Conversion of chitin derived N-acetyl-d-glucosamine (NAG) into polyols over transition metal catalysts and hydrogen in water

Abstract

N-Acetyl-D-glucosamine (NAG), the monomer of the world's second most abundant biopolymer chitin, has been for the first time converted to its corresponding amide/amino substituted sugar alcohols, smaller C2-4 polyols and N-acetylmonoethanolamine (NMEA), over noble metal catalysts in the presence of hydrogen in water. Four commercialized catalysts were investigated, and Ru/C exhibited the best performance-achieving 8.7% NMEA, 6.1% C4 polyols, and 71.9% C6 polyols (N-containing) under 180°C, 40 bar H 2 , 1 h with 1 mol% loading. Kinetic studies were conducted, which revealed four major reaction pathways that lead to various products. In particular, retro-aldol reaction-hydrogenation was confirmed to be the pathway forming NMEA. The effects of additives (NaOH and WO 3 ) on the reaction were also tested.

Pyrolysis of chitin biomass: TG–MS analysis and solid char residue characterization

“…However, chitin biomass, which is the second most abundant biomass, has received much less attention and has therefore not been widely studied for biomass utilization Nam, Park, Ihm, & Hudson, 2010;Ou et al, 2010;Stolarek & Ledakowicz, 2005;Taboada, Cabrera, Jimenez, & Cardenas, 2009;Tang et al, 2005;Zeng et al, 2011). It has been reported that chitin biomass, including these biopolymers (chitin and chitosan) and corresponding monosaccharides N-Acetyl-d-glucosamine and d-glucosamine), could produce hydroxyethyl-2-amino-2-deoxyhexopyranoside, levulinic acid, 5-hydroxymethylfurfural, 3-acetamido-5-acetylfuran, polyols and other compounds in solution phase (Bobbink, Zhang, Pierson, Chen, & Yan, 2015;Chen, Chew, Kerton, & Yan, 2014;Chen, Liu, Kerton, & Yan, 2015;Mascal & Nikitin, 2009;Omari, Besaw, & Kerton, 2012;Pierson, Chen, Bobbink, Zhang, & Yan, 2014;Wang, Pedersen, Deng, Qiao, & Hou, 2013). Our recent investigation also showed that glucosamine, the monomer of chitosan, could convert into nitrogen-containing chemicals, such as deoxyfructosazine (DOF) and fructosazine (FZ), in a homogeneous system (Jia, Wang, Qiao, Qi, & Hou, 2014).…”

Hydrolytic hydrogenation of chitin to amino sugar alcohol

“…We performed the reaction at a low temperature of 393 K, because a lower temperature generally gives higher selectivity in hydrogenation of sugars. 16,32 Reduction of NAG to ADS proceeded in a first-order manner in the presence of Ru/TiO 2 and 4 MPa of H 2 (Fig. 3a).…”

“…However, ADS was only synthesised from pure NAG, and ADS was not obtained from chitin previously. 16 Herein, we demonstrate the first catalytic conversion of chitin to ADS (Scheme 2).…”

“…15 Recently, Yan et al proposed a new chitin derivative, 2-acetamido-2-deoxysorbitol (ADS). 16 The amino alcohol is a potential precursor to polyamides and polyesteramides as an analogy of valorisation of sorbitol via isosorbide. 9,17 Hydrogenolysis of ADS gives N-acetylethanolamine, which is converted to an amide-containing polyether alcohol.…”

Valorization of Oceanic Waste Biomass: A Catalytic Perspective

“…Under 180 °C, 40 bar H 2 with 1 mol% loading of Ru/C, 71.9 % of C6 N‐containing polyols, 6.1 % C4 polyols and 8.7 % N‐acetylmonoethanolamine (NMEA) were produced. Through the kinetic studies, the mechanistic pathway was proposed which confirmed the formation of NMEA through retro aldol condensation (Scheme ) …”