GB673997A - Improvements in or relating to process for making tetraalkyllead compounds - Google Patents

Abstract

Tetra-alkyl lead compounds are prepared by reacting an alkylating agent with a sodium-magnesium-lead alloy, preferably in the presence of a catalyst, said alloy containing more than 0.2 atom of magnesium for each atom of lead, said alkylating agent comprising one or more esters of inorganic acids having the desired alkyl group attached to the negative radical, and said catalyst being one or more organic compounds selected from the group comprising ethers, cyclic ethers, tertiary amines and substituted ammonium salts. The alloy may have a composition corresponding to NaaMgbPb, in which the sum of a and b is within the limits of approximately 0.5 and 3, and b is more than 0.2 and less than 3. When a catalyst is employed, the alloy may contain from 5 to 25 per cent by weight of sodium plus magnesium and at least 2.5 per cent by weight of magnesium. When a catalyst is not employed, the alloy may contain from 5 to 20 per cent by weight of sodium plus magnesium and more than 3 per cent by weight of magnesium. The reaction may be conducted at a temperature between 50 DEG and 100 DEG C. for a time between 1\2 and 8 hours or at a temperature between 60 DEG and 85 DEG C. for a time between about 1 to 5 hours. Suitable catalysts mentioned are diethyl, methylethyl, dipropyl, dibutyl and dihexyl ethers, dimethyl ether of ethylene glycol, 1,4-dioxane, anisole, tetraethyl- and trimethylethyl-ammonium iodide, triethyl- and trimethyl-amine and dimethylaniline. Suitable alkylating agents mentioned are the monochloro, -bromo and -iodo derivatives of the paraffin hydrocarbons such as methane, ethane, propane, butane and pentane, and the corresponding trialkylphosphates, e.g. methyl bromide and iodide, ethyl chloride, bromide and iodide, n-propyl chloride, n-butyl bromide, n-amyl chloride and iodide and triethyl phosphate. In the examples, tetraethyl lead is prepared.