Chemicals from Renewable Raw Materials

For the last 70 years or so the chemical industry has been based on crude oil (petroleum) and natural gas as basic raw materials, hence the name petrochemicals. This may not be so for much longer, however. The chemical industry is currently on the brink of a new revolution, based on the switch from fossil resources to renewable agriculture-based raw materials. From a distance the production facility of Cargill in Blair, Nebraska looks very much like a small oil refinery or medium-sized petrochemicals plant. However, closer inspection reveals that it is a corn-processing plant a biorefinery producing, inter alia, high-fruc-tose corn syrup, ethanol and lactic acid. As James R. Stoppert, a senior executive of Cargill pointed out, the chemical industry is based on carbon and it does not matter if the carbon was fixed 2 million years ago or 6 months ago [1]. 

The necessity to switch from nonrenewable fossil resources to renewable raw materials, such as carbohydrates and triglycerides derived from biomass, was an important conclusion of the Report of the Club of Rome in 1972 [2]. It should be noted, however, that ca. 80% of the global production of oil is converted to thermal or electrical energy. If the world is facing an oil crisis it is, therefore, an energy crisis rather than a raw materials crisis for the chemical industry. Indeed, there are sufficient reserves of fossil feedstocks to satisfy the needs of the chemical industry for a long time to come. 

Nonetheless, a (partial) switch to renewables is desirable for other reasons, such as biocompatibility, biodegradability and lower toxicity, i.e. renewable raw materials leave a smaller environmental footprint [3]. That the chemical industry has been slow to make the transition, in the three decades following the Report of the Club of Rome, is a consequence of the fact that oil and natural gas are excellent basic feedstocks and highly atom efficient, low waste, catalytic procedures are available for their conversion into commodity chemicals. The same cannot be said for the fine chemicals industry where processes are, generally speaking, much less efficient in many respects and there is considerable room for improvement. 

Products based on renewable raw materials are derived from C02 and HzO via photosynthesis and, following their use, are ultimately returned to the bio- 

Renewable raw materials can contribute to the sustainability of chemical products in two ways (i) by developing greener, biomass-derived products which replace existing oil-based products, e.g. a biodegradable plastic, and (ii) greener processes for the manufacture of existing chemicals from biomass instead of from fossil feedstocks. These conversion processes should, of course, be catalytic in order to maximize atom efficiencies and minimize waste (E factors) but they could be chemo- or biocatalytic, e.g. fermentation [3-5]. Even the chemocatalysts themselves can be derived from biomass, e.g. expanded com starches modified with surface S03H or amine moieties can be used as recyclable solid acid or base catalysts, respectively [6]. 

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Figure 15.5 Building blocks for chemicals from renewable raw materials.

Table 5.1.33 shows the global production of important petrochemical base chemicals and base chemicals from renewable raw materials. The comparison shows that the orders of magnitude are similar. However, the use of renewable raw materials for the production of chemicals and biofuels is limited by the available land area and affects food production, respectively (Figure 5.1.12). Currently, 100 Mio. tonnes of biofuels are, globally, produced per year. This number is huge however, one has to consider that the amount of liquid fuels produced from crude oil (gasoline, kerosene, diesel) is still much larger (about 2500 Mio. ta ). 

Table 5.1.33 Comparison of global production of petrochemical base chemicals and base chemicals from renewable raw materials [data for 2005 from Behr, Agar, and Joerissen (2010) and for 2010 from OECD-FAO (2011) data for natural rubber from Ulber, Sell, and Hirth (2011)].

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