Reductive amination of glycolaldehyde (GA), the smallest sugar molecule and obtainable from biomass, creates a versatile platform for ethylamine products, potentially replacing current pathways via toxic ethylene oxide and dichloroethane. Given the high reactivity of α-OH carbonyls, the main challenge was control of selectivity in a cascade of parallel and consecutive reactions during reductive amination. The type of solvent and catalyst, preferably methanol and Pd, respectively, are key enabling parameters to achieve high product yields. A kinetic study on product intermediates accompanied with detailed product analysis (MS and NMR) suggested a general mechanistic scheme and validation with density functional theory calculations provided a rational understanding of the solvent effect in terms of energetics and kinetics. Primary alkanolamines (AA) such as 2-(dimethylamino)-ethanol are preferred products, and large excess of the amine reagent is not required to reach almost quantitative yields. Interestingly substoichiometric amine-to-GA ratio allows for high yield of higher (consecutive) AAs such as N-methyldiethanolamine (MDEA) and triethanolamine, for which a peculiar cyclic 5-membered oxazolidinic precursor was analyzed (e.g., for reaction with monomethylamine to MDEA). The shift to diamine-selective (DA) reactions is possible by switching to a two-step one-pot approach. With ethylene glycol as a preferred solvent, high yield of an unsaturated C 2 -enediamine precursor is obtained under an inert atmosphere, followed by its metal-catalyzed hydrogenation at elevated temperature to the final DA product such as N,N,N′,N′-tetramethylethylene-diamine. A conceptual model of the catalytic reductive amination routes that allows production of a variety of ethylamines with up to +90 C % yield is thus presented. The successful preparation and sensory assessment of a GA-based diester quat in fabric softener formulations demonstrates the viability of a full bio-based and drop-in production route for high-value chemicals, directly from GA as a platform molecule.
Fossil‐based platform molecules such as ethylene and ethylene oxide currently serve as the primary feedstock for the C2‐based chemical industry. However, in the search for a more sustainable chemical industry, fossil‐based resources may preferentially be replaced by renewable alternatives, provided there is realistic economic feasibility. This Review compares and critically discusses several production routes toward bio‐based structural analogues of ethylene oxide and the required adaptations for their implementation in state‐of‐the‐art C2‐based chemical processes. For example, glycolaldehyde, a structural analogue obtainable from carbohydrates by atom‐economic retro‐aldol reactions, may replace ethylene oxide's leading role. This alternative chemical route may not only allow the carbon footprint of conventional chemicals production to be lowered, but the introduction of a bio‐based pathway may also contribute to safer production processes. Where possible, challenges, drawbacks, and prospects are highlighted.
A catalytic reductive aminolysis of reducing monosaccharides into short ethylene diamines (or C 2 diamines) was recently communicated by our group (Pelckmans et al.
Fossil‐based platform molecules such as ethylene and ethylene oxide currently serve as the primary feedstock for the C2‐based chemical industry. However, in the search for a more sustainable chemical industry, fossil‐based resources may preferentially be replaced by renewable alternatives, provided there is realistic economic feasibility. This Review compares and critically discusses several production routes toward bio‐based structural analogues of ethylene oxide and the required adaptations for their implementation in state‐of‐the‐art C2‐based chemical processes. For example, glycolaldehyde, a structural analogue obtainable from carbohydrates by atom‐economic retro‐aldol reactions, may replace ethylene oxide's leading role. This alternative chemical route may not only allow the carbon footprint of conventional chemicals production to be lowered, but the introduction of a bio‐based pathway may also contribute to safer production processes. Where possible, challenges, drawbacks, and prospects are highlighted.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.