Producing levoglucosan from deciduous tree wood | Levoglikozāna ieguve no lapu koku koksnes
2009
Zurins, A., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Zandersons, J., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Spince, B., Latvian State Inst. of Wood Chemistry, Riga (Latvia)
The aim of the project was to obtain products and individual compounds (levoglucosan), the so-called ''green chemicals'', applicable in the national economy, from the local renewable raw materials - low-value deciduous wood, developing the thermo-chemical principles and technological solutions of its production. The main tasks were the investigation of the levoglucosan (LG) obtaining processes, development of the technology and its purification studies. Levoglucosan or 1.6-anhydro-β-D-glucopyranose is an anhydrosugar that is formed in the process of pyrolysis of cellulose or cellulose containing raw material at the temperature 380-420 deg C, as the depolymerisation of the cellulose macromolecules occur. In the experiments, birch and grey alder chips, treated with a catalyst - sulphuric acid - 1-3% from oven dry mass and held at elevated temperature were used as the raw material. The obtained cellolignin was washed with distilled water to remove the hemicelluloses fraction and dried to the moisture 8-12%. The yield of non-purified levoglucosan, depending on the pyrolysis conditions, was 60-80% from the theoretical in the liquid. The obtained product was further re-crystallised from ethanol or methanol as well as purified by cooking under the outflow solution with active carbon and repeatedly crystallising. As the result of the implementation of the work, an experimental levoglucosan obtaining device has been constructed and launched, on which an experimental lot (1.35 kg) has been produced, and a new levoglucosan purification technology has been developed.
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