Fossilized carbon sources

Figure 2.4.4 (A) Time-dependent electric current generated from the oxidation of HTC coal in an indirect carbon fuel cell. Solutions of Fe 111 and Vv were prepared in 0.5 mol L 1 H2SO4. (B) Development of open-circuit potential Eoc (up) and current I (down) due to Fe2+ formation in the anodic half-cell via oxidation of HTC coal, indicating the reducing potential of bare hydrothermal carbon (HC) dispersions. Charge equalization between the two half-cells was assured by a salt bridge containing a saturated KC1 solution. Carbon felt was used as electrodes. (C) Comparison of hydrothermal and fossil carbon sources in the same setup.

The 50 largest-volume chemicals contain many derived from fossil carbon sources. Their 1995 volumes in billions of pounds produced in the United States4 are ethylene (46.97), ammonia (35.60), propylene (25.69), methyl tert-butyl ether (17.62), ethylene dichloride (17.26), nitric acid (17.24), ammonium nitrate (15.99), benzene (15.97), urea (15.59), vinyl chloride (14.98), ethylbenzene (13.66), styrene (11.39), methanol (11.29), carbon dioxide (10.89), xylene (9.37), formaldehyde (8.11), terephthalic acid (7.95), ethylene oxide (7.62), toluene (6.73), p-xylene (6.34), cumene (5.63), ethylene glycol (5.23), acetic acid... 

Compound-specific A C values for 31 different lipid biomarker molecules are shown in Figure 8 for sedimentary horizons corresponding to pre-bomb (before ad 1950) and post-bomb (1950-1996) eras. These organic compounds represent phytoplank-tonic, zooplanktonic, bacterial, archaeal, terrestrial higher plant, and fossil carbon sources. The lipid classes include long-chain n-alkanes, alkanoic (fatty) acids, -alcohols, C30 mid-chain ketols and diols, sterols, hopanols, and C40 isoprenoid side chains of the ether-linked glycerols of the Archaea. 

In the chemical products sector bio-based raw materials are the only renewable alternative to replace fossil carbon sources. In some chemical product categories like, for example, detergents, renewable resources already make up a large share of the raw materials used due to their superior suitability and functionality. In the major chemical product category (with respect to the annually produced amount) of plastics, however, renewable resources still play a very small role. Nonetheless, steadily increasing numbers of bio-based polymers and products have been developed in recent years. The number of scientific papers on this topic is still growing rapidly while it remains at a constant level for traditional fossil-based polymeric materials. 

The first macromolecular substances which fotmd technical interest were based on chemically modified natural materials, for example cellulose nitrate (Celluloid) or crosslinked casein (Galalith). Only with the onset of industrialisation in the nineteenth century did these renewable raw materials become the limiting factor for further growth, and chemists began developing artificial macromolecules based on fossil carbon sources like coal, oil, and gas. Polymers like condensation products from phenol and formaldehyde (Bakelite) started the plastics age in 1910 and polymers of styrene or vinyl chloride were used since about 1930 and until nowadays as important plastics. Presently, worldwide more than 260 million tons polymers per year are produced and used as plastics, films, fibres, and synthetic rubber. 

Feedstocks Fossil carbon sources (e.g., natural gas, natural gas liquids, oil, coal)... 

In spite of the nearly universal acceptability of the chemicals mentioned above as very important intermediate species to obtain various commodity chemicals and products from biomass, it has been stated (Farmer and Mascal, 2014) that no consensus actually exists about the name by which these biomass-derived species should be called. We shall call these chemical species "bio-based platform molecules" following Farmer and Mascal s book chapter from which we also quote their definition. "A bio-based (or bio-derived) platform molecule is a chemical compoxmd whose constituent elements originate wholly from biomass (material of biological origin, excluding fossil carbon sources), and that can be utilized as a building block for the production of other chemicals."... 

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