Issue 13, 2024

Molecular structure and composition elucidation of an industrial humin and its fractions

Abstract

Humins, (side-)products of the acid-catalysed dehydration of carbohydrates, will be produced in substantial quantities with the development of industrial biorefining processes. Most structural knowledge about such humins is based on synthetic model humins prepared at lab-scale from typical carbohydrate(-derived) compounds. Here, we report the first extensive characterisation study of an industrial humin. The soluble humin was generated from pilot plant-scale methanolic cyclodehydration of D-fructose to 5-methoxymethyl-2-furfural (MMF), as part of the Avantium YXY® process to produce FDCA. Purification of the industrial humin followed by fractionation allowed isolation of a water-insoluble, high molecular weight fraction (WIPIH) and a water-soluble, low-to-middle molecular weight soluble fraction (WES). Characterisation by elemental analysis, thermogravimetry, IR and NMR spectroscopy and size exclusion chromatography provided a detailed picture of the humin structure in both fractions. Aided by a comprehensive NMR spectral library of furanic model compounds, we identified the main furanic building blocks and inter-unit linkages and propose a structure for this industrial humin sample. The WIPIH and WES fractions were found to be composed of furanic rings interconnected by short aliphatic chains containing a wide range of functionalities including alcohols, ethers, carboxylic acids, esters, aldehydes and ketones. The low level of crosslinking and high functional group content of the industrial humin differ from the more extensively studied, (highly over-)condensed synthetic model humins, towards which they can be considered intermediates. The structural and compositional insights into the nature of an actual industrial humin open up a broad spectrum of valorisation opportunities.

Graphical abstract: Molecular structure and composition elucidation of an industrial humin and its fractions

Supplementary files

Article information

Article type
Paper
Submitted
24 Sun 2024
Accepted
21 Kul 2024
First published
21 Kul 2024
This article is Open Access
Creative Commons BY-NC license

Green Chem., 2024,26, 7739-7751

Molecular structure and composition elucidation of an industrial humin and its fractions

S. Constant, C. S. Lancefield, W. Vogelzang, R. K. Pazhavelikkakath Purushothaman, A. E. Frissen, K. Houben, P. de Peinder, M. Baldus, B. M. Weckhuysen, D. S. van Es and P. C. A. Bruijnincx, Green Chem., 2024, 26, 7739 DOI: 10.1039/D4GC00429A

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements