A model that distinguishes the pyrolysis of D-glucose, D-fructose, and sucrose from that of cellulose. Application to the understanding of cigarette smoke formation

A literature review is presented on the pyrolysis chemistry of mono-, di- and polysaccharides, with emphasis on D-glucose, D-fructose, sucrose and cellulose. A model, consisting of nine factors, is proposed to explain the pyrolysis product distributions observed. Product profiles depend on experimental conditions, particularly pyrolysis temperatures and residence times and the presence of other substances, e.g. acids, bases and salts. At higher temperatures, polynuclear aromatic hydrocarbons (PAHs) are the predominant condensed-phase products from carbohydrates. At lower temperatures, pyrolysis of pure cellulose generally favors 1,6-anhydro-beta-D-glucopyranose (levoglucosan) formation as well as low molecular weight oxygenated products, e.g. glycolaldehyde. Cellulose pyrolysis also yields other products, including furans. Pyrolysis of D-glucose, D-fructose, and sucrose appears to favor furan production rather than anhydrosugars and low molecular weight carbonyl compounds. Furans distill rapidly from the pyrolysis zone rather than degrade. For reducing sugars, the ability to react from their acyclic isomers to form cyclic five-membered rings, i.e. furan precursors, may be a significant controlling factor. Multiple pathways to products are likely in all these pyrolyses. These pyrolysis studies provide parallels to mainstream (MS) cigarette smoke precursor-product relationships. (C) 2002 Elsevier Science B.V. All rights reserved.