5-Sulfoisophthalic acid monosodium salt

22326-31-4

6362-79-4

Example 5: Conversion of 5-sulfoisophthalic acid (HSIPA) to sodium isophthalic acid-5-sulfonate (NaSIPA) Synthesis Procedure: 691.5 g of acetic acid, 83.5 g of deionized water, 72.91 g of a 50% aqueous sodium hydroxide solution, and 250 g of HSIPA (94.4% purity, 4.4% water content, strong acid content of 0.85% as H2SO4). The mixture was heated to reflux temperature (106.3°C) and subsequently cooled to 25°C and maintained for 1 hour. Upon completion of the reaction, the slurry was filtered through a sintered glass funnel and the solids were washed with 2 x 63 g of acetic acid. The resulting product was placed in a vacuum oven and dried at 160 to 165 °C to yield a final 244.7 g of off-white solid sodium isophthalic acid-5-sulfonate. Note: Wet acetic acid can be recovered by distillation and used in subsequent batches to maintain consistent product quality and yield. Product purity is determined by standard analytical methods.