Production of detergent‐grade trisodium citrate

Abstract

Abstract An efficient process to produce a technical‐grade trisodium citrate suitable for detergent use has been demonstrated. Ammonium citrate is produced as an intermediate by a continuous fermentation approach using Candiada lipolytica yeast and C 10 –C 20 linear paraffin. After removing yeast cells and residual oil by centrifuge, ammonia is distilled off with addition of sodium hydroxide. Trisodium citrate is recovered by methanol precipitation. Impurities, e.g., isocitrate, coloring materials and odorous substances dissolve in methanol and are removed. The methanol is recovered and recycled. A simple approach to convert the trisodium citrate solution directly to a solid for possible use in detergents failed because of the objectionable color, odor and high hygroscopicity.