Tetraethyl lead, gasoline additive

An example of dissipation of material resulting in environmental pollution, now a very much diminished problem, was the widespread use of lead in tetraethyl lead antiknock additive in gasoline. The net result of this use was to disperse lead throughout the environment in auto exhaust gas, with no hope of recovery. 

The ratio of anthropogenic emissions to total natural emissions is highest for the atmophilic elements Sn, Cu, Cd, Zn, As, Se, Mo, Hg, and Pb (Lantzy and Mackenzie, 1979). In the case of lead, atmospheric concentrations are primarily the consequence of the combustion of leaded gasoline. For many years, lead was used as a gasoline additive, in the form of an organometal compound, tetraethyl lead. When the fuel was... 

Then he swiftly produced as many different varieties of the compounds as possible, including dimethylzinc, which convinced other scientists to accept Avogadro s theory, a foundation of atomic chemistry and methyl-mercury iodide, the first of many organomercury compounds known to poison people who eat mercury-contaminated fish. Despite his skill at synthesis, Frankland did not discover tetraethyl lead, the gasoline additive that became one of the most important industrial compounds of the mid-twentieth century (Chapter 6). 

Within two decades of the introduction of tetraethyl lead, engine efficiency doubled, power per cylinder tripled, and the octane of regular gasoline rose from 55 to 75. Midgley s gasoline additive symbolized the technological wonders of industrial research and corporate America. Cheap... 

Catalysts were expensive, however, so the petroleum industry did not solve the problem of cheap, lead-free, knock-free gasoline until the 1970s, after General Motors adopted the catalytic converter. Lead compounds inactivate the catalysts, and sophisticated catalytic cracking techniques had to be developed to replace the fuel additive. Ironically, an even more difficult job was finding a substitute for the protective coating that tetraethyl lead formed on exhaust valve seats not even newly developed, extremely hard materials prevent wear and tear on them as well as tetraethyl lead did. 

Motors support for a long-range scientific study of the poisonous gasoline additive, tetraethyl lead. Besides trouble-shooting for various Du Pont departments, Carothers published 60 papers and was listed as the inventor or coinventor of 69 U.S. patent applications during his nine years at Du Pont. Research and development were so new to American corporations that Carothers assistants drafted and he edited patent applications for Du Pont lawyers. You were supposed to be so on top of the literature that you knew whether this was something new or not.. . . Those patents are really classical scientific papers, Hill explained. Carothers considered himself unfit to be a clerk or inventor, but he dominated Du Pont s patent application process for almost a decade. 

Catalysts that decrease reaction rates are usually referred to as inhibitors. They usually act by interfering with the free radical processes involved in chain reactions, and the mechanism differs from that involved in accelerating a reaction. The most familiar example of the use of inhibitors is the addition of tetraethyl lead to gasoline to improve its antiknock properties. 

The design aim of the Hydrocol refinery was to produce abetter than 80% yield of motor gasoline from the Fe-HTFT syncrude at a quality that would be acceptable for the market (MON of 80 after tetraethyl lead addition). The refinery design (Figure 18.2) addressed the issues specific to the Hydrocol Fe-HTFT syncrude ... 

Lead is one of the most common industrial poisons, either in its metallic form and combinations or in the compound known as tetraethyl lead, which until recently was used as a gasoline additive. 

In the past, tetraethyl lead was added to gasoline to slow its burning rate in order to prevent engine knock and increase performance. This caused serious and harmful pollution, and lead has since been eliminated as a gasoline additive in most countries. Most exterior (and some interior) house paints once contained high levels of lead as well. Today, the amount of lead in paint is controlled, with not more than 0.05% allowed in the paint material. 

Tetraethyl lead was the major additive blended into gasolines in the past, and it must be carefully handled because of its high toxicity if it is still used. Sludges from finished gasoline storage tanks can contain large amounts of lead if tetraethyl lead is still used and should not be washed into the wastewater system. 

The efficacy of an additive, such as tetraethyl lead on the octane number of gasoline, shows a concave curve so that the first cubic centimeter of additive would achieve much more than the second cubic centimeter, and the third cubic centimere would do even less. This can also be described by the term diminished return, which is described by d f/dx < 0, which is the characteristic of a function with a diminishing value of df/dx with increase in x. 

Disposal Recycle programs, restore landfill sites Detergents from branched sulfonates to Unear sulfonates refrigerant from CFCs to HFCs gasoline octane additive from tetraethyl lead to oxygenates... 

Lead Tetraethyl (Tetraethyl lead, Lead Tetraethide, Tetraethyl Plumbane). Pb(C2Hs)4, mw 323.45, colorless liq, fr p -136°, bp about 200°, also stated as 227.7° with decompn, d 1.653g/cc at 20° insol in w si sol in ale, sol in benz and eth. May be prepd by die action of Pb chloride on Zn ethyl or on a Grignard reag. Used extensively as an antiknock addition to gasoline, and has been proposed by Fr investigators as a flash reducer in proplnts (Ref 2)... 

---