BTX organic chemicals

Cyclic Hydrocarbons. The cyclic hydrocarbon intermediates are derived principally from petroleum and natural gas, though small amounts are derived from coal. Most cycHc intermediates are used in the manufacture of more advanced synthetic organic chemicals and finished products such as dyes, medicinal chemicals, elastomers, pesticides, and plastics and resins. Table 6 details the production and sales of cycHc intermediates in 1991. Benzene (qv) is the largest volume aromatic compound used in the chemical industry. It is extracted from catalytic reformates in refineries, and is produced by the dealkylation of toluene (qv) (see also BTX Processing). 

Thus, the building blocks for synthesis of commodity organic chemicals— synthesis gas, the light olefins ethylene, propylene, and butadiene, and BTX— can be obtained from biomass feedstocks by thermochemical conversion. 

Thermal cracking of ethane, propane, butane, naphthas, gas oils, and/or vacuum gas oils is the main process employed for the production of ethylene and propylene butadiene and benzene, toluene, and xylenes (BTX) are also produced. Thermal cracking of these hydrocarbons is also called pyrolysis of hydrocarbons. Ethylene is the organic chemical produced worldwide in the largest amoimts and has been called keystone to the petrochemical industry. This technology is well documented in the literature. Somewhat similar thermal cracking processes are used to produce vinyl chloride monomer (VCM) from ethylene dichloride (EDQ, styrene from ethylbenzene, and allyl chloride from propylene dichloride (PDC). Production of charcoal and coke from wood and coal is actually a pyrolysis process, but it is not discussed here. 

BTX are chemically reduced compounds, thus, their biologic oxidation is thermodynamically favored (Table 7). Many biological attempts have been conducted in order to remove these volatile organic compounds from the environment. Aerobic treatments have been widely proposed for BTX elimination (Duetz et al, 1994 Haigler et al., 1992 Rozkov et al., 1998 Yerushalmi et al., 1999). Removal of BTX mixtures appeared to be favored at aerobic conditions (Deeb Alvarez-Cohen, 1999 Prenafeta-Boldu et al., 2002) however, negative effects such as inhibition or catabolic repression have also been reported at these conditions... 

Commodities are large-volume, low-price, homogeneous, and standardized chemicals produced in dedicated plants and used for a large variety of applications. Prices are cyclic and fully transparent. Petrochemicals, basic chemicals, heavy organic and inorganic chemicals (large-volume) monomers, commodity fibers, and plastics are all part of commodities. Typical examples of single products are ethylene, propylene, caprolactame, methanol, BTX (benzene, toluene, xylenes), phthalic anhydride, poly (vinyl chloride) soda, and sulfuric acid. 

At the end of each of the previous chapters there are pertinent references that cite the origin of an idea or an incident. This final chapter is dedicated to providing a list of b(X)ks. btx)klets, technical articles, organizations, web site addresses, and other resources that are essential to consider when developing or improving a Chemical PrcKess Safety Program. Many of the references listed can supply, in turn, large numbers of additional references. 

Both DMSO and sulfolane are extensively used in the chemical, pharmaceutical, polymer, and electronics industries as polar aprotic solvents, with unique properties such as a high dielectric constant, high polarity, and high miscibility with organic and aqueous materials. For example, sulfolane finds use in the refining industry for the separation of benzene, toluene, and xylene (BTX) fractions from paraffins. 

Steamcracking produces the primary chemicals which are at the basis of nearly all the large-scale industrial organic chemistry of today, from crude oil fractions, mainly ethane, propane, naphtha, obtained during oil refining alkenes (C2H4, C3H, C Hg), butadiene (C4H ), benzene, toluene, xylenes (BTX), as well as small quantities of petrol are obtained. 

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