Organolead alkalis

Organolead-alkali compounds are the least stable of the group-IVB-alkali compounds. They are thermolabile and air and moisture sensitive but are stabilized in such donor solvents as Et O, tetrahydrofuran (THF) or NHj. Information on their isolation is sparse and no physical properties of pure R PbM (M = alkali metal) or R2PbM2 are available. Nevertheless, RjPbM in situ is a powerful tool for synthesizing unsymmetrical RjPbR tetraorganoleads ... 

Methods of preparing organolead-alkali compounds are reviewed . 

Reactions of organolead-alkali metal compounds with halogenated acetylenes have seldom been used until now 281). 

However, with lead(IV)chloride or alkali metal hexachloroplumbates, considerable lead metal is formed. This has been attributed to the instability of the organolead trihalide, RPbX3, formed initially,... 

Can be used in the flame or flameless mode. In the latter instance, a very low fuel (hydrogen) flow is used to form a plasma around a heated bead of potassium or rubidium salts. This results in a reduced response to hydrocarbons and subsequently less interference. Halogens as well as organolead compounds respond to the NPD detector in the flame mode. Phosphates (from cleaning detergents), chlorinated solvents and silanizing reagents can deplete the alkali beads and should thus be avoided ... 

A from Organolead Halides with Alkali Metals. 

A detailed study has been made456 of the application of the alkali flame detector to organosilicon, organotin and organolead compounds. 

The reaction of alkali acetylides or alkynyl Grignard compounds 124) with organolead halides in liquid NH3 or an organic solvent yields alkynyl-substituted lead compounds. 

Chau et al pointed out that as the authenticity of the compounds to be analyzed must be preserved, any of the digestion methods with acids or alkalis are not suitable, and that extraction seemed to be the method of choice for removing these compounds from samples. For this traction, they adopted benzene as recommended by Sirota and Uthe for the quantitative extraction of tetramethyllead and tetraethyllead from fish homogenates suspended in aqueous EDTA solution. Although ionic forms of lead such as Pb(II), diethyllead dichloride, and trimethyllead acetate do not extract in the benzene phase, any lead compounds that distribute into the benzene phase as tetraalkyllead will be determined. Chau et al421 found that environmental samples can contain other forms of organolead compounds that are extractable into benzene but which are not volatile enough to be analyzed by the GC-AAS technique, hence the need for a speciation specific analytical system. 

Effluents from the manufacture of Pb(CH3)4 can be treated with an alkali metal borohydride, e.g., NaBH4 at pH 8 to 11 to substantially reduce the level of dissolved lead compounds, like [Pb(CH3)3][145, 146]. Zn can also be used [147]. Liquid NH3 and toluene are used to remove solid NH4Clfrom the apparatus for producing Pb(CH3)4 by the NH3- or amine-catalyzed reaction of CH3CI with a PbNa alloy [148]. Stabilization of Pb(CH3)4, and of antiknock fluids containing Pb(CH3)4, is accomplished by addition of compounds, like toluene [149], xylene [141, 150], styrenes [151], naphthalenes [149, 151, 152], anthracenes [152], substituted phenols [141, 152 to 155], olefinic hydrocarbons [152], alcohols [141, 152], amines [155], hydroquinones [156], ethers [141], saturated or unsaturated carboxylic acids [141, 152], esters of phosphoric acid [152], or of sulfuric acid [157], or of sulfonic acids [141], imidazoles [158], alkyl halides and alkyl thiocyanates [141], or tall oil [159] see also Organolead Compounds , Vol. 2, Section 1.1.1.2, to be published. 

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. ... 

The alkali metal tri-organoleads have been widely utilized as synthetic intermediates and their reactions are exemplified in the lithium organoleads. 

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