous catalysts are required for stable operation under liquid phase reaction conditions in the presence of biogenic impurities. Finally, the design and syntheses of new catalysts are required to tailor the active sites and the environment around these sites to achieve selective conversion of the functional groups present in biologically derived platform molecules.

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Section: Biobased Platformsmentioning

confidence: 99%

Bridging the Chemical and Biological Catalysis Gap: Challenges and Outlooks for Producing Sustainable Chemicals

et al. 2014

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“…Vapor-phase ketonization of carboxylic acids on metal oxide catalysts has a great potential as an economically competitive and environmentally friendly industrial process. − Ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, are used as solvents and intermediates in electronic, agricultural, and pharmaceutical industries . The noncatalytic version of ketonic decarboxylation is a classic organic chemistry reaction, one of the first known since organic chemistry separated into a specific science .…”

Section: Introductionmentioning

confidence: 99%

Distinguishing Enolic and Carbonyl Components in the Mechanism of Carboxylic Acid Ketonization on Monoclinic Zirconia

Ignatchenko

Kozliak

2012

ACS Catal.

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This study contributes toward understanding the mechanism of catalytic formation of mixed ketones in an attempt to improve their selectivity vs symmetrical ketones. A pulsed microreactor placed inside a gas chromatograph–mass spectrometer instrument was used to identify the source of carbonyl group and quantify its distribution among products of zirconia-catalyzed cross-ketonization reaction of a mixture of carboxylic acids, with the carbonyl group of one of the acids selectively labeled by 13C. A concept of enolic and carbonyl components in the ketonization mechanism was introduced to distinguish the sources of alkyl and acyl groups, respectively. The least branched acid was found to be the predominant source of CO2, the essential byproduct of ketonization. Thus the least branched acid is the preferred source of the alkyl group of the cross-ketone product, while the most branched acid provides the acyl group. Increased branching at the α carbon next to the carbonyl group decreased the reactivity of both the enolic and the carbonyl components. Following a pseudo first order kinetic analysis, the relative reaction rates for a common enolic component with a pair of different carbonyl components were measured by the method of competing reactions to obtain mechanistic insights. The distinction between two possible paths in the cross-ketonization mechanism was characterized quantitatively by assessing the difference in activation energies; the results obtained were explained by the steric effect of substituents. On the basis of detailed kinetic analysis, the rate-limiting step most likely occurs after the enolic component activation.

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“…120 The applications and commercial manufacturing methods of small molecule products are highlighted while noting their dependence on fossil fuels (factorysymbol) or sustainable production methods (leaf-symbol). [121][122][123][124][125]…”

Section: Discussionmentioning

confidence: 99%

Light-Driven Polymer Recycling to Monomers and Small Molecules

Wimberger,

Ng,

Boyer

2024

Preprint

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Only a small proportion of global plastic waste is recycled, of which most is mechanically recycled into lower quality materials. The alternative, chemical recycling, enables renewed production of pristine materials, but generally comes at a high energy cost, particularly for processes like pyrolysis. This review focuses on light-driven approaches for chemically recycling and upcycling plastic waste, with emphasis on reduced energy consumption and selective transformations not achievable with heat-driven methods. We focus on challenging to recycle backbone structures, mainly C‒C, which lack functional groups i.e. esters or amides, that facilitate chemical recycling e.g. by solvolysis. We discuss the use of light, either in conjunction with heat to drive depolymerization to monomers or via photocatalysis to transform polymers into valuable small molecules. The structural prerequisites for these approaches are outlined, highlighting their advantages as well as limitations. We conclude with an outlook, addressing key challenges, opportunities, and provide guidelines for future photocatalyst development.

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Ketones

Cited by 7 publications

References 72 publications

Bridging the Chemical and Biological Catalysis Gap: Challenges and Outlooks for Producing Sustainable Chemicals

Bridging the Chemical and Biological Catalysis Gap: Challenges and Outlooks for Producing Sustainable Chemicals

Distinguishing Enolic and Carbonyl Components in the Mechanism of Carboxylic Acid Ketonization on Monoclinic Zirconia

Light-Driven Polymer Recycling to Monomers and Small Molecules

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