Carbohydrates pyrolysis

Figure 11.9 Pyrogram of a paint sample collected from sixteenth century wall paintings in the Messer Filippo cell of the tower in Spilamberto, Italy. Pyrolysis was performed with a micro furnace pyrolyser, at 600°C, in the presence of HMDS. 1, Carbohydrate pyrolysis products 2, lauric acid 3, suberic acid 4, levoglucosane 5, azelaic acid 6, miristic acid 7, hexadecanenitrile 8, palmitic acid 9, octadecanenitrile 10, oleic acid 11, stearic acid. TMS derivative [74]...

Antal M.J, Biomass Pyrolysis A Review of the Literature Part I -Carbohydrate Pyrolysis , in Adv. in Solar Energy - an annual review of R D, Vol 1, Ed. Boer K.W. and Duffie J.A., Plenum Press, New York, bill 1(1982)... 

Antal, M.J. "Biomass Pyrolysis. A Review of the Literature -Part Is Carbohydrate Pyrolysis" in Advances in Solar Energy, (Eds. K.W. Boer and J.A. Duffie) Vol. 1, (American Solar Energy Society, Boulder, CO) 1983. 

Rossinskaja G., Dobele G., Domburg G. (1986) Thermocatalytic transformation of cellulose and lignin in the presence of phosphoric acid. 3. Characteristics of the higher - boiling oil fraction of carbohydrates pyrolysis. Khimija Drev., 6, 72-76. 

One approach utilized in carbohydrate pyrolysis is Py-MS. Py-MS using El type ionization does not differentiate well between anhydrosugar stereoisomers, and its utilization to obtain structural information on carbohydrates is rather limited. However, there are reports [10a] where the type of bond between monosaccharide units can be differentiated using Py-EI MS. As an example, the Py-EI MS results are shown for a (1 -> 2)-p-glucan and for a (1 -> 3)-p-glucan (laminaran). 

Antali M.J., Jr. "Biomass pyrolysis a review of the literature, Part I-carbohydrate pyrolysis." In Adv. in Solar Energy. Boer, K.W. Duffie, J.W. Eds., American Solar Energy Society Boulder CO, 1984, 1, 61. 

Lakshmanan CM Hoelscher HE. 1970. Production of levogjucosan by pyrolysis of carbohydrates. Pyrolysis in hot inert gas stream. Industrial Engineering Chemistry Product Research and Development 9(l) 57-59. 

Paine JB, PithawaUa YB, NaworalJD. Carbohydrate pyrolysis mechanisms from isotopic labeling. J Anal Appl Pyrol. 2008 82 42-69. 

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. 

Itaconic 2Lcid[97-65-4] (methylenebutanedioic acid, methylenesuccinic acid) is a crystaUine, high, melting acid (mp = 167-168) produced commercially by fermentation of carbohydrates (1 4). Itaconic acid is produced in the broth from citric acid (qv). Isolated from the pyrolysis products of citric acid in 1836, this a-substituted acryUc acid received its name by rearrangement of aconitic, the acid from which it is formed by decarboxylation. 

Gilbart, J. Fox, A. Morgan, S. L. Carbohydrate profiling of bacteria by gas chromatography-mass spectrometry Chemical derivatization and analytical pyrolysis. Eur. I. Clin. Microbiol. 1987, 6,715-723. 

D. Fabbri and G. Chiavari, Analytical pyrolysis of carbohydrates in the presence of hexam ethyldisilazane, Anal. Chim. Acta, 449, 271 280 (2001). 

First attempts to combine pyrolysis with in situ HMDS silylation of organic art materials were reported by Chiavari et al., who were successful in obtaining trimethylsilyl derivatives of fatty acids [52], amino acids [53] and carbohydrates [54]. The same authors also applied pyrolysis-silylation to the analysis of different kinds of natural resins and for each of them diagnostic silylated compounds were identified, even if many were difficult to assign precise structures [55],... 

Aldol and -Michael reactions can also proceed on the reaction products of retro-Aldol and -Michael reactions. The reverse (direct) Aldol and Michael reaction can also proceed on various intermediates. Hence, these few reactions can already form a very large variety of possible products. They, indeed, account for most of the reactivity of carbohydrates discussed below, being under pyrolysis, hydrolysis or fermentation conditions. 

Pyrolysis has a long history in the upgrading of biomass. The dry distillation of hardwood was applied in the early 1990s to produce organic intermediates (methanol and acetic acid), charcoal and fuel gas [3]. Today s processes can be tuned to form char, oil and/or gas, all depending on the temperature and reaction time, from 300 °C and hours, to 400-500 °C and seconds-minutes, to >700 °C and a fraction of a second [3, 19, 23, 24], The process is typically carried out under inert atmosphere. We illustrate the basic chemistry of pyrolysis by focusing on the conversion of the carbohydrate components (Fig. 2.4). The reaction of the lignin will not be covered here but should obviously be considered in a real process. Interested readers could consult the literature, e.g., [25]. Pyrolysis is discussed in more details elsewhere in this book [26],... 

As discussed above, the pyrolysis of biomass at high temperature (>1000 °C) results in the formation of synthesis gas, a valuable mixture of CO and H2. The decomposition of carbohydrate to synthesis gas is an endothermic reaction since the heating value of product is —125% of that of the feedstock (Reaction 1). The reaction becomes nearly thermo-neutral upon burning about 1/4 of the products. Since the thermodynamics favors the combustion of H2 over CO, the gasification reaction resemble the theoretical Reaction (2). Indeed numerous gasification processes feed 02 or air to drive the gasification reaction. 

Lignocellulose biomass is a mixture of phenolic lignin and carbohydrates -cellulose and hemi-cellulose. It grows abundantly on earth and is largely available as agricultural and forestry residues. Lignocellulose can be converted via four major routes pyrolysis, gasification, hydrolysis and fermentation. 

The wood pyrolysis is attractive because forest and industrial wood residues can be readily converted into liqtrid products. These liqtrids, as erode bio-oil or slurry of charcoal of water or oil, have advantages in transport, storage, combustion, retrofitting and flexibility in production and marketing (Demirbas, 2007). In the first step of pyrolysis of carbohydrates dehydration occtrrs and at low temperatures dehydration predominates. Dehydration is also known as a char-forming reaction. Between 550 and 675 K volatile products, tar, and char are formed. The volatile products are CO, CO, H O, acetals, furfural, aldehydes and ketones. Levoglucosan is the principle component in tar. 

Over the past two decades, considerable interest has been directed toward the conversion of cellulosic biomass (such materials as wood wastes, bagasse, and straw) into useful products, notably fuels. Several procedures, including fermentation, gasification, liquefaction, and pyrolysis, have been commercially applied to carbohydrates with various degrees of success. In order to use the polysaccharides present in lignocel-lulosic materials as a substrate in fermentation processes, pretreatments are necessary, such as with steam (under slightly acid conditions) or... 

---