Title of article :
Influence of selected mineral acids and alkalis on cellulose pyrolysis pathways and anhydrosaccharide formation
Author/Authors :
Shaik، نويسنده , , Salim M. and Sharratt، نويسنده , , Paul Nicholas and Tan، نويسنده , , Reginald B.H.، نويسنده ,
Pages :
9
From page :
234
To page :
242
Abstract :
The primary/initial thermal degradation pathway is via intermolecular transglycosylation reactions within the glucose monomers of cellulose. Formation of liquid tar from cellulose can also occur via β-elimination. Under this mechanism, volatile acids (e.g. carboxylic acids) formed from the initial cellulose decomposition are able to attack the remaining cellulose as Bronsted acids thus catalysing heterolytic (ring-opening) reactions. we have studied the effects of acids (H2SO4, H3PO4, H3BO3) and alkalis (Ca(OH)2, NH4OH) on the yields of levoglucosan and its derivatives (levoglucosenone, 1,4:3,6-dianhydro-α-d-glucopyranose, 1,6-anhydro-β-d-glucofuranose). It was found that the acids generally decreased the total amount of anhydrosaccharides whilst cellulose infused with the alkalis had increased anhydrosaccharide yields. The results indicate that the β-elimination pathway was catalysed by the presence of acidic species (e.g. H+ ions). The extent of cellulose conversion via the β-elimination pathway was dependant on the amount and strength of acid infused within the cellulose matrix. However, the β-elimination route could also be suppressed or controlled by the introduction of a neutralising species (e.g. OH− ions).
Keywords :
cellulose , BIOMASS , transglycosylation , Levoglucosan , Pyrolysis , Levoglucosenone
Journal title :
Astroparticle Physics
Record number :
2036201
Link To Document :
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