Ammoxidation of Lignocellulosic Materials: Formation of Nonheterocyclic Nitrogenous Compounds from Monosaccharides

Abstract

Ammoxidized technical lignins are valuable soil-improving materials that share many similarities with native terrestrial humic substances. In contrast to lignins, the chemical fate of carbohydrates as typical minor constituents of technical lignins during the ammoxidation processes has not been thoroughly investigated. Recently, we reported the formation of N-heterocyclic, ecotoxic compounds (OECD test 201) from both monosaccharides (d-glucose, d-xylose) and polysaccharides (cellulose, xylan) under ammoxidation conditions and showed that monosaccharides are a source more critical than polysaccharides in this respect. GC/MS-derivatization analysis of the crude product mixtures revealed that ammoxidation of carbohydrates which resembles the conditions encountered in nonenzymatical browning of foodstuff affords also a multitude of nonheterocyclic nitrogenous compounds such as aminosugars, glycosylamines, ammonium salts of aldonic, deoxyaldonic, oxalic and carbaminic acids, urea, acetamide, α-hydroxyamides, and even minor amounts of α-amino acids. d-Glucose and d-xylose afforded largely similar product patterns which differed from each other only for those products that were formed under preservation of the chain integrity and stereoconfiguration of the respective monosaccharide. The kinetics and reaction pathways involved in the formation of the different classes of nitrogenous compounds under ammoxidation conditions are discussed.

Assessing the climate change mitigation potential from food waste composting

“…It is also possible that abiotic ammoxidation of cellulose or lignin (oxidative C conversion with ) occurred. At high temperatures (> 70 °C), cellulose and lignin can be decomposed to monosaccharides, which react with to form long-chain amino sugars, sugar acids, and imidazoles 63 . It is also possible that was incorporated into humic-like substances 64 , 65 which can be more prevalent at the end of the composting process 66 .…”

From waste to resource: advancements in sustainable lignin modification

“…Amino group functionalized lignin Amination of lignin enables the insertion of reactive sites onto lignin, leading to applications in the field of fertilizers, 53 as well as curing agents for epoxy resins. Introduction of nitrogen to lignin can be achieved via ammonoxidation, 54,55 although it typically leads to nitriles and a mixture of N-containing functional groups, rather than amino groups. Introducing primary amino groups onto lignin could be a useful contribution to the field of biobased amines, especially towards non-isocyanate polyurethane applications or for epoxy resins.…”

From liquid to solid-state, solvent-free oxidative ammonolysis of lignins – an easy, alternative approach to generate “N-lignins”

“…33 Impurities of technical lignins, especially monosaccharides and oligosaccharides and their degradation products, were shown to be transformable into N-heterocyclic compounds or other potentially phytotoxic compounds during AO in model compound experiments. 13,35,36 However, sufficiently mild conditions avoid or at least signicantly decrease formation of (phyto)toxic substances. 13,36 In our study, we report a novel procedure to introduce N into lignins, more precisely a solvent-free solid-state ammonoxidation.…”