Production of carboxylic acids from the non-lignin residue of black liquor by hydrothermal treatments

Structural changes of lignin in soda delignification process and associations with pollution load

“…Furthermore, several typical condensed substructures, including stilbene (I), vinyl aryl ethers (J), diaryl ethers (K), biphenyl substructures (L), and diarylmethylenes (M) (δC/δH 20.7/2.1 ppm, not shown) produced during soda pulping were discovered in soda lignin, which was inconsistent with previous publications (An et al 2015). In alkaline pulping, the Cβ-Cγ bond was broken, which indicated that the primary alcohol hydroxyl group at the Cγ position was oxidized to formaldehyde, and the removed formaldehyde acted as a cross-linking agent for the reaction (Pei 2012). Lignin fragments were polymerized together under the action of a crosslinking agent to form a diarylmethylene structure (unit M).…”

Application of the TRIZ Contradictory Matrix to Foster Innovation for Sustainable Chemical Engineering

“…Their industrial production is still mainly based on chemical synthesis from petroleum-based feedstock and on fermentation of carbohydrates. Novel approaches for production from biobased residues include fermentation of wastewater [43] and solid municipal waste [44], decomposition of lignin [45], and hydrothermal treatment of nonlignin residues [46]. Carboxylic acids also occur as by-products and degradation products in various biobased process streams originating from, e.g., lignocellulose processing such as pulping [47] and pyrolysis [48,49].…”

Green is the new black – a review of technologies for carboxylic acid recovery from black liquor

“…[17][18][19] Due to the increasing interest in some of the compounds (mainly acids) present in the BL, some researchers have also targeted alternatives routes for their valorization. [20][21][22] Carboxylic acids are the best-known type of organic acids. They are used on large scale in the chemical and food industry.…”