Tetraethyl Lead: Steam-Distilled from the Reaction Mass in Water Brought to pH 7.5 with Dilute Sulphuric Acid (Bake & Parmelee, du Pont, US 2,038,703)

The tetraethyl lead in the reaction mass clings to fine lead particles, in a mass like wet sand that cannot be filtered or poured off. It is driven out with steam. Du Pont found that making the water slightly less alkaline, to pH 7.5, lets almost all of it come over. Result (Ex. 3): only 0.16 % of tetraethyl lead left in the lead sludge, against 8.4 % with plain water. Variable: what goes in the water. Plain water 8.4 % left; 0.2 part Turkey red oil 3.2 %; sulphuric acid to pH 9.3 0.35 %; acetic acid to pH 7.5 0.17 %; ammonium sulphate 0.19 %. Do not go below pH 7.0 (claims). Source: Bake & Parmelee, US 2,038,703 (1936). Not given: how the tetraethyl lead is parted from the condensed water. Danger: tetraethyl lead is a deadly poison, absorbed through skin and from its vapour. Picture drawn by Youblob.