The general procedure for the synthesis of bishexadecyl phosphate from 1-hexadecanol is as follows:
1. Phosphorus trichloride (2.5 ml, 26.8 mmol) was added slowly and dropwise to a mixture of 1-hexadecanol (19.50 g, 80.4 mmol) and benzene (100 ml) at 80 °C (solvent reflux temperature) and the reaction was continued with stirring for 12 hrs at this temperature.
2. Upon completion of the reaction, the solvent in the reaction solution was removed by distillation under reduced pressure.
3. benzene (50 ml) was added to the residue obtained after decompression distillation and the mixture was cooled overnight to promote crystallization.
4. The cooled mixture was filtered and the resulting white precipitate, i.e., bishexadecyl phosphate (1.64 g, 3.0 mmol, yield: 11%) was collected.
The product characterization data were as follows:
1H-NMR (ppm) δ: 0.87-0.89 (t, 6H), 1.25-1.37 (br, s, 52H), 1.65-1.72 (m, 4H), 4.00-4.06 (m, 4H), 7.05 (br, s, 1H).
13C-NMR (ppm) δ: 14.11, 22.69, 25.44, 29.18, 29.36, 29.54, 29.61, 29.66, 29.67, 29.70, 29.71, 30.16, 30.21, 31.93, 67.69, 67.73.
31P-NMR (ppm) δ: 2.15.
SIMS mass analysis: measured value 547.85, theoretical value 547.83, corresponding to (C32H68O4P)+.
