Iodine → 9-Dodecenoic acid

Participants

Reaction Steps

Methyl 9-dodecenoate (1273 g, 6.00 mol), water (540 mL), and isopropanol (300 mL) were added to a 5 L, 4-neck round-bottom flask at room-temperature. The flask was fitted with an over-head stirrer, condenser, a thermocouple, and an addition flask. Nitrogen was passed through the headspace for thirty-minutes while stirring. Potassium hydroxide (10 M, 660 mL, 6.60 mol) was added drop-wise over thirty-minutes. After stirring for about 45 minutes, an exotherm was observed and the mixture became homogenous. Within the next hour, stirring became impeded by formation of a gel. To re-enable stirring, an additional 300 mL of isopropanol was kneaded into the mixture with a metal spatula. The reaction was monitored by thin layer chromatography (10% EtOAc in hexanes eluent, iodine stain); reaction aliquots were quenched with aqueous hydrochloric acid, washed with water, then taken up in iPrOH. When all starting material had been consumed, the reaction was placed in an ice bath and acidified with 37% aqueous HCl (600 mL) while maintaining a temperature below 40° C. The reaction mixture was transferred into a large separatory funnel and washed with brine (3×250 mL), dried with magnesium sulfate, filtered, and dried in vacuo. The reaction was purified by vacuum distillation to give 9-dodecenoic acid (1054 g, 5.3 mol, 89% yield).

Provenance & Evidence