| 摘要 |
1,208,138. Hydrocarbon-lead compounds. HOUSTON CHEMICAL CORP. 14 Nov., 1967 [14 Nov., 1966], No. 51658/67. Heading C2J. Compounds MR 4 where M is lead (or another group IV metal, e.g. tin) and R is the same or different alkyl, alkenyl or aryl group of 2 or more carbon atoms are made by reacting metal, halide RX and high-purity metallic lithium containing as an impurity above 0À1 wt. per cent of another alkali metal, preferably sodium, there being present at least 4 moles highpurity lithium per mole of metal and sufficient halide to react with the lithium. The reactants may be simultaneously charged to the reaction vessel, or the metal may be added after reaction has been initiated between halide and lithium. The reaction vessel may be cooled during the first, exothermic reaction stage, autogenous conditions being used thereafter, or alternatively the whole reaction may be carried out autogenously. The reaction temperature should be below 60‹ C., preferably below 45‹ C. At least 10% excess of lithium and at least 100% excess of halide can be used, and the impurity content of the lithium can be up to 1 wt. per cent. The metal may be particulate lead of size less than 1 mm., and should contain less than 1000 ppm oxygen. The reaction mixture may include an alkyl ether, tetrahydropyran or tetrahydrofuran to suppress the formation of dimeric compounds. Specified halides RX are EtCl, n-PrCl, i-PrCl, n-BuCl, PhCl, ViCl, ViBr, ViI, t-BuCl, t-BuBr and t-BuI. The examples describe the preparation of tetraethyl-lead, and other compounds are mentioned. |
