Sugars pyrolysis

The furanic aldehydes 5-(hydroxy-methyl)furfural and 2-furaldehyde, systematically present in the toasted wood, can be formed by the thermal degradation of 3-deoxyosone during sugar pyrolysis or Maillard reactions (27). They could also be formed from glyceraldehyde, coming from degradation of DDMP, by condensation with subsequent elimination of water or formaldehyde (24). 

Some other molecules generated in sugar pyrolysis, while maintaining the initial monosaccharide cycle, do not show any stereoisomers. This is the case for 1,4-dideoxy-D-glycero-hex-1-enopyranos-3-ulose (1-hydroxymethyl-5-hydroxy-2,3-dihydropyranone) and for 1,6-anhydro-3,4-dideoxy-D-glycero-hex-3-enopyranos-2-ulose (levoglucosenone) (showing C-H bonds) ... 

It is formed in the pyrolysis of alanine (Merritt et al., 1970) and in the reaction of alanine with a polyphenol oxidase (Motoda, 1979). In coffee, it comes from sugar pyrolysis (Liardon et al., 1984). 

Caramelization One of the four main browning reactions due to sugar pyrolysis or intense heat treatment. Caramelization provides the characteristic color and flavor in baked products. 

Hard carbons can be produced from several carbon sources, such as polymers, petroleum products, carbohydrates and so on. Hard carbons are characterised by high H/C ratio. Hard carbon produced from sugar pyrolysis at a relatively low temperature (-1050°C) is found to have a hydrogen content of around 0.5% with high initial (first cycle) capacity of around 750 mAh/g of which -250 mAh/g of capacity comes in the region between 1.0 and 0.1 V... 

Acetone was originally observed about 1595 as a product of the distillation of sugar of lead (lead acetate). In the nineteenth century it was obtained by the destmctive distillation of metal acetates, wood, and carbohydrates with lime, and pyrolysis of citric acid. Its composition was determined by Liebig and Dumas in 1832. 

A recent study extensively investigated the pyrolysis of polysaccharide binders, with and without a silylating agent [56]. Some of the main results relative to the pyrolysis silylation of sugars and polysaccharide binders can be summarised as follows [56 59] ... 

SCHEME 32. Anhydro sugars obtained by pyrolysis of cellulose. 

D. Fabbri, C. Torri, and V. Baravelli, Effect of zeolites and nanopowder metal oxides on the distribution of chiral anhydro sugars evolved from pyrolysis of cellulose An analytical study, J. Anal. Appl. Pyrolysis, 80 (2007) 24-29. 

Recently, researchers have detected 2,5-dimethylfuran and 2-methylfuran and normal alkanes in kerogen of the 2.7 x 109 year old Belingwe, Rhodesia stromatolites, by the method of pyrolysis/ GC/MS [26]. They concluded that although furans could probably be derived from many compounds, their probable origin is in bacterial and algal sugars, and that the alkanes are either products of decarboxylation of fatty acids or unaltered constituents of ancient organisms. 

The extraction of environmental or geological particulate matter with solvents, solvent mixtures or supercritical carbon dioxide is the preferred method, because it results in minimum alteration of its polar components, avoids hydrolysis of anhydrides, esters, etc. and is highly efficient for most organic compounds (even sugars). Other workers have reported the direct vaporization by thermal desorption or flash pyrolysis of organic compounds from particulate matter into GC, MS, or GC-MS instruments. Those methods work fine for neutral compounds (e.g. hydrocarbons) but should be used with caution when analyzing polar or labile compounds. 

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