02117nas a2200265   4500008004100000022001400041245017000055210006900225260000800294300001100302490000800313520115400321653002801475653001101503653001601514653001901530653003301549653002201582100003101604700002101635700002101656700002301677700002101700856013001721       2022                        eng d  a0008-621500aSubcritical water hydrolysis of N-acetyl-D-glucosamine: hydrolysis mechanism, reaction pathways and optimization for selective production of 5-HMF and levulinic acid0 aSubcritical water hydrolysis of NacetylDglucosamine hydrolysis m  cJUN  a1085600 v5163 a<p>
	In this study, the subcritical water hydrolysis of N-acetyl-D-glucosamine (NAG), a monomer of abundant renewable marine biopolymer chitin, for production of value-added chemicals is investigated. The enhanced ionization of water at subcritical conditions (200 degrees C; 50-100 bar), provides enough acidity for deacetylation of NAG resulting in 80% yield of acetic acid along with traces of formic acid, lactic acid, glucose, fructose, 5hydroxymethylfurfural (5-HMF),etc. The significant humin formation indicates that the self-condensation and polymerisation of 5-HMF is favored in water at subcritical conditions. A catalyst p-toluenesulfonic acid (p-TsOH) was employed to selectively convert NAG to levulinic acid (LA) via ring opening of 5-HMF previously formed during hydrolysis. The maximum yield of 27.13 +/- 1% and 53.46 +/- 1% of 5-HMF and LA, respectively, was obtained at process conditions optimized using Box-Behnken design coupled with response surface methodology. Subcritical water enables greener conversion of NAG to platform chemicals wherein the selective production can be achieved by tuning the process conditions.</p>
10a5-Hydroxymethylfurfural10achitin10aGlucosamine10alevulinic acid10aResponse surface methodology10aSubcritical water1 aKulkarni, Sphurti, Prakash1 aDure, Shital, N.1 aJoshi, Sunil, S.1 aPandare, Kiran, V.1 aMali, Nilesh, A.  uhttps://library.ncl.res.in/content/subcritical-water-hydrolysis-n-acetyl-d-glucosamine-hydrolysis-mechanism-reaction-pathways