4724-48-5

1-Octylphosphonic acid is a basic building block and used in the preparation of various pharmaceutical compounds and chemical products. It is supported with calcium hydroxyapatite and used in the dental field as corrosion inhibitor and organic building block. It acts as a corrosion inhibitor in metallic household surfaces such as faucets and drains as well as prevents the rusting of can or dispenser. It is also used in the synthesis of octyl-phosphonic acid dimethyl ester by reacting with iodomethane in presence of CS2 CO3.

Octylphosphonic acid (OPA) forms a self-assembled monolayer (SAM), which serves as a protective anti-corrosive phosphonate layer on a variety of surfaces.

Nonflammable

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.

[1] Patent: CN105153224, 2017, B. Location in patent: Paragraph 0025; 0026; 0027; 0028; 0029; 0030; 0031-0036
[2] Journal of the American Chemical Society, 1945, vol. 67, p. 1182
[3] Patent: US2397422, 1945,
[4] Journal of Organic Chemistry, 1960, vol. 25, p. 1000 - 1006
[5] Patent: JP5664635, 2015, B2