WANKLl?N AND SCHENE’S SYNTHESIS OF CAPROIC ACID. 31 IV.-Synthesis of Caproic Acid. By J. ALFREDWANKLYN and ROBXRTSCHENK. CARBONIC acid attacks sodium-ethyl and sodium-methyl forming propionate and acetate of soda respectively. It seemed to 32 WANKLYN AND SCHENK'S SYNTHESIS OF CAPROIC ACID. us to be desirable to obtain a parallel reaction higher up in the series. We have selected the amylic group for this purpose. Mercury-amyl was prepared by the process of Frankland and Dupp a from iodide of aniyl and dilute sodium-amalgam a little awtic ether being added in order to effect the reaction. An analysis of the mercury-amyl gave the following result proving the purity of the substance :-0.3584 pn. taken gave 0.2082 grm. of metallic mercury.Found.. .... Hg per cent. = 58-09 Theory .... Hg per cent. = 58-50 From tliis mercury-amyl we prepared zinc-amyl by digesting it with zinc as recommended by Frankland and Duppa. The zinc-amyl was then sealed up with metallic sodium and heated in the water-bath. Under these circumstances there was formation of sodium-amyl and precipitation of zinc. On leading in carbonic acid gas there was evolution of heat just as in the case of the ethyl or methyl compounds. When the reaction was over water was aclcled and the resulting dution of soda-salt evaporated to dryness in the water-bath. The residue distilled with dilute sulphuric acid gave off an oily liquid having the smell of caproic acid. This oily distillate was dissolved in baryta-water and formed a baryta-salt. About 3 grm. of baryta-salt was made. A barium determination was made 011 the dry salt. 0.2656 grm. gave 0.1697 grm. of sulphate of baryta. Ba per cent. = 37.56. Theory reqnires Ba per cent. = 37-33. A silver-salt was also inade and analysed. 0.0614 grm. gave 0.0298 grm. of silver. Found.. .... Ag per cent. = 48.53 Theory .... Bg per cent. = 48.43 The action of carbonic acid on sodium-amyl is expressed by the following equation :-London Institution 1867.