Highly Concentrated Peroxodicarbonate for Efficient Oxidative Degradation of Kraft Lignin.

The oxidative degradation of technically relevant types of Kraft lignin is efficiently accomplished by a significantly improved two-step protocol. The key is the use of highly concentrated peroxodicarbonate solution which selectively oxidizes the lignin particles at moderate temperature which are thermally treated in a subsequent step. The liberation of low-molecular-weight phenols occurs when the oxidizer is already consumed enhancing the yield of target compounds strongly up to 15.6 wt%. Co-generated carbonates in this transformation represent the make-up chemical of pulping plants. This makes this approach suitable and attractive to be implemented as a bolt-on or integrated into the Kraft pulping process. The green metrics clearly indicate the sustainable and superior features of the method established.