Hexadecane-1 : 16-dicarboxylic acid

Reflux 6 8 g. of the dimethyl ester with a solution of 3 2 g. of sodium hydroxide in 150 ml. of 80 per cent, methanol for 2 hours on a water bath. When cold, filter oflF the solid and wash it with a little cold methanol. Dissolve the solid in 350 ml. of warm water, add concentrated hydrochloric acid to the solution at 60° until acidic to litmus, filter off the precipitated acid, wash with a little water and dry at 100°. The resulting hexadecane-1 16 dicarboxylic acid, m.p. 122°, weighs 5-3 g. Recrystallisation from absolute methanol raises the m.p. to 124 -5°. 

An excellent synthesis of myristic acid is thus achieved from readily accessible starting materials. An alternative synthesis of myristic acid utilises hexanolc acid (M-caproic acid n-hexolc acid) (X) (2 mols) and methyl hydrogen sebacate (XI) (1 mol) the products, after hydrolysis, are n-decane (XII), myristic acid (XIII) and hexadecane-1 16-dicarboxylic acid (XIV) ... 

Hexadecane-1 16-dicarboxylic acid. Dissolve 31 5 g. of methyl hydrogen sebacate in 140 ml. of absolute methanol to which 0-4 g. of sodium has been added. Electrolyse at 2-0 amps, until the pH of the electrolyte is 7-8-8-0 (3-5-4 hours). Work up as described for Sebacic acid. Upon distillation, an unsaturated ester passes over at 111-113°/ 20 mm. (4-6 g.), followed by dimethyl hexadecane-1 16-dicarboxylateat 212-219°/4 mm. (mainly at 214-215°/4 mm.), m.p. 56° (16-5 g.). 

Height equivalent per theoretical plate (H.E.T.P.), 95 n-Heptaldehyde, 251 n-Heptaldoxime, 348 n-Heptane, 238 1-Heptene, 240 n-Heptoic acid, 354, 356 n-Heptoic anhydride, 371, 374 n-Heptyl alcohol, 247, 251 n-Heptylamine, 413, 418 n-Heptyl chloride, 275 n-Heptyl iodide, 288 n-Hexacosane, 938, 941 Hexadecane-1 16-dicarboxylic acid, 938,940... 

---