The valorisation of lignin has gained significant interest in bioenergy, which is driven by the abundance of the material coupled with the potential to form value-added compounds. As a result, the range of technologies deployed for this application has increased and more recently includes advanced oxidation processes such as photocatalysis. The complexity of lignin is challenging however, and therefore model compounds, which represent key linkages in the native structure, have become crucial as both a tool for evaluating novel technologies and for providing an insight into the mechanism of conversion. Previously, the β-O-4 dimer, the most abundant linkage found in native lignin, has been extensively used as a model compound. Described herein, however, is the first report of photocatalytic TiO₂ technology for the degradation of a β-5 model dimer. Under low power UV-light emitting diode irradiation, complete degradation of the β-5 compound (6.3 10⁻³ mg ml⁻¹ min⁻¹) was achieved along with formation and subsequent removal of reaction intermediates. Investigation into the mechanism revealed within the first 2 min of irradiation there was the formation of a diol species due to consumption of the alkene sidechain. Although the data presented highlights the complexity of the system, which is underpinned by multiple oxidative reaction pathways, an overview of the key photocatalytic processes are discussed including the impact of acetonitrile and role of reactive oxygen species.

木质素的增值引起了生物能源的极大兴趣，这是由丰富的材料以及形成增值化合物的潜力所驱动的。因此，为此应用部署的技术范围有所增加，最近还包括高级氧化工艺，如光催化。然而，木质素的复杂性具有挑战性，因此代表天然结构中关键连接的模型化合物作为评估新技术和深入了解转化机制的工具变得至关重要。以前，β- O-4 二聚体是天然木质素中发现的最丰富的键，已被广泛用作模型化合物。然而，这里描述的是光催化 TiO ₂的首次报道用于降解β- 5 模型二聚体的技术。在低功率紫外发光二极管照射下，实现了β- 5化合物的完全降解（6.3 10 ^-3 mg ml ^-1 min ^-1）以及反应中间体的形成和随后的去除。对机理的研究表明，在辐照的前 2 分钟内，由于烯烃侧链的消耗，形成了二醇物质。尽管所提供的数据强调了系统的复杂性，该系统由多种氧化反应途径支撑，但讨论了关键光催化过程的概述，包括乙腈的影响和活性氧的作用。