Biomass-derived materials

The glow electrolysis technique (electrolysis with an anode immersed in the solution and the cathode above the surface) at 600-800 V dc and 300-500 mA converts a solution of starch into ethylene, methane, hydrogen, and both carbon mono- and dioxides.323 Electrochemical methods for converting polysaccharides and other biomass-derived materials have been reviewed briefly by Baizer.324 These methods are mainly oxidations along a potential gradient, which decreases the activation energy of the reactants. Starch in 5 M NaOH solution is oxidized on platinum electrodes to carboxylic acids with an activation energy of about 10 kcal/mol. In acidic media oxidation takes place at C-l followed by decarboxylation and oxidation at the C-2 and C-6 atoms.325... 

As illustrated in Fig. 33.14, biomass feedstocks can vary widely in the number of constituents and the concentration of each constituent. In biomass conversion processes, up to 20 constituents may need to be monitored to characterize the conversion of feedstock into a desired product or products. Standard wet chemical methods for the chemical characterization of biomass feedstocks and biomass-derived materials have been validated through the International Energy Agency and are available from the American Society for Testing and... 

Materials (ASTM).94 In addition, the National Renewable Energy Laboratory95 (NREL) has developed and validated a collection of standard laboratory analytical procedures specifically for the compositional analysis of biomass including, but going beyond those of the ASTM. These wet chemical methods of analysis are based on the fractionation of the biomass sample and the isolation of purified fractions that can be quantified using conventional analytical instruments.96 These methods are primarily used in feedstock-specific portfolios containing analysis methods for each of the relevant constituents. In most cases, these portfolios enable the identification and quantification of greater than 95 percent of the dry mass of biomass feedstock and biomass-derived materials. 

Fisher, T., Hajaligol, M., Waymack, B., and Kellogg, D., Pyrolysis behavior and kinetics of biomass derived materials. J Analytical Appl Pyrolysis 2002,62 (2), 331-349. 

Chum HL, Ratcliff, Schroeder HA, Sopher DW (1984) Electrochemistry of biomass-derived materials Characterization, fractionation, and reductive electrolysis of ethanol extracted explosively depressurized aspen lignin J Wood Chem Technol 4 505-532 Compton DAC, Young JR, Kollar RG, Mooney JR, Grasselh JG (1987) In McClure GL (ed) Computerized quantitative infrared analysis ASTM, Philadelphia, 36-57 Cooley JW, Tukey JW (1965) An algorithm for the machine calculation of complex Fourier series Math Comput 19 297-301... 

Chum HL, Ratcliff M, Schroeder HA, Sopher DW (1984)Electrochemistry of biomass-derived materials. I. Characterization, fractionation, and reductive electrolysis of ethanol-extracted explosively depressurized aspen lignin. J Wood Chem Technol 4 505-532... 

ABSTRACT The volatility of tars from pyrolysis of biomass and biomass-derived materials is of special interest. This interest is related to the question whether or not biomass tar evaporation has a significant effect on the total rate escape of tar from pyrolyzing substance and therefore on pyrolysis kinetics. In fact, in many practical applications (especially in fossil fuel thermal conversion processes), tar vaporization is known to be an important step during pyrolysis that influences both yield and composition of pyrolysis products. 

Typically, a biomass-derived material contains substances constituted by carbon, hydrogen and oxygen atoms. As an example, the simplified not balanced chemical equation representative of the overall gasification process for a reference substance such as glucose is ... 

Companies currently utilizing or producing biomass or biomass-derived materials and products (e.g., paper, lumber, food, and distilled spirits) are attempting to recover and use greater amounts of the resources and byproducts available to them to reduce costs, develop new products, and produce energy. 

Needless to say, solid acid and base catalysts play a key role in the transformation of biomass-derived materials to value-added compounds such as carbonyl compounds [21-33]. For example, lactic acid could be obtained from cellulose using tungstated alumina as a Lewis add catalyst [137], and from glucose using HT as a solid base catalyst [138]. In this parL selective conversions of biomass-sourced materials using solid acid and base catalysts are surveyed alongside mechanistic considerations. 

Large-scale biomass production will come at a considerable cost to the society. We have already given an order of magnitude estimate for wood plantations. When biomass raw material is processed that competes with the food chain, as vegetable oils and sugars, the situation is even worse. For instance Smil [4] mentions that if the US vehicles were to run solely on corn derived ethanol the country would have to plant corn on an area 20% larger than is currently cropland . 

As discussed in this book (Chapter 2, for example) a main difference between fossil fuels and biomass as feedstocks is that in the former case the functionalization of base chemicals obtained from the oil (ethylene, propylene, aromatics, etc.) occurs essentially by introduction of heteroatoms, while in the case of biomass-derived based chemicals (glycerol, for example) it is necessary to eliminate heteroatoms (oxygen, in particular). Consequently, the catalysts required to develop a petrochemistry based on bio-derived raw materials need to be discovered and cannot simply be translated from existing ones, even if the knowledge accumulated over many years will make this discovery process much faster than that involved in developing the petrochemical catalytic routes. 

A thorough analysis of value chains and the development of alternative value chains starting from biomass derived feedstocks, including assessment of the economic viability of the transformation of the chains, is required. This should be followed by the identification of easy entry points for the implementation of novel value chains. Technical key issues are generic methods to cope with the variability of raw materials derived from biomass and higher susceptibility to contamination by microorganisms and suitable catalysts for biorefineries. 

Development of novel synthetic routes for efficient conversion of biomass derived raw materials with high performance, stability and selectivity, by integrating bio-, chemical and catalytic processes. Synthetic pathways in which the complexity needed in a target molecule is already preformed in the biomolecule are especially favorable. 

The strategy for the development of products from biomass needs to be twofold. One approach is to identify those opportunities where we can compete economically with existing petrochemical products. Succinic acid-derived materials fit into this category (Fig. 1). The second approach must include the identification of products with novel functionality that cannot easily or cost effectively be derived from petrochemical building blocks. The challenge with developing new materials is that the market for these products must also be developed and the time and cost can be significant however, the reward may also be substantial. 

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