Glycerol → sodium 2-(2,3-Dihydroxypropoxy)ethanesulfonate

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Reaction Conditions

Reaction Steps

To a 500 ml, three neck, round bottom flask equipped with a magnetic stirring bar, modified Claisen head, condenser (set for distillation), thermometer, and temperature controller (Therm-O-Watch™, I2R) is added isethionic acid, sodium salt (Aldrich, 50.0 g, 0.338 mol), sodium hydroxide (2.7 g, 0.0675 mol), and glycerin (Baker, 310.9 g, 3.38 mol). The solution is heated at 190° C. under argon overnight as water distills from the reaction mixture. A 13C-NMR(DMSO-d6) shows that the reaction is complete by the virtual disappearance of the isethionate peaks at ~53.5 ppm and ~57.4 ppm, and the emergence of product peaks at ~51.4 ppm (--CH2SO3Na) and ~67.5 ppm (CH2CH2SO3Na). The solution is cooled to ~100° C. and neutralized to pH 7 with methanesulfonic acid (Aldrich). The desired, neat material is obtained by adding 0.8 mol % of potassium phosphate, monobasic as buffer and heating on a Kugelrohr apparatus (Aldrich) at 200° C. for ~3 hrs. at ~1 mm Hg to afford 77 g of yellow waxy solid. As an alternative, not all of the glycerin is removed before use in making the oligomers. The use of glycerin solutions of SEG can be a convenient way of handling this sulfonated monomer.

Provenance & Evidence