To bis-(4-docosoxy-phenyl)-methanol (28.5 g, 34.2 mmol) were added toluene (350 mL), ethyl carbamate (6.1 g, 68.5 mmol) and methanesulfonic acid (333 μL, 5.14 mmol) and the mixture was stirred at 110° C. for 2 hr. Methanesulfonic acid (333 μL, 5.14 mmol) was added and the mixture was stirred for 30 min. After stirring, the reaction mixture was cooled to room temperature, sodium carbonate (1.1 g, 8.73 mmol) was added and the solvent was evaporated. The residue was crystallized from methanol (400 mL) to give ethyl [bis-(4-docosoxy-phenyl)-methyl]carbamate (32.1 g, 100%).
