Lead compounds tetra-alkyls

Carbon disulphide methanol phenol n-hexane methyl n-butyl ketone organophosphorus compounds tetra-alkyl lead compounds. 

Air Lead Five tetra-alkyl lead compounds GC eluent introduced into flame-heated ceramic tube placed in light path. H2 introduced prior to tube to give diffusion flame 0.25mgPbmr3 Hewitt and Harrison (1985)... 

Tetra-alkyl lead compounds in air Personal monitoring with atomic absorption analysis or electrothermal atomization or X-ray fluorescence spectrometry or on-site colorimetry 9... 

MDHS 9 Tetra alkyl lead compounds m air (personal monitonng)... 

MDHS 14 General method for the gravimetric determination of respirable and total dust MDHS 15 Carbon disulphide MDHS 16 Mercury vapour in air Laboratory method using hopcalite adsorbent tubes, and acid dissolution with cold vapour atomic absorption spectrometric analysis MDHS 17 Benzene in air Laboratory method using charcoal adsorbent tubes, solvent desorption and gas chromatography MDHS 18 Tetra alkyl lead compounds in air Continuous on-site monitoring method using PAC Check atomic absorption spirometry... 

MDHS9 Tetra alkyl lead compounds in air (personal monitoring). 

Conversion to tetra-alkyl lead compounds using nBu MgCI then gas chromatography with atomic absorption spectrometric detector Petroleum ether extraction, glc... 

Forsyth, D.S. and Iyengar, J.R. (1989) The determination of tetra-alkyl lead and ionic alkyl lead compounds in seafood. Appl. Organomet. Chem., 3, 211-218. 

The effectiveness of lead tetra-alkyls can be degraded by the presence of sulphur compounds and enhanced by certain organic co-anti-knocks. Graiff [44] has shown that the latter effect is due to the formation of different forms of lead monoxide (red and yellow), with different catalytic activities [39]. The co-anti-knocks may be carboxylic acids or esters like r-butyl acetate [45] but, surprisingly, r-butyl and cumene hydroperoxides also work as co-anti-knocks with lead [44]. That is, when added to leaded... 

Table XIII. of the Appendix gives a list of compounds prepared by the following general method, together with their physical constants, Three times the ealeulated quantity of magnesium alkyl halide is used, and after the introduction of the tin alkyl halides the mixture is boiled under reilux for two hours, the etlier removed, and the residue baked on the water-buth lor one liour. After cooling, ether is added, and the whole deosed with water. Mixed tin tetra-alkyls are converted into inixed tin trialkyl bromides of the type R R SnX by the action of bromine at - 40° to —30° C., ati alkyl group being split out, this resembling the bromination of lead alkyls.

Lead tetra-alkyls containing one or two secondary radicles can easily be obtained by the action of lead alkyl mono- or dihalides on secondary magnesium alkyl halides, win 1st those containing three secondary radicles are derived ] )rimaril,y from the tctra-alkyls. Table XX. of the Appendix gives a list of these compounds, together with their physical constants. 

Aryl Azo Compounds. Alkyl- (including tert-butyl) and aryllithium reagents add to azo benzene to give trisubstituted hydrazines in fair to excellent yields (see Eqs. 44 and 45) alkylation of the intermediate anion in situ leads to tetra-substituted hydrazines.211 Benzyl and heteroarylmethyl (see Eq. 54) anions and the enolate of phenylacetamide add to azo benzene in fair to excellent yields.212 Aromatic Grignard reagents are reported to reduce azo benzene and its derivatives to the hydrazo compounds (cf. also Eq. 20).213 The only other aryl azo compound investigated in animations appears to be benzo[c]cinnoline.214... 

Active electrocatalyst forming soluble species whose utilization is likely for the electroformation of organometallic compounds or low-chained polymers. One typical example is the industrial preparation of tetra-alkyl-lead through the electrooxidation of the Grignard reactant on bed-leached anodes [24,25],... 

The interfacing of the eluant from an HPLC column to a flame AAS has been achieved by matching the eluant flow-rate of approximately 1 ml min to the intake rate of the nebuliser. Five tetra alkyl lead compounds were analysed on a reverse phase Cjg column using acetonitrile/water mobile phase directly connected to the inlet capillary of the AAS nebuliser [29]. Each compound was detected at the 10 ng level. 

The halides BX3 (X = Cl or Br) react with tetra-alkyl-lead (alkyl = Me or Et) to give the series of organohalogenoboranes R, BX3 (m = 1—3). I.r. and Raman data for these species, and for the fluoro-analogues, have been listed and assigned, as were those for PI1BX2 (X = F, Q, or Br). A number of compounds RBXY could be detected spectroscopically in mijctures of the simple halogeno-derivatives. ... 

He3wood, R., James, R. W., Sortwell, R. J., Prentice, D. E. and Bariy, P. S. 1. (1978). The intravenous toxicity of tetra-alkyl lead compounds in rhesus monkeys. Toxicol Lett. 2 187-197. 

Lead.— Tetra-alkyl-lead and tetra-alkyltin compounds react with hydrochloric acid in methanol or methanol-benzene mixtures thus ... 

Discussions. The analysis of tetra-alkyl lead compounds and their significance... 

Robinson, J. W., The Analysis of Tetra-Alkyl Lead Compounds and Their Significance as Urban Air Pollutants, Atmos. Environ. 12 [1978] 957 Harrison, R. M., Perry, R., Author s Reply, Atmos. Environ. 12 [1978] 957/8. 

The action of N2O4 on lead tetra-alkyls produces the compounds formulated as [R4Pb(N0)2](N03)2, in which the octahedral complex ion [R4Pb(NO)2]2+ is believed present. Although the stoichiometry of this series of compounds is well established, the structural formulation seems very dubious>J . 

Lead.— An analysis of kinetic parameters and standard free energies of transfer of the reactants for the reaction of tetra-alkyl-lead compounds with iodine suggests that the charge separation in the transition state for this iS E2... 

Other Approaches.— The determination of both kinetic and solubility data can, in favourable systems, permit the separation of solvent effects on reactivities into initial-state and transition-state components. Some interesting mechanistic conclusions have been drawn from such experiments on reactions of tetra-alkyltin compounds with mercury(n) halides and on Menschutkin reactions of primary amines with alkyl halides. In the former case solvent effects on both initial and transition states are important in determining reactivities, whereas in the latter case solvent effects on initial states are of predominant importance. This approach to the diagnosis of reaction mechanisms has been discussed and fully referenced in pp. 112—113 of Volume 1 and pp. Ill—112 of Volume 2 of this Report. A similar treatment of the reactions of tetra-alkyl-lead compounds with iodine, in a range of ten solvents, has recently indicated that solvent effects on both the initial and transition states are important factors in determining rates here, as for the tetra-alkyltin reactions mentioned above. ... 

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