Organolead hydroxides

S.8.6.3. from Organolead Hydroxides and Other Organolead Salts. 

Until recently only a few compounds possessing a Pb—N bond have been known [review up to 1963 (174)], mainly imido and sulfonamido compounds which were prepared by reacting the acidic N—H compounds with organolead hydroxides or oxides (Table XIII), i.e.. 

During the Second World War a number of triorganolead-substituted sulfonamides, phthalimides, and a sulfimide were prepared and tested as potential sternutators 111, 112,113). The methods of preparation included the reaction of triethyl- or tripropyllead chloride with the sodium derivative of a sulfonamide, and the reaction between triethyl- or tripropyllead hydroxide and a sulfonamide. Both reactions were generally carried out in ethanol, and the product was precipitated by the addition of water. This demonstrates the hydrolytic stability of these compounds. The phthalimides and the sulfimide were prepared from the organolead hydroxides. They show the same high hydrol)rtic stability. 

A number of heterocyclic products have been formed from reaction of tri-organolead hydroxide with the appropriate heterocyclic compoimd. WUlemsens reported pentacoordinated compoimds (23) for some of these products. This is probably not the true structure. The formation of oligomeric and polymeric intermediates has been suggested from the disproporationation reactions of hexaethyldilead producing products (24). Sidgwick reported the formation of pliunboxanes from diaryllead dihydroxides, shown as 25 (eq. 7). Kochkin et al. reported the... 

IV Reactions with organolead hydroxides, alkoxides and carboxylates ... 

III Exchange reactions with organolead hydroxides and alkoxldes ... 

This reaction is not useful for preparing trialkyllead(IV) alkoxides because the organolead oxides or hydroxides are less readily available, and decarboxylation is more difficult, but phenylmercury(II) alkoxides can be made in similar way from phenylmer-cury(II) hydroxide or oxide ... 

Lead enters surface water from atmospheric fallout, run-off, or wastewater. Little lead is transferred from natural minerals or leached from soil. Pb ", the stable ionic species of lead, forms complexes of low solubility with major anions in the natural environment such as the hydroxide, carbonate, sulfide, and sulfate ions, which limit solubility. Organolead complexes are formed with humic materials, which maintain lead in a bound form even at low pH. Lead is effectively removed from the water column to the sediment by adsorption to organic matter and clay minerals, precipitation as insoluble salt (the carbonate, sulfate, or sulfide) and reaction with hydrous iron, aluminum, and manganese oxides. Lead does not appear to bioconcentrate significantly in fish but does in some shellfish such as mussels. When released to the atmosphere, lead will generally occur as particulate matter and will be subject to gravitational settling. Transformation to oxides and carbonates may also occur. 

Metallic lead is soft, bluish white, highly malleable, and ductile. It is a poor conductor of heat and electricity and resistant to corrosion. A protective film of basic carbonate is formed on the surface of lead exposed to moist air. Lead reacts with water in the presence of air to form lead hydroxide. Inorganic Pb(II) compounds are mainly insoluble or slightly soluble in water. Exceptions are lead chlorate, perchlorate, nitrate, and acetate. Lead chloride is moderately soluble (9.9 g/liter at 20°C). The most important organolead compounds are tetramethyllead and tetraethyllead used as antiknock additives in fuel. Both are colorless liquids at room temperature with boiling points 110 and 200°C, respectively. Photolytically these degrade to RaPb , R2Pb , and Pb. The different chemical forms of lead have different toxicity, so that speciation information is important [1,2]. 

In addition to organotin compounds, the survey work [199] mentions organolead compounds, recommended as stabilizers of chlorine-containing high-molecular compounds - hydroxides of triallqrl- and tri-aryllead, allq/ 1- and aryllead salts of aliphatic acids, and triethyllead hexylmaleate. Alkyl- and arylplumbanes have not foimd wide use in the plastics industry on account of their high toxicity. 

A. Preparation and Reactivity of Organolead Oxides, Hydroxides, and Alkoxides. ... 

In some cases organolead halides can be used instead of the hydroxides or oxides, mainly if the hydrochloric acid formed is neutralized by an excess of amine 239, 243). 

Table 10 contains examples of some representative organolead halides. The fluorides are best prepared by the action of alkali fluorides upon organolead halides, or hydrogen fluoride upon alkyl-lead hydroxides. ... 

Under suitable conditions the action of sodium upon the organometallic lead halides produces a Wurtz type of reaction and the formation of the hexa-organodileads. The tri-organolead chlorides are reduced to the hexa-organodileads by aluminium in dilute potassium hydroxide solution2i3. 

II Neutralization reaction of organolead oxide and hydroxide RgPbO and R3PbOH with ... 

The organolead oxides and hydroxides in Table 285 are prepared by the following methods. 

Listing of organolead oxides and hydroxides continues in Table 285. 

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