Chemicals feedstock

The aromatic hydrocarbons are used mainly as solvents and as feedstock chemicals for chemical processes that produce other valuable chemicals. With regard to cyclical hydrocarbons, the aromatic hydrocarbons are the only compounds discussed. These compounds all have the six-carbon benzene ring as a base, but there are also three-, four-, five-, and seven-carbon rings. These materials will be considered as we examine their occurrence as hazardous materials. After the alkanes, the aromatics are the next most common chemicals shipped and used in commerce. The short-chain olefins (alkenes) such as ethylene and propylene may be shipped in larger quantities because of their use as monomers, but for sheer numbers of different compounds, the aromatics will surpass even the alkanes in number, although not in volume. 

In bioprocesses, the feedstocks required to grow the catalysts and produce the chemical renewable are generally renewable resources, such as sugar from crops. Conversely, purely feedstocks chemical synthesis relies largely on non-renewable resources such as oil, coal and natural gas. It follows that as non-renewable resources dwindle, it is likely that biotechnology will become increasingly important to the chemical industry. 

J. F. Knifton, R. J. Taylor, and P.E. Dai, Diisopropyl ether one-step generation from acetone-rich feedstocks, Chemical Industries (Dekker) 85 Catal. Org. React.) 131-141 (2002). 

In this chapter, all parameters were assumed to be deterministic. However, the current situation of fluctuating petroleum crude oil prices and demands is an indication that markets and industries everywhere are impacted by uncertainties. For example, source and availability of crude oils as the raw material prices of feedstock, chemicals, and commodities production costs and future market demand for finished products will have a direct impact on final decisions. Thus, acknowledging the shortcomings of deterministic models, the next Chapters will consider uncertainties in the design problem. 

The development of new syngas-based processes is one of the objectives for the near future, despite the current low price of oil. Syngas can be produced from various carbonaceous sources, including coal, heavy residue, biomass and gas, the latter being the most economical and abundant feedstock. Chemical valorization of natural or associated gas is a priority objective, since liquefaction of remote gas via alcohol synthesis permits convenient shipping to markets not directly connected to the gas source by pipeline. 

The two-zone plume interception treatment technology is designed to treat chlorinated and nonchlorinated organic compounds in groundwater using a sequence of anaerobic and aerobic conditions. The in situ technology has been applied to aquifers contaminated with benzene, toluene, ethylbenzene, and xylenes (BTEX) petroleum products hydrocarbons coal tar wastes and industrial feedstock chemicals. The technology does not treat metals. 

Batch processing involves loading feedstock chemicals into a process vessel, closing it, and reacting the vessel s contents to the desired final product. At this point, the vessel is emptied, and the entire process is repeated. Continuous processing, as the term implies, involves feeding raw materials to a reactor continuously and yields a continuous stream of desired reaction product. 

The second greener alternative that can resonate with the organic chemistry audience is biomass feedstocks, chemicals that are directly extracted from renewable sources (Tokay 2005). Biomass feedstocks... 

A major issue for biomass as a raw material for industrial product manufacture is variability. Questions of standardisation and specifications will therefore need to be addressed as new biofuels, biomaterials and bioproducts are introduced onto the market. Another major challenge associated with the use of biomass is yield. One approach to improve/modify the properties and/or yield of biomass is to use selective breeding and genetic engineering to develop plant strains that produce greater amounts of desirable feedstocks, chemicals or even compounds that the plant does not naturally produce (Fernando et al., 2006). This essentially transfers part of the biorefining to the plant (see Chapter 2 for some example of oils with modified fatty acid content). 

Buividas, L. J. Finneran, J. A. Quartulli, 0. J., "Alternate Ammonia Feedstock", Chemical Engineering Progress, October 1974. 

The 1963 Nobel Prize in Chemistry was awarded to Karl Ziegler and Giulio Natta for their research on catalysts (see Catalysis) for the oligomerization see Oligomer) and polymerization see Polymerization) of alkenes under mild conditions of temperature and pressure. Their discoveries have grown into a multibillion dollar industry for the production of plastics, elastomers, and inexpensive feedstock chemicals for copolymers, surfactants, and other useM additives. ... 

Many catalytic reactions described in this book depend on carbon monoxide and hydrogen as feedstock chemicals. Hydroformylation (CO + H2) and simple hydrogenation (H2) are typical examples. In many cases carbon monoxide undergoes side reactions, among which the water-gas shift reaction is well studied in terms of the mechanism. This explains why carbon monoxide in the presence of water (e. g., aqueous media) can be used to hydrogenate substrates such as olefins, nitroaromatics, and other unsaturated organic compounds. In a number of industrial processes (e. g., the hydrocarboxylation of ethylene), however, this is an unwanted side reaction. 

York, A.P.E., Claridge, J.B., Brungs, A.J., Tsang, S.C., and Green, M.L.H. Molybdenum and tungsten carbides as catalysts for the conversion of methane to synthesis gas using stoichiometric feedstocks. Chemical Communications, 1997, 39. 

Magnusson, F.S. (1978) Petrochemical Feedstocks, Chemicals and Rubber Program, Office of Basic Industrial Materials Division, Industry and Trade Administration, US Department of Commerce, Washington, DC, November. 

Ilaggin, J., Natural gas assumes growing role in Asia as fuel chemical feedstock, Chemical Engineering News, Aug. 3 7—13 (1992). 

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