Leaded gasoline components

The development of catalytic converters for combustion of unburned hydrocarbons prohibits a return to lead compounds and henceforth refiners are turning to oxygenated compounds that must be used as a gasoline component therefore, in amounts much greater than those of lead compounds. 

The methods most commonly used to detect the major hydrocarbon components of gasoline in environmental samples include GC/FID, GC/MS, HRGC/FID, HRGC/MS, and HRGC/photoionization detector (PID)/FID. GC combined with photoionization-ion mobility spectrometry (PI-IMS) has been used and is selective to aromatic hydrocarbons. See Table 6-2 for a summary of the analytical methods used to determine gasoline in environmental samples. Several of the gasoline components have been discussed in detail in their individual toxicological profiles (e.g., benzene, toluene, xylene, cyclohexane, ethane, ethylene, and lead), which should be constituted for more information on analytical methods. 

Are thermally and chemically stable, it is the major component of leaded gasolines. 

The compositions of fresh catalyst A and of catalyst A used after 70 000 km were analysed by means of an X-ray fluorescence spectrometer. It was identified that the relative content of main components did not change after 70 000 km. Catalyst A after the 70 000 km test was found to contain 0.4% by weight of Pb. It should have been introduced by leaded gasoline. 

Fig.2 shows the lead response, i.e. the increase in Research and Motor Octane Numbers, obtained when different concentrations of either TEL or TLM are added to various typical gasoline components. 

Blending and Additives. In the end, all gasoline components are blended together. At a modern refinery, this is done in a computer-controlled process. Additives are used primarily to boost octane rating. Lead was widely used once but was banned in 1996 in the United States, as well as in many other nations. With the increasing prohibition of methyl-tert-butyl-ether (MTBE) in many U.S. states, use of alternatives such as tertiary amyl methyl ether (TAME) or ethyl tert-butyl ether (ETBE) increased. There are many... 

Dietary components showed major reductions in Pb content over the last several decades, and Pb intakes through the diet obviously track these declines. Dietary Pb intake estimates in earlier decades were poorly recorded. Available data, however, clearly indicate that dietary Pb intakes during the era of leaded gasoline and lead-seamed cans for foods combined... 

Deposits of lead oxide in the exhaust tube and combustion engine shortened the durability of the motor components when leaded gasoline was used. From 1928, therefore, dichloroethane and dibromoethane were added as scavengers to the antilmock fluid, so that the lead oxide formed during combustion was converted to the more volatile lead halogenides (Nickerson 1954). 

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