Inorganic Chemistry and Catalysis, Utrecht University, Universiteitweg 99, 3584 CG Utrecht (The Netherlands), Fax: (+31) 30 251 1027.
ChemSusChem. 2013 Sep;6(9):1745-58. doi: 10.1002/cssc.201300332. Epub 2013 Jul 8.
Neither the routes through which humin byproducts are formed, nor their molecular structure have yet been unequivocally established. A better understanding of the formation and physicochemical properties of humins, however, would aid in making biomass conversion processes more efficient. Here, an extensive multiple-technique-based study of the formation, molecular structure, and morphology of humins is presented as a function of sugar feed, the presence of additives (e.g., 1,2,4-trihydroxybenzene), and the applied processing conditions. Elemental analyses indicate that humins are formed through a dehydration pathway, with humin formation and levulinic acid yields strongly depending on the processing parameters. The addition of implied intermediates to the feedstocks showed that furan and phenol compounds formed during the acid-catalyzed dehydration of sugars are indeed included in the humin structure. IR spectra, sheared sum projections of solid-state 2DPASS (13) C NMR spectra, and pyrolysis GC-MS data indicate that humins consist of a furan-rich polymer network containing different oxygen functional groups. The structure is furthermore found to strongly depend on the type of feedstock. A model for the molecular structure of humins is proposed based on the data presented.
尚未明确确定腐殖质副产物形成的途径及其分子结构。然而，更好地了解腐殖质的形成和物理化学性质将有助于提高生物质转化过程的效率。在这里，作为糖进料、添加剂（例如 1,2,4-三羟基苯）存在以及所采用的加工条件的函数，提出了对腐殖质的形成、分子结构和形态的广泛的基于多种技术的研究。元素分析表明，腐殖质是通过脱水途径形成的，腐殖质的形成和乙酰丙酸的产率强烈取决于加工参数。向原料中添加隐含的中间体表明，在糖的酸催化脱水过程中形成的呋喃和苯酚化合物实际上包含在腐殖质结构中。IR 光谱、固态 2DPASS（13）C NMR 光谱的剪切总和投影以及热解 GC-MS 数据表明，腐殖质由含有不同含氧官能团的富呋喃聚合物网络组成。此外，还发现该结构强烈依赖于原料的类型。根据所提供的数据提出了腐殖质分子结构的模型。
