Chemistry of Renewable Resources
With a background in organic chemistry and natural product chemistry, the focus of the working group "Chemistry of Renewable Resources" is on cellulose, lignin and extractive chemistry as well as on the overall coordination of work at the institute. Cellulose, as the most common and most important renewable raw material, plays a central role in the research, with basic fundamental and applied aspects overlapping in many topics. The cellulose-related subjects range from structure of cellulose, cellulose allomorphs, hydrogen bond networks, swelling and dissolving behavior, synthesis and analysis of cellulose model compounds and cellulose derivatives, over industrial processes of pulp production and bleaching, cellulose fibers, lyocell and viscose technologies, paper chemistry and sizing agents, to questions of special cellulose analytics. A long-standing research topic is ageing of lignocellulosic materials, formation and identification of chromophores and the investigation of degradation reactions and by-products, e.g. in cellulose solutions and during derivatization. New (ligno)cellulosic materials, such as nano-structured celluloses, gels and aerogels, and organic-inorganic hybrid materials are investigated in close cooperation with other research groups of the institute.
Lignin chemistry, especially with regard to technical lignins, is represented with analogous research aspects. However, while cellulosic materials and products are commonplace today, non-energetic lignin utilization is still in its infancy, despite the immense potential of the second most common biopolymer as a C-source in biorefineries of the future. Besides structural aspects, and the development of analytical methodology, structure-property-application relationships of technical lignins and novel lignin-based products are important areas of research.
In the field of extractives, the focus is on the identification of bioactive ingredients of plant materials traditionally used in folk medicine. Another focus is the chemistry of phenolic antioxidants, especially tocopherol (vitamin E). Here, too, the research areas range from fundamental aspects, such as ortho-quinone methide chemistry, aromaticity/antiaromaticity, spiro-polymerization as a new polymerization mechanism, to applied topics, such as tocopherol derivatives for pharmaceuticals or as stabilizers for polymers. Two active substances developed in the group, which are based on tocopherols, have already been approved as drugs, others are currently in testing phases.
Generally, the research group deals with reactions, procedures and analytical methodology which belong to the field of "green chemistry". In particular, the use of supercritical CO2 for extractions, as a reaction medium and as a solvent in chromatography is of special interest. The green-chemistry theme also includes solvent-free syntheses, water as reaction medium, recycling aspects, and the use of microwaves and ultrasound for reactions.