Technical lignin and its potential modification routes: A mini-review

Currently, the majority of chemicals are derived from petroleum-based feedstocks. In recent years, the valorization of lignin as feedstock for the production of alternative chemicals has attracted tremendous attention. Despite the renewed interest in the development of valorized lignin, few lignin-based chemicals have been produced at industrial scales and still, most of the lignin is used as an energy source. This review paper intends to discuss the technical obstacles and challenges in converting lignin moieties into value-added products effectively. Alternative modification routes have been discussed to produce lignin-based materials, while these routes strongly rely on the chemical structure of lignin. The propose of this review is to provide insight into the crucial role of the commercial lignin extraction processes on the properties of generated technical lignin and ultimately on its potential in reacting with other chemicals for inducing valorized lignin-derived materials for altered applications. Existing strategies for the functionalization of technical lignin are also summarized. The challenges, opportunities, and future direction regarding the biorefining of technical lignin are reviewed.