N-OCTYLPHOSPHONIC ACID

111-83-1

4724-48-5

General procedure for the synthesis of octylphosphonic acid from 1-bromooctane: 2.5 ml of 1-bromooctane was added to a 1000 ml flask, followed by 12.9 g of aluminum trichloride and stirred well at room temperature. The mixture was heated to 85°C and 1.0 mole of triethyl phosphite was slowly added dropwise, controlling the temperature between 85°C and 105°C. The dropwise process lasted for 3.0 hours. Upon completion of the dropwise addition, the reaction temperature was raised to 160 °C, and the reaction was continued at this temperature for 4 hours. At the end of the reaction, the system was cooled to 80°C and 506.0 g of 40% aqueous hydrogen bromide solution was slowly added dropwise for 60 minutes. After the dropwise addition, the system was heated to reflux and the reaction was maintained for 4 hours. Upon completion of the reaction, the aqueous hydrogen bromide solution was removed by atmospheric pressure distillation at 105 °C to recover the hydrogen bromide. Subsequently, 1-bromooctane was distilled at 90 °C under a vacuum of 1.0 kPa. After the system was cooled to room temperature, a mixed solution of n-hexane and water with a volume ratio of 6:1 was added to the reactor, which was thoroughly mixed and transferred to a separatory funnel for liquid-liquid separation. After separation, the lower aqueous phase was recovered, and the upper organic phase was transferred to a flask, and the hexane was removed and recovered by distillation at atmospheric pressure and 85 °C to finally obtain octylphosphonic acid. The yield of the reaction was 95.1% and the chromatographic purity of the product was 98.2% after sampling and analysis.