Klinger Karl Michael, Liebner Falk, Hosoya Takashi, Potthast Antje, Rosenau Thomas
Department of Chemistry, University of Natural Resources and Life Sciences, Vienna , Konrad-Lorenz-Straße 24, A-3430 Tulln, Austria.
J Agric Food Chem. 2013 Sep 25;61(38):9015-26. doi: 10.1021/jf401960m. Epub 2013 Sep 10.
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.
氨氧化工业木质素是有价值的土壤改良材料，与天然陆地腐殖质有许多相似之处。与木质素不同，碳水化合物作为工业木质素典型的次要成分在氨氧化过程中的化学归宿尚未得到充分研究。最近，我们报道了在氨氧化条件下，单糖（D-葡萄糖、D-木糖）和多糖（纤维素、木聚糖）都会形成N-杂环生态毒性化合物（经合组织测试201），并表明在这方面单糖是比多糖更关键的来源。对粗产物混合物的气相色谱/质谱衍生化分析表明，碳水化合物的氨氧化类似于食品非酶褐变中遇到的条件，也会产生大量非杂环含氮化合物，如氨基糖、糖基胺、醛糖酸、脱氧醛糖酸、草酸和氨基甲酸的铵盐、尿素、乙酰胺、α-羟基酰胺，甚至少量的α-氨基酸。D-葡萄糖和D-木糖产生的产物模式大致相似，仅在那些在各自单糖的链完整性和立体构型保持的情况下形成的产物方面有所不同。讨论了氨氧化条件下不同类含氮化合物形成过程中的动力学和反应途径。
