Cellulose ( IF 4.9 ) Pub Date : 2021-09-15 , DOI: 10.1007/s10570-021-04181-2 Thomas Rosenau 1, 2 , Antje Potthast 1 , Hubert Hettegger 1 , Markus Bacher 1 , Martina Opietnik 3 , Thomas Röder 3 , Immanuel Adorjan 4
|
Several literature reports describe the role of aqueous solutions of N-methylmorpholine-N-oxide monohydrate (NMMO) as a suitable medium for the generation of transition metal (nano)particles in or on cellulosic materials and further elaborate its role as a co-reactant of the transition metal salts that are reduced to the elemental metal. However, this would assign NMMO the role of a reductant, which is in contradiction of its obvious oxidative nature. In the present study, the exemplary cases of silver, gold, and platinum salts as the precursors of the respective metal (nano)particles in aqueous NMMO/cellulose mixtures were investigated. Naturally, NMMO did not act as a reducing agent in any case—this role was taken over by the frequently used NMMO stabilizer propyl gallate, or by cellulose itself, into which carbonyl and carboxyl groups were introduced. Also, hypochlorite—produced intermediately from chloride ions and subsequently undergoing disproportionation into chloride and chlorate—or transient N-methylene(morpholinium) ions generated from NMMO, which are in turn oxidized to formyl morpholide, can act as the corresponding reductants while the metal ions are reduced, depending on the reaction conditions. Apart from providing interesting mechanistic insights, the study points to the importance of a precise description of the composition of the chemical systems used, as well as the importance of seemingly inert auxiliaries, which turned out to be essential co-reactants in the metal (nano)particle generation.
Graphic abstract
中文翻译：
N-甲基吗啉-N-氧化物 (NMMO) 在纤维素材料中元素过渡金属沉淀生成中的作用
一些文献报道描述了N-甲基吗啉-N水溶液的作用-氧化物一水合物 (NMMO) 作为在纤维素材料中或表面产生过渡金属（纳米）颗粒的合适介质，并进一步阐述其作为被还原为元素金属的过渡金属盐的共反应物的作用。然而，这将赋予 NMMO 还原剂的作用，这与其明显的氧化性质相矛盾。在本研究中，研究了银盐、金盐和铂盐作为各金属（纳米）颗粒在水性 NMMO/纤维素混合物中的前体的示例性案例。自然地，NMMO 在任何情况下都不会充当还原剂——这个角色被常用的 NMMO 稳定剂没食子酸丙酯或纤维素本身取代，其中引入了羰基和羧基。还，从 NMMO 产生的N-亚甲基（吗啉）离子，然后被氧化成甲酰吗啉，可以作为相应的还原剂，而金属离子则根据反应条件被还原。除了提供有趣的机理见解外，该研究还指出了对所用化学系统组成进行精确描述的重要性，以及看似惰性的助剂的重要性，这些助剂被证明是金属（纳米）中必不可少的共反应物。 )粒子生成。
京公网安备 11010802027423号