title: Reaction pathways of glucose during esterification: effects of reaction parameters on the formation of humin type polymers.
abstract: The formation of humin-type polymers and other products during exposure of glucose to methanol/water mixtures with methanol/water mass ratios from 10 to 0.22 in the presence of the acid catalyst Amberlyst 70 was investigated. In water-rich medium (methanol/water mass ratio: 0.22), dehydration of glucose produced 5-(hydroxymethyl)furfural (HMF), furfural, and substantial amounts of polymer. In methanol-rich medium (methanol/water mass ratio: 10), the hydroxyl and carbonyl groups of glucose, HMF or furfural were protected via etherification and acetalisation. These protections stabilized these reactive compounds and significantly lowered the polymer formation (1.43% of the glucose loaded). The polymerization of glucose and HMF was also favored at high temperatures and long residence times. Conversely, high catalyst dosage mainly accelerated the conversion of glucose to methyl levulinate. Thus, the polymerization of glucose and HMF can be suppressed in methanol/water mixtures with high methanol ratios, at low temperatures and short residence times.
authors: Fuels and Energy Technology Institute, Curtin University of Technology, G.P.O. Box U1987, Perth, WA 6845, Australia.
authors: Xun
authors: X
authors: Hu
authors: Caroline
authors: C
authors: Lievens
authors: Alfons
authors: A
authors: Larcher
authors: Chun-Zhu
authors: CZ
authors: Li
mesh_terms: D002384:Catalysis; D004602:Elements; D004951:Esterification; D005662:Furaldehyde / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D006812:Humic Substances / Q000032:analysis*; D006873:Hydroquinones / Q000138:chemical synthesis / Q000737:chemistry; D007700:Kinetics; D000432:Methanol / Q000737:chemistry; D008956:Models, Chemical; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D004602:Elements; D006812:Humic Substances; D006873:Hydroquinones; D011108:Polymers; C001861:humin; D014867:Water; C013038:hydroxyhydroquinone; C008046:5-hydroxymethylfurfural; D005662:Furaldehyde; D005947:Glucose; D000432:Methanol