Development of a sustainable process for the selective catalytic conversion of biogenic humin-model substrates and biomass-derived humins to carboxylic acids by the help of tailor-made polyoxometalate catalysts

胡敏素是一种深色聚合物固体，在生物质通过酸催化转化为平台化学品的许多过程中不可避免地出现。它们只溶于强碱，目前还不适合大规模应用。其详细的结构和形成机制通常是未知的，因此科学研究仅限于避免或尽量减少指定过程中胡敏素的形成。通过对乙酰丙酸或HMF合成过程中形成的胡敏素实施新的化学增值途径，可以从生物质转化过程中创造更多的附加值。基于首次非常有希望的关于胡敏素催化氧化为低分子有机酸的初步工作，（甲酸，乙酸）的帮助下，在水介质中的均相聚氧乙烯酸盐催化剂，这是该项目的总体目标，以获得这些全新的低温转化胡敏素羧酸的基本了解，特别是在通过进行动力学研究的技术实施方面。因此，将进行关于胡敏素模型底物的结构-活性关系的研究。此外，用于具有胡敏素型结构特征的模型基质的选择性氧化的催化剂性质和工艺条件的特定调节允许调节产物选择性。反应动力学和传输现象将通过进行动力学研究来确定。此外，与模型基板的研究结果的纹理转移到真实的胡敏素以及所使用的催化剂的可回收性研究和调查的产品隔离的机制研究将进行。最后，所有调查结果的整合将导致一个连续的小型工厂的运作。

Humins are dark polymeric solids that occur inevitably in numerous processes where biomass is transformed to platform chemicals by acid catalysis. They are only soluble in strong bases and so far not suitable for large-scale applications. The detailed structure and formation mechanism are commonly not known, whereby the scientific investigations are restricted to the avoidance or minimization of humin formation in the designated process. Due to their kinetics this is mostly not possible.By the implementation of new chemical valorization pathways for humins that are formed during levulinic acid or HMF synthesis, more added value can be created from biomass conversion processes. Based on the first very promising preliminary work on catalytic oxidation of humins to low-molecular organic acids (formic acid, acetic acid) by the help of homogeneous polyoxometalate catalysts in aqueous media, it is the overall objective of the project to gain a fundamental understanding of these completely new low-temperature conversion of humins to carboxylic acids, especially in the light of a technical implementation by performing kinetic investigations.Therefore, investigations concerning the structure-activity relationships in humin model substrates will be carried out. Moreover, specific adjustment of catalyst properties and process conditions for the selective oxidation of model substrates with humin-type structural features allows for tuning of the product selectivity. Reaction kinetics and transport phenomena will be determined by performing kinetic investigations. Furthermore, mechanistic studies for the textural transferability of the findings with model substrates to real humins as well as recyclability studies of the used catalysts and investigations with respect to the product isolation will be carried out. Finally, the integration of all findings will result in a continuous miniplant operation.