Chemical Reactions of Tetraethyllead

Abstract

This report gives a compilation of the periodical and patent literature on the known chemical reactions of tetraethyllead (TEL). These are by no means con fined to antioxidant and antiknock effects. Of par ticular interest are those reactions wherein ethyl radicals, liberated from TEL by photolysis or pyrolysis, induce the polymerization, chlorination, or oxidation of other compounds. Many different diethyl-and triethyllead salts are readily obtained from the parent compound. TEL is used to prepare other organome tallic compounds, and its reaction with heavy metal chlorides produces Ziegler-type catalysts for the polymerization of olefins. In view of its ready avail ability, these relatively unexplored end uses for TEL constitute an area of considerable research potential.Tetraethyllead-commonly abbreviated to TEL-is the outstanding example of the simple or R n M type of organometallic compound of moderate chemical reactivity. It has been known for over 100 years, as it was one of the first of these compounds to be isolated, and it is now unique in industrial importance. As a consequence, the reac tions of TEL have been widely investigated. However, there still remain many oppor tunities for worthwhile research in this field.The chemistry of organolead compounds in general has often been reviewed (58,113,120), notably by Calingaert (17), Krause (82), and most recently Gilman (45,83) and their coworkers: men who have contributed much of the important ex perimental work on the subject. Reviews in particular have been made by German and Russian workers (81, 131), but these are not readily accessible and are now out of date.Considering the variety of chemical reactions into which TEL can enter, and its ready availability at a relatively low cost, there may well be good use for the follow ing compilation of the available information on these reactions. PhotolysisTEL is readily dissociated by light. The vapor shows continuous absorption in the ultraviolet with the formation of metallic lead and ethyl radicals, the latter being detected by the Paneth method (33, 103, 124) · Maximum absorption occurs at about 306

New Rare Earth Antiknock Additives that are Potential Substitutes for Tetraethyl Lead

“…This is 431 times the solubility of Pr(thd) 3 under the same conditions, the value determined for Pr(thd) 3 being 0.118 grams per liter (0.447 grams per U.S. gallon).…”

“…Nevertheless, the ability of the additives to function in ASTM 80 PRF provides much valuable information. The efficacy of the mixed rare earths, tested as RE(thd) 3 , 4 , was demonstrated.…”

“…distilled H20. A quantity of mixed Ln(thd) 3 precipitated from solution initially. Approximately 500 c.c.…”

“…In the next test, 20-ml saturated solutions of Pr(thd) 3 were prepared using isooctane and Pb-free Amoco premium gasoline. A quantity of Pr(thd) 3 equal to that required to form the respective saturated solutions was then added to each.…”

The Rise and Fall of Tetraethyllead. 2.

“…70 The volatility of tetraethyllead and its ready thermal decomposition to lead and organic products, factors important in its use as an antiknock agent in the gasoline engine, have also been useful in its application as a lead source in chemical vapor deposition of leadcontaining solid films for ferroelectric applications. Thus, films of lead titanate, PbTiO 3 , were prepared using a vapor reactant system of (C 2 H 5 ) 4 74 And now, toward the end, we come full circle and return to the beginning: to the discovery of the first organolead compounds by Carl Löwig in 1853.…”