H4 PRACTICAL ORGANIC CHEMISTRY using a Buchner funnel. Evaporate the clear filtrate by direct boiling in a beaker until crystals appear on the surface, and then allow to cool, finally chilling in ice-water. The lead formate separates as colourless crystals; filter off, wash with a small quan-tity of cold water, and dry. Yield, about 6 g. A considerable amount of the formic acid, however, still remains behind in the distilling-flask as the unhydrolysed mono-formate. Therefore, if time allows, dilute the residue in the flask with about an equal volume of water, and then steam-distil, the monoformate ester being thus completely hydrolysed and the formic acid then driven over in the steam. Collect about 400 ml. of distillate. Add this distillate to that obtained by direct heating of the reaction mixture and then treat with lead carbonate as described above. Total yield of lead formate is now about 40 g. Lead formate is only slightly soluble in cold water, and insoluble in
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