Abstract
An autoclave (120-mL) and an optical micro-reactor (50-nL) were used to study the hydrothermal decomposition of d-glucose at high temperatures and high pressures. During slow heating (0.18 °C/s) to 350 °C in the autoclave, water-soluble glucose (0.9 M) began to decompose at 220 °C and reacted completely at 280 °C. The initial decomposition products were 5-(hydroxymethyl)furfural and levoglucosan, and these subsequently converted into oil and solid residue, and finally to solid particles at a 65 wt% yield at 350 °C. When the same heating rate and temperature were used on glucose solutions in the micro-reactor, yellow and orange materials decomposed from glucose were produced. Numerous particles precipitated at 251 °C, and at 350 °C, all the glucose changed to an orange film and solid particles, which were nanoparticles as confirmed by SEM. However, when the glucose solution was rapidly heated to 410 °C (9.5-17 °C/s), yellow, brown and orange sugar-like materials were produced. A homogeneous phase with yellow color still remained at temperatures as high as 380 °C, and few particles formed until 410 °C. It can be concluded that micron-sized particles and colored solutions can be produced by slow heating, while rapid heating resulted in the formation of dye-like substances with glucose-like structures. The formation of colored solutions and particles may have technological implications in food or materials formation processes that use high temperature water with biomass feedstocks.
Original language | English |
---|---|
Pages (from-to) | 41-47 |
Number of pages | 7 |
Journal | Journal of Supercritical Fluids |
Volume | 56 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2011 Feb |
Keywords
- Biomass
- Diamond anvil cell
- Dyes
- Glucose
- Hydrothermal
- Particles
- Sub- and supercritical water
ASJC Scopus subject areas
- Chemical Engineering(all)
- Condensed Matter Physics
- Physical and Theoretical Chemistry