From Terephthalic Acid to 2,5‐Furandicarboxylic Acid: An Industrial Perspective

With the foreseeable rise of bio-based platform chemicals from starch and sucrose initially and lignocellulosic or waste feedstock streams somewhat later, the question can be raised whether new methods for defunctionalization or further functionalization will be required or can we rely on the reuse of existing catalytic conversions as a strategy? To start answering this question, we need to realize that bio-based molecules can, but most likely will not, be the same as the current petrochemical-based platform chemicals. And even if the same molecules are targeted (“drop-in”), the production routes will not be the same. Carbohydrates are the most abundant and most frequently used bio-based feedstock. They are rich in oxygen atoms, whereas the petro-based feedstocks are hydrocarbons, exclusively made up of C and H. In many cases, bio-based feedstock is overoxidized and thus a clear need for reduction, hydrogenation, dehydration, decarboxylation, and other chemistries will be needed. Perhaps an even more challenging task for these molecules is to selectively oxidize them further, as these bio-based molecules are inherently more activated due to the already present oxygen groups. This chapter provides an industrial perspective on several oxidation routes to new bio-based molecules. In particular, it focuses on the use of Co/Mn/Br catalyst systems in air oxidations, based on the Amoco Mid-Century catalyst system used for para-xylene oxidation (also see Chapter 4), as an efficient methodology for the conversion of 5-(hydroxymethyl)furfural (HMF) and 5-(methoxymethyl)furfural (MMF) to 2,5-furandicarboxylic acid (FDCA) in Avantium's YXY process. In addition, other less-studied conversions, such as methyl levulinate (ML) to succinic acid (SA), lignin to a variety of aromatic and phenolic carboxylic acids, are discussed as well.